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  • Articles  (767)
  • barley  (302)
  • Zea mays  (240)
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  • Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition  (767)
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  • 1
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    Springer
    Biology and fertility of soils 31 (2000), S. 525-532 
    ISSN: 1432-0789
    Keywords: Key words Ferrihydrite ; Phosphate ; Polygalacturonic acid ; Root mucilage ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  This study was conducted to determine the influence of root mucilage (RM) from Zea mays, polygalacturonic acid (PGA), and galacturonic acid (GA), on the adsorption, desorption, and exchangeability of orthophosphate (P) on a synthetic ferrihydrite in deionized water. The adsorption rate and affinity on the oxide decreased in the order P〉GA〉PGA≥RM. The results suggest that P and GA were adsorbed by ligand exchange on Fe-OH surface sites, while RM and PGA might in addition also be adsorbed by hydrogen and van der Waals bonds to the oxide surface. Whereas P and GA could be adsorbed at sites located inside the micropores of ferrihydrite aggregates, PGA and RM probably remained on the external surfaces because of their large molecular weight. The preliminary adsorption of organic compounds decreased the subsequent P adsorption. The larger decrease of P adsorption occurred when dry ferrihydrite powder was directly added to the RM/water suspension. This effect was due to the flocculation of ferrihydrite aggregates, which limited the transport of P to the adsorption sites. Preliminary adsorption of GA also decreased P adsorption, because both compounds competed for the same Fe-OH sites. The ability of the organic compounds to desorb P from the ferrihydrite was not very pronounced and decreased in the order GA〉PGA≥RM. The preliminary adsorption of organic compounds on the oxide resulted in an increase in isotopically exchangeable P in 300 min compared to the treatment without organic compounds. However, because of its higher affinity for the oxide surface, P exchangeability was not modified when P was added before the organic compounds.
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  • 2
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    Biology and fertility of soils 31 (2000), S. 348-355 
    ISSN: 1432-0789
    Keywords: Key words Agroforestry ; Land use ; Nitrate leaching ; Zea mays ; Musa spp.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  We hypothesized that the integration of trees and shrubs in agricultural landscapes can reduce NO3 – leaching and increase utilization of subsoil N. A field survey was conducted on 14 farms on acid soils in the subhumid highlands of Kenya, where there is little use of fertilizers, to determine the effect of vegetation types (VT) on soil NH4 + and NO3 – to 4 m depth. The VT included maize (Zea mays) with poor growth and good growth, Markhamia lutea trees scattered in maize, natural weed fallow, banana (Musa spp.), hedgerow, and eucalyptus woodlot. The effect of VT on NH4 + was small (〈1 mg N kg–1). NO3 – within a VT was about constant with depth below 0.25 m, but subsoil NO3 – varied greatly among VT. Mean NO3 –-N concentrations at 0.5–4 m depth were low beneath hedgerow and woodlot (〈0.2 mg kg–1), intermediate beneath weed fallow (0.2–0.7 mg kg–1), banana (0.5–1.0 mg kg–1) and markhamia (0.5–1.6 mg kg–1), and high beneath both poor (1.0–2.1 mg kg–1) and good (1.9–3.1 mg kg–1) maize. Subsoil NO3 – (0.5–4 m) was agronomically significant after maize harvest with 37 kg N ha–1 m–1 depth of subsoil beneath good maize and 27 kg N ha–1 m–1 depth beneath poor maize. In contrast, subsoil NO3 – was only 2 kg N ha–1 m–1 depth beneath woodlot and hedgerow. These results demonstrate that the integration of perennial vegetation and the rotation of annual and perennial crops can tighten N cycling in agricultural landscapes.
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  • 3
    ISSN: 1573-143X
    Keywords: 17 β-estradiol ; fish meal ; gonadal development ; growth ; Nile tilapia (Oreochromis niloticus) ; plant proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This study was conducted to evaluate theeffect of plant protein‐based diets on gonadaldevelopment and plasma 17 β-estradiol (E2) levelin female Nile tilapia Oreochromis niloticus.Fish with a mean body weight of 6.7 (0.1) g were fedfour different diets with the same digestible protein(DP) and digestible energy (DE) containing gradedlevels of a mixture of plant ingredients as partial ortotal replacement of fish meal protein for 20 weeks.The control diet (D0) was based on fish meal, twodiets containing 33% (D33) and 66% (D66) of plantprotein, and one diet containing only plant protein(D100). Fish were sampled at 12 and 20 weeks. Nosignificant differences were found in different stagesof oocyte development and plasma E2 levels betweentilapia fed diets D0 and D100 at 12 weeks. Eight weekslater tilapia fed diet D0 showed a higher (P 〈 0.05)level of E2 than the D100 group. This difference andthe reduced proportion of vitellogenic and matureoocytes demonstrated that diets containing only plantprotein are less efficient in terms of tilapia growthand consequently ovarian development.
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  • 4
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    Aquaculture international 8 (2000), S. 455-461 
    ISSN: 1573-143X
    Keywords: floating cages ; growth ; pink dentex (Dentex gibbosus) ; sparids (Dentex dentex, Sparus aurata, Spondyliosoma cantharus, Diplodus puntazzo)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 5
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    Aquaculture international 8 (2000), S. 531-542 
    ISSN: 1573-143X
    Keywords: feed intake ; growth ; protein utilisation ; proximate ; composition ; rainbow trout (Oncorhynchus mykiss)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Rainbow trout Oncorhynchus mykiss grew from 44 to 326 g in 96days when held at ∼12 °C. Fish were fed to satiation twice dailywith either high (L1: 30.8%, L2:31.4%) or lower-lipid feeds (C1: 18.8%,C2: 21.8%). Four feeding treatments were studied.Group C1C2 received feed C1 for 43 days(days 0–43) and C2 thereafter (days 44–96).Groups L1L2, L1C2 andC1L2 were subjected to dietary changes asindicated by the feed designations. After a short period of feedadaptation, fish ingested similar amounts of feed energy i.e., they ateless by weight of the lipid-rich (L) feeds. Feed lipid content did notaffect growth but fish fed L-feed had reduced feed conversion ratio(FCR) compared to fish fed C-feed (0.731 vs. 0.773) during days0–43 (P 〈 0.01). After 96 days,L1L2-fish were lower in body protein(15.8%) than the C1C2-fish (16.8%)(P 〈 0.01). L-feeds also tended to increase percentage lipidand reduce percentage whole body moisture and ash. A higher net proteinutilisation (NPU) was recorded in fish fed L-feeds (43.6%)compared to fish fed C-feeds (38.8%) in days 0–43(P 〈 0.05). This seemed to be the result of a lower proteinintake rather than a protein-sparing effect of feed lipid. Above athreshold value of approximately 6.5 mg protein eaten·g bodywtminus 1·day−1, NPU decreased.
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  • 6
    ISSN: 1573-143X
    Keywords: aggression ; Atlantic salmon (Salmo salar) ; dominance ; growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Aggression in groups of 0+ Atlantic salmon (Salmo salar) was monitoredat weekly intervals in two tanks containing 100 fish each. Three 1 + salmonparr were added to one of these. After 5 weeks, fish weights were measuredin both tanks and the conditions reversed. At ten weeks, weights of fish inboth tanks were measured again. In both populations, levels of aggressionamong the smaller fish were significantly lower and growth ratessignificantly higher when the large fish were present. Although the largefish attacked the small ones, the rate at which they did so was an order ofmagnitude lower that the rate at which small fish attacked each other in theabsence of larger conspecifics. This raises the possibility that levels ofaggression among farmed salmon might be reduced by the addition of a fewlarge conspecifics.
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  • 7
    ISSN: 1573-5036
    Keywords: growth ; ion-uptake ; salinity ; salt tolerance ; sugarcane ; transpiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of salinity on leaf growth, initiation and senescence, on transpiration rates, on leaf water potential and on uptake and distribution of several ions were studied in two sugarcane cultivars differing in salinity sensitivity. Plants, growing in a growing mixture in pots, were exposed to salinized irrigation water for 68 days, starting 60 days after planting. EC values of the irrigation water were 1.0, 2.0, 4.0, 8.0 and 12 dS/m, obtained by using a mixture of NaCl and CaCl2. Plants were also grown in nutrient solution and were at a similar age when exposed to a salinity level of 3 dS/m for 30 days followed by 6.0 dS/m for an additional 30 days. Two Na:Ca ratios of 18:1 and 1:2 were used for salinization of the nutrient solution. Both leaf dry weight and area decreased with increasing salinity, but in the more salinity tolerant cultivar H69-8235, the decrease was moderate. Salinity hardly reduced average area per leaf in H69-8235, while the number of leaves declined sharply. This decline was caused by enhanced senescence of mature leaves and not by a decreased rate of leaf initiation. In the more sensitive cultivar, H65-7052, leaf area and initiation of new leaves were sharply reduced by salinity while leaf senescence was less affected. Leaf water potential decreased during the early stages of salinity exposure, and the reduction in water potential was larger in H69-8235. Salinity also decreased the rate of transpiration rate but to a lesser extent than leaf development and growth. The accumulation of Cl and Na in the TVD (top visible dewlap) leaf of the tolerant cultivar H69-8235 was greater than in the sensitive cultivar H65-7052. The concentration of Cl in the TVD leaf was more than 10 times that of Na in both cultivars. The concentration of both ions, but not of K, increased during the early stages of salinity exposure and then remained constant. A gradient in concentration of Cl and Na over the plant was found in both cultivars at all salinity levels, and was steepest between the TVD and younger leaves. No specific Na effect on leaf growth or transpiration could be detected. The accumulation of Cl and Na but not of K occurred primarily in the roots rather than in the leaves and stalks.
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  • 8
    ISSN: 1573-5036
    Keywords: barley ; corn ; darkness ; light ; NO3 − uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effect of light and exogenously supplied sucrose on NO3 − uptake was studied in 9-day-old intact C3 (barley) and C4 (corn) seedlings. The seedlings used were uninduced for nitrate uptake system (i.e. had never seen nitrogen during germination and growth) and were exposed to continuous light for 3 days to avoid any diurnal variation and to load the seedlings fully with photosynthates. The uptake assay was conducted either in light or in darkness. Prior to assay, seedlings were treated with darkness or light for 24 h. Accordingly, four sets of seedlings, i.e. pretreated with light and assayed in light (LL); pretreated and assayed in darkness (DD); pretreated with light and assayed in darkness (LD); and pretreated with darkness and assayed in light (DL) were formed. Barley exhibited 55% higher NO3 − uptake than corn during light (LL) and 91% higher during darkness (DD). Shifting barley seedlings from light to dark (LD) or dark to light (DL) for uptake assay, did not affect NO3 − uptake, i.e. in LD the uptake was similar to LL and in DL it was similar to DD. However, in corn, the light conditions during the assay determined the uptake regardless of the conditions during the period preceding the assay. One percent sucrose in the medium increased NO3 − uptake by 31% in barley and 70% in corn during light (LL). The corresponding increase during darkness (DD) was 38% in both barley and corn. Removal of the corn residual endosperm decreased NO3 − uptake by 40% during darkness. Etiolated seedlings (those having never seen light) of both barley and corn were able to take up significant amount of NO3 − during darkness. Externally supplied sucrose in the assay medium of etiolated seedlings increased the NO3 − uptake to about 4 and 2 fold in barley and corn, respectively. The data presented here provide evidence that: 1. In intact seedlings, light per se is not obligatory for NO3 − uptake and that the carbohydrate supply may mimic light. 2. Light affected the NO3 − uptake differently in barley and corn.
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  • 9
    ISSN: 1573-5087
    Keywords: betaine ; ethanolamine ; growth ; Helianthus annuus L. ; salt stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The accumulation of compatible solutes is one of the strategies that plants have developed to tolerate salt stress. Proline and betaine are the main metabolites that accumulate in various species of higher plants in response to salt stress. In Helianthus annuus L., pre-treatment of seeds with ethanolamine led to enhanced seedling tolerance to conditions of saline stress during germination, as evidenced by the greater growth of pretreated seedlings (EAS group) versus untreated seedlings (S group), evaluated through such parameters as length, water and chlorophyll content. During the germination period, a considerable increase was observed in proline levels (up to 300%) in seedlings subjected to saline stress, whereas in the EAS group, the proline increment was much smaller (20%). Starting from the fourth day of germination, betaine levels in seedlings pretreated with ethanolamine and then with water (EAW group) and in EAS showed a significant increase versus C (control) and S seedlings, possibly because such a precursor promotes betaine biosynthesis. This could be responsible for the enhanced growth observed in EAS versus S seedlings, as well as for preventing the decrease in chlorophyll content in the EAS group. The accumulation of betaine seems to correlate with the greater tolerance of these seedlings against stress induced by sodium chloride.
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  • 10
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    Plant growth regulation 32 (2000), S. 151-155 
    ISSN: 1573-5087
    Keywords: ATP production ; ATPase ; auxin ; membrane vesicles ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Microsomal membrane vesicles and purified plasma membranevesicles obtained from coleoptiles of maize (Zea mays L.) weresubjected to pH shifts from pH 7.8 to 4.7. In the presence of ATPaseinhibitors such as vanadate, net accumulation of radiolabelled butyricand indole-3-acetic acid (IAA) remained higher than in controls. When 2min after the pH shift, at 4°C, the microsomal vesicles weredenatured the amount of ATP could be determined using theluciferin/luciferase assay. Significantly increased ATP production overcontrol values – no pH-shift or ionophore treatment – wasfound. Therefore, such vesicles might produce ATP for in vitrotransport processes such as auxin efflux.
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  • 11
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    Plant growth regulation 30 (2000), S. 163-170 
    ISSN: 1573-5087
    Keywords: ATPase ; bioenergetics ; Fragaria ananassa Duch ; growth ; ion transport ; photosynthesis ; proton transport ; respiration ; source-sink ; strawberry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The biochemical, physiological and anatomical properties of strawberry (Fragaria ananassa Duch.) cv. 'Cambridge Favourite' stolons were studied during growth. ATPase activity was measured, in microsomal and plasma membrane fractions, along with chlorophyll determination, in-situ photosynthesis measurements and scanning electron microscopy (SEM) and X-ray microanalysis of stolon cross-sections. Potassium-stimulated ATPase activity and proton-pumping, both together indicating the presence of plasma membrane ATPase, was greatest in the stolon tip, the tissue with the fastest growth and respiratory activity. The enzyme activity and respiration gradient from the tip of the stolon to the base was concomitant with xylem development which was more differentiated in the base than in the tip. These cross-sections also showed 30% greater amounts of calcium and potassium of the cryo-preserved basal part relative to the stolon tip. This gradient existed independent of the presence of daughter plants. A hypothesis is presented which suggests that for the long-distance longitudinal transport of nutrients this gradient between stolon tip and base is likely to be involved in stolon growth.
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  • 12
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    Plant growth regulation 32 (2000), S. 77-81 
    ISSN: 1573-5087
    Keywords: bioenergetics ; growth ; nutrition ; nutrient deficiency ; plant stress ; respiration ; root ; root:shoot ratio ; root respiration ; source-sink relationship ; stress ; stress physiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Root respiration of kohlrabi (Brassica oleraceavar. gongylodes) was measured non-destructivelyin vivo by infrared gas analysis of completeroot systems, using potted plants in sand culture andnutrient solutions, for six weeks under (a) nutrientsufficiency, (b) deficiency of all mineral nutrients,(c) potassium deficiency or (d) phosphorus deficiency.This was to study the adaptation to nutrient stress interms of changes in root growth, root respiration,assimilate allocation and energy requirement fornutrient uptake. Both deficiencies of phosphorus andpotassium increased the root:shoot-ratio. This wasattributed to the plants transferring a largerrelative proportion of assimilates to the roots thanto the shoots relative to nutrient-sufficient plants.Roots of nutrient-sufficient kohlrabi respired 1.7 or7.7 mg CO2 h−1 per g fresh or dry matter, respectively. However, potassiumdeficiency enhanced root respiration to 2.4 mgCO2 h−1 or 12.2 mg CO2 h−1 on a per g fresh or dry weight basis respectively. This originated from an additional2.6 mg glucose g−1 dry matter h−1 allocated to the roots and provided 50 Joule additional energy(150 versus 100 Joule g−1 dry matter h−1)which may become available for the proposedK+:H+ symporter for potassium uptake.
