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  • mercury
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  • Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition  (216)
  • Energy, Environment Protection, Nuclear Power Engineering  (63)
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  • 1
    ISSN: 1539-6924
    Keywords: Benchmark ; mercury ; risk assessment ; epidemiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract This paper presents benchmark (BMD) calculations and additional regression analyses of data from a study in which scores from 26 scholastic and psychological tests administered to 237 6- and 7-year-old New Zealand children were correlated with the mercury concentration in their mothers' hair during pregnancy. The original analyses of five test scores found an association between high prenatal mercury exposure and decreased test performance, using category variables for mercury exposure. Our regression analyses, which utilized the actual hair mercury level, did not find significant associations between mercury and children's test scores. However, this finding was highly influenced by a single child whose mother's mercury hair level (86 mg/kg) was more than four times that of any other mother. When that child was omitted, results were more indicative of a mercury effect and scores on six tests were significantly associated with the mothers' hair mercury level. BMDs calculated from five tests ranged from 32 to 73 mg/kg hair mercury, and corresponding BMDLs (95% lower limits on BMDs) ranged from 17 to 24 mg/kg. When the child with the highest mercury level was omitted, BMDs ranged from 13 to 21 mg/kg, and corresponding BMDLs ranged from 7.4 to 10 mg/kg.
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  • 2
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    European journal of nutrition 29 (1990), S. 54-73 
    ISSN: 1436-6215
    Keywords: Cadmium ; Quecksilber ; Blei ; Toxizität ; Säuglingsnahrung ; cadmium ; mercury ; lead ; toxicity ; infantformulas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary There are differences between young and adult organisms regarding toxokinetic aspects and clinical manifestations of heavy metal intoxications. Chronically, toxic Cd intake causes a microcytotic hypochromic anemia in young rats at lower exposure levels and after shorter exposure periods than in adult animals. Cd absorption is increased by co-administration of milk and in conjunction with iron deficiency. After long exposure periods toxic Cd concentrations accumulate in the kidney cortex; this process starts very early in life. In 3-year-old children Cd concentrations in the kidney can reach up to one-third of those found in adults. Hg++ and methyl-Hg can cause Hg encephalopathia, and frequently cause mental retardation in adults. Correspondingly, Hg++ accumulation in the brains of suckling rats is approx. 10 times higher than in grown animals. Milk increases the bioavailability of Hg++. In suckling rats Hg is bound to a greater extent to ligands in the erythrocytes. Methyl-Hg concentrations in breast milk reach 5% of those in maternal plasma and that is a severe hazard for breastfed children of exposed mothers. Toxic Pb concentrations can lead to Pb encephalopathia. A high percentage of surviving children have seizures and show signs of mental retardation. Anemia and reduced intelligence scores were recently observed in children after exposure to very low levels of Pb. Pb absorption is increased in children and after co-administration of milk. There are no definite proofs for carcinogenesis or mutagenesis after oral exposure to Cd, Hg, and Pb in man. Heavy metal concentrations were found in the same order of magnitude in commercial infant formulas and in breast milk. When infant formulas are reconstituted with contaminated tap water, however, Pb and Cd concentrations can be much higher. The average heavy metal uptake from such diets exceeds the provisional tolerable weekly intake levels set by the WHO for adults, calculated on the basis of an average food intake and a downscaled body weight. These considerations do not even provide for differences in absorption and distribution or for the increased sensitivity of children to heavy metal exposure. However, dilution effects for essential heavy metals were observed in fast-growing Young children; this effect might be extrapolated to toxic metals. These theoretical considerations are compared with epidemiological evidence. A health statistic from Baltimore shows a decline of Pb intoxications in infants. This observation correlates with a simultaneous decline in exposure to Pb which was due, for example, to decreased use of lead dyes in house paints and the abolition of tin cans for infant food. At the end of the observation period Pb-related infant mortality had decreased to zero. Maximum admissible Pb exposure from infant formulas in the USA has now been further reduced but the calculated Pb exposures in the example mentioned above are still lower. In conclusion, no hazard can be deducted from the mentioned epidemiological data regarding the present content of Cd, Hg, and Pb in commercially available infant formulas in Germany. Looking at the high toxic potential, however, it seems desirable to keep the content of these three metals in infant formulas as low as the best available technology can achieve.
    Notes: Zusammenfassung Die klinischen Symptome und die Toxokinetik von Schwermetallintoxikationen zeigen Unterschiede zwischen jungen und ausgewachsenen Organismen. Chronisch toxische Cd-Mengen verursachen eine mikrozytäre hypochrome Anämie, die bei Jungratten nach kürzerer und geringerer Exposition auftritt als bei erwachsenen Tieren. Nach der Resorption, die durch Milch und im Eisenmangel erhöht ist, akkumuliert Cd über Jahre bis zu toxischen Konzentrationen in der Nierenrinde. Dieser Fortgang beginnt im Säuglingsalter und kann in den ersten drei Lebensjahren bis zu 1/3 der Erwachsenenwerte erreichen. Hg++ und Methyl-Hg können u. a. eine Hg-Enzephalopathie hervorrufen, in deren Folge Kinder mehr als Erwachsene geistige Behinderungen zeigten. In Saugratten ist die Hg-Akkumulation im Hirn gegenüber erwachsenen Tieren zehnfach erhöht. Milch steigert die Bioverfügbarkeit von Hg++, das nach der Resorption bei Säuglingen vermehrt in den Erythrozyten gebunden wird. Methyl-Hg erreicht in der Muttermilch 5 % der mütterlichen Plasmakonzentration und führte bei epidemischen Vergiftungen zu schweren Schäden bei Säuglingen. Chronische Pb-Exposition kann Enzephalopathien verursachen, die bei Kindern in einem hohen Prozentsatz Krampfleiden und geistige Behinderungen hinterlassen. Anämien und Intelligenzminderungen werden bei Kindern nach sehr niedrigen Pb-Expositionen beobachtet. Die Pb-Resorption wird durch Milchgabe gesteigert und ist bei Kindern erhöht. Für Cd, Hg und Pb gibt es keine gesicherten Belege für Karzinogenese oder Mutagenese bei Menschen nach oraler Exposition. Der Schwermetallgehalt in kommerzieller Säuglingsnahrung liegt in derselben Größenordnung wie in der Muttermilch. Bei Verwendung von kontaminiertem Zapfwasser zur Rekonstitution von Fertignahrung ist die Belastung mit Pb und Cd jedoch erhöht. Die theoretische Metallaufnahme aus solchen Diäten, berechnet für einen normgewichtigen Säugling und einen repräsentativen Diätplan, übersteigt, bezogen auf das Körpergewicht, die „provisional tolerable weekly intakes“ der WHO für Erwachsene. Dabei führen Unterschiede in Resorption und Verteilung von Cd, Hg und Pb zu einer erhöhten Empfindlichkeit des kindlichen Organismus. Andererseits ergibt sich aus dem schnellen Wachstum von Säuglingen ein Verdünnungseffekt für essentielle Spurenmetalle, der von manchen Autoren auf toxische Metalle extrapoliert wird. Diesen theoretischen Überlegungen stehen epidemiologische Erfahrungen gegenüber. Eine Statistik über kindliche Bleivergiftungen aus Baltimore ist über einen Zeitraum von 13 Jahren stark rückläufig. Die einzelnen Stufen des Rückgangs lassen sich mit einem zeitgleichen Rückgang der kindlichen Pb-Belastung korrelieren, z. B. durch die Meidung von Bleifarben für den Hausanstrich oder die Abschaffung von bleihaltigem Verpackungsmaterial für Babynahrung. Am Ende des Beobachtungszeitraums weist die Mortalitätsstatistik keine einschlägigen Todesfälle mehr auf. In den USA wurde der zulässige Pb-Gehalt in der Säuglingsnahrung seither weiter reduziert. Die im oben genannten Beispiel aus deutschen Werten errechneten Pb-Belastungen liegen deutlich darunter. Zusammenfassend läßt sich aus den genannten epidemiologischen Erfahrungen keine akute Gefährdung durch die gegenwärtigen Cd-, Hg- und Pb-Gehalte in kommerzieller Säuglings- und Kleinkindnahrung ableiten. Das hohe toxische Potential läßt es aber wünschenswert erscheinen, die Gehalte dieser drei Metalle so niedrig zu halten, wie es nach neuestem technischem Stand möglich wäre.
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  • 3
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    European journal of nutrition 34 (1995), S. 113-117 
    ISSN: 1436-6215
    Keywords: Blei ; Cadmium ; Quecksilber ; Gewürze ; Gewürzzubereitungen ; Wurstwaren ; Lead ; cadmium ; mercury ; spices ; condiments ; meat products
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary The lead and cadmium contents of 50 spices and 19 condiments were investigated by means of flameless atomic absorption spectrophotometry. Mercury contents were determined by cold vapor atomic absorption method including amalgamation. The mean concentrations of lead, cadmium, and mercury were 0.470 mg/kg, 0.080 mg/kg, and 0.005 mg/kg, respectively. By using the detected levels of these three heavy metals in model calculations only a small carry-over of lead, cadmium, and mercury in meat products by spices and condiments can be assumed.
    Notes: Zusammenfassung 50 Gewürze und 19 Gewürzzubereitungen wurden mittels flammenloser Atomabsorptionsspektrometrie auf ihren Blei- und Cadmiumgehalt sowie mittels Kaltdampftechnik und nachfolgender Amalgamierung auf ihren Quecksilbergehalt untersucht. Im Mittel wurden hierbei 0,470 mg Blei, 0,080 mg Cadmium und 0,005 mg Quecksilber pro kg Würzmittel gefunden. Anhand von Modellrechnungen wurde ein nur geringer Blei-, Cadmium- und Quecksilbereintrag über Würzmittel in die Wurstsorten Fleischwurst, Leberwurst und Mettwurst aufgezeigt.
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  • 4
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    Nutrient cycling in agroecosystems 54 (1999), S. 243-249 
    ISSN: 1573-0867
    Keywords: Fertigation ; trickle-irrigation ; N utilization efficiency ; calcareous soil ; potato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two field experiments were conducted in the Jordan Valley to evaluate potato response to N fertigation. Nitrogen as ammonium sulphate was supplied through irrigation water (fertigation) at rates of 0, 35, 70 and 105 mg N l-1. Soil N application treatment equivalent to the fertigation treatment of 70 mg N l-1 was included. 15N labelled ammonium sulphate was used to evaluate the N recovery and utilization efficiency. Yield increased by the N rate. The soil N application gave higher yield than the zero N and lower than the fertigated treatments. The increase in yield was due to the increase in the size of the tubers. The specific gravity was the highest with the zero N. The index ratios of potato tubers were similar with all treatments. The N derived from fertilizers by both tubers and shoots, increased with the N rate regardless of the method of application. The soil application treatments had fertilizer utilization as high as the fertigation treatments and produced total tuber yield not significantly different from that obtained by the fertigation treatment with similar rate. This might be attributed to the poor fertilizer distribution in the root zone in the fine textured soil. The low value of the fertilizer utilization of the plant receiving the 15N in the preceding season suggested possibilities of rapid transformation and immobilization by the soil microorganisms.
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  • 5
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    Nutrient cycling in agroecosystems 12 (1987), S. 37-52 
    ISSN: 1573-0867
    Keywords: fertilizer recommendation ; N fertilizer ; N-response curves ; optimum N application ; potato ; sugar beet
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract N-response curves of numerous N-fertilizer trials with sugar beet and potato are described by a quadratic and a modified exponential equation. For both sugar beet and potato the modified exponential equation was much better than the quadratic equation when the residual sum of squares (RSS) was taken as a measure of the degree of fit. In order to take into account the few occasions when the quadratic model was superior, it is suggested that both models should be used for the data of each individual trial. The economically optimum application rate of fertilizer N is calculated on the basis of the best-fitting model. This procedure yielded optima which covered entire ranges of fertilizer-N levels tested: 0–250 kg ha−1 for sugar beet and 0–400 kg ha−1 for potato. The magnitude of the confidence intervals (p 〉 95%) of the optimum N-fertilizer application rate frequently was very high. In 46% of the sugar beet trials and even in 60% of the potato trials it was higher than 300 kg ha−1 N. It is suggested that N-fertilizer recommendations be drawn up only with reliable optima.
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  • 6
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    Nutrient cycling in agroecosystems 36 (1993), S. 19-27 
    ISSN: 1573-0867
    Keywords: critical concentrations ; nitrate ; nitrogen fertilization ; petiole ; potato ; short day conditions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Field experiments were conducted for three crop seasons to develop tissue analysis technology for optimizing N fertilization in potato grown under short day conditions in subtropics. Nitrogen deficiencies could be detected as early as 25 days after planting (DAP) by tissue analysis of NO3-N concentration in petioles. Petiolar NO3-N declined sharply with age of the crop from 25 to 60 DAP and was significantly correlated at all stages of growth with applied N and tuber yield of potato. Critical concentrations of Petiolar NO3-N were 1.28, 1.23, 1.07 and 0.96% in an early maturing cv. Kufri Chandramukhi and 2.16, 1.95, 1.40 and 1.18% in a late maturing cv. Kufri Badshah at 25, 40, 50 and 60 DAP, respectively. Optimum yields were obtained when petiolar NO3-N was maintained above critical concentrations through the growth period up to 60 DAP by corrective side dressing of N. Response to corrective side dressing of N decreased with increasing concentration of petiolar NO3-N. Optimum rate of N for side dressing up to 30 DAP was 142, 116, 90, 64 and 37 kg ha−1 for petiolar NO3-N of 0.5, 1.0, 1.5, 2.0 and 2.5%, respectively in Kufri Chandramukhi. Corresponding rates of side dressed N were 183, 164, 146, 127, 108 kg ha−1 in late maturing cv. Kufri Badshah. For optimum yields, fertilization of 80 to 120 kg N ha−1 at the time of planting followed by corrective side dressing as recommended by petiolar tissue analysis is advocated.
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  • 7
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    Water, air & soil pollution 85 (1995), S. 823-828 
    ISSN: 1573-2932
    Keywords: fish ; mercury ; lake chemistry ; biomagnification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract We determined mercury in fish (perch Perca fluviatilis) from 26 Russian lakes in three regions over four years. The lakes ranged in size from 2 to 395,000 ha, in pH from 4.5 to 10.0, and in color from 3 to 190 hazen. Sixteen lakes were drainage lakes, with permanent outlets, and 10 were seepage lakes, with no permanent inlets or outlets. The lakes were generally located in forested regions with little or no human habitation in the watershed. The three regions were geologically distinct: Precambrian Shield granitic bedrock covered with thin soil; Triassic bedrock covered with thick glacial tills; and Triassic bedrock covered with thin sediments. At each lake water samples were collected and analyzed for pH, add neutralizing capacity (ANC), major cations, and anions. Dissolved mercury species were estimated with a thermodynamic equilibrium model (MINTEQA2). Mercury content of dorsal muscle varied from 0.04 to 1.0 μg/g wet weight, and was linearly related to calculated HgCH3Cl (r20.68, p〈0.001). Lake HgCH3Cl, in turn, was related to lake pH (r2=0.86, p〈0.001). Stepwise multiple regression selected lake HgCH3Cl and color as the factors most highly related to fish mercury content, with the model accounting for 75% of the variation.
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  • 8
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    Water, air & soil pollution 80 (1995), S. 325-335 
    ISSN: 1573-2932
    Keywords: Atmospheric chemistry ; mercury ; plume model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A reactive plume model that includes atmospheric chemical reactions of mercury was developed. The model simulates advective transport with the mean wind flow; horizontal and vertical turbulent diffusion; gas phase; aqueous-phase and particulate chemistry; cloud microphysics; wet deposition and dry deposition. The model was applied to the simulation of clear sky, non-precipitating cloud and precipitating cloud scenarios. No significant mercury chemistry occurs in the absence of droplets. In clouds, Hg(II) is reduced to Hg(0) with more reduction taking place in precipitating clouds than in non-precipitating clouds.
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  • 9
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    Water, air & soil pollution 80 (1995), S. 1209-1216 
    ISSN: 1573-2932
    Keywords: gaseous ; particulate ; mercury ; sampling ; silver ; gold ; denuder
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A denuder-based method for sampling and separating gaseous and participate mercury in the air is described. Two different denuder configurations developed in Vilnius, Lithuania (silver) and in Gothenburg, Sweden (gold) are compared. Data were acquired at different sampling locations around the cities of Vilnius and Gothenburg. The concentration of particulate Hg was found to be 0.04 to 0.40 ng m−3 in the Vilnius region, and 0.11 to 0.57 ng m−3 in the Gothenburg region. Intel-calibration results for the silver and gold denuders are presented. The results obtained by the two different denuder configurations and sampling set-ups display satisfactory agreement.
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  • 10
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    Water, air & soil pollution 89 (1996), S. 267-275 
    ISSN: 1573-2932
    Keywords: mercury ; forest trees ; biomonitors ; contaminants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The concentration of mercury has been determined in assimilation organs of forest trees from 10 main industrial regions of Slovakia, four mountain forests and one military area and compared with concentration of mercury from 1356 permanent monitoring plots of Slovakia. The mercury concentration ranges for 2 yr old needles of Picea abies Karst. were (in mg kg−1): 1.249–4.402 (Rudnany iron ore mines), 0.013–0.749 (nine other industrial regions), 0.021–0.737 (four mountain forests) and 0.053–0.538 (military area). The mercury content in the soil (0–5 cm) from a mercury smelting plant ranged from 9.9 to 130 mg kg−1, and the moss Pleurozium schreberi contained 3.8–9.1 mg kg−1. The values obtained were compared with the available literature data.
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  • 11
    ISSN: 1573-2932
    Keywords: acid rain ; batch experiment ; Freundlich isotherm ; lysimeter experiment ; mercury ; simulation model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Increasing mercury contents are reported from freshwater systems and fish in northern Europe and North America. Mercury input from soils is a major source with the leaching being affected by increased atmospheric mercury deposition compared to pre-industrial times and by other environmental conditions such as acid rain. The results of a mathematical model-calculation of vertical inorganic Hg(II) leaching in a Scandinavian iron-humus podzol under different atmospheric input rates of mercury are presented. Leaching under background rain conditions was calculated to be considerably stronger than under acid rain conditions. Increasing fractions of deposited soluble or solute atmospheric mercury were leached from the O f(h)-horizon with decreasing soil content of soluble mercury under acid rain conditions; this effect was less pronounced under background rain conditions. The steady state concentrations of soluble mercury of the upper soil horizons were calculated and compared with the actual concentrations of total (= soluble + insoluble mercury) and extractable (= estimate of soluble) mercury measured in these horizons. The results indicate that even if the deposition of airborne mercury to soil is strongly reduced, the total mercury content of the soil decreases only slowly. It may take decades or even centuries before a new steady state concentration of total mercury is established in the soil. The decrease of the mercury concentration in the O f(h)-horizon is probably largely dependent on the turnover of organic matter, binding most of the deposited airborne mercury in an insoluble form. Hence, present day mercury leaching is likely to be dominated by mercury deposited during former times and temporarily retained in an insoluble form in the organic matter.
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  • 12
    ISSN: 1573-2932
    Keywords: mercury ; foodplains ; humic substances ; complexation ; speciation ; mobilization ; risk assessment ; water solubility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The water-mobilizability of mercury from contaminated floodplain soils of the river Elbe in Northern Germany was evaluated by batch extraction experiments. It was shown that only a small amount of the total mercury present (about 1% per extraction) can be mobilized by water. This mercury is transported entirely in the form of a complex bound to humic acids (HA); particulates and fulvic acids (FA) did not seem to contribute to the process. It could not be removed from the HA even at pH 1, indicating an extremely strong complexation e.g. by sulfur-containing ligands. Furthermore, the influence of pH on the mobilization was investigated. It was found that in the range of natural pH-values, there was no observable effect of pH on the mobilization of either mercury or dissolved organic carbon (DOC). This surprising finding is explained by an unexpectedly high buffering capacity of the humics, both in the acidic and in the alkaline region. Only at extreme pH-values there was deviation from this behaviour. In contrast to other heavy metals, the amount of mobilized mercury decreases at pH 〈 3; and at pH 〉 12, an increased mobilization of mercury was observed because the humics are mobilized completely, accompanied by the total amount of mercury bound to them.
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  • 13
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    Water, air & soil pollution 97 (1997), S. 205-207 
    ISSN: 1573-2932
    Keywords: mercury ; gold mining ; ecosystems ; methyl-Hg ; cycling ; global sources
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract As described by Jemelov and Ramel (1995), the Scientific Committee on Problems of the Environment (SCOPE) sponsored an investigation of Hg in ecosystems with special emphasis on tropical regions. In these regions small-scale gold mining activities have occupied about 10 million people worldwide who use Hg for extracting gold.
