ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (134)
  • Hordeum vulgare  (71)
  • 15N  (63)
  • Springer  (134)
  • 1995-1999  (114)
  • 1975-1979  (20)
  • 1960-1964
  • 1945-1949
  • Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition  (134)
Collection
  • Articles  (134)
Keywords
Publisher
  • Springer  (134)
Years
Year
Topic
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 19 (1995), S. 29-35 
    ISSN: 1432-0789
    Keywords: Ammonium sulphate ; Biomass N ; Clay CO2 ; Gross mineralization ; 15N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A sandy loam soil was mixed with three different amounts of quartz sand and incubated with (15NH4)2SO4 (60 μg N g-1 soil) and fresh or anaerobically stored sheep manure (60 μg g-1 soil). The mineralization-immobilization of N and the mineralization of C were studied during 84 days of incubation at 20°C. After 7 days, the amount of unlabelled inorganic N in the manure-treated soils was 6–10 μg N g-1 soil higher than in soils amended with only (15NH4)2SO4. However, due to immobilization of labelled inorganic N, the resulting net mineralization of N from manure was insignificant or slightly negative in the three soil-sand mixtures (100% soil+0% quartz sand; 50% soil+50% quartz sand; 25% soil+75% quartz sand). After 84 days, the cumulative CO2 evolution and the net mineralization of N from the fresh manure were highest in the soil-sand mixutre with the lowest clay content (4% clay); 28% fo the manure C and 18% of the manure N were net mineralized. There was no significant difference between the soil-sand mixtures containing 8% and 16% clay, in which 24% of the manure C and -1% to 4% of the manure N were net mineralized. The higher net mineralization of N in the soil-sand mixture with the lowest clay content was probably caused by a higher remineralization of immobilized N in this soil-sand mixture. Anaerobic storage of the manure reduced the CO2 evolution rates from the manure C in the three soil-sand mixtures during the initial weeks of decomposition. However, there was no effect of storage on net mineralization of N at the end of the incubation period. Hence, there was no apparent relationship between net mineralization of manure N and C.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 19 (1995), S. 49-54 
    ISSN: 1432-0789
    Keywords: N2 fixation ; N supplying potential ; Grain legumes ; Green manuring ; 15N ; Wetland rice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Studies were conducted on paddy soils to ascertain N2 fixation, growth, and N supplying ability of some green-manure crops and grain legumes. In a 60-day pot trial, sunhemp (Crotalaria juncia) produced a significantly higher dry matter content and N yield than Sesbania sesban, S. rostrata, cowpeas (Vigna unguiculata), and blackgram (V. mungo), deriving 91% of its N content from the atmosphere. Dry matter production and N yield by the legumes were significantly correlated with the quantity of N2 fixed. In a lowland field study involving sunhemp, blackgram, cowpeas, and mungbean, the former produced the highest stover yield and the stover N content, accumulating 160–250 kg N ha-1 in 60 days, and showed great promise as a biofertilizer for rice. The grain legumes showed good adaptability to rice-based cropping systems and produced a seed yield of 1125–2080 kg ha-1, depending on the location, species, and cultivar. Significant inter- and intraspecific differences in the stover N content were evident among the grain legumes, with blackgram having the highest N (104–155 kg N ha-1). In a trial on sequential cropping, the groundnut (Arachis hypogaea) showed a significantly higher N2 fixation and residual N effect on the succeeding rice crop than cowpeas, blackgram, mungbeans (V. radiata), and pigeonpeas (Cajanus cajan). The growth and N yield of the rice crop were positively correlated with the quantity of N2 fixed by the preceding legume crop.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-0789
    Keywords: Leucaena ; Nodulation ; Nitrogen fixation ; Nitrogen use ; 15N ; Time course
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The dynamics of nodulation, N2-fixation and N use in Leucaena leucocephala cv. K28 over time was investigated in a screenhouse at 4, 8, 12 and 16 months after planting (MAP) using the 15N-labelling method. Leucaena had a consistently increasing pattern of nodulation, dry biomass and nitrogen yield. A sharp rise in nodulation was observed between 12 and 16 MAP, whereas for biomass, N accumulation and N2-fixation, and N2-fixation, an upward surge occurred between 4 and 12 months. Nodulation, N accumulation, N2-fixation and biomass yield all peaked at 16 MAP. Along with the steady increase in N2-fixation throughout the 16-month growth period, the % N derived from the atmosphere rose from 17.9% to 61.5%, 70.1% and 74%, equivalent to 191, 1623, 2395 and 3385 mg N2 fixed plant-1 at 4, 8, 12 and 16 MAP, respectively. Nitrogen assimilation from soil and fertilizer decreased inversely to the increase in symbiotic nitrogen fixation with time.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-0789