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  • 13
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    Plant growth regulation 32 (2000), S. 295-305 
    ISSN: 1573-5087
    Keywords: Cold stress ; Immunolocalization ; Phaseolus vulgaris ; Zeatin O-glycosyltransferase ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Zeatin O-glycosides have been reported as inactive and stable storage forms of cytokinins whose concentrations increase in cold stressed plants. Zeatin O-glycosides accumulation in developing bean seeds has been correlated with an increase of zeatin O-glycosyltransferase , which is specific to trans-zeatin, and catalyzes the conjugation of zeatin O-glycosides. When Phaseolus vulgaris and Zea mays seedlings were grown for 3 days at 25 and then incubated at 4 or 10 for 6 days no further growth was observed in roots. Hypertrophy was observed in the root tips of both species. In shoot-hypocotyl complexes, in contrast, growth occurred when seedlings were incubated at 10 . Western analysis, with Mabs specific to zeatin O-glycosyltransferase, detected antigenically related proteins in roots, shoot tips and cotyledons after seedlings were cold stressed for 1–6 days at 4 or 10 . Immunolocalization, of both maize and bean root sections grown at 25 revealed antigenically related proteins that were detected at low levels in cortical cells. The signal intensified upon cold stress. The localization of zeatin O-glycosyltransferase in Z. mays root tips was directly comparable to the distribution of the zeatin O-glycosides. The enzyme was detected in the nucleus, cytoplasm, and closely associated with the plasma membrane and in the cell wall of Z. mays root cells. Southern analysis suggested that more than one gene in Z. mays that were homologous to zeatin O-glycosyltransferase in P. vulgaris. Zeatin O-glycosyltransferase may be involved in modulation of cytokinins under cold stress.
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  • 14
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    Plant growth regulation 32 (2000), S. 219-230 
    ISSN: 1573-5087
    Keywords: Arabidopsis thaliana ; arbuscular mycorrhiza ; biosynthesis ; indole-3-acetic acid ; indole-3-butyric acid ; regulation ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Within the last ten years it has been established by GC-MS thatindole-3-butyric acid (IBA) is an endogenous compound in a variety ofplant species. When applied exogenously, IBA has a variety of differenteffects on plant growth and development, but the compound is stillmainly used for the induction of adventitious roots. Using moleculartechniques, several genes have been isolated that are induced duringadventitious root formation by IBA. The biosynthesis of IBA in maize(Zea mays L.) involves IAA as the direct precursor. Microsomalmembranes from maize are able to convert IAA to IBA using ATP andacetyl-CoA as cofactors. The enzyme catalyzing this reaction wascharacterized from maize seedlings and partially purified. The invitro biosynthesis of IBA seems to be regulated by several externaland internal factors: i) Microsomal membranes from light-grownmaize seedlings directly synthesize IBA, whereas microsomal membranesfrom dark-grown maize plants release an as yet unknown reaction product,which is converted to IBA in a second step. ii) Drought and osmoticstress increase the biosynthesis of IBA maybe via the increaseof endogenous ABA, because application of ABA also results in elevatedlevels of IBA. iii) IBA synthesis is specifically increased byherbicides of the sethoxydim group. iv) IBA and IBA synthesizingactivity are enhanced during the colonization of maize roots with themycorrhizal fungus Glomus intraradices. The role of IBA forcertain developmental processes in plants is discussed and somearguments presented that IBA is per se an auxin and does notact via the conversion to IAA.
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  • 15
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    Plant and soil 219 (2000), S. 177-185 
    ISSN: 1573-5036
    Keywords: alfalfa ; growth ; Medicago sativa L. ; nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The dynamics of biomass and N accumulation following defoliation of alfalfa and the application of N fertilization has rarely been studied under field conditions, particularly in the seeding year. Our objectives were to determine the effect of N fertilization on the dynamics of biomass and N accumulation during the first regrowth of alfalfa in the seeding year, and to determine if a model describing critical N concentration developed for established stands could be used in the seeding year. In two separate experiments conducted in 1992 and 1993, the biomass and N accumulation of alfalfa grown with three N rates (0, 40 and 80 kg N ha-1) were determined weekly. Maximum shoot growth was reached with 40 kg N ha-1 in 1992, and maximum shoot growth was not reached with the highest N fertilization rate in 1993. Nitrogen fixation, root N reserves and soil inorganic N uptake when no N was applied were, therefore, not sufficient to ensure non-limiting N conditions, particularly when growth rates were the highest between 14 to 21 d after defoliation. Nitrogen fertilization increased shoot biomass accumulation in the first 21 d of regrowth, biomass partitioning to the shoots and shoot and taproot N concentrations. The model parameters of critical N concentration developed by Lemaire et al. (1985) for established stands of alfalfa were not adequate in the seeding year. The N requirements per unit of shoot biomass produced are greater in the seeding year than on established stands, and this was attributed to a greater proportion of leaves in the seeding year.
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  • 16
    ISSN: 1573-5036
    Keywords: growth ; light intensity ; Phaseolus vulgaris L. ; phosphorus–zinc interaction ; photosynthesis ; yield ; zinc deficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two experiments were conducted in a factorial combination of three Zn levels (0, 10 and 40 mg Zn kg-1 soil) and two P levels (0 and 200 mg P kg-1 soil). Experiment 1 was carried out during winter in a heated glasshouse, and experiment 2 during summer under a rain shelter. Plants of dwarf bean (Phaseolus vulgaris L., cv. Borlotto nano) were grown in pots filled with sandy soil. In both experiments, leaf Zn concentration was reduced by the addition of P to plants grown at low Zn supply. However, leaf Zn concentration lower than the critical level was observed only during experiment 2, and the main effects of low Zn were reductions of internode length, light use efficiency and maximum photosynthetic rate. In plants with leaf Zn concentration lower than the critical level, saturating irradiance levels fell from ∼1000 μmol m-2 s-1 PPFD to ∼300–400 μmol m-2 s-1 PPFD. Reduction of net photosynthesis was observed from the beginning of flowering and led to decreased seed production.
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  • 17
    ISSN: 1573-5036
    Keywords: Crop residues ; dry-matter yields ; Medicago sativa ; N mineralization ; 15N uptake ; Zea mays ; VAM fungi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Legume crop residues serve as a source of nitrogen (N) for succeeding crops in low-input production systems, and characterizing the release of this N supports efforts to develop sound economic and environmental management practices. Nitrogen mineralization of 15N-labelled field crop residues was monitored in a Greenville sandy loam during a 140-day laboratory incubation at 25°C. Residue type strongly influenced the rate of N mineralization; decomposition rate constants were 0.283, 0.083, 0.00047 and 0.0014 day-1 for alfalfa (Medicago sativa L.) stover (above-ground plant parts), alfalfa roots, maize (Zea mays L.) stover (above-ground plant parts excluding cob and kernels) and maize roots, respectively. At the end of the incubation, 50% of alfalfa stover and 25% of alfalfa root residues N were mineralized, whereas these proportions were 8% for maize stover and 12% for root residues. Mineralization of 15N from alfalfa stover residues was also monitored in a greenhouse experiment to determine N availability during the growth of maize inoculated or not with vesicular-arbuscular mycorrhizal (VAM) fungi, and to evaluate the effects of the presence of plants on the decomposition of the residues. Stover and root dry matter yields were greatest for maize inoculated with VAM fungi and grown in residue-amended soil. At the final harvest, maize grown in residue-amended soils had accumulated 44% more dry matter and 40% more N than maize grown in unamended soils. Enhanced VAM colonization of roots inoculated with a mixture of three Glomus spp. increased the residue N accumulation in maize roots at 5 weeks after silking and at the final harvest. Alfalfa stover decomposed rapidly both in the presence and absence of maize plants, but the amount of 15N mineralized at the end of the experiment was influenced by the presence of living roots; 23% of the 15N in alfalfa stover residues was mineralized in soil without plants compared to about 38% when maize plants were present. These results suggest that N mineralization is enhanced by the presence of living roots.
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  • 18
    ISSN: 1573-5036
    Keywords: agricultural practices ; extra-radical mycelium ; Gliricidia sepium ; organic matter addition ; Peltophorum dasyrachis ; soil disturbance ; species richness of AMF ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two pre-established agricultural field trials were assessed for the abundance of arbuscular mycorrhizal fungi (AMF) in the soil (density of spores, species richness and lengths of extra-radical mycelium [ERM]) in association with one of three tropical plant species (Gliricidia sepium, Peltophorum dasyrachis and Zea mays). The trials were managed by one of three agricultural practices: soil disturbance in a monoculture system, a root barrier to prevent interactions between plants in an agroforestry system or the addition of organic matter (OM) in an agroforestry and a monoculture system. The lengths of ERM of AMF in the soil were greater in the agroforestry system than the monoculture system. These were greater when a root barrier was present, but decreased when OM was added. Soil disturbance reduced the density of spores, species richness and the lengths of ERM of AMF compared with the undisturbed soil. This work indicates that agricultural trials may provide a useful tool to monitor the abundance of AMF in the field. Clearly, there is potential to increase the abundance of AMF, from different genera, in the soil through the management of agricultural practices. The significance of the abundance of AMF for subsequent benefits to plant growth and development and ultimately the sustainability of tropical agro-ecosystems are discussed.
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  • 19
    ISSN: 1573-5060
    Keywords: Andean maize ; cold tolerance ; germplasm evaluation ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Cold in the initial growth stages is an important stressfactor for maize grown in regions with a temperate climate,particularly in case of early sowing. Sources of tolerancehave been identified in adapted genotypes, but promisinggenes for cold tolerance should also be found in materialdeveloped under the lower-temperature margins of the cropdistribution. This research was conducted in order to testAndean maize accessions for cold tolerance expressed duringboth the heterotrophic and early autotrophic growth stages.Experiments were conducted in controlled environments tostudy cold tolerance traits (germination %, germinationindex and plant growth rate) at continuous 10°C (heterotrophic growth) and at varying 10–16°C (autotrophic growth). An experiment was also performed inthe field with early sowing (both heterotrophic and autotrophic growth). In each experiment, a control trialwas conducted in more favourable conditions (i.e. continuous25°C in a controlled environment or late planting inthe field) so that cold tolerance traits could also beexamined as the ratio between the stress and the controltrial. None of the accessions was superior for all coldtolerance traits. However, several Andean maize accessionsoutperformed the US Corn-belt hybrid checks for one or moretraits, both in heterotrophic and autotrophic growth. Overall, BOZM 855, PMS 636, Poblacion D, Poblacion E andBOZM 696 were the best accessions, suggesting that they canbe a promising source of genes for improving cold toleranceof adapted maize genotypes.
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  • 20
    ISSN: 1573-5060
    Keywords: barley ; genotype by environment interaction ; Hordeum vulgare ; farmer participation ; PPB ; participatory plant breeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Decentralized selection, defined as selection in the target environment, has been used to emphasize favorable interactions when significant genotype by environment interactions exist. However, crop breeding based on decentralized selection can still miss its objectives if it does not utilize the farmers' knowledge of the crops and the environment, and it may fail to fit crops to the specific needs and uses of farmers' communities unless it becomes participatory.One cycle of decentralized participatory selection was conducted in eleven locations in Syria. 208 barley entries (fixed lines and segregating populations) were planted unreplicated in two research stations and in the fields of nine Syrian (host) farmers, where they were managed (except planting) by the farmers themselves. Visual selection was conducted by a breeder at all locations and by the host farmers on their own fields and on both stations. In five farm locations, there was also a one-time group selection by neighboring farmers.Host farmers were able to handle the large number of entries making observations during the cropping season using different scoring methods. They did not use the performance of entries on station for their final selection and used a higher selection pressure than the breeder. In their own fields, they selected about one tenth the number of entries selected by the breeder, while on station the farmers selected, on average, about half the number of lines selected by the breeder. For some broad attributes, such as modern germplasm versus landraces, selection was mostly driven by environmental effects. Selection for other attributes was partly environmentally driven and partly based on individual farmers preferences.Selection preferences were similar for fixed or segregating populations. There was wider diversity among farmers' selections in their own fields than among farmers' selections on research stations and among breeder's selections, irrespective of where the selection was conducted. Larger kernels, higher grain yield and biomass, and taller plants (particularly in environmentally stressed locations) were the characteristics most frequently used as selection criteria by both breeder and farmers.Entries selected by the farmers yielded as much, and in one case significantly more, than those selected by the breeder.Decentralized-participatory selection was significantly more efficient in identifying the highest yielding entries in farmers' fields than any other type of selection. There was also evidence suggesting that the breeder was more efficient in selecting higheryielding entries in the research station in a high rainfall area, while the farmers were more efficient in selecting under stress conditions. The results suggest that farmers can handle selection choices among a large number of lines, and because farmers' selections are at least as high yielding as breeder's selections, it is possible to transfer the responsibility of selection to farmers in their fields.
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  • 21
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    Plant and soil 218 (2000), S. 91-101 
    ISSN: 1573-5036
    Keywords: alfalfa ; Aphelenchoides composticola ; Aphelenchus avenae ; barley ; fungi ; host ; nematodes ; N-mineralization ; organic substrates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Isolates of Alternaria alternata, Botrytis cinerea, Fusarium oxysporum, Penicillium sp., Rhizoctonia solani, Stemphylium sp., Thielaviopsis basicola, and Verticillium dahliae were cultured on potato–dextrose agar (PDA), barley-sand and alfalfa-sand substrates in petri-dish or in column microcosms. N-mineralization by fungi and fungal-feeding nematodes in combination or fungi alone was assessed. Numbers of Aphelenchus avenae or Aphelenchoides composticola supported by the fungi were measured every 7 days. Times for full colonization of the substrates by fungi ranged from 5 to 15 days. Rhizoctonia solani and B. cinerea on PDA supported the largest A. avenae and A. composticola populations, respectively. Penicillium sp. was a nonhost for A. composticola and A. avenae. Rhizoctonia solani, B. cinerea, V. dahliae, and F. oxysporum supported significantly more nematodes than the other four fungal species. The ranked order of fungi based on the amount of N mineralized in columns free of nematodes was A. alternata (with a rate of 0.052 μg N/g-sand per day), Stemphylium sp., V. dahliae, T. basicola, B. cinerea, F. oxysporum, R. solani, and Penicillium sp. (with a rate of 0.0045 μg N/g-sand perday). The presence of A. avenae resulted in significant increases in mineral N, compared to nematode-free columns colonized by F. oxysporum, R. solani, and T. basicola alone. The presence of A. composticola resulted in significant increases in mineral N, compared to nematode-free columns colonized by A. alternata, B. cinerea, F. oxysporum, and R. solani alone. There was more mineral N incolumns in the presence of A. composticola than A. avenae in most cases.
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  • 22
    ISSN: 1573-5036
    Keywords: AM fungi ; colonisation ; growth ; mineral nutrition ; red raspberry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Growth, development and nutrient status of micropropagated Rubus idaeus cv. Glen Prosen in response to inoculation with nine species of arbuscular mycorrhizal (AM) fungi from three different genera was investigated. The nine species of AM fungi included, Glomus clarum, G. etunicatum, G. intraradices, Gigaspora rosea, Gi. gigantea, Gi. margarita, Scutellospora calospora, S. heterogama and S. persica. Plant responses to AM fungi varied from growth enhancement to growth depression. Depressive growth effects were specific to Gigaspora species. Furthermore, particular species of AM fungi had unique effects on the mineral status of the raspberry plants. Importance of isolate selection for inoculation of micropropagated raspberry plants is discussed.
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  • 23
    ISSN: 1573-5036
    Keywords: growth ; inflow ; magnesium ; potassium ; (Prunus)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects (and interaction) of two solution concentrations of Mg (50, 500, μM) and two of K (250, 4250 μM) on the growth of micropropagated plants of “F. 12/1” and “Colt” were investigated using a flowing solution culture system. Magnesium inflow and growth of “Colt” and “F. 12/1” were inhibited to a similar extent by an increased concentration of K in the nutrient solution. However, the consequences of this inhibition were different. Reduced inflow of Mg in “F. 12/1” caused Mg deficiency symptoms at high and low concentrations of K, whereas this only occurred with a combination of high K concentration and low Mg concentration in “Colt”. The distribution of dry matter within the plant was significant in determining susceptibility to Mg deficiency. Since “F. 12/1” has a smaller root:shoot ratio than Colt it is unable to sustain the same concentration of Mg in leaves as “Colt” irrespective of external K concentration. The molar ratio of K:Mg in soil solutions should remain 〈8.5:1 in order to ensure maximum growth of “F. 12/1” and “Colt”.