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  • 14
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    Water, air & soil pollution 97 (1997), S. 257-263 
    ISSN: 1573-2932
    Keywords: mercury ; atmosphere ; rainwater ; marine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Total gaseous mercury (TGM) and rainwater were collected on board of two research vessels (F. S. ALKOR and R.V. BELGICA) positioned 200 km apart in the center of the North Sea during the North Sea Experiment, September 1991. On the F. S. ALKOR (up-wind ship) TGM concentrations ranged from 0.7 to 2.6 ng·m−3 with an average of 1.5 ng m−3 and on the R. V. BELGICA (down-wind ship) TGM ranged from 0.7 to 1.9 ng·m−3 with an average of 1.2 ng·m−3. An average 20% decrease is observed from the up-wind to the down wind ship. which may largely be affected by entrainment into the free troposphere. An overall removal (entrainment) velocity of 0.95 cm·s−1 was calculated for the whole experiment. The average removal velocity was 0.5 cm·s−1 for dry periods and varied between 1 to 5 cm·s−1 during rain events. Rainwater concentrations varied between 5 and 25 ng·1−1. Based on these data an annual wet deposition flux of 1.08 ng Hg cm−2 yr1− was estimated for the North Sea.
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  • 15
    ISSN: 1573-2932
    Keywords: mercury ; methylmercury ; sediment ; polychaete ; Nereis diversicolor ; methylation ; bioaccumulation ; Scheldt estuary
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Total mercury (Hg) and methylmercury (MeHg) concentrations were determined in sediments and in the polychaete worm Nereis diversicolor at 13 stations of a brackish water intertidal mudflat of the Scheldt estuary. Hg and MeHg concentrations in sediments ranged from 144 to 1192 ng g−1 dw and from 0.8 to 6 ng g−1 dw, respectively. Both Hg and MeHg concentrations increased with an increase of organic matter (OM) content and fine grain fraction. In contrast, Hg accumulation by N. diversicolor was significantly (p 〈 0.05) higher at stations with sandy sediments (mean value: 125 ng g−1 dw) than at stations with muddy sediments (mean value, 80 ng g−1), probably because Hg availability for bioaccumulation at muddy stations was reduced by high OM content of the muddy sediments. MeHg accounted for an average of 0.7% of the total Hg in sediments and 18% of the total Hg in N. diversicolor. Seasonal variations significantly affected Hg concentrations in sediments and MeHg in N. diversicolor. Total Hg concentrations in sediments were significantly (p 〈 0.05) higher in autumn and winter than in spring and summer whereas MeHg concentrations were lowest in winter compared to the other seasons. On the other hand, total Hg concentrations in the worms were lowest in spring whereas MeHg concentrations were significantly (p 〈 0.01) higher in spring and summer than in autumn and winter.
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  • 16
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    Water, air & soil pollution 99 (1997), S. 217-223 
    ISSN: 1573-2932
    Keywords: selective leach ; organic ; humic ; fulvic ; analysis ; mercury ; zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The international reference lake sediment, LKSD-4, was used to compare Hg, organic C and Zn extracted from its ‘soluble organic’ phase by two commonly used reagents: 0.1 M Na4P2O7 solution at pH 10 and 0.5 M NaOH solution at pH 12. While recoveries of Hg and Zn by 0.1 M Na4P2O7 are not affected by changes in sample weight to reagent volume ratio (W/V) or contact time, those by NaOH show a marked dependency. In general, the NaOH leach extracts more organic C and Hg from LKSD-4 but less Zn. Over the range of conditions studied, the NaOH-based method extracted 4.7–9.8% C, 27–103 ng g−1 Hg and 19–69 μg g−1 Zn from LKSD-4, compared to 2.3–2.8% C, 17–24 ng g−1 Hg and 64–72 μg g−1 Zn by the Na4P2O7 leach. Clearly, different groups of organic substances are being dissolved by these two reagents and therefore a comparison of data from different laboratories becomes meaningless. This paper suggests that more research is needed into the exactNature of metal-organic associations extracted by selective leaches and into associated artifacts of extraction such as readsorption phenomena.
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  • 17
    ISSN: 1573-3017
    Keywords: mercury ; body distribution ; feather concentrations ; body burden ; tern chicks
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: We studied mercury concentrations and amounts in tissues of 19 starved young Common Tern chicks (median age 4 days) and in eggs from the same colony. Concentrations and burden were similar between eggs and newly hatched chicks. Mercury concentrations were highest in down, which contained at least 38% of the body mercury. The mercury burden of the whole body and of the tissues as well as the concentration in down increased with age and body mass, indicating the importance of down as an elimination pathway. Conversion ratios between mercury concentrations in tissues and the whole chick body varied according to the contamination level.
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  • 18
    ISSN: 1573-3017
    Keywords: fish ; mercury ; natural selection ; allozyme ; population
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Measurements of the differential tolerance between enzyme genotypes and shifts in allozyme frequencies in populations from contaminated habitats have prompted the use of allozymes as markers of population-level toxicant effects. However, such studies often do not consider other factors that influence allele frequencies, including natural clines, migration, the intensity and specificity of selection and toxicant-induced genetic bottlenecks. In addition, selection components other than survival are not included. Consequently, the associated conclusions remain speculative. To assess this approach rigorously, a simulation study was conducted with the mosquitofish (Gambusia holbrooki) GPI-2 locus. Laboratory studies have shown the GPI-238/38 homozygote at this locus to be less tolerant than other genotypes during acute exposure to mercury. The GPI-2100/100 genotype has also been shown to have a reproductive disadvantage at lower mercury concentrations. Simple and then more complex models were used to quantify the relative effects of viability selection, random genetic drift and migration on the GPI-238 allele frequency. Simulations were also performed to assess the contribution of sexual and fecundity selection. A simple population model suggested that viability selection plays a greater role than does mortality-driven, genetic drift in the decrease of the sensitive allele under the conditions of this study. A more complex, stochastic model indicated that no significant mortality-driven drift was taking place in this system. In both models, migration mitigated the effect of selection. Sexual and fecundity selection had little effect on the allele frequencies in these simulations. We conclude that, provided the system under study is clearly understood, shifts in allele frequency can indicate the population-level effects of pollutants.
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  • 19
    ISSN: 1871-4528
    Keywords: waste ; potato ; insects ; soft rot coliform bacteria ; Erwinia carotovora var.carotovora ; Erwinia carotovora var.atroseptica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Zusammenfassung Zwölf Arten von Insekten der Gattung Diptera, periodisch gesammelt auf zwei grossen Kartoffelabfallhaufen in Schottland, waren mit koliformen Nassfäulebakterien kontaminiert (Tab. 2, 3, 5 und 6). Nur zwei der Arten galten vorher als mögliche Uberträger dieser Organismen. 1973 waren 4,6% der an den beiden Orten während der Saison gesammelten Insekten mit diesen Organismen behaftet, 1974 waren es 4,5%. Nicht weniger als 9,6% der Insekten waren bei einigen Fängen im Jahre 1973 und 14,7% im Jahre 1974 Träger von NassfäuleErwinia sp. Die Fruchtfliegen (Parascaptomyza sp. undDrosophila spp.) waren 1973 die am häufigsten kontaminierten Insekten (Tab. 2 und 3). Diese Gruppe von Insekten war auch 1974 meistens kontaminiert, aber am häufigsten wurden die Bakterien vonScatophaga spp. undDelia spp. (Tab. 5 und 6) isoliert. Sowohl 1973 als auch 1974 wurdeErwinia carotovora var.carotovora (in der FolgeE. carotovora genannt) häufiger von den Insekten isoliert alsErwinia carotovora var.atroseptica (in der FolgeE. atroseptica genannt) (Tab. 1 und 4), obwohl die Knollen. die ursprünglich den Abfallhaufen ausmachten, fast sicher meistens mitE. atroseptica infiziert waren. Das Verhältnis vonE. carotovora zuE. atroseptica, isoliert von Insekten beider Haufen, war 1973 9,5∶1 (13,5∶1 und 5,5∶1 je Abfallhaufen) und 1974 3,8∶1 (2,7∶1 und 6,8∶1 für die beiden Orte).E. atroseptica wurde 1973 nur früh in der Vegetationszeit (vor dem 30. Juli) von den Insekten isoliert (Tab. 1), 1974 nur früh (vor dem 30. Juli) oder spät in der Vegetationszeit (nach dem 10. Oktober) (Tab. 4).E. carotovora dagegen konnte in beiden Jahren über die ganze Vegatationszeit isoliert werden (Tab. 1 und 4). Die Wiedergewinnung vonE. atroseptica von Insekten war mit dem Vorhandensein von frisch abgelagerten faulen Knollen zur Zeit. wenn die Insekten gesammelt werden. verbunden. EinzigE. carotovora wurde von Insekten isoliert. die zu einer Zeit gesammelt wurden, wenn auf den Abfallhaufen nurälteres verfaulendes Material vorhanden war. Isolationen von faulenden Ueberresten, die 1975 dem Abfallhaufen entnommen wurden (Tab. 7), zeigten, dass sowohlE. carotovora als auchE. atroseptica in der Regel das ganze Jahr vorhanden waren.E. atroseptica herrschte früh im Jahr (Januar bis Juni) vor und an einem Ort auch spät in der Zeit der Musterentnahme (Oktober bis Dezember).E. carotovora war von Juni bis Oktober der am meisten isolierte Organismus. Das Vorherrschen vonErwinia carotovora var.atroseptica war mit dem Vorhandensein von frisch weggeworfenen Kartoffelknollen früh und spät in der Zeit der Musterentnahme verbunden.E. carotovora schien in den faulenden Knollen länger zu überleben und war der am meisten isolierte Organismus aus älterem verwesendem Material. Die Verhältniswerte vonE. carotovora zuE. atroseptica. isoliert von Insekten. waren höher alsjene, die für das verfaulende Material aus den Abfallhaufen gefunden wurden. Es ist anzunehmen, dass die Insekten selbst einen selektiven Einfluss zu Gunsten vonE. carotovora ausüben. Von einem der Abfallhaufen gesammelten Insekten übertrugen im GlashausE. carotovora sogleich auf verletzte Kartoffelstengel. Man nimmt an, dass Kartoffelbestände. die mit Hilfe des Stengelschnittes von koliformen Nassfäuleerregern befreit wurden, durch Insekten, die von Kartoffelabfallhaufen kommen, wieder verseucht werden können.
    Abstract: Résumé 12 genres d'insectes appartenant à l'ordre des Diptères, capturés périodiquement en Ecosse. sur deux grands tas de déchets de pommes de terre se sont révélés être contaminés par des bactéries coliformes. agents de la pourriture molle (tableaux 2, 3, 5 et 6). Auparavant, seuls 2 genres avaient été cités comme vecteurs possibles de ces microorganismes. En 1973, 4.6% des insectes capturés aux 2 endroits, et en cours de saison. portaient ces parasites de la pomme de terre. En 1974. 4,5% étaient également contaminés. Pour l'ensemble de ces captures. il y a eu 9.6% des insectes en 1973. et 14.7% en 1974 qui portaientErwinia sp. Les mouches des fruits (Parascaptomyza etDrosophila spp.) ont été le plus fréquemment contaminés en 1973 (tableaux 2 et 3). Ce groupe d'insectes était également atteint en 1974. mais les bactéries on été plus fréquemment isolées à partir deScatophaga spp. etDélia spp. (tableaux 5 et 6). En 1973 et 1974.Erwinia carotovora var.carotovora (dans la suiteE. carotovora) a été plus fréquemment isolé de ces insectes qu'Erwinia carotovora var.atroseptica (dans la suiteE. atroseptica) (tableaux 1 et 4) bien que les tubercules constituant à l'origine les tas de déchets étaient certainement plus infestés parE. atroseptica. Le rapport entreE. carotovora etE. atroseptica pour les isolements sur insectes provenant des deux endroits a été 9,5/1 (respectivement 13.5/1 et 5.5/1 pour chacun des tas de déchets) en 1973 et 3,8/1 (2,7/1 et 6,8/1) en 1974.E. atroseptica n'a été isolé que tôt dans l'année (avant le 30 juillet) en 1973 (tableau 1) et 1974 (tableau 4) elle l'a été précocement (avant le 30 juillet) ou tardivement (après le 10 octobre).E. carotovora, par contre, l'a été durant toute la saison pendant les deux années (tableuaux 1 et 4) l'isolement d'E. atroseptica est lié au moment de la capture des insectes, à la présence de tubercules nouvellement pourris lors de la mise en tas. Par contreE. carotovora a été isolé à partir des insectes capturés sur les tas où il n'y avait que du matériel présentant des pourritures plus agées. En 1975, des isolements effectués sur les tas de déchets ont montré qu'E. carotovora etE. atroseptica étaient habituellement présents toute l'année (tableau 7).E. atroseptica était prédominante en début de saison (de janvier à juin). II n'y a eu qu'un seul cas où on l'a observé plus tardivement durant la période d'échantillonage (octobre à décembre).E. carotovora a été le principal organisme isolé de juin à octobre. La prédominance d'E. atroseptica était associée à la présence de tubercules nouvellement entreposés précocement et tardivement durant la période d'échantillonage.E. carotovora semblait subsister plus longuement dans les tubercules pourris et était le principal organisme isolé à partir de matériel altéré le plus agé. Les rapportsE. carotovora surE. atroseptica obtenus à partir des isolements effectués sur insectes ont été plus élévés que ceux trouvés à partir du matériel pourri en provenance des tas. Les auteurs suggèrent que les insectes euxmêmes peuvent exercer une action sélective en faveur d'E. carotovora. Les insectes collectés à partir d'un des tas peuvent transmettre facilementE. carotovora aux pommes de terre se trouvant en serre et dont les tiges sont endommagées. Les auteurs suggèrent que les lots de pommes de terre indemnes de bactéries coliformes grace au procédé de bouturage peuvent être à nouveau recontaminé à partir des tas de déchets de pommes de terre et par l'intermédiaire des insectes.
    Notes: Summary Insects belonging to 12 genera in the Order Diptera, found at two large waste potato dumps in Scotland. were contaminated with soft rot coliform bacteria. In 1973, 5.7% and 3.2% and in 1974, 4.8% and 4.1% of the insects caught at each site yielded these organisms. The bacteria were identified mainly asErwinia carotovora var.carotovora, though some isolates wereErwinia carotovora var.atroseptica. Isolations from potato dump waste showed that at the time when fly activity was greatest the majority of soft rot coliforms in the waste wereE. carotovora var.carotovora, despite the fact that tubers originally forming the dumps were almost certainly infected mostly withE. carotovora var.atroseptica. Contaminated insects could readily transmit soft rot coliforms to damaged areas on the aerial parts of potato plants. It is suggested that potato stocks freed from these organisms by the stem cutting procedure could become re-contaminated by insects that disperse from potato dumps.
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  • 20
    ISSN: 1871-4528
    Keywords: ring rot diagnosis ; potato ; Arthrobacter globiformis ; A. aurescens ; A. chrystallopoites ; A. oxydans ; A. ramosus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Zusammenfassung Es wird über die Ergebnisse einer vergleichenden serologischen Untersuchung von drei Stämmen vonCorynebacterium sepedonicum und 11 Stämmen vonArthrobacter mit Hilfe der Immunfluoreszenz-Antikörper-Färbung (IFAS) berichtet. Die Immunfluoreszenzfärbung wurde mit der indirekten Methode quantitativ durchgeführt. Das Antiserum wurde mit durch Erhitzen abgetöteten Zellen vonC. sepedonicum NCPPB2140 hergestellt und sein Titer mit 1∶2000 durch einen quantitativen Agglutinationstest ermittelt. Die Bakterien wuchsen auf Hefe-Dextrose-Kalzium Agar (YDC) bei 27°C. Erhitzte und nicht erhitzte Zellen von jungen (24 h) und alten (1 Woche) Kulturen aller Stämme wurden geprüft. Für jeden Stamm wurde die Anfärbung in allen Kombinationen mit zwei Verdünnungen des Antiserums (1∶100 und 1∶1000) durchgeführt. Die mit Fluorescein markierten Antiglobuline wurden in einer Verdünnung von 1∶16 benutzt. Eine Kreuzreaktion trat nur zwischenA. polychromogenes undC. sepedonicum auf (Tabelle 1). Bei einer Verdünnung des Antiserums von 1∶1000 war jedoch die Fluoreszenz der Zellwände sehr schwach und in den jungen erhitzten Zellen nicht zu finden. Sehr schwer zu deuten waren die Reaktionen mitA. aurescens, A. chrystallopoites, A. oxydans undA. ramosus. C. sepedonicum NCPPB2140 undA. polychromogenes wurden sowohl in Reinkultur als auch vermischt mit Kartoffelgewebe bei steigender Verdünnung des Antiserums bis 1∶3000 verglichen. Bei Verdünnungen über 1∶500 wurden nur Zellen vonC. sepedonicum angefärbt. Einige Aspekte der Technik der Immunfluoreszenzfärbung, die Natur der gemeinsamen Antigendeterminanten und die Anwendbarkeit der Immunfluoreszenzfärbung für den Nachweis vonC. sepedonicum in infizierten Knollen werden besprochen.
    Abstract: Résumé Cette étude sérologique en immunofluorescence par coloration des anticorps (IFAS) met en comparaison trois souches deCorynebacterium sepedonicum et onze souchesd'Arthrobacter. La coloration par la méthode indirecte pour l'immunofluorescence a été quantitativement performante. L'antisérum a été préparé avecC. sepedonicum NCPPB 2140 détruit par la chaleur et le titre de la préparation a été évalué à 1/2000 par les test d'agglutination. Les bactéries ont été cultivées sur YDC agar à 27°C. Les cellules bactériennes traitées et non traitées par la chaleur des jeunes (24 h) et vieilles (1 semaine) cultures de toutes les souches ont été testées. Pour chaque souche, la coloration a été faite pour toutes les combinaisons en présence de deux dilutions d'antisérum (1/100, 1/1000). Des globulines de lapin marquées à la fluoresceine ont été utilisées à la dilution de 1/16. SeulA. polychromogènes a donné une réaction croisée avecC. sepedonicum (tableau 1). Cependant, à la dilution de 1/1000, la fluorescence des parois cellulaires a été très faible et non décelable dans les jeunes cellules bactériennes traitées par la chaleur.A. aurescens, A. chrystallopoites, A. oxydans etA. ramosus ont donné des réactions difficiles à interpréter.C. sepedonicum NCPPb 2140 etA. polychromogènes ont aussi été comparés à des dilutions de l'antisérum plus élevées telles que 1/3000 dans des cultures pures et en mélange avec des tissues de pomme de terre. Pour un dilution antérieure au 1/500, seules les cellules deC. sepedonicum ont été colorées. Quelques aspects de la technique par coloration en immunofluorescence, la nature de la fonction antigènique commune et l'application de la coloration en immunofluorescence pour la détection deC. sepedonicum dans les tubercules infectés sont discutés.
    Notes: Summary In a comparative serological study using indirect fluorescence antibody staining (IFAS) on three strains ofCorynebacterium sepedonicum and eleven strains of the genusArthrobacter, onlyA. polychromogenes cross-reacted withC. sepedonicum. The antiserum titre was 1∶2000 and its dilution was critical for identifying cross-reactions. At dilutions higher than 1∶500, onlyC. sepedonicum showed intense fluorescence and sharp edges of the walls; species ofArthrobacter gave reactions of uncertain interpretations. Some aspects of the immunofluorescence staining technique, the nature of common antigenic determinants, and the applicability of the immunofluorescence staining for detectingC. sepedonicum are discussed.