    Keywords: Key words Microbial biomass ; Organic farming ; Soil respiration ; Farmyard manure ; Poultry manure ; Hordeum vulgare ; Barley ; Fumigation extraction ; technique ; Fumigation incubation technique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Temporal behaviour of microbial biomass C, N and respiration was measured under barley crops in two experiments on successive years in a recently converted organic production system in Scotland. Soils were fertilised with farmyard manure or poultry manure. Control soils received no manure at the start of the growing season. The effects of plants was also investigated by maintaining fallow subplots. C-flush values approximately doubled over the growing season in both years of the trial, showing a decline to pre-sowing values between the two seasons. This occurred in all soils, whether manured or not, or planted or fallow. Manure tended to increase the C-flush in the 2nd year only. N-flush in the 2nd year showed no increase in planted control plots but did increase in fallow soils. Manures significantly increased the N-flush. Respiration rates were stimulated by the presence of plants. Respiration rates were measured from soils taken from the field at post-sowing, mid-season and post-harvest occasions and incubated under constant conditions for up to 1 year. Here there was evidence that the effects of sampling and adjusting the moisture status could be as great upon microbial activity as the addition of the manures. C-flush also showed a consistent and persistent increase in these incubated soils. This suggests that the fundamental C-supplying characteristics of these soils was such that the biomass was moving towards a new equilibrium value fuelled by the relatively recent introduction of the organic farming regime.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 22 (1996), S. 345-349 
    ISSN: 1432-0789
    Keywords: Vertisol ; pH ; Cation exchange capacity ; Moisture ; Urea ; 15N ; Nitrogen losses ; Ammonia volatilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The N loss from Vertisols was estimated by measuring the loss of 15N-labelled urea N under conditions that promote NH3 volatilization. Urea granules were placed on the top of 150-mm deep soil columns (Vertisols) collected from three sites with a range in pH, electrical conductivity, and cation exchange capacity. There were two contrasting moisture treatments, one near field capacity (wet) and another with intermittent wetting of the soil surface before allowing the columns to dry (moist-dry). The results indicated that losses were influenced markedly by pH and moisture treatment, being 29.5, 33.5, and 33% from the wet soils and 37, 42, and 40.5% from the moistdry soils with pH values of 7.7, 8.2, and 9.3, respectively. These observations clearly indicate that broadcasting of urea on the surface of Vertisols may cause substantial N losses.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 23 (1996), S. 93-98 
    ISSN: 1432-0789
    Keywords: Added nitrogen interaction ; Alkaline-hydrolysing fertilizer ; Aqua ammonia ; Gross N immobilization ; Gross N mineralization ; 15N ; Soluble organic N availability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Organic N solubilized by NH3(aq) was extracted from 15N-labelled or unlabelled soil, concentrated and added to non-extracted soil, which was incubated under aerobic conditions at 27±1°C. Gross N mineralization, gross N immobilization, and nitrification in soils with or without addition of unlabelled soluble organic N were estimated by models based on the dilution of the NH 4 + or NO inf3 sup- pools, which were labelled with 15N at the beginning of incubation. Mineralization of labelled organic N was measured by the appearance of label in the mineral N pool. Although gross N mineralization and gross N immobilization were increased in two soils between day 0 and day 7 following addition of unlabelled organic N solubilized by NH3(aq), there was no increase in net N mineralization. Solubilization of 15N-labelled organic N increased and the 15N enrichment of the soluble organic N decereased as the concentration of NH3(aq) added increased. A constant proportion of approximately one-quarter of the labelled organic N added at different rates to non-extracted soil was recovered in the mineral N pool after an incubation period of 14 days, and the availability ratios calculated from net N mineralization data were 1.1:1 and 2.1:1 for 111 and 186 mg added organic-N kg-1 soil, respectively, indicating that the mineralization of organic N was increased by solubilization.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 23 (1996), S. 161-165 
    ISSN: 1432-0789
    Keywords: Key words ANI ; Baythroid ; Cyfluthrin ; Insecticide ; 15N ; Nitrification ; N uptake ; Synthetic pyrethroid ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A pot experiment was conducted to compare the uptake and dry matter production potential of NH+ 4 and NO– 3 and to study the effect of Baythroid, a contact poison for several insect pests of agricultural crops, on growth and N uptake of maize (Zea mays L.). Nitrogen was applied as (15NH4)2SO4, K15NO3, or 15NH4NO3 and in one treatment Baythroid was combined with 15NH4NO3. Source of N had, in general, a nonsignificant effect on dry matter and N yield, but uptake of NO– 3 was significantly higher than that of NH+ 4 when both N sources were applied together. Substantial loss of N occurred from both the sources, with NH+ 4 showing greater losses. Baythroid was found to have a significant positive effect on dry matter yield of both root and shoot; N yield also increased significantly. Uptake of N from both the applied and native sources increased significantly in the presence of Baythroid and a substantial added nitrogen interaction (ANI) was determined. The positive effect of Baythroid was attributed to: (1) a prolonged availability of NH+ 4 due to inhibition of nitrification, (2) an increased availability of native soil N through enhanced mineralization, and (3) an enhanced root proliferation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1432-0789