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  • 24
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    Plant and soil 226 (2000), S. 113-116 
    ISSN: 1573-5036
    Keywords: aluminium ; root cells ; stress adaptation ; structural response ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Plant cells respond to a certain stress factor in different ways depending on their developmental stage and type of tissue. Structural damage may be severe or even lethal in individual cells within a tissue that exhibits moderate or no effects of stress. In the case of aluminium toxicity, detailed observations of root tips of 3 day old Zea mays L., cv. TO360 seedlings revealed differences in the response of some cells. Two different structural changes appeared within root epidermis just behind the root cap. Cells with dark and shrunken cytoplasm occurred next to swollen cells with preserved cellular compartments. Within the root cortex, individual cells or a few cells of a file have severely damaged cytoplasm, in contrast to almost undisturbed cytoplasm of adjacent cells. Such extremely sensitive cells appear irregularly within the root apex. Their structural similarity with cells that are observed after a hypersensitive response in infected plant tissues suggests a role to accumulate aluminium, in order to allow the surrounding tissue to survive the stress.
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  • 25
    ISSN: 1573-5060
    Keywords: barley ; resistance ; Rhynchosporium secalis ; scald ; virulence spectrum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The virulence spectra of 50 Rhynchosporium secalis isolates from a population in the Western Cape province of South Africa were determined, and 21 races were detected when evaluated against 17 differential cultivars. The virulence spectrum of the R. secalis population shows considerable variation, and carries unnecessary virulence genes which is quite unexpected, since chiefly susceptible barley cultivars are grown in the south Western Cape. The two most prevalent races, namely races 4 and 7 had three and four virulence genes respectively. Both race 4 and 7 were virulent on the most susceptible cultivars, West China, Steudelli, C.I.8618 and C.I.2226. Considering the resistance genes reported for the cultivars Atlas 46, Turk, and C.I.3515 which showed no susceptible cultivar-pathogen interaction, it would appear that the Rh-Rh3-Rh4 complex is primarily involved in conferring resistance to the local R. secalis isolates
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  • 26
    ISSN: 1573-5060
    Keywords: barley ; GISH ; in situ hybridization ; translocation ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Wheat-barley translocations were identified by genomicin situ hybridization (GISH) in backcross progenies originating from in vitro regenerated wheat (Triticum aestivum L. cv. Chinese Spring) × barley (Hordeum vulgare L. cv. Betzes) hybrids. The regenerated hybrids were pollinated with the wheat line Martonvásári 9 kr1. Five translocated wheat-barley chromosomes were recovered among 51 BC2F2 progeny from the in vitro regenerated wheat × barley hybrids. All were single breakpoint translocations with the relative positions of the breakpoints ranging from the centromere to about 0.8 of the relative arm length. Of the four translocations with intercalary breakpoints, three were transfers of terminal barley segments to wheat chromosomes; one was a transfer of a terminal wheat segment to a barley chromosome. Because of the absence of diagnostic N-bands, the identity of three barley segments could not be determined; in one translocation the barley chromosome involved had a NOR so it must have been 5H or 6H, and the centric translocation was 4HS.2BL. Following selfing, homozygotes of four translocations were selected. The experiment suggests that in vitro culture conditions are conducive for major genome rearrangements in wheat-barley hybrids.
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  • 27
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    Euphytica 112 (2000), S. 157-166 
    ISSN: 1573-5060
    Keywords: barley ; cer ; β-diketone ; glaucous ; pre-harvest sprouting ; waxes ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Morphological features of the cereal ear, including awns, alter pre-harvest sprouting damage by changing the rate of water absorption during rainfall. In this paper, the potential for wheat (Triticum sp.) arid barley (Hordeum vulgare L.) waxes to reduce sprouting by increasing water repellency of the mature ear has been examined. Six barley F2 populations segregating for different non-glaucous single-gene mutants controlling waxes on ears were examined. Water repellency was assessed by measuring both the contact angle of a water drop placed on the lemma surface (internal angle) and by repetitive weighings of whole ears during their exposure to simulated rainfall. The lemma of glaucous (wild type) lines had larger water drop contact angles, an indication of poorer spread of water over the surface. In simulated rainfall, ears of the glaucous lines showed a clear reduction of wetting (20–30% less) and, after 72 h of wetting, their in-ear sprouting was reduced by 50 to 65%. When pre-wet, the glaucous ears also shed water more readily when shaken to simulate the combined effect of wind and rainfall. To reduce pre-harvest sprouting of barley it may be possible to screen visually for ears that are more glaucous but a more specific screen would be to select for lemma water drop contact angle since it is a good indicator of ear wettability and so allows differences in surface properties to be assessed. For bread wheat (T. aestivumL.), as for barley, the more glaucous the ear, the greater the water drop contact angle and the more tubular surface wax coverage seen in scanning electron microscope images. In addition, surface wax amount apparently affected in-ear wettingin lines of durum wheat, (T. turgidum L.). Possible genetic relationships between waxy/waxless genes in wheat and barley are suggested with the aim, ultimately, of altering ear glaucousness to give increased water repellency and a reduction of in-ear sprouting of wheat.
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  • 28
    ISSN: 1573-5060
    Keywords: anthers ; barley ; culture density ; doubled haploid ; microspores ; regeneration medium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A comparison of anther and microspore culture efficiency for green doubled haploid plant production was undertaken using 17 F1 crosses with potential agronomic performance. Green doubled haploid plants were produced from all F1 crosses by anther and microspore cultures, although there was a great variation among crosses. On average, anther culture resulted in a production of green plant twice that of isolated microspore culture (30 and 14 greenplants/100 anthers, respectively).The effect of microspore culture density on green plant regeneration was studied with the cultivars Igri, Reinette and Hop which have a high, medium and low androgenic response. The highest number of dividing microspores was obtained at a density of 2.4 ×105 viable microspores/ml for the three cultivars. However, the optimal density for the percentage of embryos/dividing microspores and greenplants/103 microspores depended on the cultivar. The highest number of green plants/103microspores was produced at 1.2 × 105 viable microspores/ml for cv. Igri and 2.4 × 105 for cultivars Reinette and Hop. Percentage of green plants/total plants was raised when the culture density was increased up to 6.0 × 105 viable microspores/ml, especially for cv. Reinette. Six regeneration media differing in maltose concentration, organic nitrogen and type of auxin were assayed with embryos from cultivar Reinette. Media without organic nitrogen containing 31 g l-1maltose and the auxins IAA or NAA produced more vigorous green plants.
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  • 29
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    Euphytica 115 (2000), S. 149-158 
    ISSN: 1573-5060
    Keywords: Maize ; mature plant resistance ; Striga hermonthica ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Twelve maize genotypes with different degrees of resistance were evaluated in plots inoculated with seeds of the phytoparasite Striga hermonthica (Del.) Benth. and in Striga-free (control) plots for three seasons between 1991 and 1993. Resistant genotypes, although showing similar levels of underground infection as susceptible 9 weeks after maize planting (WAP), had significantly fewer emerged parasitic plants and sustained lower damage. Host damage was not determined by the severity of infection. Percent height and dry matter reductions increased from 3 to 6 WAP for resistant and susceptible genotypes. While percent height and dry matter reductions for resistant genotypes declined at 9 and 12 WAP, susceptible genotypes either maintained or increased their levels of damage. Correlation between the severity of height and dry matter reductions at the vegetative (3 and 6 WAP) and reproductive (9 and 12 WAP) stages of maize growth were not significant, indicating that damage at early stages of growth cannot be used to predict mature plant response. Maize damage score (1–9) at 8 WAP, a non destructive and composite shoot indicator of host performance under Striga infestation, was significantly correlated (r = 0.88, r = 0.82; p 〈 0.01) to the level of shoot reduction at mature plant stages. Emerged Striga count at 8 WAP was significantly correlated (r = 0.98, p 〈 0.01) to the count at 10 WAP, the time when parasite emergence was highest. Under high and uniform infestation, mature plant resistance can be detected at 8 WAP, the onset of flowering in maize.
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  • 30
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    Aquaculture international 7 (2000), S. 369-382 
    ISSN: 1573-143X
    Keywords: growth ; haddock (Melanogrammus aeglefinus) ; larvae ; light intensity ; photperiod ; tank colour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In two separate experiments, haddock (Melanogrammus aeglefinus) larvae were raised under different photoperiods (24L : 0D or 15L : 9D), or different combinations of tank colour (black or white) and light intensity (1.1 μmol s−1 m−2 or 18 μmol s−1 m−2). Growth (0.8% day−1 in standard length; 2.9% day−1 in body area) and survival (2%) were not significantly different between photoperiod treatments after 35 days. Larval survival was greater in white versus black tanks after 41 days (2% versus l%, respectively). Growth of larvae was impaired in black tanks at low (1.1 μmol s−1 m−2) light intensity (0.8% day−1 in standard length and 2.2% day−1 in body area versus 1.1% day 21 in standard length and 3.1% day−1 in body area, for all other treatments). Transmission and reflection of light was low in black tanks at low incident light, and there was very little upwelling light. The resultant poor prey to background contrast probably resulted in larvae being unable to consume sufficient food to sustain a level of growth comparable to that in other treatments.
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  • 31
    ISSN: 1573-143X
    Keywords: bivalve ; fouling ; growth ; Newfoundland ; nursery ; sea scallop (Placopecten magellanicus) ; spat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Hatchery-reared sea scallop (Placopecten magellanicus) spat weremonitored for growth and recovery in three experiments to determine themost suitable system for nursery culture. In Experiment I, four size classesof nursery-sized spat held at two depths from October to July exhibiteddeclining growth rates over the winter period and increased growth ratesin the spring. Overall, season, depth and initial size had a significantinfluence on the absolute and specific growth rates of scallops. Recovery,defined as number of scallops remaining after mortality and loss of spatthrough gear mesh, was influenced by season and initial size, but notdepth. Scallops in the 3.0 mm+ size class had higher growth rates andrecovery than those in the 1.4–1.6 mm, 1.7–1.9 mm and 2.0–2.9 mm sizeclasses. In Experiment II, two gear types containing similar size spat werecompared. Growth rates were significantly higher in 3.0 mm pearl nets thanin 3.0 mm collector bags, although recovery was similar between the twoequipment types. Experiment III, two stocking densities of nursery-sizedspat were compared in collector bags. Neither growth rate nor recoverywere significantly different for the two densities (2600 and 5200spat/collector bag) tested. Overall, these studies indicated that importantparameters for optimizing the growth and recovery of scallops in a farm-based nursery system include season, initial spat size, deployment depthand gear type.
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  • 32
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    Aquaculture international 8 (2000), S. 381-389 
    ISSN: 1573-143X
    Keywords: Arctic charr (Salvelinus alpinus) ; growth ; low temperature ; stocking density ; time restricted feeding,/kwd〉
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of time restricted feeding, possibility of bottomfeeding and stocking density on the growth of Arctic charr(Salvelinus alpinus L.) were examined in fish held at lowtemperature (〈2 °C). Fish fed for a restricted time (1 h) hadsignificantly (p 〈 0.05) lower specific growth rate (0.15 vs0.32% per day) than those fed the same ration over an extendedtime period (12 h). Increasing stocking densities had a positive andsignificant effect (p 〈 0.05) on growth with SGR increasing from 0.27to 0.52% per day at 2–30 kg m-3. Fish withaccess to feed on the tank floor had a significantly higher (p 〈0.05) growth rate (0.3 vs 0.13% per day) than those without thepossibility to feed from the bottom. When fish were held underconditions without access to the bottom a doubling of the feed rationdid not result in a significant (p 〉 0.05) increase in growth rate(0.13 vs 0.12%percnt; per day).
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  • 33
    ISSN: 1573-143X
    Keywords: body composition ; catfish (Mystus nemurus) ; feeding rate ; growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A 10 week experiment was conducted to determine theeffects of feeding rate on growth, feed utilizationand body composition of the tropical bagrid catfish,Mystus nemurus. Catfish fingerlings with anaverage initial body weight of 12 g were fed apractical diet (36.2% protein, 16.5 kJ/g diet) atrates of 1, 2, 2.5, 3, 3.5, 4 or 5% of their bodyweight (BW) per day in two equal meals. Watertemperature was approximately 29 °C throughoutthe experiment. Percent weight gain increased almostlinearly with increasing feeding rates up to 2.5%BW/day beyond which no significant (P 〉 0.05)improvement in weight gain was observed. The specificgrowth rate of catfish fed rations of 1% BW/day was0.72%/day and this increased significantly to anaverage of 1.39%/day for catfish fed 2.5% BW/day andbeyond. Feed utilization did not differ significantly(P 〉 0.05) between fish fed 1.0 to 2.5%BW/day but decreased when rations were increased to3.0% BW/day and above. Feed efficiency ratio was0.79 for catfish fed 1.0% BW/day compared to a ratioof 0.27 for fish fed at 5% BW/day. Catfish fed 1.0%BW/day had the lowest condition factor, hepato- andviscerosomatic indices, but the highest carcass tobody weight ratio. These fish also had lowerproportions of whole body dry matter, lipid andprotein, carcass dry matter and lipid, and visceraldry matter and lipid than fish in other groups. Therewere no significant differences in either conditionindices or relative body composition of fish fedrations of 2.0 to 5.0% BW/day. Based on the growth,feed efficiency and body composition data obtained, afeeding rate of 2.5% BW per day is recommended forM. nemurus fingerlings raised at 29 °C.
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  • 34
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    Aquaculture international 8 (2000), S. 159-168 
    ISSN: 1573-143X
    Keywords: emersion ; growth ; Pecten maximus ; scallop spat ; survival ; transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Scallop spat production normally requires transfer between growthsystems. Simulated transport experiments were carried out in April, June,December and February to evaluate effects of transport time on greatscallop (Pecten maximus) spat growth and survival. The spat (1.7–1.8 mm in shell-height and 21–25 µg ash free dry weight [AFDW]) wereheld in moist coffee filters at a temperature of 10 °C for up to 24 h,before being replaced into sieves in rearing tanks at 15 °C. The studyshowed that by increasing air emersion time, survival and growthdecreased. No significant difference in the results between 0 and 4 h of airemersion was found, while the effects after 12 and 24 h differed betweenspat groups. Survival and growth rates showed seasonal differences. Meansurvival was 35–71% in April and 77–99% from June to February. In Junemean growth rates attained were 115–128 µm shell-height and 15–18µg AFDW per day compared with 49–69 µm and 3.8–7.0 µgper day for the other spat groups. Great scallop spat may survive atransfer time of 24 h, but transportation for longer than 12 h is notrecommended if subsequent high survival and growth rates are to beensured.
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  • 35
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    Aquaculture international 8 (2000), S. 207-225 
    ISSN: 1573-143X
    Keywords: growth ; mortality ; Pecten maximus ; suspended culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Growth and mortality of the king scallop, Pecten maximus, werecompared when grown in cages and by ear hanging in suspended culturein Fuengirola, Malaga, in southern Spain. Seed (juveniles) used in theexperiment was collected in September 1997 that had settled on collectorsin April-June, of that year. Culture in suspended cages began in January1998 when the seed measured 42.7 (3.3) mm shell height and ended inFebruary 1999. Significantly faster growth was found at a minimum culturedensity (16 scallops/cage) than at two other densities (24 and 36scallops/cage). Depth (1, 5 and 10 m from the bottom) influenced growth,poorest growth occurred closest to the bottom. Under optimum growingconditions, 16 scallops/cage suspended 10 m from the bottom, scallops grewto 10 cm shell length (legal size) by February 1999.In ear hanging culture, ropes were moored in April (51.3 (4.5) mm),June (58.2 (4.5) mm) and November 1998 (64.3 (4.9) mm).Initially, rapid shell growth was observed in all three cultures.Subsequently, the shells became covered with barnacles, Balanus sp.,that possibly caused total mortality of the April culture and led to highmortalities in the two other cultures.
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  • 36
    ISSN: 1573-143X
    Keywords: growth ; silver perch (Bidyanus bidyanus) ; size grading ; size variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This study presents two experiments addressing growth and size variation in fingerling silver perch (Bidyanus bidyanus. In the first experiment, fish close to mean population size were raised either in the presence or absence of five larger fish for 60 days. Mean specific growth rate (SGR) and increases in the coefficient of variation and skewness were lower in the presence of larger fish, indicating a negative effect of large fish on the growth of smaller ones. In the second experiment, fingerlings were graded into groups smaller and larger than the median size of the population and raised in size-sorted groups of 60 large or small fish and mixed groups of 30 fish of each size category, for 60 days. There was no difference in mean SGR among groups, nor between the mixed group ad the weighted mean of the small and large groups. Biomass gain was higher in the mixed groups than in the weighted small-and-large groups, probably due to a slightly lower survival in the groups comprised of large fish. The fact that the effect of large fingerlings on the growth of smaller ones was evident in the first, but not the second, experiment may be attributed to higher size disparity between large and small fingerlings in the first experiment.