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  • 21
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    Potato research 25 (1982), S. 227-237 
    ISSN: 1871-4528
    Keywords: diploid ; gene action ; heritability ; potato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Zusammenfassung Es wurde die Analyse der Kombinationsfähigkeit einer diallelen Kreuzung von einer zufälligen Auswahl aus vier verschiedenen kultivierten diploiden Kartoffelpopulationen —Solanum tuberosum Gruppe Andigena (haploid, AH), Gruppe Tuberosum (haploid, TH), Gruppe Phyreja (PHU) und Gruppe stenotomum (STN) — durchgeführt, um das Ausmass an Heterosis und Genwirkung zu ermitteln, welches an der Vererbung von Knollenertrag, Ertrag von frischem Kraut, gesamter pflanzlicher Akkumulation (Knollen und Kraut, frisch und getrocknet), trockenem Krautertrag und Dichte beteiligt war. Das mittlere Gesamtgewicht an Knollen (Tab. 2) war für die TH×STN-F1-Hybriden (0,75 kg/Pflanze) am höchsten, danach folgte TH×PHU (0,59 kg/Pflanze), AH×TH (0,38 kg/Pflanze) und AH×PHU (0,23 kg/Pflanze). Eine ähnliche Folge der Mittelwerte war beim Gewicht von Knollen+Kraut und bei der Gesamtproduktion an Trockenmasse zu beobachten. Bei Gewicht von frischem und trockenem Kraut hatten gewöhnlich die AH-Hybriden den höchsten Ertrag. Die STN-Hybriden ergaben hohe Dichte. Beim Vergleich mit den Elternmittel-Werten glichen oder übertrafen die Hybriden diese in allen sechs Eigenschaften (Tab. 2). Die TH, STN und PHU-Hybriden übertrafen das elterliche Mittel entsprechend um 135, 145 und 117%. Die Hybriden aller vier Elternpopulationen übertrafen das elterliche Mittel bei Gesamttrockenmasse und drei der vier Hybriden beim Gewicht von Knollen+Kraut. Die Dichte aller Hybriden glich dem Elternmittel-Wert, der potentielle Bereich des prozentualen elterlichen Mittels ist jedoch gering. Die F1-Hybriden übertrafen ohne Ausnahme das elterliche Mittel für Gesamtgewicht der Knollen, Gewicht von Knollen+Kraut und Gesamtproduktion von Trockenmasse (Tab. 2). Die mittleren Quadrate der allgemeinen Kombinationsfähigkeit (GCA) waren hochsignifikant für Gesamtgewicht der Knollen, Gewicht des frischen Krautes, Trockengewicht des Krautes und Dichte, dagegen nichtsignifikant für die Gesamtakkumulation bei frischen und bei getrockneten Pflanzen (Knollen+Kraut, Tab. 3). Ebenso wenig waren die mittleren Quadrate für spezifische Kombinationsfähigkeit (SCA) für eine der Eigenschaften signifikant. Eine starke GCA×Standort-Wechselwirkung zeigte sich bei Gesamtgewicht an Knollen und bei Gesamttrockenmasse, sie wurde deshalb von GCA eliminiert, um die Vererbung dieser Eigenschaft in engerem Sinne zu berechnen. Gesamtgewicht der Knollen (h 2 =0,875) und Dichte (h 2=0,703) zeigten hohe Vererbbarkeit, während gesamte pflanzliche Akkumulation (Knollen+Kraut) frisch (h 2=0,040) und trocken (h 2=0,184) niedrige Vererbbarkeit zeigten. Gewicht von frischem Kraut (h 2=0,499) und von getrocknetem Kraut (h 2=0,573) ergaben mässige Vererbbarkeit. Daraus wurde geschlossen, dass additive Geneffekte als wichtig bei der Verbesserung dieser Populationen anzusehen sind. Sogar bei bekannten nachteiligen Effekten wie grosser Tageslänge und hoher Temperatur auf die Knolleninitiierung und-entwicklung, erhöhten die im Kurztag kultivierten und in dieser Arbeit verwendeten südamerikanischen Gruppen AH, STN und PHU im Hybridstadium die Knollenbildung beträchtlich, obwohl die maximale Vitalität der Hybriden hinsichtlich der Knollenbildung durch die ungünstige Photoperiode beeinträchtigt war. Die gesamte pflanzliche Akkumulation (Knollen+Kraut) mag ein guter Indikator für Heterosis-bedingte Reaktionen sein, die gesamte Akkumulation an Trockenmasse (Knollen+Kraut) erscheint jedoch zur Ermittlung der Heterosis in nichtadaptiertem Material noch geeigneter.
    Abstract: Résumé L'analyse de la capacité de combinaison a été faite sur un échantillon issu de croisement diallèle, pris au hasard dans les populations de quatre types de pommes de terre diploïdes cultivées:Solanum tuberosum groupe Andigena haploïdes (AH), groupe Tuberosum haploïde (TH), groupe Phureja (PHU) et groupe Sténotonum (STN) pour déterminer le degré d'hétérosis et l'effet génétique dans la transmission du rendement en tubercules et en fanes, de la production totale (tubercules+fanes) par rapport à la matière fraîche et à la matière sèche, de la densité. La moyenne du poids total de tubercules (tableau 2) a été la plus élevée pour l'hybride F1, TH×SIN (0,75 kg/butte) suivie par TH×PHU (0,59 kg/butte), AH×TH (0,38 kg/butte) et AH×STN (0,32 kg/butte). Un classement analogue des moyennes a été obtenu pour le poids des tubercules plus celui des fanes et la production totale de matière sèche. En ce qui concerne le poids des fanes fraîches et sèches, les hybrides AH ont eu généralement le rendement le plus haut. Les hybrides STN ont donné une densité élevée. Quand les hybrides ont été comparés au ‘mid parent’ (voir définition tableau 2) leur valeur a généralement dépassé celle de ce dernier pour les six critères (tableau 2). Les hybrides TH, STN et PHU ont dépassé respectivement le rendement total en tubercules du ‘mid parent’ de 135, 145 et 117%. Les hybrides des quatre populations parentales ont dépassé le ‘mid parent’ pour la matière sèche totale, et trois d'entre eux pour les poids de tubercules plus fanes. La densité a égalé la valeur du ‘mid parent’ pour tous les hybrides, mais la fourchette du pourcentage au niveau de ce critère était petite pour le ‘mid parent’. Les performances des hybrides F1 ont été supérieures à ce dernier pour le poids total de tubercules, le poids de tubercules plus fanes et la production totale de matière sèche (tableau 2). Les carrés des moyennes de la capacité générale de combinaison (GCA) ont été hautement significatifs pour le poids total des tubercules, le poids de fanes fraîches et sèches et la densité; toutefois, il n'ont pas été significatifs pour la production de matière fraîche et sèche du total tubercules plus fanes (tableau 3). Les carrés des moyennes de la capacité spécifique de combinaisons (SCA) n'ont été significatifs pour aucun des critères. Une forte interaction GCA×localité a été observé pour le poids total des tubercules et la matière sèche totale; elle a été éliminée de la GCA pour le calcul précis de la transmission à ce niveau. On a déduit de ces résultats que l'effet des gènes additifs a été important vis à vis de ces populations. Même avec l'action des jours longs et des températures élevées, préjudiciables à l'initiation de la tubérisation et au développement des tubercules, les groupes Sud Américains cultivés AM, STN et PHU, atilisés dans cette étude, ont accru la tubérisation au stade hybride bien que leur vigueur maximum ait été pénalisée par une photopériode défavorable. La production totale de matière fraîche (tubercules+fanes) peut être un bon indicateur de la réponse à l'hétérosis, mais la production totale de matière sèche (tubercules+fanes) est souvent meilleure pour la détermination de l'hétérosis d'un matériel inadapté.
    Notes: Summary Combining ability analysis was done on a diallel cross of a random sample of four different cultivated diploid potato populations (Solanum tuberosum Group Andigena haploid, Gp. Tuberosum haploid, Gp. Phureja and Gp. Stenotomum) to determine the amount of heterosis and the gene action involved in the inheritance of tuber yield, fresh vine yield, total plant accumulation (tuber+vine) fresh and dried, dry vine yield and density (specific gravity). The analyses of variance on data from two locations demonstrated significant general combining ability for most traits, indicating a preponderance of additive gene action. Specific combining ability was not significant for any of the traits. Heritabilities for the more important traits such as tuber yield and density were large enough to ensure progress from selection.
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  • 22
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    Potato research 25 (1982), S. 127-130 
    ISSN: 1871-4528
    Keywords: potato ; virus breeding ; resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A clone ofSolanum berthaultii P.I. 265858 was not systemically infected when manually inoculated with isolates of PVX groups 1 to 3 but developed top-necrosis when grafted-inoculated, demonstrating it is hypersensitive. Plants sap- or graft-inoculated with an isolated of PVX group 4 or with PVXHB (a recently-discovered strain overcoming all reported sources of resistance to PVX) were infected systematically. The plants were extremely sensitive to these isolates, young leaves becoming necrotic and the plant dying within a few weeks and, whilst still alive, plants contained little virus and were a poor source of infection. These characteristics suggest that this clone could provide a means of breeding cultivars that would be protected against all known strains of PVX.
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  • 23
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    Potato research 31 (1988), S. 129-135 
    ISSN: 1871-4528
    Keywords: potato ; Solanum tuberosum L. ; tuber growth ; bulking ; diurnal periodicity ; circadian rhythm ; water movement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The long-term and short-term changes in volume of tubers from plants grown under controlled conditions, when assessed by an accurate, non-destructive tuber-volume meter, showed sigmoid increases in volume. The diel changes were remarkable: the rate of volume increase was very high shortly after the onset of the dark phase, but it declined sharply directly after the onset of the light phase; it was much faster during the night than during the day, especially in the later stages of growth. The nocturnal rate of volume increase was greatest when the tubers showed their greatest overall rate of growth. The daytime increases in volume were fastest during the early stages of tuber development. The key process underlying these phenomena seems to be the movement of water out of and into the tuber.
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  • 24
    ISSN: 1871-4528
    Keywords: biotin ; potato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary When using two restriction enzymes and DNA probes from different sources, high levels of restriction fragment length polymorphism (RFLP) were observed in Southern blot hybridisation experiments, among 6 di(ha)ploid genotypes ofSolanum tuberosum and some closely related species. In 3 F1 sample populations of 14 individuals each, both heterozygosity and segregation of hybridisation patterns were observed. The non-radioactive biotin-dUTP/SA-AP method for DNA detection on Southern blots proved to be satisfactory and reliable.
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  • 25
    ISSN: 1871-4528
    Keywords: potato ; Solanum tuberosum L. ; tuber growth ; leaf growth ; water movement ; water stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Single-stemmed potato plants, cv. Bintje, were grown on a nutrient solution under controlled conditions. They were exposed to a short drought stress, or remained untreated. Long-term measurements of tuber volume were carried out with a non-destructive volume-meter. Specific leaf weight was monitored with a β-gauge. Tubers from the same plant varied in rate and duration of growth. The relative growth of stressed tubers was 43–54% less than that of the control tubers. The hierarchy of tubers from one stem changed over time in plants that were exposed to the stress. Specific leaf weight declined during the stress period but there was a prompt recovery after the relief from drought. This response was similar to the response of the average rate of volume increase of the tuber.
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  • 26
    ISSN: 1871-4528
    Keywords: potato ; cyst nematodes ; Solanum tuberosum L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Accessions of tuber-bearingSolanum spp. related toS. tuberosum subsp.tuberosum were obtained from the German-Dutch collection (Braunschweig, Germany) and the Inter-regional potato collection (Sturgeon Bay, USA). They were screened for resistance toG. rostochiensis Rol andG. pallida Pa2/3. Among 1567 clones from 52 accessions, 135 clones (23 accessions) were resistant toG. rostochiensis. They mainly representedS. andigena, gourlayi, spegazzinii andvernei. Among 1689 clones (74 accessions), 105 clones (32 accessions) were resistant toG. pallida. They representedS. gourlayi, spegazzinii, sparsipilum andvernei. About 25 clones were resistant to both species.
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  • 27
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    Potato research 39 (1996), S. 533-540 
    ISSN: 1871-4528
    Keywords: radiation ; interception ; light ; potato ; Solanum tuberosum L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Two methods for measuring the proportion of crop ground cover were compared. Both employed a rectangular grid of cords fitted in a frame at regular distances. One was based on the proportion of rectangles in which green area occupied more than half, and the other was based on the proportion of intersects coinciding with green area. The second method was accurate under all circumstances. Whereas the first method was found to give biased records when the smallest details in the canopy were small compared to the grid cell size. A theoretical estimate of the standard error of the intersect method was derived for homogeneous canopies and confirmed by experimental data.
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  • 28
    ISSN: 1871-4528
    Keywords: potato ; mitochondria ; chloroplast ; protoplast fusion ; somatic hybridization ; cytoplasmic inheritance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Creation from 4x hybrid clones from protoplast fusion of 2x clones of potato was evaluated. Besides combined nuclear genomes, composition of the cytoplasm significantly influenced the phenotypic traits of hybrid clones. To ascertain the influence of parental cytoplasm on the success of protoplast fusion and regeneration of hybrid plants, data from 74 fusion combinations of 50 dihaploid clones were analyzed. The majority of dihaploid breeding clones belonged to the cytoplasm types Wα, Tβ and Wγ. When the closely related mt types α, β and γ were used, fusion combinations had a better combining ability compared with more distantly related cytoplasms δ and ⃛. Fusions containing the same mitochondrial type (homofusions) were not superior to closely related mitochondrial types. However, homofusions of cytoplasm type Wα yielded significantly more hybrids than homofusions of type Tβ. In general, parental cytoplasm types had little impact on the fusion combining behaviour. Thus the cytoplasm type of the fusion parents is not a suitable marker for predicting the combining ability in protoplast fusion experiments.
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  • 29
    ISSN: 1871-4528
    Keywords: potato ; dry rot ; Fusarium coeruleum ; F. sulphureum ; general combining abilities
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Neotuberosum clones with differing levels of resistance toFusarium coeruleum andFurarium sulphureum, and putative resistance toPhytophthora infestans, were selected and used in crosses with Tuberosum clones. The resulting progenies were assessed for their resistance to each of these pathogens and for breeders' preference. There was little correlation between disease scores for the twoFusarium species (r=0.21 and 0.34 for the Neotuberosum and hybrid clones respectively), indicating that resistance to each species is distinct. Statistical analyses revealed differences between the Neotuberosum parents and between the Tuberosum parents for all traits, but the Neotuberosum differences for late blight were not significant (P=0.10–0.05) when tested against the interaction between the two sets of parents. The interaction was significant forF. coeruleum and breeders' preference, but notF. sulphureum. No reciprocal differences were found. The only statistically significant correlation between traits for the 72 progenies was a small one (r=0.33; P=0.01–0.001) between the twoFusarium species; for all other pairs of traits r was less than 0.10. It is concluded that there are good prospects for combinding resistances to the twoFusarium species from different sources and also for achieving high levels of other desirable characteristics.
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  • 30
    ISSN: 1871-4528
    Keywords: aphid ; epidemiology ; flight ; potato ; mosaic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Alate green peach aphids,Myzus persicae (Sulzer), tested in a flight chamber during their maiden flight period displayed behaviours ranging from repeated trivial flights to settling on the plants. The interaction of alate vector density and PVYn spread was dichotomous, virus spread was significantly related to vector density in some trials but virus spread was nil or limited and not significantly dependent on vector density in others. The green peach aphid colony used in these experiments provided a mixture of active and highly active alate populations. Results suggest that inactive and active vectors came from the active and highly active alate populations, respectively. Therefore, winged aphids within a species cannot all be attributed the same vector efficiency unless known to originate from the same population. At a 15% inoculum level the intercept for the regression model for the spread of PVYn was 5.03% indicating that there is a significant probability of propagation at aphid densities as low as one. However, over the range of aphid densities tested, the rate of spread per aphid was low, 0.08%, suggesting that reinfection of newly infected plants or movement interference between aphid vectors rapidly became important factors negatively affecting virus spread. Although these results cannot be directly transferred to field conditions they provide confirmation that lowM. persicae numbers can transmit unacceptable levels of mosaic and that low inoculum levels are required to decrease the risk of transmission by the small aphid numbers which cannot be realistically controlled.
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  • 31
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    Potato research 42 (1999), S. 427-436 
    ISSN: 1871-4528
    Keywords: germplasm ; potato ; in vitro ; microtuber ; cryo-conservation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary To prevent the loss of important genetic information cultivars are conserved in several collections of gene banks. In principal, there are two options for the medium to long-term storage of potato cultivars: storage as in vitro plantlets or microtubers and storage of meristems or shoot-tips in liquid nitrogen. In the Braunschweig potato cultivar collection, 360 cultivars are maintained under slow-growth conditions. Ten microplantlets of each cultivar are stored in test tubes containing filter paper bridges and 5 ml Murashige and Skoog (MS) liquid medium. The cultures were maintained at 10°C with a light intensity of 2 klux and 16 hours-day and can be stored under these conditions up to three years. Two hundred and forty-five cultivars are cryostored in liquid nitrogen. About 300 trimmed shoot-tips of each cultivar are incubated in MS-Towill-medium and then transferred into the cryoprotective solution. After an incubation time of about 2 hours trimmed shoot-tips fixed on an aluminium foil were put in cryo vials and stored in a container. The survival rate of the thawed, trimmed shoot-tips varies from 55%–100%. More important for a gene bank, however, is the plant regeneration. The average regeneration of all cultivars is about 40%.
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  • 32
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    Potato research 42 (1999), S. 611-617 
    ISSN: 1871-4528
    Keywords: dormancy ; potato ; losses ; Solanum tuberosum L. ; seed potato production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Microtubers can be stored longer, transported and handled easier than plantlets, but they have some disadvantages related to long dormancy. Dormancy, number of sprouts per tuber and loss of microtubers under different storage temperatures were studied. Microtubers of four genotypes originated from different tuberization treatments (photoperiod combinations) were observed. We found that dormancy depended on cultivar and — in some cases — on the photoperiod treatment applied during tuberization. Generally, the dormacy was long and was greatly elongated by low storage temperature. One of the photoperiod treatments shortened while the other treatment prolonged the rest-period compared to the control, maybe due to a change in temperature accompanying the change in daily light (photoperiod combination). Besides, these treatments affected the number of sprouts per tuber. There was no significant difference in duration of dormancy between different tuber-size groups, but the loss increased significanctly with a decrease in tuber size. Based on this information we can use microtubers more effectively in the seed potato production programme.
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  • 33
    ISSN: 1871-4528
    Keywords: tuber soft rot ; 2n gametes ; sexual hybridization ; somatic hybridization ; germplasm exploitation ; potato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The resistance to tuber soft rot caused byErwinia carotovora ofSolanum tuberosum x S. tarijense andS. tuberosum (+) S. commersonii hybrids and their backcrosses is reported. A number of resistant diploid sexual hybrids and tetraploid/hexaploid somatic hybrids were selected. Backcross progenies were obtained through 2x×4x crosses involving a resistant diploid hybrid and tetraploidS. tuberosum, and through 4x×4x crosses between a resistant somatic hybrid andS. tuberosum. The hybrids showed high variability interms of resistance to tuber soft rot. The resistance of progeny from 2x×4x backcrosses was similar to that of the parental sexual hybrid. By contrast, the resistance of genotypes deriving from 4x×4x backcrosses was reduced compared with the resistant somatic hybrid. In general, tuber characteristics of the backcross hybrids improved considerably as compared with their parents, and tuber yield per plant was good.
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  • 34
    ISSN: 1871-4528
    Keywords: auxin ; cytokinin ; potato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Shoot regeneration was investigated on explants from different leaves and leaflets of three potato cultivars Posmo, Folva and Oleva. Explants were excised from glasshouse grown plants and grown for 6 days on callus induction medium with indole-3-acetic acid or 2,4-dichlorophenoxyacetic acid. Explants were then transferred to auxin free shoot regeneration medium with gibberellic acid and 6-benzyladenine or zeatin. By using the optimum combinations and concentrations of plant growth regulators and by excision of explants from particular regions of proximal leaflets from newly unfolded leaves, shoot regeneration frequencies of 97.0% were obtained for cv. Posmo and 32.1% for cv. Folva. Shoot regeneration frequency of cv. Oleva was very low and could not be improved by the different treatments.
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  • 35
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    Potato research 28 (1985), S. 443-448 
    ISSN: 1871-4528
    Keywords: russet scab ; common scab ; Streptomyces scabies ; soil pathogen ; potato ; Solanum tuberosum ; sugar beet ; girth scab
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In this paper it is argued from published descriptions and experimental results, that russet scab in the USA and russet scab in Europe are two different diseases. To resolve this nomenclatural problem in the English language we propose that the name ‘netted scab’ should henceforth be used for the russet scab in Europe in agreement with the other European common names, viz. the Danish ‘netskurv’, the Dutch ‘netschurft’, the Swedish ‘Nätskorv’ and the German ‘Netzschorf’.
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  • 36
    ISSN: 1871-4528
    Keywords: potato ; tuber-size distribution ; size grading ; dry-matter content ; tuberization ; growth regulators
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In two outdoor pot experiments with potato (cv. Bintje) gibberellic acid (GA) was applied to the soil on different dates at 25 (Exp. 1) or 12.5 (Exp. 2) mg/pot. Dry-matter yields were reduced by early treatments in Exp. 1. In both experiments fresh yields were increased by an application about 40 days or later after planting (DAP). GA increased the number of tubers, especially when applied 38 or 40 DAP, treatments which also induced the largest shift in size distribution towards the smaller grades. GA reduced the dry-matter content of the tubers, especially when applied 60 (Exp. 1) or 48 (Exp. 2) DAP. Because the development over time of sensitivity to GA was not similar for all yield and quality variables, GA can be used to alter tuber-size distribution without greatly affecting other quality characteristies or yield.
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  • 37
    ISSN: 1871-4528
    Keywords: potato ; Solanum tuberosum L. ; tuber growth ; leaf growth ; diurnal periodicity ; circadian rhythm ; water movement ; water stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Single-stemmed potato plants, cv. Bintje, were grown on a nutrient solution under controlled conditions. They were exposed to a short drought stress, or remained untreated. Short-term changes in tuber volume and in specific leaf weight were measured non-destructively. Tubers from control plants increased rapidly in volume during the night and did not grow, or even shrivelled during the day. Tubers of stressed plants did not show a uniform response; some tubers markedly declined in volume during the day. The patterns of volume increase of stressed plants became erratic after the stress, mainly because some plants never fully recovered. Patterns of diurnal fluctuation in tuber volume were similar to diurnal changes in specific leaf weight; tubers within the same stressed plant sometimes reacted differently. In these cases the effects on the diurnal fluctuation partly reflected the long-term effects, reported in an earlier paper.
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  • 38
    ISSN: 1871-4528
    Keywords: potato ; bacteria ; pectic enzymes ; Erwinia carotovora ; E. chrysanthemi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Two modifications of the selective-diagnostic crystal violet pectate (CVP) medium for soft rot erwinias were developed using a new formulation of sodium polypectate; these were a single layer medium and a double layer medium consisting of an agar base with a pectate overlayer. Both media contained 0.1% tryptone to promote growth and cavity formation by erwinias and 40 μg ml−1 novobiocin instead of sodium lauryl sulphate to increase recovery rate and selectivity. Colonies of the three erwinias commonly associated with potatoes formed characteristic deep cavities in the single layer modified CVP. Cavities in the double layer CVP although deep were smaller but remained distinct longer. Recovery rate and selectivity with both media were better than with the original CVP.