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  • 37
    ISSN: 1572-9788
    Keywords: AFLP markers ; barley ; genetic linkage map ; partial resistance ; Puccinia hordei ; QTL mapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Using AFLP markers, a linkage map was constructed based on a recombinant inbred population of barley derived from a cross between a leaf rust susceptible line, L94, and a partially resistant line, 116-5. The constructed map showed a similar marker distribution pattern as the L94 × Vada map. However, it contained more large gaps, and for some chromosome regions no markers were identified. These regions are most likely derived from L94 because 116-5 was selected from the progeny of a cross of L94 × cv. Cebada Capa. Five QTLs for partial resistance to isolate 1.2.1. were mapped on the L94 × 116-5 map. Three QTLs were effective in the seedling stage, jointly contributing 42% to the total phenotypic variance. Three QTLs were effective in the adult plant stage, collectively explaining 35% of the phenotypic variance. Evidence for two additional linked minor-effect QTLs effective in the adult plant stage was also uncovered. The major-effect QTL, Rphq3, was the only one that was effective in both developmental stages. Moreover, Rphq3, was also identified in the L94 × Vada population, being effective to two rust isolates. The other QTLs were detected in either of the two populations, providing evidence for the existence of many loci for partial resistance to leaf rust on the barley genome. To date, 13 QTLs for partial resistance have been mapped, therefore, a strategy of accumulating many resistance genes in a single cultivar, resulting in a high level of partial resistance, is feasible.
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  • 38
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    Genetic resources and crop evolution 47 (2000), S. 571-581 
    ISSN: 1573-5109
    Keywords: allelic variation ; barley ; core collection ; genetic diversity ; isozyme loci
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Genetic diversity in 79 European accessions of the Barley Core Collections was surveyed using isozyme electrophoresis. A total of 26 alleles were observed at the ten isozyme loci. All loci were polymorphic except Pgd-1 which was monomorphic. The comparison of the results with those of previous studies indicates that most of the alleles occurring in the European Barley are also observed in this set of the European Barley Core Collections. Only five alleles (Est-1 Al; Est-5 Ag, Te; Pgi-1 C and Ndh-2 B) were absent. Nine of 26 alleles were rare alleles, which were detected only in one or two accessions. Moreover, most of rare alleles were detected in 6-rowed winter barley. It is very important to include rare alleles for maximising the genetic variations in core collections. In the set of European Barley Core Collection, 6-rowed barley contained larger diversity than 2-rowed barley; winter type contained larger diversity than spring type. The cluster analysis separated 79 accessions into three major groups. Group I is more complex and comprised 2-rowed spring, 2-rowed winter and 6-rowed winter barley. In this group, 18 accessions in the cluster A and 14 accessions in the cluster B possessed identical genotypes as judged from the ten isozyme data. Principal coordinate analysis could not clearly separate the spring cultivars from the winter barley lines, as well as not separate 2-rowed from 6-rowed barley.
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  • 39
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    Aquaculture international 7 (1999), S. 179-187 
    ISSN: 1573-143X
    Keywords: feeding ; growth ; larvae ; micro-algae ; pearl oyster (Pinctada margaritifera L.) ; survival
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This paper reports on an experiment to determine growth and survival of blacklip pearl oyster, Pinctada margaritifera (L.), larvae fed a 1:1 mixture of Isochrysis aff. galbana clone T-ISO and Pavlova salina at six different densities (1, 2, 5, 10, 20 and 30 × 103 cells ml-1. Larval growth and survival were assessed every four days over a 20–day period. Exponential and logistic regression models were fitted to the growth and survival responses, respectively. Overall growth of larvae fed ≥5 × 103 cells ml-1 was significantly greater (p 〉 0.01) than growth of larvae reared at other algal densities. The optimal food ration for maximum larval growth was 20 × 103 cells ml-1, which resulted in larvae with antero-posterior shell length of 230 μm after 20 days. These larvae were significantly larger (p 〉 0.05) than those in all other treatments at the end of the experiment. Survival of larvae fed 0, 1 and 2 × 103 cells ml-1 was significantly lower than that of larvae in all other treatments at the end of 15 days (p 〉 0.01). Maximal survival (8%) over the 20 day period was shown by larvae fed 10 × 103 cells ml-1, while lower survival was shown by larvae fed 2 × 103 cells ml-1 (2%) and 1 × 103 cells ml-1 (0%).
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  • 40
    ISSN: 1573-143X
    Keywords: Convict cichlid (Cichlasoma nigrofasciatum ; environmental UV effects ; growth ; ultraviolet radiation ; UVA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The long term (two generations) effect an enhanced (5%) sub-lethal ultraviolet-A (320–400 nm) irradiation on growth and survival rate of a convict cichlid (Cichlasoma nigrofasciatum is presented. Two UVA irradiated populations (G1-UVA and G2-UVA) and two control populations (G1-control and G2-control) were observed from age 60 to 403 days. The UVA populations were exposed to enhanced UVA irradiation from 4 months of age (G1-UVA and from egg's state (G2-UVA). The specific growth rates (daily weight and length increase) and the condition factors of the populations were not affected by the enhanced UVA, it depended more on the population size. At the adapted temperature range (27–29 °C) the survival rate of those populations was not affected by enhanced UVA. A combined effect of enhanced UVA and increased temperature (31–32 °C) was responsible for a high mortality rate in the GI-UVA. A total of 67% of the G1-UVA population died just within a week of exposure to high temperature.
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  • 41
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    Aquaculture international 7 (1999), S. 251-260 
    ISSN: 1573-143X
    Keywords: bacterial biofilm ; common carp (Cyprinus carpio) ; growth ; rohu (Labeo rohita) ; Tilapia (Oreochromis mossambicus)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Experiments were conducted to enhance the growth of common carp (Cyprinus carpio), rohu (Labeo rohita) and Mozambique tilapia (Oreochromis mossambicus) through use of sugarcane bagasse as substrate. Bagasse was suspended in water with or without supplementation with fertilizers. Bagasse supplemented with cattle dung and urea favoured higher zooplankton production and significantly (p 〈 0.05) increased fish growth by over 50% compared to bagasse or fertilizers on their own. This higher production of fish is attributed to bacterial biofilm promoted on the substrate which, apart from forming food for zooplankton and fish, contributed to improved water quality by lowering ammonia.
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  • 42
    ISSN: 1573-143X
    Keywords: bighead carp (Aristichthys nobilis) ; growth ; Laguna Lake ; salinity tolerance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Bighead carp (Aristichthys nobilis Oshima) fry of various ages (11, 18, and 35 days post-hatch) were exposed to the low salinities encountered during the annual intrusion of seawater in Laguna Lake, Philippines. Practical indices of salinity tolerance assessed the effect of a 96 h direct exposure to low salinities (0–16‰). Mean (MST) and median survival times (MST50) of fry decreased as salinity of rearing medium increased. Younger fry were less able to tolerate exposure to these salinities than their older cohorts. Median lethal salinity after 96 h (MLS) revealed higher tolerance among 35–day old fry (7.6‰) than 11 (2.3‰) and 18–day old fry (6.0‰), demonstrating that survival in saline water depends on their age at initial exposure to low salinities. Mean body weight of 18–day old fry reared in 0 and 2‰ for 3 and 4 weeks was higher than for those reared in 4 and 6‰ for the same period. Growth over these periods was inversely related with the range of salinities tested. These results demonstrate that, despite their known stenohalinity, bighead carp fry possess some degree of osmoregulatory capability, allowing them to survive and grow in lakes subjected periodically to saltwater inflow.
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  • 43
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    Biodegradation 10 (1999), S. 177-191 
    ISSN: 1572-9729
    Keywords: AQUASIM ; biodegradation ; biofilm ; growth ; kinetics ; methane ; modelling ; nitrification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This article discusses the growth of methanotrophic biofilms. Several independent biofilm growths scenarios involving different inocula were examined. Biofilm growth, substrate removal and product formation were monitored throughout the experiments. Based on the oxygen consumption it was concluded that heterotrophs and nitrifiers co-existed with methanotrophs in the biofilm. Heterotrophic biomass grew on soluble polymers formed by the hydrolysis of dead biomass entrapped in the biofilm. Nitrifier populations developed because of the presence of ammonia in the mineral medium. Based on these experimental results, the computer program AQUASIM was used to develop a biological model involving methanotrophs, heterotrophs and nitrifiers. The modelling of six independent growth experiments showed that stoichiometric and kinetic parameters were within the same order of magnitude. Parameter estimation yielded an average maximum growth rate for methanotrophs, μm, of 1.5 ± 0.5 d−1, at 20 °C, a decay rate, bm, of 0.24 ± 0.1 d−1, a half saturation constant, $${\text{K}}_{{\text{S(CH}}_{\text{4}} {\text{)}}} $$ , of 0.06 ± 0.05 mg CH4/L, and a yield coefficient, $$Y_{CH_4 } $$ , of 0.57 ±: 0.04 g X/g CH4. In addition, a sensitivity analysis was performed on this model. It indicated that the most influential parameters were those related to the biofilm (i.e. density; solid-volume fraction; thickness). This suggests that in order to improve the model, further research regarding the biofilm structure and composition is needed.
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  • 44
    ISSN: 1572-9680
    Keywords: A,nus rubra ; hedgerow intercropping ; Robina pseudoacacia ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The objective of this study was to determine crop and tree productivity in several alley cropping planting patterns. The four- year study was conducted in western Oregon, United States and involved irrigated sweet corn (Zea mays) intercropped between hedgerows of red alder (Alnus rubra) and black locust (Robina pseudoacacia). Three alley cropping planting patterns with variable plant populations and tree-crop proximity were tested with each tree species in a randomized block design. Space available to trees and crops determined yield of both plant components. High crop yield coincided with low pruning yield, and vice versa. Compared to monocropping, yield reductions in traditional alley cropping planting patterns with widely spaced, double tree rows ranged from 5% to 15%. A. rubra and R. pseudoacacia coppiced readily and produced 0.9 to 4.7 tons of dry matter pruning biomass per growing season, depending on planting pattern and year. A. rubra yield continually increased during the trial, while the ability of R. pseudoacacia to produce green manure after frequent coppicing appeared to weaken. After four years, soil organic matter was 4 to 7% higher in the topsoil of an alley cropping system compared to a monocropping system. However, continuous growing of sweet corn resulted in decreased soil organic matter levels in both cropping systems compared to original levels. Crop yield reductions and the need for additional management inputs constrain the implementation of alley cropping in temperate climates. Only if benefits other than minor soil fertility improvements are realized is alley cropping a feasible alternative in temperate climate regions.
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  • 45
    ISSN: 1573-143X
    Keywords: apparent digestibility coefficient ; fish meal ; growth ; Nile tilapa (Oreochromis niloticus) ; plant proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Apparent digestibility coefficient (ADC) values for a number of ingredients of plant or animal origin were obtained in order to formulate diets based on such values and to evaluate growth performance of Nile tilapia Oreochromis niloticus fed four experimental diets in which fish meal was gradually replaced by a mixture of other ingredients. The digestibility of various diet components was measured by using an inert marker in the feed and by using the Guelph faeces collecting system. ADC values of the ingredients tested were generally high, especially for fish meal. It was found that extruded pea seed meal (92.6%), defatted soybean meal (94.4%), full-fat toasted soybean (90.0%) and micronized wheat (88.6%) were the best vegetable proteins tested. Lupin seed meal and faba bean meal had similar ADC values for protein and energy. Groups of tilapia, initial mean body weight (SD) 6.7 (0.1) g, were fed experimental diets with the same digestible protein (DP) and digestible energy (DE) containing graded levels of a mixture of vegetable ingredients as partial or total replacement of fish meal protein. A growth trial was conducted over 12 weeks as partial or total replacement of fish meal protein. A growth trial was conducted over 12 weeks at a water temperature of 25 °C. Significant differences were observed for weight gain among tilapia fed diets D0, D33, D66 and D100 (containing only animal protein, 33, 66, and 100% of plant protein, respectively). No significant differences were observed for voluntary intake among tilapia fed diets D0, D33 and D66. These values were significantly lower than those observed for tilapia fed plant protein based diet (D100) and suggest the possibility of partial replacement of fish meal by vegetable proteins without negative effects.
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  • 46
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    Aquaculture international 7 (1999), S. 357-360 
    ISSN: 1573-143X
    Keywords: feed intake ; growth ; silver trevally (Pseudocaranx dentex) ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 47
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    Nutrient cycling in agroecosystems 54 (1999), S. 73-80 
    ISSN: 1573-0867
    Keywords: anhydrous ammonia ; dicyandiamide ; nitrification inhibitor ; urea-ammonium nitrate ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract One approach to reduce NO3 movement to groundwater is increasing the proportion of N supplied to the crop as NH4–N. Nitrification inhibitors (NI's) can be used to enhance NH4–N supply, but most studies have focused on yield response, with little attention given to environmental impacts. To determine the effect of enhanced NH4 sources on corn grain yield, N uptake and NO3 movement to groundwater, three sidedress materials were compared during three different growing seasons. Application of anhydrous ammonia (AA) and addition of the NI, dicyandiamide (DCD) to urea-ammonium nitrate (UAN) both reduced NO3 leaching losses relative to that incurred with UAN. With AA and UAN + DCD (as compared with UAN) subsoil solution NO3 concentrations were reduced by an average of: 1.1 mg NO3–N kg-1 soil following (fall 1993) a dry growing season; 2.4 mg NO3–N kg-1 soil during (spring and summer 1994) and 1.4 mg NO3–N kg-1 soil after (fall 1994) a wet growing season; and 0.5 mg NO3–N kg-1 soil following (fall 1995) a growing season with intermediate rainfall. Based on average solution NO3 concentrations and approximate drainage after harvest, estimated N losses between harvest and freeze-up were 43, 22 and 19 kg N ha-1 with UAN, UAN + DCD and AA, respectively (average of 3 years). Grain yields and aboveground N uptake were greater with AA and UAN + DCD than with UAN, and residual fertilizer N (applied N less aboveground N uptake) was 18, 6 and -2 kg N ha-1 with UAN, UAN + DCD and AA, respectively (average of 3 years). As is often observed, the trend for greater yield with addition of the NI was not large or consistent enough to meet registration criteria. Data demonstrating reduced NO3 leaching are also relevant, and positive environmental impacts should be a criterion for registration. For growers who are reluctant to use AA, this would provide an alternative source to maximize yield while minimizing NO3 movement to groundwater.
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  • 48
    ISSN: 1573-5036
    Keywords: barley ; genetic variation ; phosphate uptake ; rhizosphere ; root hairs ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Low phosphorus (P) availability in soils and diminishing P reserves emphasize the need to create plants that are more efficient P users. Knowledge of P efficient germplasm among the existing cereal varieties may serve as the basis for improving soil P use by selection and breeding. We had identified some cereal cultivars (winter wheat: Kosack and Kraka; winter barley: Hamu and Angora; spring barley: Canut, Alexis, Salka, Zita;) which differed (p〈0.05) in P depletion from thin slices (0.2 mm) of the rhizosphere soil under controlled conditions. In the present study, the same cultivars were studied under field conditions at three levels of P supply (no-P, 10 and 20 kg P ha-1) and the differences in P uptake as found in the previous work were confirmed. Under both conditions, the variation between the cultivars was greatest in soil without P fertilizers (no-P) for about 30 years. The variation in P uptake with most cultivars disappeared when 10 kg P ha-1 was applied. Root development did not differ between the cultivars much, but there was wide, consistent variation in their root hairs, regardless of growth media (solution, soil column and field). Increase in soil P level reduced the length of root hairs. The variation in root hairs between the cultivars was largest in no-P soil. When 10 kg P ha-1 was applied, the root hair lengths did not differ between the cultivars. Barley cultivars with longer root hairs depleted more P from the rhizosphere soil and also absorbed more P in the field. The relationship between root hairs and phosphorus uptake of the wheat cultivars was less clear. The wide variation in P uptake among the barley cultivars in the field and its relationship to the root hair development confirms that root hair length may be a suitable plant characteristic to use as criterion for selecting barley cultivars for P efficiency, especially in low-P soils.
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  • 49
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    Plant and soil 216 (1999), S. 93-101 
    ISSN: 1573-5036
    Keywords: Acacia cyanophylla ; endomycorrhizae ; growth ; nutrition ; Rhizobia ; salinity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The behaviour of Acacia cyanophylla Lind. plants submitted to salinity stress was followed in the greenhouse. The plants were associated with indigenous symbiotic microorganisms isolated from the coastal dunes of the Souss-Massa region. A two months period of salinity had a large negative impact on plant growth and acquisition of macro nutrients. However, the study underlined the role of the microbial inoculum for the plant in the achievement of salt tolerance. An isolate of Bradyrhizobium sp., RCM6 (R1), originating from the Massa dunes, was highly efficient in improving growth and nutrition of the A. cyanophylla. Double inoculation with the rhizobia and an endomycorrhizal complex, isolated from the Lamzar dunes had a clear additional positive effect, i.e. the fungi further increased the tolerance of the A. cyanophylla plants to salinity.
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  • 50
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    Plant and soil 217 (1999), S. 1-15 
    ISSN: 1573-5036
    Keywords: anchorage ; development ; growth ; root systems ; symmetry ; tree stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The stability of shallowly rooted trees can be strongly influenced by the symmetry of the ‘structural’ system of woody roots. Root systems of forest trees are often markedly asymmetric, and many of the factors affecting symmetry, including root initiation and the growth of primary and woody roots, are poorly understood. The internal and environmental factors that control the development, with respect to symmetry and rigidity, of shallow structural root systems are reviewed and discussed with particular reference to Sitka spruce (Picea sitchensis Bong. Carr.). Areas where there is insufficient knowledge are highlighted. A scheme is proposed that represents the root system as a set of spokes that are variable in number, size and radial distribution. Rigidity can vary between and along each of the spokes. The root system is presented as a zone of competition for assimilates, where allocation to individual roots depends upon their position and local variations in conditions. Factors considered include the production of root primordia of different sizes, effects of soil conditions such as the supply of mineral nutrients and water on growth of primary and woody roots, and the effect of forces caused by wind action on growth of the cambium, giving rise to roots which, in cross section, resemble I- or T-beams, and efficiently resist bending.
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  • 51
    ISSN: 1573-5036
    Keywords: ammonium ; H+ flux ; H+-selective microelectrode ; mineral uptake ; pH-indicator dye ; nitrate ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two methods for measuring proton fluxes along intact maize roots grown with NH 4 + or NO 3 − at pH 6.5 were compared. Videodensitometric measurement of changes in a pH-indicator dye by video camera was used to map pH around roots and determine the amounts of protons released by various root regions. This method was compared with potentiometric determination of the concentration of H+ in the unstirred layer at the root surface using ion-selective microelectrodes. With NH 4 + the roots released large amounts of H+ in preferential regions where the rate of flux can reach 1.4 or even 2.5 nmol m−1 s−1. Videodensitometry indicated a first region of root acidification in the subapical zone, but this was more difficult to localize with microelectrodes. With NO3 − both methods showed that the roots released small amounts of H+ and that the apical region took up H+ in the first 10 mm then sometimes released H+ over the following 10 mm of root. The H+ flux profiles obtained by both methods were in good agreement in terms of both order of magnitude of the fluxes and spatial differences along the root. These results suggest that videodensitometry, which is easier to use than potentiometry, can be used to screen different plant species or cultivars under various experimental conditions. The microelectrode technique is indispensable, however, for studying the underlying mechanisms of net H+ fluxes.
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  • 52
    ISSN: 1573-5036
    Keywords: 14CO2 labelling ; flow detection of beta radiations ; rhizosphere respiration ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The present work describes an original method to follow rate of 14CO2 and total CO2 production from rhizosphere respiration after plant shoots had been pulse-labelled with 14CO2. We used a radioactivity detector equipped with a plastic cell for flow detection of beta radiation by solid scintillation counting. The radioactivity detector was coupled with an infrared gas analyser. The flow detection of 14CO2 was compared to trapping of 14CO2 in NaOH and counting by liquid scintillation. First, we demonstrated that NaOH (1 M) trapped 95% of the CO2 of a gaseous sample. Then, we determined that the counting efficiency of the radioactivity flow cell was 41% of the activity of gaseous samples as determined by trapping in NaOH (1 M) and by counting by static liquid scintillation. The sensitivity of the 14CO2- flow detection was 0.08 Bq mL−1 air and the precision was 2.9% of the activity measured compared to 0.9% for NaOH trapping method. We presented two applications which illustrate the relevance of 14CO2-flow detection to investigations using 14C to trace photoassimilates within the plant-soil system. First, we examined the kinetics of 14CO2 production when concentrated acid is added to NaH14CO3. This method is the most commonly used to label photoassimilates with 14C. Then, we monitored 14CO2 activity in rhizosphere respiration of 5-week old maize cultivated in soil and whose shoots had been pulse-labelled with 14CO2. We conclude that alkali traps should be used for a cumulative determination of 14CO2 because they are cheap and accurate. On the other hand, we demonstrated that the flow detection of 14CO2 had a finer temporal resolution and was consequently a relevant tool to study C dynamics in the rhizosphere at a short time scale.
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  • 53
    ISSN: 1573-5087
    Keywords: barley ; distribution ; GC-MS ; gibberellin ; gibberellin-O-glucoside ; reconversion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The distribution of GA20 and GA20-13-O-glucoside was examined in mature caryopses of Hordeum vulgare L. cv. Himalaya. It was shown by GC-MS that GA20-13-O-glucoside is localized mainly in the embryo-containing part of the grain. In order to study the reconversion of GA20-13-O-glucoside during early germination, the glucoside pool of cv. Himalaya was [17-D2]-labelled by feeding [17-D2]GA20. The metabolites of [17-D2]GA20-13-O-glucoside were quantified by GC-MS during germination on the basis of doubly labelled standards. As soon as 6 h after incubation an increase of [17-D2]GA20 could be observed, followed by an increase of [17-D2]GA1 after 12 h, showing that the enzymes of the late GA metabolism are present before de novo biosynthesis started.
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  • 54
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    New forests 18 (1999), S. 301-314 
    ISSN: 1573-5095
    Keywords: chilling stress ; drought stress recovery ; field performance ; growth ; morphology ; nursery culture ; tree nursery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Five week old white spruce [Picea glauca (Moench) Voss] seedlings were placed within controlled-temperature growth chambers, and subjected to one of four periodic, chilling treatments for approximately 16 weeks. The treatments differed in the frequency of 24 hour exposure to 5 °C the seedlings received, and ranged from no chilling (control), to once every two, three or four days. After 25 weeks of growth, the control seedlings were significantly taller than all chilling-exposed seedlings, but stem diameters were similar. Chilling did not affect either needle length or needle density compared to control seedlings. During a water deficit test, frequently chilling-exposed seedlings maintained significantly higher mid-day shoot water potentials under extreme water stress. Re-watering after the drought resulted in all chilling-treated seedlings recovering faster to pre-stress shoot water potential levels than the control seedlings. Measurements of new root growth after 21 days at 10 °C indicated that previous chilling exposure delayed or inhibited new root production.
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  • 55
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    Genetic resources and crop evolution 46 (1999), S. 251-260 
    ISSN: 1573-5109
    Keywords: α-amylase ; β-amylase ; barley ; β-glucanase ; grain residual proteins ; grain size ; hordeins ; Hordeum vulgare ; landraces
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Thirty-two unimproved landraces of barley ( Hordeum vulgare L.) based on single plant selections in SE Finland were studied. Some of the lines still had ancient features, e.g., rachis brittleness in the tip of the spike. The lines showed 17 different and 16 unique hordein patterns and three lines showed more than one pattern, suggesting heterozygosity, and six different residual grain protein patterns. The three enzyme activities (α-amylase, β-amylase and β-glucanase) of grains germinated aseptically for 120 h were determined. The average activity levels were high compared with a standard of five global barleys and with those determined previously in wild barley (H. vulgare ssp. spontaneum (Koch) Archers et Graebn.) grown in Finland. The ssp. spontaneum sample of 257 accessions showed significantly (P〈0.001) less variation in β-amylase and significantly (P〈0.001) lower mean activity of all three enzymes. The high variation of these chemotypes indicates great potential variation of possible use by breeders has been lost by the disappearance and displacement of local barleys with commercial cultivars since 1950 in Finland before which barley cultivation and adaptation to the local environment had occurred over more than 3000 years. Selection for currently preferable plant characteristics in the descendants of the cross of HA52 (a landrace selection) × Adorra discriminated the hordein pattern of HA52 not being directly selected. The best landraces outyield the standard cultivars especially when there was no lodging. Top yield and small grains appeared to be associated characteristics under the environmental selection pressure, conflicting with the man-made regulations of the EU.
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  • 56
    ISSN: 1573-5060
    Keywords: barley ; Erysiphe graminisDC. f.sp. hordei Marchal ; genetic mapping ; Hordeum vulgare L. ; partial resistance ; QTL ; specific resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The genetic basis of resistance to powdery mildew (Erysiphe graminis DC. f.sp. hordei Marchal) was analyzed using doubled haploid barley (Hordeum vulgare L.) lines from the cross Harrington/TR306. Based on infection types observed after inoculation with defined single-conidium isolates, the lines were classified into four groups. The observed phenotypic ratio fit a two-locus model. The two putative loci were mapped relative to molecular markers. One coincided with the previously mapped dMlg locus on chromosome 4. Based on the observed infection types, Harrington carries the Mlg resistance allele, and TR306 carries a second locus on chromosome 7 (5H); this was tentatively designated Ml(TR). It is the first reported race-specific powdery mildew resistance gene located on that chromosome. These two loci were also detected by simple interval mapping of disease severity data from naturally infected field plots. Composite interval mapping with the first two resistance loci as co-factors detected an additional locus on chromosome 6, with a minor effect on resistance. Finally, superimposing the race-specific classification onto the field data provided evidence for a minor-effect locus on chromosome 7 (5H). The Mlg locus had the largest effect, the Ml(TR) locus had an intermediate effect and the other two loci had very small effects. This study demonstrates the effectiveness of an integrated approach to identifying and mapping resistance loci using classification data from inoculated experiments and quantitative data from field experiments.
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  • 57
    ISSN: 1573-5060
    Keywords: barley ; frost-tolerance ; cold-regulated genes (COR) ; winterhardiness ; winter survival
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Winterhardiness is a basic trait for successful winter survival barley (Hordeum vulgare L.) crop. Freezing tolerance, a fundamental component of winterhardiness, is based on an inducible process known as hardening or cold acclimation that occurs when plants are exposed to low non-freezing temperatures. In the recent years, many temperature-dependent genes specifically expressed during hardening have been isolated. Current data on relationship between gene expression and cold tolerance are mostly based on plants grown and hardened under environmentally controlled conditions and, usually, over a short period of time. In order to verify whether variations in the molecular response to cold are likely to be of significant adaptive value under natural environments, we have followed the accumulation of several COR genes ( pt59, pao86 and paf93) and proteins (COR14a and COR14b) during the 1996/97 and 97/98 winter seasons in barley cultivars with contrasting winterhardiness capacity grown under field conditions. In the 1996/97 experiment, a winter cultivar Onice and a spring cultivar Gitane were tested for the accumulation of the cold-regulated genes and proteins. The ability of the plants to promote a strong molecular response to cold was found to be associated with the winterhardiness capacity of the two cultivars. This result was further tested in the winter season 1997/98 using 10 barley varieties. All winter cultivars showed high accumulation of the cold-regulated proteins COR14a and COR14b, while some variations for this character were detected in the spring cultivars suggesting that the selection for winter survival has been effective to fix the high COR14 accumulation capacity. We conclude that a high level of COR14 may be a component the winter survival capacity of barley.
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  • 58
    ISSN: 1573-5087
    Keywords: auxin biosynthesis ; auxin inhibitors ; indole analogues ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Maize liquid endosperm extracts contain the enzymes necessary for all of the steps of the plant IAA biosynthetic pathway from tryptophan, and provide a means to assay the pathway in vitro. We have analyzed the reactions in the presence of a series of indole and indole-like analogues in order to evaluate the potential of these compounds to act as inhibitors of IAA biosynthesis. Such inhibitors will be useful to investigate the tryptophan to IAA pathway, to determine the precursors and intermediates involved, and to select for mutants in this process. A number of such compounds were tested using in vitro enzyme assays for both the tryptophan dependent IAA biosynthesis pathway and for tryptophan synthase β activity. Some compounds showed strong inhibition of IAA biosynthesis while having only a slight effect on the reaction rate of tryptophan synthase β. These results: (1) show that IAA biosynthesis can be selectively inhibited relative to tryptophan biosynthesis; (2) suggest potential ways to screen for IAA biosynthetic pathway mutations in plants; and (3) provide additional tools for studies of IAA biosynthesis in plants.
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  • 59
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    Plant growth regulation 29 (1999), S. 101-112 
    ISSN: 1573-5087
    Keywords: ABA ; cell wall-associated peroxidase ; expansins ; growth ; pH ; XET
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Over the past decade it has become clear that we cannot always explain the observed reduction in leaf expansion rates during drought by measuring the plant's water relations. This has led us to question the possibility of a role for the cell wall and its biochemical machinery in controlling the rate of leaf expansion during drought. However, if we are to reject or modify previous assumptions regarding the control of leaf expansion during drought, then we must offer alternative explanations. This article addresses recent work from this laboratory and in the literature, concerning the involvement of cell wall-enzymes, pH and abscisic acid (ABA) in regulating leaf expansion during water deficit.
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  • 60
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    Plant and soil 209 (1999), S. 217-224 
    ISSN: 1573-5036
    Keywords: barley ; H+-ATPase ; malondialdehyde ; salt ; silicon ; superoxide dismutase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two contrasting barley (Hordeum vulgare L.) cultivars: Kepin No.7 (salt sensitive), and Jian 4 (salt tolerant) were grown in a hydroponics system containing 120 mol m-3 NaCl only and 120 mol m-3 NaCl with 1.0 mol m-3 Si (as potassium silicate). Compared with the plants treated with salt alone, superoxide dismutase (SOD) activity in plant leaves and H+-ATPase activity in plant roots increased, and malondialdehyde (MDA) concentration in plant leaves decreased significantly for both cultivars when treated with salt and Si. The addition of Si was also found to reduce sodium but increase potassium concentrations in shoots and roots of salt-stressed barley. Sodium uptake and transport into shoots from roots was greatly inhibited by added Si under salt stress conditions. However, Si addition exhibited little effect on calcium concentrations in shoots of salt-stressed barley. Thus, Si-enhanced salt tolerance is attributed to selective uptake and transport of potassium and sodium by plants. The results of the present study suggest that Si is involved in the metabolic or physiological changes in plants.
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  • 61
    ISSN: 1573-5036
    Keywords: field root studies ; modelling ; root ; root growth ; root mapping ; root orientation ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Root length density (RLD) is an important determinant of crop water and nutrient acquisition, but is difficult to measure in the field. On a soil profile, in-situ counts of root impacts per unit surface on soil profiles (NI) can be used to calculate RLD if crop-specific parameters for preferential root orientation (anisotropy) are known. An improved method for field determinations of RLD was developed and validated for maize at sites in Côte d'Ivoire and Burkina Faso. Root anisotropy was measured with cubes of undisturbed soil with 0.1 m sidelength, based on NI observed on three planes oriented perpendicularly to each other. RLD was also measured for the enclosed volume. Repetition of such measurements enabled estimation of the robustness across sites of empirical and geometric models for the relationship between RLD and NI:RLD = NI CO, with CO being the coefficient of root orientation, theoretically equals 2 for an isotropic distribution. Root systems were found to be nearly isotropic, except near the root front (0.3 to 0.5 m), where roots had a preferentially orthotropic orientation. Measured RLD was generally about 50% larger than RLD calculated from observed NI and CO, indicating that at least one of the measurement techniques had a systematic error. The ratio between measured and calculated RLD (CE), which ranged from 0.8 to 2, increased with the age of the plants and decreased with soil depth. CE was therefore introduced as an additional coefficient, resulting in RLD = NI CO CE. The empirical value for CO CE was between 2 and 5. The empirical coefficients CO and CE were the same for the sites in Cote d'Ivoire (oxisol with an iron pan at 0.6 to 0.9 m) and Burkina Faso (alfisol with an iron pan at 0.4 to 0.8 m). The model was validated with independent data sets at both sites, and gave satisfactory predictions of RLD on the basis of NI obtained from single soil planes, which can be easily measured in the field.