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  • 39
    ISSN: 1871-4528
    Keywords: potato ; solt rot ; blackleg ; early selection ; Solanum tuberosum L. ; Solanum brevidens Phil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Eleven clones obtained from a cross between cv. Katahdin and fusion products betweenSolanum tuberosum and the non tuber-bearing speciesS. brevidens, were backcrossed again withS. tuberosum (clone AR80-127-5). Small tubers harvested from 583 seedlings of these second backcross (BC2) populations were screened for tuber tissue resistance toErwinia carotovora subsp.atroseptica under aerobic conditions. After multiplication in the field. BC2 clones again were screened for soft rot resistance under aerobic as well as anaerobic conditions. In general, the resistance of the BC2 populations was reduced in comparison with the BC1. Variation for resistance was found within the BC2 populations, but there was no correlation between the results of the three tests performed. Four BC2 populations were also screenned for resistance to blackleg in the field. Significant differences were found between populations for mean percentage of diseased plants, but these differences could not be explained by the resistance of the parental clones.
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  • 40
    ISSN: 1871-4528
    Keywords: somaclonal variation ; chromosome number ; potato ; polyploidization ; aneuploidization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Leaf protoplasts of dihaploid (2n=2x=24) and tetraploid (2n=4x=48)Solanum tuberosum, and diploidS. bulbocastanum (2n=2x=24) were cultured in liquid medium. The cultures were studied for early karyological changes during their development. Giemsa staining of spread preparations revealed extremely low percentages of protoplasts developing into calli with the parental chromosome number, and high percentages of acytokinetic cells. The nuclear divisions within a cell were synchronous which allowed the occurrence of spindle interaction, resulting in nuclear poly- and aneuploidization. Although polyploidization was also found in uninucleate cells, a major increase in the formation of true-to-type calli would certainly be established by the improvement of early cross wall formation.
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  • 41
    ISSN: 1871-4528
    Keywords: α-chaconine ; α-solamargine ; α-solanine ; α-solasonine ; Solanum ; potato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Methods were developed for clean-up of potato tuber extracts on solid phase extraction CN-cartridges and for analysis of steroidal glycoalkaloids by reversed phase HPLC. The alkaloids α-solanine, α-chaconine, α-solasonine and α-solamargine could be separated on C8 or C18 reversed phase columns using a mobile phase of acetonitrile/Tris-buffer (3∶2, v/v). The analysis time of tuber extracts containing these alkaloids was less then 4 min, if the pH of the mobile phase was adjusted to 7.4 and run at a flow rate of 0.5 ml/min.
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  • 42
    ISSN: 1871-4528
    Keywords: foliage blight ; tuber blight ; Phytophthora infestans ; breeders' preference score ; specific combining ability ; potato ; Solanum tuberosum L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Screening tests to detect resistance to late blight in both foliage and tubers were done on glasshouse-grown seedling progenies in parallel with visual assessments by three experienced potato breeders of the yield and quality of glasshouse-grown tubers of the same progenies. There were large differences between the parents of the progenies in their general combining ability (GCA) for both foliage and tuber blight, despite some variation due to specific combining ability for foliage blight. There were also differences between parents in their GCAs for visual preference scores, but these GCAs and those for blight resistance were not correlated. The blight-resistant cv. Stirling had the best combination of high GCAs for all three attributes. The use of these and other seedling progeny tests in a multitrait genotypic recurrent selection scheme is discussed.
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  • 43
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    Potato research 41 (1998), S. 69-82 
    ISSN: 1871-4528
    Keywords: potato ; diploid ; Erwinia ; yield ; tuber characters ; breeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Offspring were produced from a cross between two long-day-adaptedSolanum phureja clones which carried resistance to tuber soft rot (Erwinia carotovora subsp.atroseptica). In tests carried out on the produce of field-grown plants raised from tubers, over fifty per cent of the 173 offspring were found to be highly resistant. Assessments were also carried out of tuber yield, mean tuber weight, tuber number, shape, regularity, flesh colour, texture of the steamed flesh, fry colour, after-cooking blackening, sprout length after storage and overall dormancy. There were statistically significant differences between clones for all characters (P〈0.001). Twelve of the clones were selected on the basis of high resistance, yield, tuber weight, regularity of shape and absence of after-cooking blackening. The value of resistant long-day-adapted diploid material for commercial breeding is discussed.
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  • 44
    ISSN: 1871-4528
    Keywords: post harvest disease ; potato ; Solanum tuberosum L. ; resistance ; toxin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Virulence of 12Fusarium oxysporum isolates was determined on three potato cultivars Late Harvest, BP1 and Kimberley Choice. The production of fusaric acid by the 12F. oxysporum isolates was also determined. The aim of the study was to determine whether a correlation exists between fusaric acid production and virulence ofF. oxysporum isolates. Late Harvest was the most tolerant and BP1 the most susceptible cultivar. Virulence ranking, order of theF. oxysporum isolates with the different cultivars corresponded with the mean of value of the ranking order for all three cultivars. A correlation was found between virulence of isolates and fusaric acid production except for Late Harvest. Fusaric acid production may play a major role in the development of dry rot in potato tubers.
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  • 45
    ISSN: 1871-4528
    Keywords: potato ; wild species ; disease ; bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Long-day-adaptedSolanum phureja clones were assessed for resistance to blackleg caused byErwinia carotovora subsp.atroseptica under field and controlled environmental conditions over two years. In the field, twenty-two of the twenty-three clones ofS. phureja assessed were as resistant to blackleg as the commercial cultivar Ailsa, the most resistant control, and were significantly (P〈0.001) more resistant than the intermediate and susceptible cultivars Wilja and Estima, respectively. Under controlled environmental conditions, resistance in commercial cultivars was more easily overcome. However, 18 of the 21S. phureja clones assessed were significantly more resistant to blackleg than these cultivars.
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  • 46
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    Potato research 40 (1997), S. 413-416 
    ISSN: 1871-4528
    Keywords: α-chaconine ; α-solanine ; potato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A new, efficient and economic method employing Medium Pressure Liquid Chromatography (MPLC) for the isolation of the two majorSolanum tuberosum L. glycoalkaloids (α-solanine and α-chaconine) is described. Potato peelings are homogenised with 5% acetic acid, the glycoalkaloids purified by filtration through an XAD-2 column and then by precipitation from the aqueous solution. The resulting glycoalkaloid fraction was purified by MPLC using a Silica Gel column and a CHCl3:MeOH:2% NH4OH mixture (70∶30∶5) as mobile phase to yield pure α-chaconine and a-solanine. This methodology can be used to obtain glycoalkaloids for enthomology and toxicological research where large amounts of these compounds are required.
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  • 47
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    Potato research 20 (1977), S. 127-130 
    ISSN: 1871-4528
    Keywords: Micro-precipitin test ; Chenopodium quinoa ; potato virus S ; potato ; bioassay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The micro-precipitin test and a bioassay using the local-lesion hostChenopodium quinoa were compared for their efficiency in detecting potato virus S in some potato cultivars grown in the open. TheC. quinoa bioassay was more sensitive than the serological test but used more space and was time-consuming.
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  • 48
    ISSN: 1871-4528
    Keywords: common scab ; Streptomyces scabies ; potato ; genotype ; resistance ; environment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Zusammenfassung Die Knollen wurden auf ihre Anfälligkeit für Flachschorf bestimmt, indem der Bedeckungsgrad geschätzt und der schlimmste Schorftyp auf den einzelnen Knollen notiert wurden. Der Bedeckungsgrad wurde anhand einer Skala bestimmt, wobei 0=kein Schorf, 1=bis zu 10% der Oberfläche von Schorf befallen und jede weitere Einheit eine Zunahme von 10% bedeuten. Der Schorftyp wurde anhand einer Skala von 0–5 bonitiert: 0 = keine Schorfarten, 1 = wenig, oberflächliche Läsionen, 2 = gross, oberflächliche Läsionen, 3 = gross, rauhe Läsionen, 4 = grosse Läsionen, entweder aufgeworfen oder flachnarbig, 5 = grosse Läsionen, tiefnarbig. Die Mittelwerte für die Parzellen wurden errechnet. Das Verhältnis zwischen dem mit Flachschort befallenen Umfang der Knollenoberfläche und der Schwere des Schorftypes wurde untersucht, indem für acht Versuche an zwei Orten über zwei Vegetationsperioden (Abb. 1) Regressionen für den Umfang pro Typ errechnet und die Homogenität der Regressionen durch Varianzanalysen (Tabelle 1) verglichen wurden. Alle Regressionskoeffizienten waren hoch signifikant und wichen nicht signifikant voneinander ab. Die Tatsache, dass der Schorfbefall sich im gleichen Mass wie der Schorftyp verändert, weist darauf hin, dass — innerhalb der untersuchten Population von Genotypen — die Resistenz der Kartoffel gegen das Eindringen von sich entwickelnden Lentizellen und die Besiedlung von Knollengewebe eng zusammenhängen. Die Interaktion des Kartoffelgenotyps mit der Umwelt kann manchmal Knollen mit nur wenigen, tiefen Läsionen, wie im Versuch mit frühen Sorten in Trumpington 1975 (Abb. 11), oder mit zahlreichen oberflächlichen Schorfen, wie im Versuch mit mittelfrühen bis mittelspäten Sorten in Trumpington 1976 (Abb. 17), bewirken. Es ist daher nicht angezeigt, nur aufgrund des Vorhandenseins von oberflächlichen oder normalen Schorfen eine Auslese auf Resistenz oder Anfälligkeit zu treffen. Obwohl alle Regressionskoeffizienten hoch signifikant waren, gab es doch einzelne Abweichungen von den Regressionslinien. Ein Beispiel ist der in Abb. 15,6 mit × bezeichnete Klon, der eine kleinere Befallsfläche aufwies als 1976 an beiden Orten zu erwarten gewesen wäre.
    Abstract: Résumé On a étudié la sensibilité des tubercules à la gale commune par estimation de la surface atteinte et par notation du type de gale le plus grave sur chaque tubercule. On a établi une échelle de 1 à 10 en fonction du degré d'attaque, ou 0=pas de gale, 1=jusqu'à 10% de la surface atteinte. A chaque unité supplémentaire correspond une augmentation de 10%. Une échelle de 0 à 5 a été utilisée pour le type de gale; 0=pas de gale, 1=petites lésions superficielles, 2=grandes lésions superficielles, 3=grandes lésions rugueuses, 4=grandes lésions en relief ou en creux peu profonds, 5=grandes lésions en creux profonds. On a calculé des moyennes pour chaque parcelle. La relation entre la surface du tubercule couvert de lésions et la sévérité du type de gale a été examinée par calculs de régressions entre ces deux facteurs à partir de huit essais situés à deux endroits durant deux saisons (fig. 1) et par un test d'homogénéité des coefficients de régression par analyse de variance (tableau 1). Tous les coefficients de régression ont été hautement significatifs sans être différents de manière significative entre eux. Le fait que la surface des lésions change de manière uniforme à l'intérieur de la population des génotypes testés, conduit l'auteur à penser que la résistance des pommes de terre à la pénétration par les lenticules formées et la colonisation des tissue du tubercule sont intimement liées. L'interaction entre le génotype et l'environnement peut quelquefois produire des tubercules ayant seulement quelques lésions profondes, comme cela s'est produit dans l'essai récolté tôt de Trumpington en 1975 (fig. 11), où de nombreuses lésions superficielles, comme pour l'essai de Trumpington en 1976 (fig. 17) récolté plus tardivement. Par conséquent, dans le cadre d'un programme de sélection, il est insuffisant de classer des plantes résistantes ou sensibles uniquement à partir de gales respectivement superficielles ou normales. Bien que tous les coefficients de régression soient hautement significatifs il y a des déviations individuelles à partir des courbes de régression. Un exemple est donné par le clone marqué d'une croix (×) dans la fig. 15,6 lequel avait une surface atteinte plus petite que ce que l'on pouvait expecter pour les deux endroits en 1976.
    Notes: Summary The relationship between the area of tuber surface covered with lesions of common scab and the severity of the scab type was examined by calculating regressions of cover on type for eight trials at two sites over two seasons. All the regression coefficients were highly significant and did not differ significantly from each other. This suggests that resistance to penetration and to colonization of tubers by the parasite are closely related. Differences in the position of regression lines were probably due to local environmental conditions. The interaction of the potato genotype with the environment can result in relatively few severe scabs or many superficial scabs.
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  • 49
    Electronic Resource
    Electronic Resource
    Springer
    Potato research 21 (1978), S. 171-181 
    ISSN: 1871-4528
    Keywords: maturity ; potato ; conversion tables
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Zusammenfassung Fünfzig Kartoffelsorten wurden in 4 geographischen Gebieten auf Zypern (Abb. 1) getestet und entsprechend dem Spezifischen Gewicht ihrer Knollen in vier Gruppen eingeteilt (Tabelle 1). Das Spez. Gewicht schwankte von 1.0669 (17.62% Trockensubstanz) bis 1.0850 (21.62% Trockensubstanz); die erhaltenen Werter für das Spez. Gewicht wurden mittels Standardformeln in % Stärkegehalt und % Trockensubstanzgehalt umgerechnet. Das spez. Gewicht schwankte von Ort zu Ort und war am höchsten in Althalassa (eine späte Kartoffellage). Für die festgestellten Unterschiede im Spez. Gewicht waren mikroklimatische und Bodenfaktoren in diesen Gebieten verantwortlich (Tabellen 2–4). Unterschiede zwischen den Orten waren stets unabhängig von Sorte und Jahreszeit. Das Spez. Gewicht nahm mit der Reife zu, und es wurden signifikante Unterschiede zwischen Ernten, die 3 Wochen auseinanderlagen. festgestellt. Das Mass der Zunahme an Spez. Gewicht war bei mittelspäten und späten Sorten, z.B. Arran Banner. Up-to-Date, Cardinal und Maris Piper, grösser als bei frühen Sorten, z.B. Premiere und Spunta (Tabelle 5). Zur Erleichterung der Information und der Verwendung der von Simmonds (1977) vorgeschlagenen Formeln wurde eine Tabelle zur Umrechnung der Spez. Gewichtswerte innerhalb des Bereichs von 1.0600 bis 1.1090 in % Trockensubstanz und % Stärke vorbereitet (Tabelle 6).
    Abstract: Résumé Cinquante variétés de pommes de terre ont été testées dans quatre régions de l'lle de Chypre (figure 1) et ont été classées en 4 groupes selon le poids spécifique de leurs tubercules (tableau 1). La valeur du poids spécifique est répartie entre 1,0669 (17.62% de matière sèche) et 1,0850 (21,62% M.S.); les valeurs obtenues ont été converties en pourcentage d'amidon et en pourcentage de matière sèche (tableau 1) par l'emploi d'une formule standard. Le poids spécifique a varié d'une région à l'autre et a été le plus élevé en Athalassa (localité à pommes de terre tardives). Les facteurs climatiques (micro-climats) et le type de sol de ces diverses régions ont été responsables des différences de valeur de poids spécifique observées (tableaux 2–4); ces dernières ne dépendant ni de la variété, ni de la saison. Le poids spécifique a augmenté avec la maturité des pommes de terre et des différences significatives ont été observées entre des récoltes faites à 3 semaines d'intervalle. Il a été plus élevé chez les variétés demi-hâtives et tardives telles que Arran Banner, Up-to-Date, Cardinal et Maris Piper que chez les variétés hâtives telles que Première et Spunta (tableau 5). Pour faciliter l'emploi de la formule proposée par Simmonds (1977) une table de conversion des valeurs de poids spécifique (entre les classes de 1,060–1,100) et les pourcentages de matière sèche et d'amidon a été réalisée (tableau 6).
    Notes: Summary Fifty potato varieties were grown at different geographic areas in Cyprus and were classified into groups according to the specific gravity of their tubers. Specific gravity varied from location to location; it was high at Athalassa, low at Xylophagou, and intermediate in the Paphos and Morphou areas. Specific gravity increased with maturity and significant differences were observed between lifting dates 3 weeks apart; the rate of increase in specific gravity was higher in medium-late than in early varieties. Specific gravity values obtained by the potato hydrometer method were converted into dry matter (DM) and into starch content by standard formulae and a conversion table was prepared and is presented for reference.
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  • 50
    ISSN: 1871-4528
    Keywords: potato ; rotting ; immunodiffusion serology ; transmission ; rot-inducement ; weather
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Zusammenfassung Im Jahr 1977 zeigten die Ergebnisse eines kleinen Feldversuches, dass nach Inokulation von Stengeln der Sorte King Edward mitErwinia carotovora subsp.carotovora der Organismus von den Stengelläsionen auf die Tochterknollen übertragen werden konnte. Um diese Beobachtung abzusichern, die Häufigkeit solcher Übertragung zu untersuchen und die relative Bedeutung von Stengelläsionen und verfaulenden Pflanzknollen als Quelle des Inokulums zu bestimmen, werden 1978 und 1979 Versuche mit serologisch identifizierbaren Stämmen der Subspeziescarotovora undatroseptica durchgeführt. 1978 wurden zwei Versuchspaare angelegt und in einem Versuch wurden Pflanzknollen (die vorher von den wachsenden Pflanzen weggenommen wurden), inokuliert mit subsp.atroseptica untergeschoben (siehe Lapwood & Harris, 1977) und Stengel der gleichen Pflanzen der Sorte Pentland Crown durch Injektion von Subsp.carotovora unter die Epidermis inokuliert. Im zweiten Versuch jedes Paares, vom ersten durch vier Leerreihen getrennt, waren die Inokulationsstellen umgekehrt. Die Versuchspaare waren von einander durch sechs Leerreihen getrennt und ein Paar wurde durch Beregnung mit ungefähr 25 mm Wasser zu jedem der drei Termine während der Vegetationsperiode versorgt (17. Juli und 6. September; der für Mitte August geplante Termin entfiel wegen Regen). 1979 wurde nur ein Versuchspaar angelegt, die Beregnung wurde weggelassen. 1978 wurde an drei Terminen inokuliert (Tab. 1) und 1979 an neun (Tab. 2); die Daten der Probenahme sind ebenfalls in den Tabellen angegeben. Bei der Probenahme wurden aus jeder der drei Wiederholungen von jedem Inokulationstermin (und aus den nicht inokulierten Kontrollparzellen) 2 Pflanzen in nebeneinander liegenden Reihen mit einer, des-infizierten Grabgabel aufgenommen. Die in-okulierte (untergeschobene) Knolle wurde entfernt bevor Bodenproben genommen und fünf Tochterknollen jeder Pflanze geerntet wurden. Das die Läsionen enthaltende Stengelgewebe wurde zur Bestimmung und Isolierung von den Pflanzen abgeschnitten. Die Proben einer Parzelle wurden zusammengefasst und Bodenproben auf das Vorhandensein der Subspezies vonE. carotovora geprüft. Bei den Tochterknollen wurde durch Untertauchen in Wasser die Fäule provoziert und der dafür massgebende Erreger durch den von Vruggink & Maas Geesteranus (1975) beschrieben und von Lapwood & Harris (1980) modifizierten Immun-Diffusiontest identifiziert. Die 1978 mit subsp.carotovora inokulierten Knollen verfaulten sehr schnell, aber das Bakterium konnte weder in den faulenden Tochterknollen noch im die inokulierten Knollen umgebenden Boden gefunden werden, mit Ausnahme am 27. September (inokulier am 29. August) in den beregneten Versuchen. Nach der Inokulation der Stengel konnten die Bakterien schnell aus Stengeln isoliert werden, aus den Tochterknollen aber nur am 14. August (Inokulation am 26. Juli) und niemals aus dem Boden, gleichgültig, ob die Parzellen beregnet waren oder nicht. Die Ergenisse der Stengel-und Knolleninokulation mit subsp.atroseptica für die nicht beregneten Parzellen sind in Tabelle 1 zusammengefasst. Das Bakterium wurde mehrmals in Bodenproben aus der Umgebung der inokulierten Knollen gefunden, jedoch niemals im Boden nahe der Tochterknollen, gleichgültig, ob beregnet wurde oder nicht. Es konnte nur am 24. Juli (beregneter Versuch) und am 7. August (nicht beregneter Versuch) in induzierten Fäulen der Tochterknollen identifiziert werden, wobei die inokulierte Pflanzknolle das Inokulum lieferte, aber in vielen Fällen, wenn das Inokulum vom Stengel stammt. Das Muster der Verbreitung (Abb. 1) zeigt, dass das meiste während der nassen, kühlen Witterung Ende Juli und Anfang August geschah. 1979 konnte die Ausbreitung der subsp.carotovora während der Vegetationszeit achtmal von inokulierten Knollen und zwölfmal von inokulierten Stengeln ausgehend beobachtet werden und bei subsp.atroseptica von 22 bzw. 19 (Tabelle 2); Abb. 1 zeigt, die Ergebnisse im Verhältnis zu den Witterungsbedingugen. Die Ergebnisse zeigen, dass in Stengel inokulierte Bakterien darauffolgend in Tochterknollen wiedergefunden werden können wahrscheinlich durch das Abwaschen und den Transport durch Regen. Stengelläsionen scheinen als Quelle des Inokulums ebenso wichtig zu sein, wie die Pflanzknollen, für subsp.atroseptica in beiden Jahren und für subsp.carotovora 1979. Die Stengelläsionen können für fast die gesamte Wachstumsperiode eine Quelle des Inokulums darstellen, während nassfaule Pflanzknollen, die schnell bis auf einen leeren Stengel reduziert sind, ihr gesamtes Inokulum bald entleert haben können. Zusätzlich wird die Zerfallsrate der Pflanzknolle vielleicht auch durch das Eindringen von Sekundär-Erregern beschleunigt, wodurch sowohl der Gehalt an Inokulum und die Dauer seiner Verfügbarkeit begrenzt wird, Bedingungen, die vielleicht weniger bei den Stengelläsionen auftreten.