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  • 62
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    Plant and soil 215 (1999), S. 65-72 
    ISSN: 1573-5036
    Keywords: barley ; boron deficiency ; Hordeum vulgare ; Triticum aestivum ; variation ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Responses of a range of barley (Hordeum vulgare L.) genotypes to boron (B) deficiency were studied in two experiments carried out in sand culture and in the field at Chiang Mai, Thailand. In experiment 1, two barley genotypes, Stirling (two-row) and BRB 2 (six-row) and one wheat (Triticum aestivum L.) genotype, SW 41, were evaluated in sand culture with three levels of applied B (0, 0.1 and 1.0 μM B) to the nutrient solution. It was found that B deficiency depressed flag leaf B concentration at booting, grain number and grain yield of all genotypes. In barley Stirling, B deficiency also depressed number of spikes plant-1, spikelets spike-1 and straw yield. However, no significant difference between genotypes in flag leaf B concentration was found under low B treatments. Flag leaf B concentration below 4 mg kg-1 was associated with grain set reduction and could, therefore, be used as a general indicator for B status in barley. In experiment 2, nine barley and two wheat genotypes were evaluated in the field on a low B soil with three levels of B. Boron levels were varied by applying either 2 t of lime ha-1 (BL), no B (B0) or 10 kg Borax ha-1 (B+) to the soil prior to sowing. Genotypes differed in their B response for grain spike-1, grain spikelet-1 and grain set index (GSI). The GSI of the B efficient wheat, Fang 60, exceeded 90% in all B treatments. The B inefficient wheat SW 41 and most of the barley genotypes set grain normally (GSI 〉80%) only at the B+. In B0 GSI of the barley genotypes ranged from 23% to 84%, and in BL from 19% to 65%. Three of the barley with severely depressed GSI in B0 and BL also had a decreased number of spikelets spike-1. In experiment 3, 21 advanced barley lines from the Barley Thailand Yield Nursery 1997/98 (BTYN 1997/98) were screened for B response in sand culture with no added B. Grain Set Index of the Fang 60 and SW 41 checks were 98 and 65%, respectively, and GSI of barley lines ranged between 5 and 90%. One advanced line was identified as B efficient and two as moderately B efficient. The remaining lines ranked between moderately inefficient to inefficient. These experiments have established that there is a range of responses to B in barley genotypes. This variation in the B response was observed in vegetative as well as reproductive growth. Boron efficiency should be considered in breeding and selection of barley in low B soils.
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  • 63
    ISSN: 1573-5036
    Keywords: growth ; porewater ; salt marshes ; silicon ; Spartina ; tissue concentrations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Analysis of silicon concentrations of various halophytes from salt marshes in the S.W. Netherlands shows that the silicon concentration of Spartina anglica (Gramineae) is relatively high. To study the influence of dissolved Si concentrations on growth and plant tissue concentrations of S. anglica, silicic acid was introduced into the sediment of natural patches of this halophyte occurring on a tidal flat. This resulted in a strong increase in dissolved silicon levels in the sediment porewater. In addition, S. anglica was cultured in the laboratory on nutrient solution enriched with dissolved silicon. Neither in the field nor in the laboratory experiment did the increased silicon levels have effects on shoot growth or led to consistent increases in the silicon concentration of plant tissues. Finally, different S. anglica stands in a number of salt marshes around the Oosterschelde basin were examined on sediment porewater silicon concentrations and silicon plant tissue concentrations. Sediment porewater silicon levels ranged between 36 and 554 μM. The average silicon concentration of the shoots from the various populations ranged between 3.52 and 11.73 mg/g DW. Consistent with the results of the field and laboratory experiments, there was no correlation between porewater silicon concentrations and average shoot length at the different sites, nor between porewater silicon concentrations and shoot silicon levels. Apparently, vegetative growth and tissue silicon concentrations of S. anglica do not respond to concentrations of dissolved Si in the range to which the plants were exposed naturally or experimentally in the field and in the laboratory (ca. 15–550 μM). In the data set pertaining to the different S. anglica field populations, however, negative correlations were observed between the average number of leaves per shoot at the different locations and the total silicon content of the 4th and 2nd leaves and of the entire shoots. The possible mechanisms explaining differences in tissue Si concentrations are discussed.
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  • 64
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    Euphytica 110 (1999), S. 175-180 
    ISSN: 1573-5060
    Keywords: barley ; Hordeum vulgare ; Pyrenophora teres
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A half-diallel was made between five six-rowed Nordic spring barleys to study the genetics of resistance to net blotch. Twenty-five doubled-haploid (DH) lines from each cross and the parents were sown in hill plots in Finland in 1997 and 1998. The plots were artificially inoculated with Pyrenophora teres Drechs. f. teres Smedeg. and assessed for resistance to net blotch. There were statistically significant differences in resistance of the five parents to net blotch. General combining ability (GCA) of the parents and specific combining ability (SCA) effects in the progeny were statistically significant in both years, but GCA effects predominated. Evidence for additive epistasis was minimal. Progeny of a particular cross were less resistant to net blotch than the better parent. The most resistant progeny were derived from the cross between the two most resistant parents, Pohto and WW7977, and resistance was governed by at least eleven effective factors. Narrow sense heritability estimates for resistance to net blotch were high during both years (0.84–0.99). It appears that net blotch resistance of progeny from crosses can be largely predicted from reactions of the parents. Quantitative resistance to net blotch can be further advanced by identification and incorporation of superior parents, from a screening such as reported here, into a recurrent selection breeding programme.
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  • 65
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    Plant and soil 209 (1999), S. 9-20 
    ISSN: 1573-5036
    Keywords: barley ; response functions ; saline sprinkling ; salt leaf content ; salt tolerance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Evaluation of the salt tolerance of crop cultivars under field conditions is greatly complicated by the typical temporal and spatial variability of soil salinity. We obtained the grain yield – salinity response functions of 124 barley genotypes by growing them in ten salinity treatments imposed by a Triple Line Source Sprinkler (TLS) system during five consecutive years. Additional objectives were to ascertain the consistency and reproducibility over years of these functions, to quantify the deleterious effects of saline sprinkling irrigations, and to assess correlations between salinity tolerance and leaf sap salt concentration. The consistency and reproducibility of the response functions within and between years were adequate (only 8% of the response functions were discarded for statistical reasons). The Y m (grain yield without salinity) and the EC50 (the EC e that reduces yield by 50%) estimates were not correlated (P 〉 0.05) suggesting that the most productive genotypes were not necessarily less salinity tolerant. Y m was positively and significantly (P 〈 0.01) correlated with Y6 and Y12 (fitted grain yields at EC e values of 6 dS m-1, and 12 dS m-1, respectively), indicating that it is a useful statistic in the selection of barley genotypes most productive under medium and high salinities. Foliar salt uptake due to saline sprinkling irrigations decreased the EC50 by around 50% as compared with the salinity tolerance obtained with surface irrigation systems. No consistent relationships were found between either Y m or EC50 and the leaf sap osmotic potential, Cl, Ca, Na and K concentrations. They could not therefore be used in screening for salinity tolerance of barley. On the basis of the evidence from the present study, Y m is the best statistic for predicting the most productive barley genotypes in salt-affected soils.
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  • 66
    ISSN: 1573-5036
    Keywords: 2 ; 4-D ; germination ; growth ; salinity-tolerance ; seed treatment ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Experiments were conducted under laboratory and greenhouse conditions to study the effect of 2,4-D on rooting and salinity tolerance of wheat. Seeds of one commercial wheat (Inqalab-91) and three salt-tolerant wheat lines (WL-41, WL-359, and WL-1073 developed through wide hybridization) were included in the study. Preliminary and short-term experiments were conducted to determine the level of 2,4-D (administered through seed soaking for 24.5 h. at 25 °C in the dark) at which the maximum number of roots emerged. Under hydroponic conditions, 2,4-D treatment of seeds caused an increase of 60 to 100% in the number of primary roots. The maximum increase in the number of roots was observed in one of the salt tolerant wheat lines (WL-41). The roots appeared in bunches but showed stunted growth at higher levels of 2,4-D. Dry matter accumulation decreased markedly; the effect was more pronounced in Inqalab-91 which is less tolerant to stress than other wheat lines. In all wheat types, allocation of dry matter to roots relative to shoot increased due to 2,4-D treatment. In soil, seeds treated with different levels of 2,4-D showed a germination delay of 1–3 days. Although the number of primary roots increased, 2,4-D treatment caused a decrease in total dry matter accumulation by plants grown for 40 days. In another experiment, conducted under greenhouse conditions, seed germination and growth of seedlings was significantly retarded in saline compared to that in non-saline (normal) soil. Initially, the pace of germination of treated seeds as well as seedling growth was slower in both soils, but after six weeks, the leaf area of seedlings raised from treated seeds was greater than those raised from untreated seeds. Towards maturity, plants arising from treated seeds developed wider and longer flag leaves leading to enhanced yield. Root biomass decreased in saline soil as compared to normal soil. However, 2,4-D treatment caused a substantial increase in root biomass in saline soil and the roots were harder in texture in wheats other than Inqalab-91. Seed treatment with 2,4-D led to a significant improvement in the number of productive tillers, yield of straw and grain, and grain protein content of all wheats grown in saline soil. Plants grown in normal soil did not show any marked effect of seed treatment on grain yield and other agronomic parameters. The four wheats showed substantial differences for different parameters but the salt tolerant wheat lines performed better compared to the commercial variety Inqalab-91.
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  • 67
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    Euphytica 108 (1999), S. 145-150 
    ISSN: 1573-5060
    Keywords: maize ; North Carolina model 2 ; salinity tolerance ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The genetic basis of salt tolerance was examined in selected salt tolerant and sensitive material from a sample of accessions previously assessed for variability in salinity tolerance. The North Carolina Model 2 Design and analysis was followed, tolerance being assessed in 10-day-old seedlings grown in salinized solution culture at control (0 mM), 60 mM and 80 mM NaCl concentrations). Salinity tolerance was shown to be under the control of genes with additive and non-additive effects, with broad and narrow sense heritability estimates being approximately 0.7 and 0.4 over all treatments.
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  • 68
    ISSN: 1573-5060
    Keywords: barley ; embryogenesis ; medium ; regeneration ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Media have been developed for somatic embryogenesis and plant regeneration from immature inflorescences and immature scutella of elite cultivars of wheat, barley and tritordeum. For wheat and tritordeum inflorescences, regeneration from embryogenic calluses induced on medium with picloram was almost twice as efficient as regeneration from cultures induced on 2,4-dichlorophenoxyacetic acid (2,4-D). The addition of zeatin at 5 or 10 mg l−1 to regeneration media had a positive effect on regeneration. For scutella, the highest frequencies of embryogenesis (85%) and regeneration (50%) was obtained using an induction medium containing 2 mg l−1 of 2,4-D and half concentration of aminoacids. The morphogenetic capacities of 19 different cultivars of wheat, barley and tritordeum were compared, and clear differences were found both between explants and genotypes. In wheat, embryogenic capacity from inflorescences (average of 92%) was higher than from immature scutella (average of 62%). However, shoot regeneration from scutella was clearly higher than from inflorescences (averages of 63%, and 18% respectively). Frequencies of regeneration in wheat and barley varied widely among the cultivars tested and in both species no difference was found between spring and winter varieties.
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  • 69
    ISSN: 1573-5060
    Keywords: α- and beta-amylase ; barley ; diastatic power ; embryo and endosperm genetic effects ; malt N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Seed of seven cultivars of two-rowed barley (Hordeum Vulgare L.) and F2 seed from a half-diallel set of crosses among the cultivars were malted in two years to obtain data on diastatic power (DP), alpha-amylase activity (αAA), beta- amylase activity (βAA) and malt nitrogen (N) content. Embryo and endosperm genetic effects on the traits were studied by using a genetic model including genotype × environment interaction for malting quality characters. Variation of the four malting quality traits was affected by gentic effects and environmental interaction. Performance of DP and βAA was mainly controlled not only by endosperm dominance effects but also by embryo genotype × environment interaction and endosperm dominance × environment interaction. Variation of αAA and malt N content was controlled by both embryo and endosperm genetic effects, but the embryo dominance and endosperm additive effects contributed a major part to the total genetic effects. Significant interaction variances (embryo additive × environment and dominance × environment and endosperm dominance × environment) were also observed for αAA and malt N content. Diastatic power was related positively to βAA. Malt N content was associated positively with DP, largely because of the relationship between malt N and βAA. No obvious phenotype association between DP and αAA was found. General narrow-sense heritabilities of αAA and malt N content were 26.1% and 27.8%, respectively.
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  • 70
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    Aquaculture international 7 (1999), S. 201-205 
    ISSN: 1573-143X
    Keywords: fingerlings ; growth ; light regimes ; photoperiod ; silver catfish (Rhamdia quelen) ; survival
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 71
    ISSN: 1573-143X
    Keywords: gilthead sea bream (Sparus aurata) ; growth ; hybridization ; red porgy (Pagrus pagrus) ; survival
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Hybridization between gilthead sea bream, Sparus aurata, and red porgy, Pagrus pagrus, was undertaken and viable hybrids were produced by an artificial hormonal-induced cross. The hybrids, from the cross of female red porgy and male gilthead sea bream (Pp × Sa), survived through the yolk-sac larval stage. The hybrids produced from the cross of female gilthead sea bream and male red porgy (Sa × Pp) presented higher mortality in the larval stage (98.4%) compared to gilthead sea bream (80.0%) and red porgy (92.5%). Afterwards, the Sa × Pp hybrid was compared to the offspring of its parental species under the same rearing conditions (tanks of 500 l capacity, natural light, ambient temperature, self-feeding with commercial feed) in a 40–week experiment. In this comparative study, the Sa × Pp hybrid had intermediate mortality rate (6%), compared to gilthead sea bream (0%) and red porgy (21%). The growth profile of this hybrid resembled the slow growing phases of its parents (red porgy in warm period and gilthead sea bream in cold period). The feed conversion ratio between fish forms was not significantly different (1.54–1.84 in the Sa × Pp hybrid, 1.53–1.56 in the maternal species and 1.33–1.40 in the paternal one). The body weight variation in the Sa × Pp hybrid was quite high (31.7–37.9%), compared to that in gilthead sea bream (19.7–24.7%) and red porgy (18.0–31.3%). With respect to body coloration, the Sa × Pp hybrid was distinguishable and classified into groups of red porgy-like (55.1%), gilthead sea bream-like (40.6%), and intermediate forms (4.3%). The preliminary results of this study proved that the produced Sa × Pp hybrid had too low a performance for aquaculture use, but the interesting consequent hereditary potential could be a useful tool in fish hybridization practice.
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    Aquaculture international 7 (1999), S. 287-293 
    ISSN: 1573-143X
    Keywords: bone mineralization ; calcium requirement ; feed efficiency ; growth ; semi-purified diet ; tiger puffer (Takifugu rubripes)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Juvenile tiger puffer (Takifugu rubripes) were fed semi-purified diets with graded levels (0–0.40%) of calcium (Ca) supplements for 8 weeks at a temperature of 23.0–25.5 °C. At the end of the feeding experiment, average final body weight increased with increasing dietary Ca levels. A diet without Ca supplement resulted in poor average final body weight and 0.05% dietary Ca supplement could not significantly improve the growth. However, supplemental Ca levels of 0.10–0.40% significantly increased growth. Dietary Ca supplements of 0.10% or more also improved the feed efficiency in tiger puffer. Ca and phosphorus contents of the bone were independent of dietary Ca supplements. However, 0.40% Ca in the diet decreased the zinc and manganese contents of bone. Results indicated that supplemental Ca levels of 0.10–0.20% in a semi-purified diet were required to maintain normal growth, feed utilization and bone mineralization of tiger puffer.
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  • 73
    ISSN: 1573-143X
    Keywords: body composition ; dietary protein ; fecundity ; gonad maturation ; growth ; Nile tilapia (Oreochromis niloticus)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Six-week-old Nile tilapia (Oreochromis niloticus) fry with an average weight (SD) of 0.51(0.2) g were reared for 140 days on five formulated, isocaloric diets of different protein levels (25, 30, 40 and 45% by dry weight). Fish fed diets of higher protein levels (40 and 45%) showed better growth and feed conversion ratio than those on lower protein levels. Fast-growing fish matured earlier. Maturation rate was affected by the dietary protein levels. Males matured earlier than females: the first mature males were recorded when they were 14 weeks old, whereas the females matured after 18 weeks. In both sexes, mean percentage of mature fish rose with increasing dietary protein level, the percentage of mature males being higher than that of the females. Similarly, the percentage of mature fish rose with the increasing age of fish, with more than 50% males and females mature at the age of 22 and 24 weeks, respectively, the exception being the 25% protein diet fed fish, where the percentage of mature fish was below 50%. In all treatments, spawning was initiated when the fish were 22 weeks old. Smallest size at spawning of males and females was 9.2 cm (13.1 g) and 8.1 cm (8.9 g), respectively, and dietary protein levels influenced the size of fish at first maturity. For both sexes, no difference was found in the gonado-somatic index (GSI) among different treatments. Fecundity increased with increasing dietary protein levels, but significant differences were found only between 40–45% and 25–35% dietary protein levels. The relative fecundity (eggs g−1 female) was higher at the lower dietary protein levels (25–35%) than at the higher dietary protein levels (40–45%). The dietary protein levels did not have any significant influence on the size and weight of mature eggs. The chemical composition of fish and mature ovaries was significantly influenced by the dietary protein level.