    Abstract: Résumé Les résultats d'une expérimentation au champ, à petite échelle, à Rothamsted en 1977, montraient que lorsqueErwinia carotovora subsp.carotovora était inoculé dans les tiges de la variété King Edward, l'organisme pouvait être transmis à partir des lésions sur tiges, aux tubercules-fils. Pour confirmer cette observation, pour rechercher la fréquence de ce type de propagation et pour déterminer l'importance relative des lésions de tiges et des tubercules de semence pourris comme sources d'inoculum, des expérimentations ont été conduites en 1978 et en 1979 en utilisant une souche identifiée sérologiquement de subsp.carotovora et aussi de subsp.atroseptica. En 1978 deux séries d'expérimentations ont été mises en place et dans la première expérimentation de chaque série, des tubercules de semence (prélevés sur des plantes en culture), inoculés avec subsp.atroseptica ont été introduits (voir Lapwood & Harris, 1977) et les tiges des mêmes plantes de variétés Pentland Crown ont été inoculées avec subsp.carotovora par injection hypodermique. Dans la seconde expérimentation de chaque série, séparée de la première par quatre rangs non plantés, les sites d'inoculation étaient inversés. Les séries d'expérimentations étaient séparées l'une de l'autre par six rangs non plantés et la première série était irriguée par aspersion pour couvrir approximativement un besoin de 25 mm en trois occasions durant la saison (à savoir, 27 Juillet et 6 Septembre; celle prévue à la mi-août n'a pas été appliquée à cause de la pluie). En 1979, seule une série d'expérimentations a été mise en place, l'irrigation ayant été omise. En 1978, il y avait trois date d'inoculation (Tableau 1) et en 1979, neuf (Tableau 2). Les dates d'échantillonnage sont également indiquées dans les tableaux. Pour l'échantillonnage, deux plantes de rangs adjacents sont arrachées avec une bêche désinfectée, à raison de 3 répétitions pour chaque date d'inoculation (et pour les parcelles témoins non inoculées). Le tubercule inoculé était enlevé avant de prendre les échantillons de sol et cinq tubercules fils sur chaque plante. Les tissus de tiges contenant la lésion étaient détachés de la plante pour détermination et isolement. Les échantillons de chaque parcelle étaient groupés. Les sols étaient examinés en ce qui concerne la présence des subsp. d'E. carotovora et les tubercules fils étaient mis à pourrir par immersion dans l'eau et l'agent causal était identifié par la méthode sérologique d'immunodiffusion décrite par Vruggink & Maas Geesteranus (1975) et modifiée par Lapwood & Harris (1980). En 1978, les tubercules inoculés avec subsp.carotovora pourrissaient rapidement mais la bactérie n'a pas été détectée dans les pourritures des tubercules fils induits et dans le sol entourant le tubercule inoculé sauf le 27 Septembre (inoculation du 29 Août) dans l'expérimentation conduite en irrigation. Lorsque les tiges étaient inoculées, les bactéries étaient à nouveau isolables des tiges, mais elles n'étaient retrouvées dans les pourritures des tubercules fils que le 14 Août (inoculation du 26 Juillet) et jamais dans le sol, que les parcelles soient irriguées ou non. Les résultats de l'inoculation des tiges et des tubercules avec subsp.atroseptica sont indiqués dans le Tableau 1 pour la condition non irriguée seulement. La bactérie a été retrouvée de nombreuses fois dans le sol entourant les tubercules inoculés mais jamais dans le sol environnant des tubercules fils que les parcelles soient irriguées ou non. Elle est retrouvée dans les pourritures des tubercules fils induits seulement le 24 Juillet (conditions irriguées) et le 7 Août (condition non irriguée) lorsque le tubercule de semence inoculé était la source d'inoculum, mais dans de nombreuses occasions lorsque l'inoculum provenait de la tige. Le modèle indique (fig. 1) qu'il y avait plus de propagation par temps humide et frais de fin juillet et début août. En 1979, la propagation de subsp.carotovora était mise en évidence à neuf reprises durant la saison à partir des tubercules inoculés et en 12 occasions à partir des tiges inoculées et celle de subsp.atroseptica dans 22 et 19 occasions respectivement (Tableau 2); les résultats sont en relation avec les param⪻tres climatique dans la fig. 1. Les résultats montrent que les bactéries inoculées aux tiges peuvent être retrouvées dans les tubercules fils, probablement à cause du lessivage et du transport par la pluie. Les lésions de tiges apparaissent comme était aussi importantes que le tubercule de la semence en tant que source d'inoculum pour subsp.atroseptica pour les deux années et pour subsp.carotovora en 1979. Les lésions de tiges peuvent être une source d'inoculum persistante durant la saison de culture du fait que les tubercules de semence sont atteints de pourriture molle. Ces lésions peuvent rapidement se limiter à une tige détruite et ainsi éliminer rapidement leur inoculum. De plus, le niveau de dégradation des tubercules de semence peut être accru par l'intervention d'organismes secondaires qui limitent à la fois le taux d'inoculum produit et la durée de sa disponibilité, conditions moins vraissemblables peut être d'apparaitre avec les lésions sur tiges.
    Notes: Summary In 1978 and 1979 field experiments were made in which serologically distinct isolates ofErwinia carotovora subsp.atroseptica and subsp.carotovora were inoculated on different dates into stems or seed tubers. The latter had been removed from emerging plants, inoculated and replaced on different dates. Samples of soil and progeny tubers were taken at intervals after inoculation to monitor spread. Progeny tubers were induced to rot and the bacterium responsible was identified by immunodiffusion tests. In 1978 no spread of subsp.carotovora from placement tuber lesions to progeny tubers was detected and spread on one occasion only from stem lesions was detected. Spread of subsp.atroseptica was detected from both inoculum sources. In 1979 spread of subsp.carotovora was detected on eight occasions during the season from placement tubers and on twelve from inoculated stems and for subsp.atroseptica on twenty two and nineteen occasions respectively.
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  • 51
    ISSN: 1871-4528
    Keywords: experimental design ; control plots ; adjustment ; yield trials ; potato ; breeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Zusammenfassung Selektion bei frühen Generationen in Kartoffelzüchtungsprogrammen beruht auf hochvererbbaren Merkmalen, wie Augentiefe, Knollengestalt, Chipsfarbe, spezifischem Gewicht etc. Weitere Selektion betont Adaption an Umgebungen innerhalb des Schwerpunktes des Zuchtprogrammes und in diesem Selektionsstadium wird grösser Aufmerksamkeit auf den Knollenertrag gerichtet. Allerdings verbietet die grosse Zahl oft einbezogener Linien, zusammen mit der begrenzten Verfügbarkeit an Material von jeder Linie, die Anwendung von Standardmodellen mit Wiederholungen. Das modifizierte erweiterte Modell (MAD), kürzlich von Lin u. Poushinsky (1983) als Methode zur Anpassung von umweltbedingter Heterogenität vorgeschlagen, wurde in Adaptionsversuchen des ‘Prairie Cooperative Kartoffelzuchtprogramms’ (Kanada, 1982) an vier Stellen erprobt. In dem MAD werden Kontrollsorten, die in Mengen erhältlich sind, welche Wiederholungen erlauben, zufallsgemäss auf eine Gruppe ganzer Parzellen verteilt, die in einem Standardmuster ausgelegt sind, hier als Lateinisches Quadrat (Abb. 1). Anpassungen für die Testlinien erfolgen auf der Basis von Trends, die sich in den Kontrollparzellen ergeben. Die Daten der Kontrollparzellen werden entsprechend der Varianzanalyse (ANOVA) für das Lateinische Quadrat geprüft. Wenn Säulen- und Reiheneffekte zum gesamten Parzellenfehler relativ gross sind, werden die nicht wiederholten Testlinien anhand der Reihen-und/oder Säulenkorrekturen nach Schätzung der Kontrollparzellen berichtigt (Methode 1). Wenn Bodenunterschiede dadurch nicht eliminiert werden können, dient ein Index für Nährstoffgehalt für jede Parzelle, als Differenz zwischen dem Wert der Kontrollparzelle für diese gesamte Parzelle und dem Mittel aller Kontrollparzellen mit der entsprechenden Sorte entweder als Anpassungsfaktor (Methode 2), oder wird als begleitende Variable behandelt und die Testlinien werden durch Kovarianzanalyse berichtigt (Methode 3). Der durchschnittliche Gesamtertrag und die mittleren Quadrate, in der ANOVA als Gesamtertrag der Kontrollparzellen an den vier Versuchsorten, ergibt sich aus Tabellen 1 bzw. 2. Die Reihen- und Säulenvarianzen waren gross (im Verhältnis zum Gesamt-Parzellenfehler) für Edmonton I und II und für Brooks II, sie deuten auf die Notwendigkeit für Reihen- und Säulenanpassungen hin. Eine Prüfung der Irrtumsvarianzen für Carman I und II, möglicherweise auch Brooks I zeigen starke Heterogenität in mehrere Richtungen zwischen den Parzellen, zumal die ganzen Varianzen der Parzellen grösser als die doppelte Höhe der Unterparzellen-Varianzen waren. Bei Outlook war keine der Varianzen relativ gross gegenüber den anderen. Diese Trends erklären die Anpassungsmethode 1 für Edmonton I und II, die Anpassungsmethode 3 für Carman I und II und Brooks I und II, und keine Anpassung bei Outlook I. Detaillierte Kriterien zur Entscheidung für die angemessene Anpassungsmethode wurden im Computer verrechnet. Die durchschnittlich geschätzte Varianz einer Differenz zwischen beliebigen zwei Testlinien wurden für jede Methode berechnet, dann wurden die Methoden durch Berechnung der Verhältnisse dieser Varianzen ermittelt (Tabelle 3). Ebenso wurden die Methoden durch Anwendung der Anpassungen an die Kontroll-Unterparzelle und druch Berechnung der gepoolten Varianzen innerhalb der Linien von angepassten Daten (Tabelle 4) verglichen. Die relativen Effizienzen der Anpassungsmethoden wurden als Verhältnisse der Varianz der nichtangepassten Daten zu den angepassten Daten berechnet. Die Varianzdaten in Tabelle 4 zeigen, dass im allgemeinen die Anpassung durch Regressionsanalyse (Methode 3) sich entweder durch geringfügige Änderungen oder durch beträchtlichen Gewinn an Effizienz auswirkten. Ausser bei Edmonton I verursachten die Methoden I und II einen deutlichen Anstieg in der gepoolten Varianz innerhalb der Linien und folglich einen Verlust an Effizienz. Das wichtige Ergebnis der Anpassung bei der Selektion von Zuchtmaterial sind die Änderungen bei den relativen Schwankungen in der Rangfolge der Testlinie. Diese Änderungen, nach Verwendung der drei Anpassungsmethoden verrechnet, zeigt Tabelle 5. Verwendung ungeeigneter Testmethoden ergibt oft sehr grosse, wahrscheinlich auch unechte Rangfolge-Änderungen. Die Leichtigkeit der Anwendung und die Möglichkeit nachzuforschen sowie der groberen Anpassungen wegen umweltbedingter Heterogenität machen das Modell sehr geeignet für den Gebrauch in frühen Stadien von Kartoffel-Züchtungsprogrammen.
    Abstract: Résumé La sélection des premières générations dans les programmes d'hybridation de la pomme de terre est basée sur la haute héritabilité des caractères tels que la profondeur des yeux, la forme des tubercules, la couleur après friture, le poids spécifique, etc. Plus tard, la sélection met l'accent sur l'adaptation aux conditions d'environnement et, à ce stade, la plus grande attention est apportée au rendement. Cependant, un grand nombre de lignées est souvent impliqué et le matériel disponible pour chaque lignée est limité, empêchant des répétitions conformément au modèle standard d'expérimentation. Le modèle modifié (MAD) récemment proposé par Lin et Poushinsky (1983) comme méthode d'ajustement de l'hétérogénéité a été adapté dans des essais réalisés par le Prairie Cooperative Potato Breeding Program (Canada) en 1982 sur quatre localités. Dans le MAD, le contrôle des variétés disponibles en quantité permettant les répétitions est randomisé en une série de parcelles établies selon un modèle standard, ici un Carré Latin (figure 1). Pour les lignées-tests, les ajustements sont faits sur la base des valeurs fournies par les parcellestémoins, après une analyse de variance (ANOVA) adaptée au Carré Latin. Si les effets du rang et de la colonne sont grands par rapport à l'erreur de la parcelle entière, les valeurs des lignées-tests sans répétition sont ajustées en utilisant les corrections rang et/ou colonne estimées à partir des parcelles-témoins (méthode 1). Si l'effet de l'hétérogénéité du sol ne peut être éliminé par ce procédé, un index de fertilité pour chaque parcelle entière, évalué comme la différence entre la valeur de cette parcelle et la valeur moyenne de toutes les parcelles-témoins des autres variétés, est utilisé comme facteur d'ajustement (méthode 2) ou est traité comme une variable concomitante et les valeurs des lignées-tests sont alors ajustées par l'analyse de covariance (méthode 3). La moyenne du rendement total en tubercules et les carrés moyens du rendement total des parcelles-témoins des quatres localités d'essais, calcultés par l'ANOVA, sont présentés respectivement dans les tableaux 1 et 2. Les variances du rang et de la colonne sont grands (relativement à la parcelle entière) pour Edmonton I et II et pour Brooks II, suggérant la nécessité d'ajustements. L'observation des variances de l'erreur de Carman I et II et probablement de Brooks I montre une forte hétérogénéité multidirectionnelle entre parcelles puisque les variances des parcelles entières sont deux fois plus grandes que celles des sous-parcelles. Pour Outlook, aucune des variances n'est élevée par rapport à chacune des autres. Ces résultats suggèrent l'emploi d'un ajustement de type méthode 1 pour Edmonton I et II, de type méthode 3 pour Carman I et II, Brooks I et II et pas d'ajustement pour Outlook I. Des critères détaillés pour décider de la méthode d'ajustement à utiliser ont été étudiés. La variance moyenne estimée entre deux lignées-tests a été calculée pour chaque méthode et les méthodes ont été comparées en calculant les rapports de ces variances (tableau 3). Elles ont été aussi comparées par application des ajustements aux sousparcelles-témoins et pour l'ensemble des données ajustées au sein de chaque lignée (tableau 4). L'efficacité relative des méthodes d'ajustement a été calculée comme un rapport entre la variance de la donnée non ajustée et celle de la donnée ajustée. La variance de la donnée présentée dans le tableau 4 indique qu'en général l'ajustement par l'analyse de régression (méthode 3) provoque un petit changement ou cause un gain substanciel d'efficacité. Excepté pour Edmonton I, l'ajustement par les méthodes I et 2 apporte une augmentation marquée de la variance de l'ensemble interlignées, donc une perte d'efficacité. Les résultats importants de l'ajustement dans la sélection du matériel d'hybridation modifient le classement relatif des lignées-tests. La modification de ce classement, apportée par les trois méthodes d'ajustement est présentée dans le tableau 5. L'emploi des méthodes d'adjustement inappropriées conduit vraisemblablement souvent à des modifications de classement erronées. La facilité d'utilisation et la capacité d'investigation pour déceler l'hétérogénéité due aux conditions d'environnement fait de ce modèle un outil bien souhaitable durant les premiers stades du programme d'hybridation de la pomme de terre.
    Notes: Summary The modified augmented design, recently proposed as a method of adjusting for environmental heterogeneity where large numbers of cultivars are being tested in non-replicated plots, was used in a potato breeding programme at four locations in 1982. Of three methods of adjusting for soil variation, only the row-column and covariance adjustments worked efficiently. Decisions about which adjustment method to use could be based on easily computed mean squares. Changes in ranking due to adjustment of test cultivars were large in three of the seven trials, but application of inappropriate adjustment methods produced large and misleading ranking changes in some trials. Because of ease of use and ability to investigate environmental variation, the design can be recommended for use in early stages of potato breeding programmes.
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  • 52
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    Potato research 35 (1992), S. 111-125 
    ISSN: 1871-4528
    Keywords: potato ; reflectance ; ground cover ; light interception
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In nine field trials, the proportion of ground covered by potato canopy was estimated using near-infrared and visible reflectance measurements. The data set spanned a range of cultivars, treatments, soil types, soil moisture regimes and growing conditions that ranged from severely stressed to near-potential growth. Near-infrared reflectance of the canopy, corrected for soil reflectance (WDVI), was related to ground cover estimated by a trained expert with or without the use of a grid-frame. Different linear regressions between ground cover and WDVI for the early phase of growth and for the late phase, allowed the calculation of ground cover of potato from WDVI with anabsolute accuracy of 3.5–6.5%. The derived regression lines are expected to have a general applicability for potato grown on soils of temperate regions. It is concluded that reflectance measurement is an objective, fast and reliable method for estimating the proportion of ground covered by potato canopies.
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  • 53
    ISSN: 1871-4528
    Keywords: potato ; blackleg ; Solanum tuberosum L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Soft rot caused by Erwinia carotovora ssp. atroseptica is a major disease of stored potatoes. Since varietal resistance can contribute to control, the work reported was designed to find new sources of resistance among related tuber-bearing Solanum spp. True seeds were imported from two international collections and families were screened for resistance to tuber soft rot. Forty-eight resistant clones were found in 21 out of 100 accessions. These clones will be used in breeding programmes at the diploid or tetraploid level.
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  • 54
    ISSN: 1871-4528
    Keywords: environmental effects ; interspecific hybrids ; potato ; unreduced gametes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Solanum phureja (PP)xSolanum chacoense (CC) hybrid families (PC) were evaluated for pollen fertility and frequency of 2n pollen in two seasons in Morocco. PP clones produced high frequencies of 2n pollen, whereas CC clones produced none. The percentage of plants with 2n pollen ranged from 2 to 63% among 20 PC families and was consistent in some PC families over two growing seasons, whereas others varied between fall and spring growing seasons. The expected ratio of 2n to non-2n pollen-producers within a PC family based on a single recessive gene model [i.e. 1∶0 with CC homozygous dominant (PsPs) or 1∶1 with CC heterozygous (Psps)] was observed in only 5 of 20 progenies. Narrow sense heritability was 0.71, allowing gain from further selection. Only clones producing more than 10% 2n pollen exhibited more stable expressivity across seasons.
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  • 55
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    Potato research 40 (1997), S. 229-235 
    ISSN: 1871-4528
    Keywords: potato ; Solanum tuberosum L. ; bacteria ; dispersal ; field trial
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Plant-to-plant transmission of the bacterial ring rot (BRR) pathogen,Clavibacter michiganensis subsp.sepedonicus (Spieck. et Kott.) Skapt. et Burkh. of potato (Solanum tuberosum L.), was studied in field trials over a three year period. Healthy and infected seed tubers were planted 35 cm apart. In one treatment, a subsurface barrier was placed between the healthy and infected seed tubers separating the root systems of neighbouring plants. In this treatment, none of 216 plants grown from healthy seed tubers was infected at harvest, as determined by indirect immunofluorescence antibody staining (IFAS) with monoclonal antibodies. In the other treatment, no subsurface barrier was used. In this treatment, two of 368 plants (0.5%) grown from healthy seed tubers were infected at harvest. It is concluded that plant-to-plant transmission may occur but at very low frequency, and is unlikely to play a significant role compared with the potential of transmission by shared potato handling equipment.
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  • 56
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    Potato research 28 (1985), S. 65-70 
    ISSN: 1871-4528
    Keywords: Rhopalosiphum padi ; potato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Zusammenfassung In Laborversuchen übertrugen ca, 1% der GetreideblattläuseRhopalosiphum padi undMetopolophium dirhodum, nicht jedochSitobion avenae das Kartoffel-Y-Virus (PVY). 65% vonMyzus persicae übertrugen PVY.R. padi übertrugauch dann weniger häufig alsM. persicae, wenn die Aphiden bei Einzelentnahmen untersucht wurden.R. padi übertrug PVYO und PVYN von und auf die Tabaksorte White Burley und die Kartoffelsorte King Edward. Zwei oder zehn Minuten Einwirkung waren optimal fürM. persicae, um PVY zu erlangen, währendR. padi PVY häufiger nach längeren Entwirkungszeiten übertrug (Tabelle 1).R. padi undM. persicae beinhalteten PVY für eine ähnliche Zeitdauer (Tabelle 2). Sowohl alatae als auch apterae vonR. padi übertrugen unregelmässig, ebenso Nachkommen von individuellen Aphiden, welche PVY übertragen hatten.
    Abstract: Résumé En tests de laboratoire, environ 1% des pucerons des céréalesRhopalosiphum padi etMetopolophium dirhodum, aucun deSitobion avenae et environ 65% deMyzus persicae transmettent PVY.R. padi transmet également moins fréquemment queM. persicae lorsque les pucerons sont mis en comparaison par piqûre unique.R. padi acquiert PVYO et PVYN à partir des variétés de tabac White Burley et de pomme de terre King Edward et les transmet à ces deux mêmes variétés. Deux ou 10 minutes d'acquisition sont optimum pour queM. persicae acquiert PVY tandis queR. padi transmet PVY plus fréquemment après une plus longue période d'acquisition (tableau 1).R. padi etM. persicae conservent PVY dans les mêmes délais (tableau 2). Les ailés et les aptères deR. padi transmettent rarement PVY comme les descendants de pucerons ayant transmis PVY.
    Notes: Summary The cereal aphidRhopalosiphum padi transmitted PVYO and PVYN from and to both tobacco and potato. However, it transmitted much less frequently thanMyzus persicae, even when aphids making single probes were compared.R. padi andM. persicae retained PVY for a similar duration. Both alatae and apterae ofR. padi transmitted infrequently, as also did progenies of individual aphids that had transmitted PVY.Metopolophium dirhodum also transmitted PVY infequently butSitobion avenae did not transmit.
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  • 57
    ISSN: 1871-4528
    Keywords: potato ; analysis of binary data (success fraction) ; incomplete diallel cross ; combining ability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Zusammenfassung Dieser Artikel beinhaltet theoretische Prinzipien und Methoden für die statistische Analyse eines unvollständigen Diallels, bei der der Anteil von Pflanzen in jeder Nachkommenschaft mit einer höheren Expressivität einer Eigenschaft entsprechend zugeordnet wird. Dies wird als ‘Erfolgsfraktion’ bezeichnet (Formel 1) und ist in Formel 2 transformiert. Griffings Modell mit fixen Effekten (Formel 3) wird hierbei vorausgesetzt. Die Methode der gewichteten kleinsten Quadrate wurde zur Schätzung der Parameter und zur Varianzanalyse verwendet. Die Ergebnisse von Garretsen & Keuls (1973, 1978) und Keuls & Garretsen (1977), die eine Methode zur Analyse quantitativer Merkmale in unvollständigen diallelen Kreuzungen auf der Basis eines Vektorraumes vorschlugen, wurden modifiziert. Die Modifikation beruht auf der Multiplikation eines Schätzraumes mit der Gewichts-Diagonal-Matrix (Formel 5, 6 und 7). Die Varianzanalyse (Tab. 1) berücksichtigt die theoretische Fehlerstreuung (Gleichung 1). Dies erlaubt die Prüfung der Signifikanz aller Effekte in dem Modell, wie GCA (allgemeine Kombinationsfähigkeit). SCA (spezifische Kombinationsfähigkeit) und reziproke Effekte. Die theoretischen Ergebnisse werden an einem praktischen Beispiel aus einem Zuchtprogramm bei Kartoffeln (Solanum tuberosum) illustriert. Achtzehn Eltern wurden in Form eines unvollständigen Diallels gekreuzt (Tab. 2). Die Ergebnisse der Varianzanalyse zeigt Tabelle 3. Die Signifikanz der SCA-Varianz ist auf eine einzige Kreuzung (60968 x Pentland Marble) zurückzuführen. Die Schätzwerte der GCA-Effekte werden in Tabelle 4 und Abbildung 1 dargestellt. Weil der grösste Teil der genetischen Variation additiv ist, können die Schätzwerte der GCA-Effekte zur Vorhersage der nachkommenschaftswerte und deren Vergleich mit den beobachteten Werten verwendet werden. Die Korrelation zwischen diesen beiden Variablen war hoch (0,89) und wird in Abbildung 2 gezeigt. Die Methode ist auf jede Pflanzenart anwendbar, erfordert jedoch eine ausreichend grosse Zahl von Nachkommen und Vollgeschwistern innerhalb der Nachkommenschaft, wenn die Schätzungen zuverlässig sein sollen.
    Abstract: Résumé Cette étude présente les principes théoriques et les méthodes d'analyse statistique du croisement diallèle incomplet, où la variable est la proportion de plants de chaque descendance présentant une expression satisfaisante du caractère. Cette variable se nommera ‘la proportion de réussite’ (formule 1), qui est transformée selon la formule (2). Le modèle fixe de Griffing (formule 3) est supposé vérifié au cours de cette étude. On utilise la méthode des moindres carrés avec pondération, pour estimer les paramètres et pour l'analyse de variance. Les résultats de Garretsen & Keuls (1973, 78) et Keuls & Garretsen (1977), qui proposent une méthode d'analyse de caractères quantitatifs des croisement diallèles, ont été modifiés. Cette modification réside dans la multiplication de l'espace estimé, par la matrice diagonale de pondération (formules 5, 6 et 7). L'analyse de variance (tableau 1) prend en compte la variance résiduelle théorique (égalité 1). Cela permet d'évaluer la signification de tous les effets du modèle, c'est-à-dire de la capacité générale à la combinaison (GCA) de la capacité spécifique à la combinaison (SCA) et des interactions. Les résultats théoriques sont illustrés par un exemple de travail pris dans un programme de sélection de la pomme de terre (Solanum tuberosum). Dix huit parents sont combinés dans un croisement diallèle incomplet comme indiqué dans tableau 2. L'analyse de variance est indiquée dans tableau 3. La signification de la variation dûe à la SCA est attribuable à un seul croisement, 60 968 x Pentland Marble. Les estimations de la GCA sont portées dans tableau 4 et figure 1. Une grande partie de la variation d'origine génétique étant additive, il est possible d'utiliser les estimateurs de la GCA pour prévoir les valeurs de la descendance, et les comparer aux valeurs observées. La corrélation entre ces deux variables est hautement significative (0,89), et représentée dans figure 2. Cette méthode est applicable à toute culture, mais requiert und nombre suffisamment important de descendance et de complets à l'intérieur des descendances, pour que les estimateurs soient assez précis.
    Notes: Summary A method for the statistical analysis of binary data (derived from a retain, reject selection process) from incomplete diallel crosses is presented. Based on the fixed statistical model of Griffing (1956), formulae are derived which allow the estimation of parameters and the analysis of variance by weighted least squares. The method results from the application of vector theory to the work of Keuls & Garretsen (1977, 1978). The theory is illustrated by a worked example with data from an incomplete potato diallel cross involving 18 parents, although the method itself is applicable to any crop.
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  • 58
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    Potato research 29 (1986), S. 451-462 
    ISSN: 1871-4528
    Keywords: callus ; potato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Zusammenfassung Es wurde die Protoplastenproduktion derSolanum tuberosum L. spp.tuberosum-Sorten Russet Burbank, Butte, La Chipper, Superior, Lemhi, Green Mountain, Atlantic, Kennebec und Katahdin, ferner einer F1-Hybride,S. phureja × S. chacoense, JV-2, verglichen. Es kamen zwei Methoden der Isolation und Kultur zur Anwendung: Methode 1 als Modifikation der Methode von Grun & Chu (1978) und Methode 2 als Modifikation von Shepard (1980). Bei Anwendung beider Methoden ergaben sich signifikante Unterschiede unter den Klonen in der Protoplasten-Ausbeute (Tabellen 1 und 2). Der Zeiteffekt war nach Anwendung von Methode 1 hochsignifikant, nicht aber nach Methode 2 (Tabellen 2a und 2b verglichen mit 2c und 2d). Die Probengrössen bei Blattgewebe beeinflussten die Protoplastenproduktion signifikant; keine Proben ergaben mehr Protoplasten pro Gramm als grössere (Tabelle 2a). Der Klon JV-2 konnte nach der Methode von Grun & Chu (1978) erfolgreich kultiviert werden, die Sorten jedoch nicht. Bei Gebrauch der auf Shepard (1980) basierenden Methode entwickélten 6 Klone Kalli (Tabellen 3 und 4), während Atlantic und Kennebec normalerweise keine Zellwände bildeten und während der Kultur früh abstarben. Der von Katahdin verwendete Stamm versagte in neun Versuchen bei der Bildung steriler Präparationen, was auf interne Kontamination hindeutet. Protoplasten, bei 80 000, 40 000, 20 000 und 10 000/ml kultiviert, zeigten durchweg Zellteilungen (Tabelle 3) und entwickelten Kalli (Tabelle 4). Es ergaben sich signifikante Unterschiede zwischen den Klonen im Prozentsatz an Protoplasten, welche Zellwände bildeten und sich teilten (Tabelle 3), ferner im Ausmass des Kalluswachstums (Tabelle 4). Triebe entwickelten sich auf Kalli von JV-2, Russet Burbank und Lemhi, nicht aber auf Butte, Superior oder Green Mountain (Tabelle 5).
    Abstract: Résumé On compare la production de protoplastes des variétés deSolanum tuberosum L. ssp.tuberosum suivantes: Russet Burbank, Butte, la Chipper, Superior, Lemhi, Green Mountain, Atlantic, Kennebec, Katahdin et un hybride F1 deS. phureja × S. chacoense, JV-2. Deux méthodes d'isolement et de culture sont utilisées: la méthode 1, modification de celle de Grun & Chu (1978) et la méthode 2, modification de celle de Shepard (1980). On obtient des différences significatives entre les variétés comparativement aux deux méthodes (tableaux 1 et 2). Les effets sont hautement significatifs pour la méthode 1, mais non significatifs pour la méthode 2 (tableaux 2a et 2b comparés aux 2c et 2d). La tailie du prélèvement de tissu foliaire influence significativement la production de protoplastes; les petits échantillons produisent plus de protoplastes par gramme que les grands (tableau 2a). L'hybride JV-2 pourrait être cultivé avec succès par la méthode de Grun & Chu modifiée mais pas les variétés. Quand la méthode de Shepard est utilisée les protoplastes de six variétés produisent des cals (tableaux 3 et 4) tandis qu'Atlantic et Kennebec ne forment pas habituellement de parois cellulaires et meurent précocement durant la culture. Katahdin ne peut pas, dans neuf essais, donner des préparations stériles, ce qui suggère une contamination interne. Les protoplastes cultivés à la concentration de 80 000, 40 000, 20 000 et 10 000/ml ont des divisions cellulaires (tableau 3) et produisent des cals (tableau 4). Il existe des différences significatives entre variétés dans le pourcentage de protoplastes qui forment des parois et se divisent (tableau 3) et le taux de croissance des cals (tableau 4). Des pousses se forment sur les cals de JV-2, Russet Burbank et Lemhi mais pas sur ceux de Butte, Superior ou Green Mountain (tableau 5).
    Notes: Summary Protoplast production and regeneration of nine cultivars ofSolanum tuberosum spp.tuberosum and a hybridSolanum phureja × S. chacoense (JV-2) were compared by using methods based on Grun & Chu (1978) and Shepard (1980). The yield of protoplasts differed significantly among clones. Small leaf samples produced more protoplast per gram than large ones. Significant environmental effects on protoplast production when only the light that the plants received was controlled became non-significant when both light and temperature were controlled by use of a growth chamber. JV-2 was successfully cultured by the method based on Grun & Chu (1978), but the cultivars were not. Protoplasts of six clones developed calli, when the method based on Shepard (1980) was used, but cvs. Atlantic and Kennebec usually failed to form cell walls. Success in growth and development during each stage of protoplast and callus culture was clone specific. Calli of JV-2, Russet Burbank, and Lemhi developed shoots while those of Butte, Superior, and Green Mountain did not.
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  • 59
    ISSN: 1871-4528
    Keywords: incubation period ; length of longest sprout ; potato ; Solanum tuberosum L., virus diseases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The production of healthy and high yielding seed potatoes is closely related to the control of virus diseases and to other cultural practices, like those modifying the physiological age of tubers. Seed crops from cv. Bonaerense La Ballenera MAA, were defoliated early in 3 seasons, 1983/84, 84/85 and 85/86. After harvest, the seed tubers were stored in heaps in the field and, later, their sprouting capacity and physiological age, and their tuber yield were evaluated. Results showed that early haulm killing did not affect these variables nor diminish the quality of the seed potatoes obtained.
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  • 60
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    Potato research 35 (1992), S. 333-337 
    ISSN: 1871-4528
    Keywords: potato ; Solanum tuberosum L. ; nematodes ; eelworm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary An apparatus was developed for inoculating large numbers of experimental units with cysts ofGlobodera spp. The inoculator is adjustable and releases different and equal volumes of cysts from an internal reservoir. It was found to dispense accurate amounts of inoculum and to be much faster than manually counting cysts.
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  • 61
    ISSN: 1871-4528
    Keywords: Phoma foveata ; potato breeding ; potato ; Solanum tuberosum L. ; Solanum tuberosum subsp ; andigena
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A seedling progeny test for resistance to gangrene (Phoma foveata) was used to evaluate progenies from a 15×15 half diallel set of crosses, including 14 selfs and 25 reciprocal crosses, which was originally made to investigate the inheritance of resistance to late blight and cyst nematodes. Nine out of the 14 selfs were more susceptible than the crosses involving their parents, so that overall the selfs were slightly more susceptible than the crosses, thus providing evidence of non-additive gene action in favour of resistance. However, when the selfs were omitted from the analysis, all of the variation between progenies could be attributed to differences in the General Combining Abilities (GCAs) of their parents. The four parents with the best GCAs for gangrene resistance all had sizeable contributions fromSolanum tuberosum subsp.andigena in their pedigrees.
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  • 62
    ISSN: 1871-4528
    Keywords: antifungal proteins ; potato ; Fusarium wilt ; hydrolytic enzymes ; β-1,3-glucanases ; chitinases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Fusarium solani (Mart.) Sacc. f. sp.eumartii (Carp.) Snyder & Hansen is the causative agent of two important types of disease in potato (Solanum tuberosum) plants: wilt in stems and leaves and dry rot in tubers. The aim of this work was to study the molecular response of the potato to fungal attack. Micropropagated plantlets were tested, using a biological assay to detect antifungal proteins. An inhibitory activity of spore germination was detected in protein fractions from infected plantlets 7 days after inoculation with the pathogen. In addition, β-1,3-glucanase activity (glucanase III) was measured in protein fractions with antifungal activity. Induction of hydrolytic enzymes and antifungal activity in infected plantlets ofSolanum tuberosum subp.andigena suggests that it could be a suitable source of resistance genes.
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  • 63
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    Potato research 40 (1997), S. 59-68 
    ISSN: 1871-4528
    Keywords: pollen stainability ; anthers ; breeding ; potato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Male sterility in dihaploids ofSolanum tuberosum is often a barrier to their utilization in breeding and genetical studies. Although the male fertility of primary dihaploids (obtained directly from tetraploids) was generally low, a few were produced by the author which produced seed when used as pollen parents on female fertile dihaploids. The population of further generation dihaploids (from dihaploid intercrosses) produced from the showed a marked improvement in male fertility. Comparative data from measurements of different aspects of male fertility in dihaploids are presented. These showed that the weight of pollen per anther, the percentage of (iodine) stainable pollen and the number of seeds per berry were greater in further generation dihaploids than in primary dihaploids. It is suggested that interspecific crosses using dihaploids are not necessarily useful for increasing male fertility in diploid potatoes. The advantages of breeding at the diploid level withinS. tuberosum are discussed. Rare male-fertile dihaploids could be used to generate diploids with a high frequency of male fertility. These could then be used to cross with any other flowering dihaploids to combine characters at the diploid level, so exploiting the simpler genetic ratios associated with disomic inheritance.
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  • 64
    ISSN: 1572-9788
    Keywords: BSA ; Globodera rostochiensis ; potato ; RFLP ; SCAR ; Solanum vernei
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A population of diploid potato (Solanum tuberosum) was used for the genetic analysis and mapping of a locus for resistance to the potato cyst nematode Globodera rostochiensis, introgressed from the wild potato species Solanum vernei. Resistance tests of 108 genotypes of a F1 population revealed the presence of a single locus with a dominant allele for resistance to G. rostochiensis pathotype Ro1. This locus, designated GroV1, was located on chromosome 5 with RFLP markers. Fine-mapping was performed with RAPD and SCAR markers. The GroV1 locus was found in the same region of the potato genome as the S. tuberosum ssp. andigena H1 nematode resistance locus. Both resistance loci could not excluded to be allelic. The identification of markers flanking the GroV1 locus offers a valuable strategy for marker-assisted selection for introgression of this nematode resistance.
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  • 65
    ISSN: 1572-9788
    Keywords: biopanning ; chymotrypsin ; phage display ; potato ; proteinase inhibitor II ; trypsin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Potato proteinase inhibitor II (PI2) is a serine proteinase inhibitor composed of two domains that are thought to bind independently to proteinases. To determine the activities of each domain separately, various inactive and active domain combinations were constructed by substituting amino acid residues in the active domains by alanines. These derivatives were expressed as soluble protein inEscherichia coli and exposed on M13 phage as fusions to gene 3 in a phagemid system for monovalent phage display. Inactivation of both active domains by Ala residues reduced binding of phage to trypsin and chymotrypsin by 95%. Ten times more phage were bound to proteinases by domain II compared to domain I, while a point mutation (Leu5 → Arg) altered the binding specificity of domain I of PI2 phage from chymotrypsin to trypsin. The mutants were used to show that functional PI2 phage mixed with nonfunctional PI2 phage could be enriched 323 000-fold after three rounds of panning. Thus, these results open up the possibility to use phage display for the selection of engineered PI2 derivatives with improved binding characteristics towards digestive proteinases of plants pests.
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  • 66
    ISSN: 1572-9788
    Keywords: potato ; late blight ; quantitative resistance ; marker-assisted selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Late blight caused by the oomycete Phytophthora infestans is the most important fungal disease in potato cultivation worldwide. Resistance to late blight is controlled by a few major genes (R genes) which can be easily overcome by new races of P. infestans and/or by an unknown number of genes expressing a quantitative type of resistance which may be more durable. Quantitative resistance of foliage to late blight was evaluated in five F1 hybrid families originating from crosses among seven different diploid potato clones. Tuber resistance was evaluated in four of the families. Two of the families were scored for both foliage maturity and vigour. The five families were genotyped with DNA-based markers and tested for linkage with the traits analysed. QTL (quantitative trait locus) analysis identified at least twelve segments on ten chromosomes of potato having genes that affect reproducibly foliage resistance. Two of those segments also have major R genes for resistance to late blight. The segments are tagged by 21 markers that can be analyzed based on PCR (polymerase chain reaction) with specific oligonucleotide primers. One QTL was detected for tuber resistance and one for foliage vigour. Two QTLs were mapped for foliage maturity. Major QTL effects on foliage and tuber resistance to late blight and on foliage maturity and vigour were all linked with marker GP179 on linkage group V of potato. Plants having alleles at this QTL, which increased foliage resistance, exhibited decreased tuber resistance, later maturity and more vigour.
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  • 67
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    Molecular breeding 5 (1999), S. 417-428 
    ISSN: 1572-9788
    Keywords: QTLs ; tuberization earliness ; in vitro conditions ; sugars in leaf exudate ; marker-assisted selection ; potato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A relationship between quantitative trait loci (QTLs) detected for in vitro and greenhouse growing conditions was studied in a backcross population of 155 genotypes derived from a haploid potato (Solanum tuberosum) and a diploid wild species (S. berthaultii). Both plant height and tuberization earliness were characterized under two growing conditions. Main-effect QTLs and QTLs identified only through interaction were detected for each of the traits. For traits associated with plant height as well as for traits associated with early tuberization, the most significant QTL detected for greenhouse cultivated plants was also found when the population was grown in vitro. The most significant QTL for earliness of tuberization in vitro, which was located on chromosome 8, coincides with that detected for sucrose concentration in leaf exudate. The absence of a S. berthaultii allele was associated both with a higher amount of sucrose in the exudate and with earlier in vitro tuber formation. Epistasis was found to have a significant effect on all traits investigated. The QTL model that included main-effect QTLs and all significant interactions explained 83–88% of the total genetic variance for each of the developmental traits. The possibility of using an in vitro system combined with marker-assisted selection for preliminary selection of early tuberizing clones is discussed.
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  • 68
    ISSN: 1572-9788
    Keywords: potato ; late blight ; QTL ; Linkage mapping ; earliness ; vigour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Field resistance to Phytophthora infestans, the causal agent of foliage and tuber blight in cultivated potatoes, earliness (maturity) and vigour, were examined in a diploid segregating potato population grown in replicated trials over three consecutive growing seasons. A genetic linkage map of this population was constructed in parallel using PCR-based SSR, AFLP and CAPS markers. Analysis of the trait scores alongside the marker segregation data allowed the identification of regions of the genome which were significantly correlated with components of the respective characters. The most significant associations for all four traits were with marker alleles on potato linkage group V originating from the male (susceptible) parent. In the case of foliage resistance to late blight, the positions of the majority of the effects, which were located on eleven of the twelve potato linkage groups, have been detected in previous [16] and parallel studies [21]. The absence of Solanum demissum-derived R genes for hypersensitive response to late blight and the co-localisation of QTL for resistance, vigour and earliness suggest that developmental and/or physiological factors play a major role in determining the level of foliage resistance in this population. In contrast with previous findings, a negative correlation was found between foliage and tuber blight resistance.