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    Genetic resources and crop evolution 46 (1999), S. 361-369 
    ISSN: 1573-5109
    Keywords: barley ; Chinese germplasm ; disease resistant ; dwarf ; protein content
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A total of 16,251 barley accessions including 6,026 naked barley have been collected over the whole country in China. Among them 8,865 were landraces, 1,035 bred lines and 6,351 foreign accessions. The agroecological distribution, classification and characterization of agricultural traits, abiotic stress tolerance, disease and pest resistance of the collection are described.
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  • 75
    ISSN: 1572-9788
    Keywords: barley ; ethyl carbamate ; fermentability ; molecular markers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two barley quality characters of specific interest to whisky distillers are fermentability and production of the ethyl carbamate precursor, epi-heterodendrin. The former is a quantitative trait, while the latter may be determined by a single Mendelian genetic factor. Molecular markers have been used to map, to barley chromosome 5(1H), the locus responsible for epi-heterodendrin synthesis and the inheritance of this character and a closely linked microsatellite have been followed through the pedigrees of several contemporary cultivars. Six loci, which affected fermentability in random inbred lines from a barley cross, have been mapped to chromosomes 2(2H), 3(3H) and 7(5H). This would permit the use of molecular markers in a breeding programme, to select barleys best suited for distilling. In addition, one of the loci related to fermentability mapped to an area of the genome indicated, by a previous study, to affect the activity of β-amylase, a character likely to influence fermentability. Molecular markers may, therefore, be powerful tools in exploring the contribution and detecting the mode of action of the genetical components influencing malt whisky distilling.
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  • 76
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    European journal of plant pathology 104 (1998), S. 29-36 
    ISSN: 1573-8469
    Keywords: biological control ; Zea mays ; Pythium spp. ; Fusarium spp. ; seed bacterization Burkholderia cepacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Burkholderia cepacia (syn. Pseudomonas cepacia) strain PHQM100 applied as a seed coating was tested in growth chamber experiments for its ability to suppress preemergence damping-off, and postemergence damping-off in corn induced by Pythium and Fusarium spp. The symptoms observed in bioassays with soils naturally infested with the fungal pathogens were seed rot with Pythium spp. and mesocotyl and root tissue necrosis in the presence of Fusarium spp. Three corn cultivars that differed in their susceptibility to damping-off pathogens were used. Cultivar L was susceptible to pre- and postemergence damping-off, whereas cv. LPDP and cv. LG11 were moderately resistant and resistant to the damping-off diseases respectively. In the presence of Pythium spp., seed treatment with B. cepacia reduced seed rot, as compared to the untreated seeds, and this reduction was more consistent in the cv. LPDP than in the resistant cv. LG11 or the susceptible cv. L. In soils infested with Fusarium spp., seed treatment significantly reduced root and mesocotyl necrosis as compared to the untreated seeds, and this reduction was more consistent in the resistant cultivars LG11 and LPDP than in the susceptible cv. L. Root colonization levels by B. cepacia were similar in the three corn cultivars tested. Biocontrol efficiency of B. cepacia varied among cultivars mainly due to the differences in their susceptibility to the fungal pathogens. In spite of variability and also irrespective of the soil characteristics, B. cepacia increased seedling emergence and decreased mesocotyl and root necrosis when used as a seed coating.
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  • 77
    ISSN: 1573-8469
    Keywords: barley ; resistance elicitor ; cultivar mixtures ; complexity ; diversity ; RAPD ; virulence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Powdery mildew populations were analysed to determine the effects of a resistance elicitor and cultivar mixtures on genetic complexity and diversity. Isolations were made from a range of spring barley monocultures and mixtures in a field trial, and characterised for virulence and RAPD profile. In a second trial, isolates were taken from a single mixture from untreated and resistance elicitor-treated areas and from the components of the mixture in monoculture. The mildew population was not only highly heterogeneous for virulence characteristics, but also proved heterogeneous within pathotypes for molecular markers, indicating the major impact of sexual recombination on population structure and the lack of clonal dominance. Various diversity measurements were compared and the value of dissimilarity measurement for revealing genetic distance within a population was highlighted. There was a trend towards increasing complexity as the season progressed, but there was no consistent relationship between cultivar or mixture, disease control treatment, fertiliser treatment, replicate or position in trial, and pathogen genotype. Whilst the resistance elicitor did reduce mildew by 78% in the first trial, and there was no interaction with fertiliser level in its expression, control was substantially less in the second trial. There were no differences between mildew isolates from elicitor and control treatments. It was felt that more effective and consistent resistance elicitors need to be developed before it can be stated that they are unlikely to be eroded by selecting resistant or adapted mildew genotypes.
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  • 78
    ISSN: 1573-8469
    Keywords: automatic immersion system ; barley ; peanut clump virus ; Plasmodiophoromycetes ; sorghum ; sugar beet
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The temperature requirements of three single cystosorus strains of Polymyxa sp. from India were studied at 15–18, 19–22, 23–26 and 27–30 °C (night-day temperature), and compared with the temperature requirements of three strains of P. graminis from Belgium, Canada and France and two strains of P. betae from Belgium and Turkey. Sorghum was used as the host-plant for the Indian strains; the strains of P. graminis and P. betae from temperate areas were cultivated on barley and sugar beet, respectively. The cystosori germination and the development of plasmodia, zoosporangia and cystosori of Polymyxa sp. from India were optimal at 27–30 °C. Infection progression was slower at 23–26 °C than at 27–30 °C. At 19–22 °C, infection was insignificant. No infection occurred below 19 °C. In contrast, the infection of barley with P. graminis strains from temperate areas was optimal at 15–18 °C, but at 19–22 °C the progression appeared inconsistent and infection stayed low. Above 22 °C, infection was insignificant. P. betae strains showed consistent infection in the range of 15–18 °C to 27–30 °C. Plasmodia formation and cystosori detection of the Belgian strain were slightly advanced at 23–26 °C compared to 19–22 °C but clearly restrained at 27–30 °C. Fungus development of the P. betae strain from Turkey was almost as high at 27–30 °C as at the lower temperatures. These results strengthen the case for distinguishing between Polymyxa sp. from India and P. graminis or P. betae from temperate areas.
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  • 79
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    European journal of plant pathology 104 (1998), S. 829-833 
    ISSN: 1573-8469
    Keywords: colony morphology ; mass fractal dimension ; branching ; mildew ; barley ; Erysiphe graminis f.sp. hordei ; nutrition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The mass fractal dimension (MFD) of colonies of mildew (Erysiphe graminis f.sp. hordei) growing on barley was calculated as a measure of their spatial structure. Despite the elongated shape of the colonies imposed by the leaf cellular structure, the MFD remained constant with scale. The mildew MFD differed on different cultivars of barley, and was greater on leaves produced under higher nutrient level indicating a physiological component. Lower MFD values correspond with the thin spreading growth associated with exploration strategies and higher values correspond to the denser, more branched structure associated with exploitation of the substrate. Cultivars showing exploration strategies induced by resistance expression responded to increased nutrient levels more than those expressing little resistance such as Golden Promise.
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  • 80
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    Agroforestry systems 42 (1998), S. 107-120 
    ISSN: 1572-9680
    Keywords: erosion ; Gliricidia sepium ; Oryza sativa ; Paspalum conjugatum ; Penisetum purpureum ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Farming systems that minimize the rate of soil degradation and optimize food crop yields are needed to sustain soil productivity on sloping, acid, infertile soils in the humid tropics. Research was conducted on two Oxisols with slopes ranging from 22 to 30% to evaluate the performance of several contour hedgerow systems, with and without the addition of 60 kg N ha−1 per crop, on rice (Oryza sativa) and maize (Zea mays L.) production. Contour hedgerows were double rows of the tree legume Gliricidia sepium (G); Gliricidia and the native grass Paspalum conjugatum (GPas); Gliricidia and an exotic fodder grass Penisetum purpureum (GPen); double rows of Penisetum (Pen); and a conventional open field (C) farming system without hedgerows. Gliricidia prunings and all crop residues were applied to the soil surface in the alleys, but Penisetum was harvested. Food crop yields in all hedgerow treatments tended to be less than the Control for the first two years, presumably due to the displacement of land planted to the food crop. In the third and the fourth years, the rice and maize yields of Treatments G and GPas exceeded the Control, most consistently when N was not applied. Penisetum reduced food crop yields regardless of N application presumably due to nutrient removal in the fodder. The results indicate that Gliricidia in a contour hedgerow increases food crop yield on strongly acid Oxisols by recycling nutrients and partially supplementing the N demand by the food crops.
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  • 81
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    Nutrient cycling in agroecosystems 52 (1998), S. 61-65 
    ISSN: 1573-0867
    Keywords: acidulated phosphates ; available P ; cationic impurities ; corn ; phosphorus sources ; water soluble P ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In Brazil, where the rock phosphates are high in impurities, no attempthas been made to evaluate the P supplying efficiency of the neutral ammoniumcitrate fraction (NAC) of P fertilizers, or to verify if the NAC +H2O extraction solution (AOAC) is satisfactory for estimatingthe P availability. To attain these objectives, a greenhouse experiment wascarried out with samples of a Typic Hapludox soil. Four acidulatedphosphates obtained from Brazilian raw materials were studied; monocalciumphosphate p.a.[Ca(H2PO4)2·H2O]was included as a standard source of P, as well as leached samplescontaining no water-soluble P. The fertilizers were thoroughly mixed withthe whole soil in the pots or with only 1% of its volume, at the rateof 50 mg kg-1 of P, soluble in NAC + H2O. Cornplants (Zea mays, L.) were grown for 35 days and the amounts of dry matterand P accumulated in plant tops were determined. Increasing the amount ofcationic impurities in the raw materials decreased the concentration ofwater-soluble P, NAC + H2O-soluble P and water-soluble P/NAC+H2O soluble P ratio of the fertilizers obtained. The P in theNAC fraction was not as much available to plants as in the NAC +H2O fraction or in pure MCP. The great variation found in drymatter (5.4 to 17.1 g pot-1) and in P uptake (6.3 to 22.2 mgpot-1) indicates that the AOAC method is not an adequate indexfor evaluating the P availability of fertilizers with high amounts ofcationic impurities.
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  • 82
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    Nutrient cycling in agroecosystems 51 (1998), S. 155-162 
    ISSN: 1573-0867
    Keywords: barley ; maximum possible yields ; N demand ; soil N mineralization ; tropical highlands
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A methodology to quantify N fertilizer requirement for a barley crop is proposed. The method consists of establishing a relationship between barley N demand (DEM) and an index of soil N supply (NS). NS values were obtained adding the inorganic N, i.e, (N-NO- 3 + N-NH+ 4, (Ni), measured just before planting in the soil to an index of soil N mineralization (Nor): NS = Ni + Nor Soil organic matter (SOM) was selected as an index of Nor: Nor = 25.9 + 17.9 (SOM) R2; = 0.89; p 〈 0.01 and Ni was measured in a soil extract obtained with KCl (1N). Ns values were related to both grain yield (Y) and N accumulated in the above ground biomass of barley (AB) grown under greenhouse conditions. The following relationships were obtained: Y = 0.81 + 0.99 (NS) - 0.0002 (NS)2 R2 = 0.77; p 〈 0.01 AB = -0.006 + 0.002 (NS) - 0.000003 (NS)2 R2 = 0.84; p 〈 0.01 A graphic relationship was established between DEM and NS, in order to extrapolate the greenhouse results to field conditions. Using this relationship, AB was converted from g N pot-1 to kg N ha-1, and NS from μg g-1 of N in the soil to kg ha-1.
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  • 83
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    Plant and soil 199 (1998), S. 283-291 
    ISSN: 1573-5036
    Keywords: dry matter partitioning ; maize ; 15N ; nitrogen uptake ; nitrogen use efficiency ; senescence ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In eastern Canada, the use of fertilizer N has been identified as the most energy-consuming component of maize (Zea mays L.) grain production. As the economic and environmental costs of excessive N fertilization rise, there is an increased emphasis on selection of hybrids with greater N use efficiency (NUE; defined as the ratio of the amount of 15N recovered in grain or stover dry matter to the amount of fertilizer 15N applied to the soil in this study). Using an 15N-labelling approach, a field study was conducted on a tile-drained Brandon loam soil (Typic Endoaquoll) on the Central Experimental Farm at Ottawa, Canada (45°22′ N, 75°43′ W) in 1993 and 1994. Fertilizer N uptake and partitioning within the plant in relation to dry matter changes were monitored during development of a current stay-green maize hybrid and an older early-senescing hybrid grown with three fertilizer N levels (0, 100, 200 kg N ha-1). Dry matter, N concentration and15 N atom% enrichment of plant components were determined at five growth stages. The current stay-green hybrid, ‘Pioneer 3902’ had greater NUE than the old early-senescing hybrid, ‘Pride 5’, which was associated with 24% more dry matter production and 20% more N uptake during grain fill for Pioneer 3902. There was no indication of greater allocation of N to the grain in Pioneer 3902. Our data suggest that prolonged maintenance of green leaf area for photosynthate production during grain fill and the ability to take up available soil N later in grain filling are characteristics of maize hybrids with greater NUE.
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  • 84
    ISSN: 1573-5036
    Keywords: corn ; growth ; nitrogen ; root ; water
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Proper management of water and fertilizer placement in irrigated corn (Zea mays L.) has the potential to reduce nitrate leaching into the groundwater. Potential management practices tested in a two year field experiment included row or furrow fertilizer placement combined with every or alternate furrow irrigation. To understand how fertilizer availability to plants could be affected by these management practices, root growth and distribution in a Ulm clay loam soil were examined. Spring rains were greater than normal in both years providing adequate moisture for early root growth in both irrigated and non-irrigated furrows. As the non-irrigated furrow began to dry, root biomass increased as much as 126% compared with the irrigated furrow. The greatest increase was at lower depths, however, where moisture was still plentiful. When early season moisture was available, roots proliferated throughout the soil profile and quickly became available to take up fertilizer N in both irrigated and non-irrigated furrows. Root growth responded positively to fertilizer placement in the furrow in 1996 but not in 1995. Excessive N leaching in 1995 may have limited the response to fertilizer N.
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  • 85
    ISSN: 1573-5087
    Keywords: greening ; growth ; hypocotyl ; leaf ; red light ; ultraviolet radiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Effects of red light (R), far-red light (FR) and UV radiation on growth and greening of lettuce seedlings (Latuca sativa L., cv. Berlinskii) have been investigated. UV-B and UV-C inhibited hypocotyl elongation and stimulated cotyledonary growth. R in combination with UV-B and UV-C partly eliminated these effects, but FR increased those and reversed the R effect. Chlorophyll accumulation was inhibited by UV-B and UV-C. In comparison with cotyledonary growth, R strengthened the UV inhibitory effect, and FR reversed this effect of R. Thus, UV and phytochrome system modify the effects of each other on hypocotyl and leaf growth in lettuce seedlings depending on the level of active phytochrome formed.
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  • 86
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    New forests 15 (1998), S. 271-281 
    ISSN: 1573-5095
    Keywords: early selection ; genotype × environment interaction ; growth ; retrospective ; seedling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Seedlings from 20 families of black spruce (Picea mariana (Mill.) B.S.P.), representing a large range in field productivity, were subjected to a greenhouse retrospective test under ambient (409 ppm – year 1, 384 ppm – year 2) and high (686 ppm – year 1, 711 ppm – year 2) atmospheric CO2 environments. After one and two growth cycles, seedling height and diameter growth significantly increased under elevated CO2. At the end of the experiment, seedlings grown under high CO2 had a mean above-ground dry weight of 48.77 g as compared to 26.36 g for seedlings grown under ambient atmospheric CO2. Families were a significant source of variation for all growth parameters. Although the family × CO2 environment interaction was not a statistically significant source of variation in the analysis of variance, the correlation between greenhouse and 15-year field height growth was weaker (r = 0.29, p = 0.2177) under elevated CO2 compared to ambient CO2 (r = 0.51, p = 0.0223) following the first growth cycle. However, following the second growth cycle, greenhouse-field correlations were similar between the two CO2 environments (ambient CO2: r = 0.55, p = 0.0115; elevated CO2: r = 0.56, p = 0.0101). Thus, with this set of families, growth performance ranking after two years appears relatively stable under ambient and elevated CO2.