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  • 69
    ISSN: 1572-9788
    Keywords: late blight ; Phytophthora infestans ; potato ; resistance,Solanum berthaultii ; Solanum tuberosum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Under controlled field conditions, a Solanum backcross population segregated for resistance to Phytophthora infestans. The population (`BCT') had been derived previously by crossing the Solanum tuberosum dihaploid USW2230 × Solanum berthaultii PI473331 to obtain the hybrid M200-30, and then backcrossing the hybrid to the S. tuberosum dihaploid HH1-9. Resistance was assessed from analyses of epidemics in small plots of each individual genotype, and data were recorded as area under the disease progress curve (AUDPC). The parents of the original cross (USW2230 and a selection from PI473331) were not included in the test, but the hybrid was incompatible and HH1-9 was compatible with the tester strain of P. infestans (US-8 lineage). Somewhat more than half of the progeny also were incompatible with the tester strain, indicating the presence of an R gene. This gene segregated from the S. berthaultii parent and mapped 4.8 cm from the RFLP marker TG63 on chromosome 10. We deduce that the R gene is not R-1, R-2, R-3, R-6, or R-7 and is probably not R-4, R-5, or R-10. Among the remaining, compatible progeny, there was a wide range of quantitative resistance. All were more resistant than the susceptible cultivar Superior, and most individuals were much more resistant than the moderately resistant cultivar Kennebec. AUDPC values among the sub-population of compatible genotypes ranged from about 400 to 1500 units the first year and from 400 to 1760 units the second year. At least five quantitative trait loci (QTLs) were detected in this sub-population in both 1997 and 1998, including one detected through segregation of alleles from both the hybrid parent and the recurrent S. tuberosum parent. A model of main and epistatic effects explained 56% and 66% of the variation observed for quantitative resistance to late blight in 1997 and 1998, respectively. Several of the QTLs for late blight resistance were located in regions of the genome to which QTLs for late maturity have previously been mapped.
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  • 70
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    Molecular breeding 4 (1998), S. 313-319 
    ISSN: 1572-9788
    Keywords: antibody ; endoplasmic reticulum ; phytofarming ; potato ; production ; scFv
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Potato tubers have been successfully used for high-level production of a recombinant single-chain Fv (ScFv) antibody. Ubiquitous high-level expression was achieved under control of the CaMV 35S promoter through retention of the scFv protein in the endoplasmic reticulum. Recombinant antibodies accumulated up to 2% of total soluble tuber protein. After 1.5 years of tuber storage at 4 °C still half of the amount of scFv present in freshly harvested tubers was detectable. Its specific activity did not decrease during tuber storage. Recombinant protein could be efficiently purified from crude extracts by affinity chromatography.
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  • 71
    ISSN: 1572-9788
    Keywords: AFLP ; genetic relationships ; potato ; RAPD ; SSR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The application of AFLPs, RAPDs and SSRs to examine genetic relationships in the primary northwestern European cultivated potato gene pool was investigated. Sixteen potato cultivars were genotyped using five AFLP primer combinations, 14 RAPD primers, and 17 database-derived SSR primer pairs. All three approaches successfully discriminated between the 16 cultivars using a minimum of one assay. Similarity matrices produced for each marker type on the basis of Nei and Li coefficients showed low correlations when compared with different statistical tests. Dendrograms were produced from these data for each marker system. The usefulness of each system was examined in terms of number of loci revealed (effective multiplex ratio, or EMR) and the amount of polymorphism detected (diversity index, or DI). AFLPs had the highest EMR, and SSRs the highest DI. A single parameter, marker index (MI), which is the product of DI and EMR, was used to evaluate the overall utility of each marker system. The use of these PCR-based marker systems in potato improvement and statutory applications is discussed. Abbreviations: PCR, polymerase chain reaction; AFLP, amplified fragment length polymorphism; RAPD, randomly amplified polymorphic DNA; DNA, deoxyribonucleic acid; EMR, effective multiplex ratio; DI, diversity index; MI, marker index; RFLP, restriction fragment length polymorphism.
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  • 72
    ISSN: 1572-9788
    Keywords: Acidothermus cellulolyticus ; cellulase ; dual-crop production ; E1 endoglucanase ; expression optimization ; potato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Optimization of Acidothermus cellulolyticus endoglucanase (E1) gene expression in transgenic potato (Solanum tuberosum L.) was examined in this study, where the E1 coding sequence was transcribed under control of a leaf specific promoter (tomato RbcS-3C) or the Mac promoter (a hybrid promoter of mannopine synthase promoter and cauliflower mosaic virus 35S promoter enhancer region). Average E1 activity in leaf extracts of potato transformants, in which E1 protein was targeted by a chloroplast signal peptide and an apoplast signal peptide were much higher than those by an E1 native signal peptide and a vacuole signal peptide. E1 protein accumulated up to 2.6% of total leaf soluble protein, where E1 gene was under control of the RbcS-3C promoter, alfalfa mosaic virus 5′-untranslated leader, and RbcS-2A signal peptide. E1 protein production, based on average E1 activity and E1 protein accumulation in leaf extracts, is higher in potato than those measured previously in transgenic tobacco bearing the same transgene constructs. Comparisons of E1 activity, protein accumulation, and relative mRNA levels showed that E1 expression under control of tomato RbcS-3C promoter was specifically localized in leaf tissues, while E1 gene was expressed in both leaf and tuber tissues under control of Mac promoter. This suggests dual-crop applications in which potato vines serve as enzyme production `bioreactors' while tubers are preserved for culinary applications.
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  • 73
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    Mathematical geology 12 (1980), S. 489-522 
    ISSN: 1573-8868
    Keywords: mercury ; resource estimation ; production data
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract A simple technique based on historical records of tonnage and grade of ore produced provides a means for calculating how much of a mineral product will be available in the future at various average grades. Estimates made on this basis are independent of geologic considerations or changing economic and political factors, although they are based on mining history, which was largely determined by these factors. The relatively minor element, mercury, was used for the test case reported here, but the method has been found applicable to forecasts of resources for other mineral products. Mercury resources available in ore in which the average grade is as low as 0.1% are estimated to be 53 ×10 6 kg (1.5 ×10 6 flasks) for the United States and 1551 ×10 6 kg (45 ×10 6 flasks) for the world; this amount is more than adequate to meet predicted demand to the year 2000. The expectable price of mercury in 1978 dollars at this 0.1% grade is projected to be $58.75 per kg ($2,025 per flask), but at a 10% annual inflation rate, it would be more than $12,000 per flask. To satisfy just the projected U.S. demand for mercury by 2000, the price is calculated to be $48.96 per kg ($1,688 per flask) in 1978 dollars at an average annual grade of 0.12%.
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  • 74
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    European journal of plant pathology 105 (1999), S. 753-760 
    ISSN: 1573-8469
    Keywords: hypersensitive-like response ; Phytophthora infestans ; potato ; proteases ; Solanum tuberosum ; zoospores
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The proteolytic activity present in the extracellular preparation (ECP) from suspension media of infective structures of the late blight pathogen Phytophthora infestans was partially characterized. The proteolytic activity was analyzed in gelatin-containing SDS-PAGE. A discrete band of digested gelatin was visualized at approximately 45 kDa in ECPs from zoospores and germinating cysts media. Treatment of ECP with the protease inhibitor phenylmethylsulfonyl fluoride (PMSF) or incubation at 100°C for 5 min completely abolished the proteolytic activity in the zymograph assay. When microinjected in potato leaves, ECP induce localized necrosis within 24 h post inoculation. This necrosis appeared in potato and was not visible in two non-host plants. Moreover, the necrosis seems to be dependent on active host metabolism. Treatments of ECP with Proteinase K, PMSF and boiling inhibited their ability to induce the necrotic response. These results suggest a correlation between, proteolytic and necrosis-inducing activities in ECP. A preliminary characterization with protease inhibitors suggests that the ECPs contain serine protease(s).
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  • 75
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    European journal of plant pathology 101 (1995), S. 705-709 
    ISSN: 1573-8469
    Keywords: image analysis ; microsclerotia ; potato ; Solanum tuberosum ; Verticillium dahliae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A procedure for the quantification of microsclerotia ofVerticillium dahliae with an image analysis system was compared with counting by eye. Colonised potato plant material was used from plants grown in pathogen-free soil in a greenhouse and from twelve crops (including four potato cultivars) grown outdoors in pots filled with pathogen-free soil under natural conditions. The values obtained from the potato material from the greenhouse were comparable for both methods. Variation in the results mainly resulted from sampling errors. The numbers of microsclerotia in plants grown outdoors were overestimated by image analysis for most crops. The source of the error was related to the presence of plant and soil particles that did not discolour during boiling of the samples in sodium hydroxide. Image analysis was a suitable and reliable method for assessing the number of microsclerotia only in potato haulm samples from plants grown in pathogen-free soil in the greenhouse.
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  • 76
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    European journal of plant pathology 104 (1998), S. 263-269 
    ISSN: 1573-8469
    Keywords: cotton ; potato ; vegetative comptability ; Verticillium dahliae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Nitrate-nonutilizing (nit) mutants were used to determine vegetative compatibility among 34 isolates of Verticillium dahliae from cotton, potato, olive, eggplant, chrysanthemum and tomato from 12 sites in Israel. Based on the formation of complementary heterokaryons, 33 isolates were assigned to two vegetative- compatibility groups (VCGs): one VCG contained 15 isolates from cotton, eggplant, chrysanthemum and olive; and the other VCG contained 18 isolates from potato, olive and cotton. The status of an additional isolate from tomato, which was compatible with both VCGs, remained unclear. In a limited pathogenicity test with 10 isolates, two (from tomato and eggplant) were pathogenic on tomato, eggplant and cotton; most isolates from cotton were pathogenic on cotton and eggplant only; and one from cotton was non-pathogenic. Fewer isolates were pathogenic on tomato than on cotton or eggplant. The diversity of vegetative compatibility found in our V. dahliae collection is comparable to that found in studies of American populations.
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    European journal of plant pathology 94 (1988), S. 243-252 
    ISSN: 1573-8469
    Keywords: potato ; stem canker ; disease severity ; infection cushions ; runner hyphae ; ethoprophos ; aldicarb ; oxamyl ; side-effects ; non-target effect ; scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Samenvatting Het infectieproces vanRhizoctonia solani AG-3 werd bestudeerd op aardappelspruiten, cv. Bintje, in een klimaatcel bij 15†C. Aanvankelijk groeide de schimmel met runnerhyfen voornamelijk in de lengterichting van de spruit. Via SEM kon waargenomen worden, dat de hyfen hierbij vooral over de begrenzingen van de epidermiscellen groeiden. Het mycelium vormde veel zijvertakkingen, bestaande uit iets gezwollen korte cellen, welke voornamelijk halverwege op het ondergrondse deel van de spruit gevormd werden. Een dichte massa van deze cellen vormde een infectiekussentje. Lesies, welke vanaf vijf dagen na inoculatie werden waargenomen, bevonden zich slechts onder spruitoppervlak bezet met infectiekussentjes. De lesiegrootte was recht evenredig met het spruitoppervlak dat bezet was met infectiekussentjes. De diepte van de lesies reikte tot aan de vaatbundels. De spruit werd alleen door de schimmel gekoloniseerd in gezond epidermisweefsel onder het infectiekussentje en in necrotisch weefsel. Enkele dagen na verschijning van lesies vormde R.solani bruin, niet infectieus, mycelium op en rondom de lesies. Aldicarb had geen effect op het infectieproces. Ethoprophos vertraagde de opkomst en verhoogde het aantal tot ontwikkeling gekomen spruiten per knol in gestoomd zand. Direct na opkomst had ethoprophos echter een sterk groeistimulerend effect. Ethoprophos vertraagde de lesievorming en reduceerde de lesiegrootte, vergeleken met onbehandelde planten. Oxamyl vertoonde deze effecten in geringere mate. Daar de lesiegrootte direct gecorreleerd blijkt met de grootte van het infectiekussentje, mag verwacht worden dat elke beïnvloeding van de ontwikkeling van het mycelium van R.solani, bijvoorbeeld door pesticiden of antagonisten, een verandering van de lesiegrootte ten gevolge heeft.
    Notes: Abstract The infection process ofRhizoctonia solani AG-3 was studied on potato sprouts, cv. Bintje, in growth chamber trials at 15 °C. Initially hyphae ofR. solani grew predominantly in the longitudinal direction of the sprouts (runner hyphae). They tended to follow the junctions between epidermis cells as was observed by SEM. The hyphae formed side-branches mainly half-way of the subterranean parts of the sprouts. They branched several times with short swollen cells to form infection cushions. Lesions developed only underneath the infection cushions and were first observed five days after inoculation. The necrotic area was proportional to the area covered with infection cushions on the sprouts. Depth of the lesions could extend up to the vascular bundle. Sprouts were colonized only in healthy tissue in the epidermal layer underneath the infection cushion and in necrotic tissue. A few days after appearance of the lesions,R. solani formed brown, uninfective mycelium on and in the circumference of these lesions. Aldicarb did not influence any part of the infection process. Ethoprophos delayed the emergence of sprouts, but increased the number of sprouts per tuber. As soon as sprouts had emerged, growth was considerably promoted by ethoprophos. Ethoprophos delayed the appearance of lesions and reduced their size. Oxamyl showed the same effects to a smaller extent. As the size of lesions appears to be proportional to the size of the infection cushions, any agents that change the size of the infection cushions, such as pesticides or antagonists, may alter the severity of the disease.
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  • 78
    ISSN: 1573-5036
    Keywords: cell sap ; chloride ; fertilizer ; potassium ; potato ; Solanum tuberosum L. ; solute potential ; source: sink ; sulphate ; tuber
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In pot experiments with Solanum tuberosum L. (cv Saturna) the application of KCl as compared to K2SO4 delayed tuber development. The solute composition of leaves of the KCl treated plants was significantly lower in K+ and NO3 -, but higher in Mg2+, Ca2+ and Cl-. Since the solute potential in the KCl treated plants was more negative and associated with a higher water content, a higher turgor pressure can be assumed. This could explain the enhanced shoot growth observed with KCl. Application of K2SO4, on the other hand, accelerated the development of tubers. This might result from a less competitive shoot sink in K2SO4 treated plants and a stimulated phloem loading and translocation of assimilates by higher concentrations of leaf-K.
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  • 79
    ISSN: 1573-5036
    Keywords: enzyme activity ; potassium nutrition ; potato ; Solanum tuberosum L. ; starch synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Starch synthesis in potato tubers grown at varied K nutrition 0.1 (K1), 0.25 (K2) and 1.0 mmol K L- nutrient solution (K3) was investigated with particular regard to the activity of selected enzymes (sucrose synthase, UDP-D-glucose pyrophosphatase, starch phosphorylase, amylases) in dependence on tuber K content. Allocation of K to the tubers was nearly the same in all treatments. The activity of enzymes related to tuber K content did not differ significantly. Starch and K content of tubers increased with progressing age, whereas a decrease was observed in growth rate, starch synthesis per day and K uptake per day. Positive correlations between the rates of K uptake, starch production and growth indicate that the dynamic phase of K supply to the tubers is of greater importance for starch synthesizing processes than the influence of total K content.
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  • 80
    ISSN: 1573-5036
    Keywords: chemical compounds ; field and pot trials ; mathematical optimization model ; mineral nutrients ; potato ; Solanum tuberosum L. ; threshold values ; tuber yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Data of yield characteristics and the main chemical compounds of potato tubers, received from special NPK-fertilized pot and field trials, were individually evaluated by multiple regression analysis. The best suited mathematical functions, including linear, quadratic and interactive terms of N-, P- and K-concentrations in tuber dry matter, were integrated as independent variables into the models and the SUMT-method was applied for the nonlinear programming. Particular nutrient requirements could be derived from different NPK-ratios which were obtained by optimization. These ratios led to maximum tuber yield (=objective function) while at the same time observing special threshold values (e.g. nitrate) or limiting indices (=constraints) of tuber quality. By means of simulation it was possible to demonstrate characteristic differences between the effect of N-fertilization and varied N-concentrations on tuber yield and composition. Calculation of dependent variables by fixed NPK-ratios of the tubers resulted in excellent correspondence of the values for several parameters with the predictions made by both models, which were based on pot or field experiments.
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  • 81
    ISSN: 1573-8469
    Keywords: breeding ; genetic variation ; potato ; resistance management ; selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In 1995 two fields in the Netherlands, naturally infested withMeloidogyne hapla (Wageningen) andM. fallax (Baexem), were used to evaluate resistant and susceptibleSolanum genotypes under natural conditions. In April, genotypes were planted in circular microplots. Soil samples were taken and analyzed for the occurrence of second-stage juveniles every six weeks. From August onwards, large differences between resistant and susceptible genotypes in numbers of juveniles were found in the soil. For all resistant wildSolanum genotypes the level of infection in soil at the end of the growing season in October was equal to or lower than at the beginning. Glasshouse experiments were performed with the same genotypes and nematode populations (i.e. originally derived from these fields) and the results were comparable with the observations from the field. It is concluded that resistance, as selected in glasshouse trials, corresponds well with resistant behaviour in the field and that it is worthwhile to transfer the resistance from theseSolanum sources to commercial potato cultivars for successful control of root-knot nematodes.
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  • 82
    ISSN: 1573-8469
    Keywords: Phytophthora infestans ; potato ; wild Solanum spp. ; resistance ; detached leaves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Physiological and molecular research on resistance responses of Solanum tuberosum cultivars and partially resistant Solanum species to Phytophthora infestans requires a reliable resistance test that can be used in the laboratory. Laboratory tests performed on detached leaves and intact plants were compared with field tests for similarity of late blight reactions. Detached leaves from field-grown plants were as resistant as detached leaves from climate chamber-grown plants when challenged with P. infestans. However, detached leaves incubated in covered trays at high relative humidity were more susceptible than detached leaves kept in open trays or leaves on intact plants. The incubation conditions of detached leaves in covered trays rather than detachment itself appeared to affect the resistance expression. Detached leaves of some wild Solanum genotypes became partially infected, whereas intact plants were completely resistant when inoculated. Inoculation of leaves on intact plants, however, resulted in lower infection efficiencies. These limitations should be taken into account when choosing the appropriate inoculation method for specific purposes. For resistance screening, laboratory tests proved to be a good alternative for field tests. The ranking of resistance levels for twenty plant genotypes was similar under laboratory and field conditions.
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  • 83
    ISSN: 1573-8469
    Keywords: metalaxyl ; late blight ; fungicide resistance ; potato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Samenvatting Resistentie tegen fenylamiden in dePhytophthora infestans populatie in Nederland nam af van een niveau van 77% van het aantal monsters met resistente stammen in 1980 tot 0% in 1986 in relatie tot een verminderd gebruik van metalaxyl, het enige fungicide uit de groep van fenylamiden, dat tot nu toe in dit land voor de bestrijding van de aardappelziekte is toegelaten. Het gebruik van metalaxyl nam af omdat het als afzonderlijk fungicide en in een mengsel met preventieve fungiciden ter bestrijding van de aardappelziekte commercieel niet beschikbaar was vanaf 1981 tot het midden van het groeiseizoen van 1984. Toen het fungicide weer beschikbaar kwam in combinatie met mancozeb in augustus 1984 en in 1985 in een combinatieprodukt met maneb en fentinacetaat, gebruikten de telers het in deze jaren slechts tweemaal per seizoen en alleen wanneer van preventieve middelen onvoldoende resultaat werd verwacht vanwege de aanwezigheid van de ziekte in het gewas bij kritieke weersomstandigheden. In 1986 werd het combinatieprodukt nauwelijks gebruikt vanwege de lage ziektedruk. In 1987 en 1988 werden in respectievelijk 16% en 42% van het aantal monsters resistente stammen aangetroffen. Een op grote schaal tweemalig gebruik van het combinatieprodukt in alle aardappelteeltgebieden ter bestrijding van een hevige epidemie wordt hiervoor verantwoordelijk geacht. In partijen pootgoed die in 1988 waren geoogst varieerde het percentage zieke knollen waaruit een resistente stam kon worden geïsoleerd van 13% voor de gebieden waar het pootgoed voornamelijk wordt geteeld voor consumptieaardappelen en aardappelen voor de verwerkende industrie tot 41% voor het teeltgebied van fabrieksaardappelen. Het, gedurende meerdere jaren, intensievere gebruik van het combinatieprodukt in dit gebied waar de pootgoedteelt vaak op het eigen bedrijf plaats vindt, is hiervoor waarschijnlijk verantwoordelijk. Toepassing van het combinatieprodukt leidde in de meeste jaren tot een verschuiving in de populatie naar meer resistentie, gezien de hogere frequentie waarmee resistente stammen werden aangetroffen in blad- of knolmonsters van behandelde percelen. De strategie die door de Nederlandse aardappeltelers wordt gevolgd voor het tegengaan van fenylamide resistentie inP. infestans inhoudende een beperkt gebruik van maximaal twee keer onder kritische omstandigheden, heeft tot nu de resistentie op een zodanig niveau weten te houden dat van metalaxyl nog een bijdrage kan worden verwacht aan de effectiviteit van het combinatieprodukt. De Toename in resistentie in 1988 na twee seizoenen met een zware epidemie geeft evenwel aan dat de werkzaamheid van metalaxyl zal verminderen indien elk jaar de aardappelziekte in hevige mate voorkomt en dezelfde strategie wordt gevolgd ten aanzien van het gebruik van fenylamide combinatie produkten.
    Notes: Abstract Resistance to phenylamide fungicides in thePhytophthora infestans population in the Netherlands decreased from a level of 77% of the samples containing resistant strains in 1980 to 0% in 1986 with decreasing use of metalaxyl, the only phenylamide fungicide registered for use against late blight in this country. Use of metalaxyl decreased because the fungicide alone and combinations of metalaxyl with preventive late blight fungicides were not commercially available from 1981 through the first part of the potato growing season of 1984. When metalaxyl was made available again in August 1984 in a mixture with mancozeb and from 1985 in a mixture with almost full rates of maneb and fentinacetate its use remained limited because growers were advised to apply the combination only two times per season in critical situations only to control the severe late blight epidemics of 1984 and 1985. Moreover application on seed potato crops was not allowed. In 1986 the combination was hardly used because the mild epidemic was easily controlled by preventive compounds only. In 1987 and 1988 phenylamide resistance increased to 16 and 42%, respectively, inherent to a general use of the combination in both years in most potato growing regions of up to two applications to combat a very severe epidemic. In lots of seed potatoes harvested in 1988 the percentage of blighted tubers yielding resistant isolates significantly differed from 13% for regions where seed potatoes are predominantly grown for table and processing crops to 41% for a region where predominantly starch potatoes are grown, both as seed and production crops. The more intensive use of metalaxyl combinations in the latter area through the years as compared to the other areas is assumed to be responsible for the higher incidence of resistance. In most years application of the combination induced a significant shift in the population to resistance as is indicated by the higher frequency at which resistant isolates were present in leaf samples taken from treated fields or tuber samples from the harvested crop. The strategy adopted by Dutch potato growers to combat phenylamide resistance in late blight, involving limited use of metalaxyl mixtures to a maximum of two times in critical situations only, has kept up to now resistance in the population at a level at which metalaxyl still significantly contributes to the efficacy of the combination in controlling the disease. Never-theless the observed increase in resistance in the population of 1988 after two consecutive late blight years indicates that this may change if severe epidemics occur each year.
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  • 84
    ISSN: 1573-5036
    Keywords: herbicides ; phyllosphere ; potato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Three herbicides, Benthiocarb, 2,4-D and Fluchloralin were evaluated for their effect on leaf surface microflora of potato. In general, the application of herbicides resulted into a drop in the microbial population. Throughout the study herbicide treated leaves harboured less population compared to the untreated ones.
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  • 85
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    Plant and soil 154 (1993), S. 139-144 
    ISSN: 1573-5036
    Keywords: fertilizer ; optimum application ; plant nitrogen ; potato ; soil nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Mathematical models of crop growth can provide estimates of the potential yield of potato, and also the minimum, critical N-concentration required, [Nc], to attain that yield. Efficient use of nitrogen requires that the crop incorporates sufficient nitrogen to attain its potential yield and that excess uptake is avoided. Predictions of the rate of supply of nitrogen from the soil are imprecise and so it has been difficult to estimate accurately the required application of fertilizer-N. Our work has shown the feasibility of using the growing crop as a monitor of the rate of supply of N from the soil. Using a low initial application rate of N at planting and monitoring uptake rate, we can estimate the contribution from the soil, and couple that information with estimates of yield and the related [Nc] to give an estimate of the requirement for supplementary applied-N. The method can be seen, therefore, as a means to determine the size of a second or subsequent part of a split application of fertilizer. This approach avoids much of the uncertainty over the fate of applied nitrogen and should offer growers the double benefits of economic use of fertilizer and of minimizing leaching losses. Further, by tailoring applications of N-fertilizer to the crop's requirements the grower will be better able to ensure the quality considerations in his crop.
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  • 86
    ISSN: 1573-5036
    Keywords: PGPR ; plant growth promotion ; potato ; Pseudomonas ; marker stability ; rhizobacteria ; rifampicin resistance ; root colonization ; soil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The stability of rifampicin resistance in plant growth-promoting Pseudomonas putida strain WCS358 was studied in potato rhizosphere in the field. Three out of seven rifampicin-resistant mutants of strain WCS358 were selected in this study. Their specific growth rate, competitive growth in liquid medium and colonization of potato roots in non-sterile soil, was comparable to that of their parental strain. These rifampicin-resistant mutants were used to treat potato seed tubers, which were thereafter sown in the field. To test the stability of the rifampicin resistance in the field, about 1200 fluorescent Pseudomonas isolates obtained from underground plant parts at 82, 95, 109 and 130 days after seeding, were tested for rifampicin resistance and for agglutination with an antiserum specific for strain WCS358. Ail fluorescent Pseudomonas isolates that showed a positive agglutination reaction with the antiserum, were also rifampicin-resistant. Twelve agglutination-positive isolates, selected at random, were all identified as strain WCS358 from patterns of lipopolysaccharides after sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Thus, rifampicin resistance seems to be a stable marker in the mutants of strain WCS358 tested, also under field conditions. It is concluded that rifampicin resistance can be used as a reliable marker for ecological studies on rhizosphere pseudomonads.
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  • 87
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    Euphytica 108 (1999), S. 137-144 
    ISSN: 1573-5060
    Keywords: ELISA ; genetic modification ; PLRV ; potato ; Solanum phureja ; virus resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Strong resistance to accumulation of potato leafroll virus (PLRV) was identified in a clone of the diploid potato species Solanum phureja (cv. ‘Egg Yolk’, clone 5010) using a quantitative enzyme-linked immunosorbent assay (ELISA). The resistance is expressed very strongly in leaf tissue (virus could not be detected in leaves of some plants although other tissues were infected) but less strongly in petiole and stem tissue of infected plants. The titre of PLRV in leaves of S. phureja (5010) is approximately 2%, or less, of the titre in S. tuberosum cv. Maris Piper. The pattern of virus accumulation in different tissues of S. phureja (5010) and the distribution of virus-infected cells in phloem bundles suggest that this resistance is different to a similar form of resistance to PLRV accumulation previously identified in clones of Solanum tuberosum. Plants of S. phureja (5010) were transformed with the coat protein gene of potato leafroll virus (PLRV). Transgenic lines of S. phureja (5010) expressing transgene RNA transcript were no more resistant to aphid-borne infection with PLRV or to virus accumulation than were non-transgenic lines.
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  • 88
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    Euphytica 25 (1976), S. 663-670 
    ISSN: 1573-5060
    Keywords: Solanum tuberosum ; potato ; coagulable protein ; screening method ; breeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary From tubers of 34 varieties of Solanum tuberosum, extracts were prepared and analysed for crude protein and coagulable protein by the Kjeldahl method. Content of coagulable protein was 0.37–1.24%. From the same material, juice was prepared with a juice centrifuge and analysed for coagulable protein by the Kjeldahl and microbiuret method. The average amount of coagulable protein in the juice was 81.8% of the total coagulable protein. The correlation coefficient between coagulable protein in the juice and total coagulable protein was 0.956. The correlation coefficient between Kjeldahl and microbiuret data for coagulable protein in the juice was 0.956. Analysis of tuber juice by the microbiuret method is recommended as a rapid screening technique for coagulable protein. Relationships between protein data of the 34 varieties and earliness, yield and content of dry matter were analysed statistically. Content of coagulable protein in fresh material correlated with content of dry matter (rs=−0.756), yield of fresh potatoes (r=−0.615) and earliness (r=−0.361) but not significantly with yield of dry matter (rs=−0.309). Coagulable protein in dry matter correlated with fresh yield (r=−0.525), but not significantly with content of dry matter (r=−0.260), yield of dry matter (r=−0.131) and earliness (r=−0.054). Path coefficient analysis showed that 67% of the variation in coagulable protein in fresh material was statistically determined by earliness, content of dry matter, fresh yield and content of uncoagulable protein in fresh material, whereas only 34% of the variation in content of coagulable protein in dry matter was determined by these components. A high content of coagulable protein in fresh or dry matter can be combined with early maturity and with high yield of dry matter. Coagulable protein in dry matter seems to be a more suitable criterion of selection than coagulable protein in fresh material.
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  • 89
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    Euphytica 25 (1976), S. 313-320 
    ISSN: 1573-5060
    Keywords: Solanum chacoense ; deformed flower ; genetics ; trisomics ; potato ; ancuploid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The gene df (deformed flower), which is expressed as short anther in sensitive cytoplasm, has been incorporated into the trisomic series of S. chacoense Bitt. The cytoplasmic sensitivity and genotypes for the gene df were tested in the original trisomics and their parents. Two diploid parents were found to be homozygous dominant for Df, while one was homozygous recessive. All the parents and trisomics tested had resistant cytoplasm. Six trisomics were heterozygous for df, segregating with a 1:1 ratio when they were crossed to the homozygous testers ([df s]dfdf). When the F1 trisomics (trisomics x [Df r]dfdf) were crossed to the homozygous testers, nine of the 13 trisomics segregated with a 1:1 ratio, three with a 0:1 ratio (all deformed) and one trisomic (V1682.3) with a 2:1 ratio. All the parents of the trisomic V1682.3 were homozygous dominant for Df. This clone is believed to be trisomic for the gene df.
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  • 90
    ISSN: 1573-5060
    Keywords: Solanum tuberosum ; potato ; Solanum verrucosum ; monohaploid ; chromosome doubling ; parthenogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Dihaploid and dihaploid derived clones of Solanum tuberosum and diploid genotypes of S. verrucosum produced 85 viable monohaploids by female parthenogenesis. All were induced using diploid S. phureja clones, homozygous for embryo spot, as pollinator. Frequency of S. tuberosum monohaploids per 100 berries was rather constant in three successive years (14, 17 and 17 respectively). No male and female fertility was found in flowering monohaploids. Colchicine-induced chromosome doubling yielded homozygous s. tuberosum diploids with low pollen quality but good seed fertility. Two diploid self-incompatible species (S. multidissectum and S. berthaultii) produced no monohaploids. The presence of genes for female parthenogenesis in some dihaploids is discussed.
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  • 91
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    Euphytica 26 (1977), S. 585-600 
    ISSN: 1573-5060
    Keywords: Solanum ; potato ; polyploidy ; 2n gametes ; sexual polyploidization ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The extent and pattern of polyploidy in the tuber-bearing Solanums varies among the many taxanomic series that have been identified in this subsection of Solanum. While several series appear to be entirely diploid, others exhibit a range of ploidy levels from 2x to 6x, and some contain only polyploid species. In many diploid, triploid and tetraploid species 2n gametes (gametes or gametophytes with the sporophytic chromosome number) have been detected. Both 2n eggs and 2n pollen occur. 2n gametes provide the opportunity for unilateral and bilateral sexual polyploidization. The genetic determination and consequences of sexual polyploidization strongly suggest that 2n gametes have been the major instrument in the polyploid evolution of the tuber-bearing Solanums. Somatic doubling of species and interspecific hybrids appears to be of very limited importance. New evidence for the occurrence of 2n eggs and 2n pollen in many species is reported, and data from the literature are added to illustrate the widespread distribution of 2n gametes throughout the subsection. A very high correlation is found between polyploidy and 2n gametes, and its significance is discussed. Proof is presented for the occurrence of alleles governing 2n pollen production in the cultivated tetraploids, providing additional evidence for the hypothesis that 2n gametes have been involved in their origin. Multiple unilateral and bilateral sexual polyploidizations are proposed for the origin of the cultivated tetraploids: this accounts for the large variability encountered in this group, which closely resembles that of the related diploids. Similar evolutionary pathways are hypothesized for the other polyploid complexes in the subsection. A scheme is proposed in which participation of both 2n and n gametes link together all ploidy levels in the tuber-bearing Solanums, thus overcoming the ploidy barriers and providing for gene flow throughout the sympatric species of the subsection.
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  • 92
    ISSN: 1573-5060
    Keywords: Solanum tuberosum ; potato ; self-compatibility ; dihaploid ; linkage ; virescens ; translocation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Three dihaploids of Solanum tuberosum (two self-compatible, one self-incompatible) were found to be heterozygous for a monogenic recessive virescent mutant. Intercrossing resulted in the expected 3 : 1 ratio only in crosses involving one self-compatible and one self-incompatible parent. Self-compatible x self-compatible matings produced F1's in which 6:1 was found. The same ratio was observed in the self progeny of the two self-compatible dihaploids. This significant deviation could be explained by assuming linkage (25% crossing-over) between v and an S-bearing translocation. This translocation causes self-compatibility in the dihaploids used and early lethality when homozygous.
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  • 93
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    Euphytica 27 (1978), S. 541-551 
    ISSN: 1573-5060
    Keywords: Solanum tuberosum ; potato ; ploidy ; gene-flow ; ‘triploid block’ ; crossability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The formation of triploids in 4x×2x crosses was studied in primitive potato varieties from the Andes of Peru and Bolivia. Triploid frequencies were as high as 80–100% in some crosses, although the actual number of seeds was low. The ‘triploid block’ varied according to the tetraploid parent, and was never entirely absent. The likelihood of triploid formation was studied in 4x×2x crosses where pollen from both tetraploids and diploids of known genotype was used. Even though the diploids were chosen for their non-production of 2n gametes, as detected in pollen grain size, 66% of the hybrids were tetraploid. The amount and probability of gene-flow between the tetraploid and diploid gene-pools, either directly through 2n gametes or through ‘triploid bridges’ was examined. Most of the 20 cultivars of S. x chaucha produced seed in crosses with tetraploids and diploids, although the fertility of the latter crosses was four times higher. The female fertility of some of the triploids thus allows them to exchange genes with the tetraploids and diploids, although gene-flow occurs more rapidly through direct transfer from diploids to tetraploids via 2n gametes.
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  • 94
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    Euphytica 31 (1982), S. 565-572 
    ISSN: 1573-5060
    Keywords: Solanum ; potato ; gene transfer ; interspecific hybridization ; meiosis ; chromosome doubling ; non-tuberous
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The distant hybrids between non-tuberous Solanum species and tuberous S. pinnatisectum display little or no pairing in F1 and predominantly bivalent formation (preferential pairing) after chromosome doubling. In such a situation the question about the potential and extent of gene transfer from the non-tuberous parent to the tuberous one is relevant to potato breeding. This question was investigated by studying meiosis in triploid and hexaploid hybrids from crosses between diploid TV5 x tetraploid (S. etuberosum x S. pinnatisectum). TV5 is similar to S. verrucosum with cytoplasm of S. tuberosum. The following evidence was found for the desirable transfer of S. etuberosum genes to the tuberous species. The triploid F1 hybrids did not display the configurations 12 II+12 I expected if no gene exchange would take place between S. etuberosum and the tuberous species; however, a considerable number of multivalents per cell was observed in all plants studied. In the hexaploid F1 hybrids, obtained from the triploids through somatic doubling in vitro, 36 bivalents could reasonably be expected. Although bivalents were predominant (an overall average of 24.2 per cell) quite a few chromosomes were associated as multivalents in all plants investigated. It is concluded that in the hybrids studied a considerable amount of pairing and chiasma formation occurs between chromosomes of non-tuberous and those of tuberous Solanum species. This pairing affinity is larger than that found in 2x and 4x hybrids from S. etuberosum x S. pinnatisectum. Some hypotheses are put forward to explain this increased pairing affinity.
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  • 95
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    Euphytica 32 (1983), S. 601-605 
    ISSN: 1573-5060
    Keywords: Solanum ; potato ; wild species ; genetic resources ; rejuvenation ; sexual propagation ; true seed production ; incompatibility ; spatial isolation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary True seed production was studied of self-incompatible diploid tuber-bearing Solanum species grown in the field under spatial isolation in cereals in 1979 and 1982. In comparison with hand pollinations in the greenhouse, extremely high amounts of seeds were obtained, the potential seed yield of 20 plants in 1979 being 66 000 to 540 000. As no indication of interspecific hybridization was found, the chosen isolation is considered to be adequate. It is concluded that sexual propagation of self-incompatible tuber-bearing Solanum species in the field is highly efficient.
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  • 96
    ISSN: 1573-5060
    Keywords: Solanum tuberosum ; potato ; protoplast ; somaclonal variation ; breeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Striking similarities appear to exist between selected protoplast-derived variants (PD-clones) of the potato cultivar Russet Burbank, and commonly occurring somatic potato sports, called ‘bolters’. A limited survey of individuals involved in the certification of Russet Burbank, revealed that bolters do commonly occur in this variety, are highly variable, and sometimes occur at high frequency. It is therefore suggested that bolters and the more promising selected PD-clones of Russest Burbank may be one and the same, arising from the same type of macromutation. One selected PD-clone, three different Russet Burbank bolters, and two controls were analyzed for 15 isozymes in the hope of determining if bolters and promising PD-clones belong to the same class of variants. No isozyme variation between Russet Burbank and its subclones was observed. The breeding value of protoplast-derived variation is discussed in this light.
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  • 97
    ISSN: 1573-5060
    Keywords: Solanum tuberosum ; potato ; potato yield trials ; replication ; trial efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effect on yield trials of altering plot size was examined by investigating plots with varying numbers of drills (each with six tubers) planted. No evidence was found of the ware yield per drill being affected by different plot sizes nor any effect attributable to neighbouring drills, whether these were planted with another clone or left unplanted. Increasing the number of drills per plot did increase the precision of the estimated clone means as did, of course, increasing the number of replicates. It appeared, however, that increasing the number of replicates was a more efficient way to increase precision. Thus it was concluded that the most efficient utilization of limited planting space was to grow single drill plots with maximum replication.
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  • 98
    ISSN: 1573-5060
    Keywords: Solanum tuberosum ; potato ; Solanum tuberosum Group Phureja ; dihaploid ; cytoplasmic inheritance ; reciprocal difference
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Yield components including total tuber yield, total tuber number, vine maturity, vine vigor and average tuber weight as well as seed germination and pollen stainability were studied in 28 exact reciprocal hybrid families, between 12 Solanum tuberosum Group Tuberosum (haploid) (TH) and 12 S. tuberosum Group Phureja (PH) clones in a NC Mating Design II in 4 sets of 3 by 3 reciprocal hybrids at three locations, one in Minnesota (USA) and two in Morocco. TH parents were insensitive to daylength whereas most PH clones required critical photoperiods equal to or less than 14 hours for tuberization. Mean reciprocal differences were significant for most traits at all 3 locations. Hybrids with TH cytoplasm were superior to those with PH cytoplasm by 18% for tuber yield, 21% for tuber number, and 9% for vine maturity, but inferior to hybrids with PH cytoplasm by 11% for vine vigor and 19% for time to reach 80% seed germination. Reciprocal differences were not detected for average tuber weight. Six reciprocal crosses revealed significant differences for pollen stainability but the overall mean difference (one location) was not significant. Possible reasons for the observed reciprocal differences included gamete selection, pseudo-self-compatibility and/or interaction of cytoplasm with both nuclear genes and environment. Differences for critical photoperiod of TH and PH parents were also demonstrated as a probable source of reciprocal differences.
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  • 99
    ISSN: 1573-5060
    Keywords: Solanum tuberosum ; potato ; single plant selection ; potato breeding ; selection efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The efficiency of single plant selection in the initial selection stage of a potato breeding programme was examined. A random sample of potato clones was grown in single plant plots and also in tworeplicates of five plant plots. After harvest, each plot was visually assessed by three potato breeders; total tuber weight and number of tubers per plant were also recorded, from which mean tuber weight was calculated. The error variances of the single plant plots were found to be significantly greater than from the five plant plots for total tuber weight, mean tuber weight and number of tubers per plant, but not significantly different for breeders' preference. Coefficients of correlation between single and five plants plots were significantly greater than zero for all traits examined, but they were lower than the corresponding correlations between the two replicates of five plant plots. Although a random sample of clones was examined, each clone had been assessed for breeders' preference the previous year. When the clones were grouped according to the previous years preference scores, it was found that the correlation coefficients between single and five plant plots for breeders' preference were inversely related, in magnitude, to the mean preference score of each group. It was concluded that single plant selection was generally ineffective, particularly when only the ‘better’ clones, from the previous years assessment, are examined.
    Type of Medium: Electronic Resource
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  • 100
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 37 (1988), S. 149-156 
    ISSN: 1573-5060
    Keywords: Solanum chacoense ; potato ; wild species ; diversity ; multivariate analysis ; isozymes ; allozyme variation ; in situ conservation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The morphological and isozyme variation was studied in 22 accessions of Solanum chacoense from Paraguay and Argentina. Clear geographic groups were identified through the use of multivariate analyses. S. chacoense from mountain sites in Argentina could be readily distinguished from plains forms from Paraguay, on the basis of several correlated morphological characters. Three isozyme systems, namely phosphoglucose isomerase (PGI), glutamate-oxaloacetate transaminase (GOT) and peroxidase (PRX) were studied using starch gel electrophoresis. The banding patterns indicated that for each isozyme there were several loci, which were polymorphic. A genetic interpretation of one of the PGI loci was made, and indices of genetic diversity and genetic identity calculated. Principal components analysis, cluster analysis and genetic diversity indicated a close relationship between the geographical groups. These results are discussed in the context of in situ genetic conservation.
    Type of Medium: Electronic Resource
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