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  • 87
    ISSN: 1573-5087
    Keywords: antioxidant system ; brassinolide ; drought stress ; methyl jasmonate ; uniconazole ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of brassinolide, uniconazole and methyl jasmonate on the antioxidant system were studied in seedlings of drought-resistant (PAN 6043) and drought-sensitive (SC 701) cultivars of Zea mays L. When seedlings treated with the three regulators were subjected to water stress (−1.0 MPa PEG 6000 solution), the activities of superoxide dismutase, catalase and ascorbate peroxidase, as well as the ascorbic acid and total carotenoid contents, increased in the resistant cultivar, whereas the levels remained unaltered in the sensitive cultivar. The increased tolerance to drought stress induced by the growth regulators in the resistant cultivar seems to be due to the maintenance of increased antioxidant enzyme activity and antioxidant substance levels.
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  • 88
    ISSN: 1573-5087
    Keywords: androgenesis ; anther ; cold pretreatment ; endogenous IAA ; peroxidase ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A cold pretreatment is usually applied to induce maize androgenesis. Peroxidase activity, including indole-3-acetic acid (IAA) oxidase activity, and endogenous IAA concentrations were followed during a cold pretreatment (14 days, 7°C) in anthers of two maize genotypes, Seneca 60 and DH5×DH7, respectively with a low or high androgenetic response. The most prominent result was the absence of a detectable IAA oxidase activity in DH5×DH7. Adding effectors of IAA-oxidase activity or IAA transport did not affect significantly the crude peroxidase activity of DH5×DH7 anthers while inducing a clear inhibition of androgenesis at higher concentrations. No strict correlation was found between IAA level and physiological response, the low responding variety having as much IAA as DH5×DH7. However, for DH5×DH7, every treatment that lowered the IAA level after 14 days of cold resulted in a decrease in androgenetic response.
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  • 89
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    Genetic resources and crop evolution 45 (1998), S. 525-531 
    ISSN: 1573-5109
    Keywords: aluminium and manganese tolerance ; Al × Mn interaction ; leaf chlorosis and necrosis ; relative root length ; solution culture ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Tolerance to aluminium and manganese toxicity at the seedling stage for 72 maize accessions was examined in solution culture. 0.22 mM Al and 2.0 mM Mn gave better genotypic separation for aluminium and manganese tolerance assessed on the basis respectively of relative root length, and visual symptoms of leaf chlorosis and necrosis. There was considerable variability among accessions for tolerance to aluminium and to manganese. Three accessions, Bozm 1335, Bozm 1337, and Bozm 1536 showed tolerance to Al, while 4, Chzm 01009, Champ, Bozm 0715, LG 20.80 exhibited tolerance to Mn. Accession, Zea 769 was tolerant to both metals. A significant Al x Mn interaction was found when five accessions were grown in a mixture of 0.22 mM aluminium and 2.0 mM manganese. Root length inhibition in Al alone was slightly ameliorated when the accessions were grown in the Al + Mn solution. Tolerance to aluminium and manganese does not necessarily coincide, different mechanisms being involved in tolerance to the two metals.
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  • 90
    ISSN: 1573-5060
    Keywords: Cicadulina ; leafhoppers ; disease resistance ; geminivirus ; West Africa ; yield reduction ; plant growth ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Field experiments were conducted from 1989 to 1991 at Ibadan, Nigeria, to assess effects of maize streak virus (MSV) disease on growth and yield of maize varieties having different levels of disease resistance. MSV disease reduced yield and growth in all years, but varieties differed significantly in amount of loss, disease severity and incidence. MSV disease was negatively correlated with plant height and dry weight, grain weight per plot, 1000-grain weight, ear length and diameter. In 1989 MSV disease decreased yield of resistant variety TZB-SR by 1.5%, of resistant hybrid 8321-21 by 10%, and of moderately resistant hybrid 8329-15 by 17%. Yield of susceptible variety TZB Gusao was reduced significantly more, by 71%. Plant age at time of virus challenge had significant effects on yield and growth characters, with earlier infection resulting in greater disease severity and yield reduction. A significant interaction between variety × age at challenge was also detected, indicating that varieties were differentially affected by MSV in relation to the growth stage when challenged. Disease incidence after challenge was lower for the most resistant varieties. This property of lower disease incidence under equal challenge opportunities (tolremicity) is an important aspect of resistance. The resistant varieties discussed here were bred for tolerance - good yield performance when diseased -, but TZB-SR and 8321-21 also exhibited tolremicity. Tolremicity combined with tolerance constitutes the overall disease resistance of a variety to a systemic pathogen such as MSV.
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  • 91
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    Euphytica 103 (1998), S. 307-318 
    ISSN: 1573-5060
    Keywords: barley ; genotype by environment interaction ; Hordeum vulgare ; low-input agriculture ; response to selection ; specific adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract To determine the optimum selection environment for barley (Hordeum vulgare L.) targeted at low-input, stress environment, barley lines were selected for high yield under stress (YS), high yield under non-stress (YNS), or average yield in stress and non-stress conditions (YA) during three breeding cycles (cohorts) of three years each. The lines were then tested in a total of 21 year-location combinations with average grain yields ranging from 0.35 to 4.86 t ha-1. Yield under stress of the YS lines was between 27% and 54% higher than that of the YNS lines, with the top YS lines yielding under stress between 16% and 30% more than the top YNS lines. Realized heritability was between 0.35 and 0.67 when selection was conducted under stress and was significant in all three cohorts. By contrast, selection under non-stress gave a significant response in only one cohort, and its efficiency in improving yield under stress was significantly lower than selection under stress. The best YNS line ranked only 19th for yield under stress. The highest-yielding lines under stress were not only selected under stress, but were also landraces collected in very dry areas (〈 250 mm total annual rainfall). This confirms earlier findings and supports the idea that the most effective way to improve productivity of crops grown in less-favored areas is to use locally adapted germplasm and select in the target environment(s).
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  • 92
    ISSN: 1573-5060
    Keywords: Agrobacterium ; barley ; C1/Lc ; GFP ; GUS ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Transfer of T-DNA from Agrobacterium tumefaciens and A. rhizogenes to cells of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) is demonstrated following the inoculation of immature embryos and immature embryo-derived callus. Agrobacterium T-DNA vectors containing the C1/Lc anthocyanin-biosynthesis regulatory genes, the gusA gene or a synthetic green fluorescent protein gene (sgfp-S65T) were constructed from original binary vectors. The visual T-DNA markers were used as cell-autonomous reporters of early Agrobacterium-mediated transformation events in the wheat and barley cells. This localization of the transformed cells revealed a non-random distribution throughout each embryo and callus piece.
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    Euphytica 99 (1998), S. 175-182 
    ISSN: 1573-5060
    Keywords: digestibility ; feeding value ; ingestibility ; silage maize ; registration ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The in vivo feeding value of 118 early maize (Zea mays L) hybrids, registered in France between 1958 and 1994, has been estimated from digestibility measurements with sheep at INRA Lusignan (France). There were great variations in the digestibilities of organic matter and crude fibre, and in the energy value of these hybrids, ranging respectively between 65.1 and 73.5%, 45.4 and 60.0%, and 0.79 and 0.95 UFL. There was a regular decrease in the average feeding value, regarding the year of registration, for each of the feeding value traits investigated. From 1958 to date, the frequency of hybrids lower than Mammouth increased, while the number of hybrids higher than LG11 or Brutus clearly decreased. Across the years, the increase in variations among hybrids occurred because of the introduction of hybrids with a poorer feeding value, particularly since the end of the 80's. The extremely efficient genetic pressure in breeding for whole plant yield and stalk standability could explain the drift in feeding value. A silage maize hybrid with a high yield, a high lodging resistance, and a good feeding value can be available only if breeders use a digestibility assessment, proved as representative of the digestion in cattle. In addition to a digestibility evaluation, the prediction of maize ingestibility could be taken into account as soon as a criterion is established.
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  • 94
    ISSN: 1573-5087
    Keywords: cooling ; cytokinins ; growth ; immunoassay ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Changes in the concentration of cytokinins were studied following root cooling. Simultaneously, the growth rate of the second leaf was monitored with a highly sensitive growth sensor attached to its tip. Cytokinins were separated by thin layer chromatography and immunoassayed using antibodies to zeatin riboside. The extension rate of the second leaf decreased within 15 minutes of cooling the nutrient medium from 24 °C to 4 °C. The concentration of cytokinins in shoots decreased with similar rapidity. In contrast cytokinins in roots increased slightly during the initial period of cooling before declining. The sharp decrease in cytokinin concentrations in shoots 15 minutes after cooling of roots may contribute to the abrupt inhibition of shoot growth.
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    Plant growth regulation 24 (1998), S. 55-66 
    ISSN: 1573-5087
    Keywords: antioxidant system ; brassinolide ; callus ; methyl jasmonate ; paraquat ; sodium benzoate ; uniconazole ; water stress ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of brassinolide, uniconazole and methyl jasmonate on several aspects of antioxidant defences, were studied in callus tissues of drought-resistant (PAN 6043) and drought-sensitive (SC 701) cultivars of maize. When regulator-treated calli were subjected to water stress with PEG for 24 h the activities of antioxidant enzymes, such as superoxide dismutase, catalase, ascorbate peroxidase, peroxidase and glutathione reductase, remained higher in callus of the drought-resistant than in callus of the drought-sensitive cultivar. Damage, as indicated by the levels of hydrogen peroxide and malondialdehyde, the reduction of ascorbate and carotenoids, and leakage of electrolytes from cells was apparent in callus of both cultivars as a consequence of the applied water stress. However, the damage was less marked in the drought-resistant cultivar. The regulator-treated callus of this cultivar also had a higher survival percentage than that of the drought-sensitive cultivar. The present results also compare the effects of growth regulators on antioxidant systems in callus tissue of different drought-resistant cultivars when exposed to paraquat and water stress.
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  • 96
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    Genetic resources and crop evolution 45 (1998), S. 475-481 
    ISSN: 1573-5109
    Keywords: barley ; core collection ; Spain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Spanish barleys constitute a germplasm group of particular interest for breeding purposes, as Spain has been proposed as a possible centre of origin of the crop. The Spanish National Germplasm Bank (Banco Nacional de Germoplasma, BNG), holds a collection of about 2000 barley accessions, mostly landraces collected in Spain prior to extensive introduction of modern varieties. The objective of this work is to create a core collection of barleys representative of old barley genotypes grown in Spain. The core collection will be constituted by three groups of germplasm: successful old varieties (15); entries in common with previously existing barley core collections (15); and 2-row (8) and 6-row (122) entries from the BNG, for a total of 160 entries. Entries were allocated by stratified sampling in agro-ecological uniform zones of barley cultivation in Spain. Classification of agro-ecological regions for barley was based on historical yield records for Spanish provinces. The number of entries for each region was determined in proportion to the logarithm of historical barley acreage. Final choice of accessions within provinces tried to maximize the diversity and avoid duplications by looking at passport data, and to agronomic evaluation data available for a group of about 900 accessions.
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  • 97
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    Genetic resources and crop evolution 45 (1998), S. 415-421 
    ISSN: 1573-5109
    Keywords: barley ; diversity ; microsatellites ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Microsatellite (SSR) profiles from 65 wheats and 135 barleys have been generated, involving 14 and 22 loci, respectively. The wheat and barley varieties were chosen to represent the bulk of the area sown to these crops in the UK over the past 70 years. The profiling identified genotypic mixtures in some seed samples. Null alleles were common in wheat, but rare in barley. We describe attempts to increase the efficiency of data acquisition. High resolution agarose gel electrophoresis was unable to satisfactorily resolve 1–2 repeat unit differences in the common size range for SSR loci, and was therefore unsuitable for mass screening of allelic variants. Multiplex PCR was very dependent on the choice of primer combinations and seldom produced amplifications as consistently as when primer pairs were used individually. Background (non-specific) amplification was common to many primer pairs, and this hindered the use of both multiplex PCR and multiple sample loading. Sequential sample loading was the most effective strategy, although this was the least time-efficient of the measures used.
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  • 98
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    Plant and soil 200 (1998), S. 55-61 
    ISSN: 1573-5036
    Keywords: cell length ; growth ; lateral roots ; lead ; phytotoxicity ; roots ; seedling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This work was undertaken to follow the appearance and development of symptoms of lead toxicity in growing roots of seedlings. The effects of lead nitrate (10-2–105 M) were studied on the roots of maize (Zea mays) seedlings, cvs. Diamant and Sterling. The roots were grown on filter paper either on glass in trays or in large Petri dishes. The following characteristics of root growth were studied: seed germination, length of primary and seminal roots, number of seminal and lateral roots, length of branching zone, length of meristem and fully-elongated cells and the number of fully-elongated cells along the daily length increment. 10-2 M lead nitrate exerted a clear toxic effect on root elongation just after radicle emergence; its influence on shoot growth was weak. However 10-2 M Pb solution did not affect either radicle emergence itself or seminal root emergence, which can be explained by the impermeability of seed testa to lead salt. The inhibitory effect of 10-3 M lead nitrate appeared a day later and was not as toxic: the growth of primary and seminal roots proceeded at lower rate due to a partial inhibition of cell division and cell elongation in them. 10-3 M lead nitrate modified the root system morphology: it exerted no effect on the emergence of lateral roots and their number, but induced a more compact distribution of lateral roots along a shorter branching zone due to a reduced length of mature cells in the primary root. As a result of the more prominent inhibition of primary root growth, a shorter branching zone with more compactly located lateral roots occupied a position much closer to the root tip than in roots grown without the influence of lead.
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  • 99
    ISSN: 1573-5036
    Keywords: barley ; iron deficiency ; light intensity ; phytosiderophore ; wheat ; zinc deficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effect of varied light intensity (50 – 600 μmol m-2 s-1) on the rate of phytosiderophore release was studied under zinc (Zn) deficiency using a bread (Triticum aestivum L. cv. Aroona) and a durum wheat cultivar (Triticum durum Desf. cv. Durati) differing in zinc (Zn) efficiency and under iron (Fe) deficiency using a barley cultivar (Hordeum vulgare L. Europe). Plants were grown under controlled environmental conditions in nutrient solution for 15 days (wheat plants) or 11 days (barley plants). Phytosiderophore release was determined by measuring capacity of root exudates to mobilize copper (Cu) from a Cu-loaded resin. With increasing light intensity visual Zn deficiency symptoms such as whitish-brown lesions on leaf blade developed rapidly and severely in wheat, particularly in the durum cultivar Durati. In wheat plants supplied well with Zn, increases in light intensity from 100 to 600 μmol m-2 s-1 did not clearly affect the rate of phytosiderophore release. However, under Zn deficiency increases in light intensity markedly enhanced release of phytosiderophores in Zn-deficient Aroona, but not in Zn-inefficient Durati. When Fe-deficient barley cultivar Europe was grown first at 220 μmol m-2 s-1 and then exposed to 600 μmol m-2 s-1 for 24 and 48 h, the rate of release of phytosiderophores was enhanced about 4-fold and 7-fold, respectively. Transfer of Fe-deficient plants from 600 to 50 μmol m-2 s-1 for 48 h reduced the rate of release of phytosiderophores by a factor of 7. The effect of light on phytosiderophore release was similar regardless of whether the rate of phytosiderophore release was expressed per plant or per unit dry weight of roots. The results demonstrate a particular role of light intensity in phytosiderophore release from roots under both Zn and Fe deficiency. It is suggested that in the studies concerning the role of phytosiderophore release in expression of Zn or Fe efficiency among and within cereals, a special attention should be given to the light conditions.
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  • 100
    ISSN: 1573-5060
    Keywords: barley ; crossability ; hybridization ; mapping ; quantitative trait loci ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract To study genetic variation in crossability, 80 barley accessions of diverse geographic origin consisting of 50 wild barleys (H. vulgare ssp. spontaneum or ssp. agriocrithon) and 30 cultivated barleys (H. vulgare ssp. vulgare) were crossed as the male parent with a highly crossable wheat variety, Shinchunaga. Crossabilities, expressed as the percentage of pollinated florets giving embryo-containing caryopses, ranged from 0% to 68.6%. Barley accessions from East Asia had generally a low crossability, while barley accessions from other regions exhibited a wider range of crossability including highly crossable genotypes. No significant difference in mean crossability was found between wild and cultivated barleys. To estimate the number and location of barley genes controlling the crossability, doubled haploid lines derived from the cross between the barley varieties Steptoe and Morex were crossed as the male parent with wheat. Quantitative trait loci (QTL) analysis using molecular markers identified four QTL. These were mapped to the centromeric regions of chromosomes 2H, 3H and 5H and the short arm of chromosome 7H. The QTL on chromosomes 3H and 5H had larger effects than those on chromosomes 2H and 7H. The four QTL collectively explained 35.4% of the total variance under a multiple QTL model. Relationships of the QTL identified in the present study with previously reported crossability genes of barley and wheat are discussed.
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