    Keywords: Isotope dilution ; 15N ; Lupin ; Symbiotic dependence ; Biological N2 fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The proportional contribution of atmospheric N2 to the N nutrition of lupin (P atm) was estimated in a field experiment following addition of NH4Cl of KNO3 to unconfined microplots (1.5 m2) at 2.5 g N m-2 (10 atom% 15N). The integrated 15N enrichment, or ‘mean pool abundance’, of nitrate extracted from 0- to 15-cm samples taken under the lupin crop on eight occasion between 28 and 190 days after sowing was used as the reference criterion to estimate P atm by the 15N-isotope dilution technique. Estimates of P atm were similar to those obtained using canola as a non-fixing reference plant, but were higher than estimates obtained using a yield-dependent model. Use of ‘mean pool abundance’ obviates the need for a non-fixing reference plant, and the frequent sampling and isotope-ratio analysis of the legume biomass required with the yield-dependent model is unnecessary. However, further work is needed to validate a sampling strategy commensurate with the growth of the legume roots.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1432-0789
    Keywords: Key words Isotope dilution ; 15N ; Lupin ; Symbiotic dependence ; Biological N2 fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The proportional contribution of atmospheric N2 to the N nutrition of lupin (P atm) was estimated in a field experiment following addition of NH4Cl of KNO3 to unconfined microplots (1.5 m2) at 2.5 g N m–2 (10 atom% 15N). The integrated 15N enrichment, or ’mean pool abundance‘, of nitrate extracted from 0- to 15-cm samples taken under the lupin crop on eight occasion between 28 and 190 days after sowing was used as the reference criterion to estimate P atm by the 15N-isotope dilution technique. Estimates of P atm were similar to those obtained using canola as a non-fixing reference plant, but were higher than estimates obtained using a yield-dependent model. Use of ’mean pool abundance‘ obviates the need for a non-fixing reference plant, and the frequent sampling and isotope-ratio analysis of the legume biomass required with the yield-dependent model is unnecessary. However, further work is needed to validate a sampling strategy commensurate with the growth of the legume roots.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1432-0789
    Keywords: Key words Soybean ; Isotope dilution ; Nitrogen fixation ; Bradyrhizobium japonicum ; Soil sterilization ; 15N ; Azospirillum brasilense ; Bacterial inoculation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of inoculation with Bradyrhizobium japonicum and Azospirillum brasilense strains on the growth of soybean were evaluated with regard to the estimation of N2 fixation using the 15N isotope dilution technique. Inoculation, in general, increased the dry mass of soybean as well as nitrogen content. Dual inoculation with a mixture of B. japonicum and A. brasilense strains was superior over single inoculation with B. japonicum. Nitrogen fixed (Ndfa) varied according to inoculant and soil conditions. Percentages of nitrogen derived from air (% Ndfa) using a non-nodulating isoline were 72% and 76% for B. japonicum and B. japonicum plus A. brasilense, respectively, in non-sterile soil. A similar but higher trend was recorded in sterilized soil, in which the percentages of N2 fixed were 81% and 86% for single and dual inoculation, respectively. The correlation coefficient between N2 fixed and N uptake (r=0.94) and dry mass (r=0.89) was significant. Application of special bacterial inoculants in agricultural systems of Egypt seems to be a promising technology and could be used for improving soybean growth as well as soil fertility, thus minimizing environmental pollution.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 24 (1997), S. 413-420 
    ISSN: 1432-0789
    Keywords: Key words Ammonium analysis ; 15N ; Nitrate ; Nitrite ; Inorganic N ; Soil extract diffusion method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Diffusion methods previously developed for inorganic-N analysis of soil extracts were modified to improve reliability, increase the dynamic range, extend the scope of applications, and simplify the processing of samples for N-isotope analysis. In these methods, the soil extract is treated with MgO, or MgO plus Devarda‘s alloy, in a 473-ml (1-pint) wide-mouth Mason jar to convert NH4 +-N, NO3 –-N, and/or NO2 –-N to NH3-N. The NH3 thereby liberated is collected in H3BO3-indicator solution in a Petri dish suspended from the Mason-jar lid and determined quantitatively by acidimetric titration. With the modifications described, analyses can be performed on 10- to 100-ml samples of water, 0.5MK2SO4, 1MKCl, 2MKCl, or 4MKCl, at temperatures between 20 and 30°C. Recovery from 10 or 20ml was quantitative in 18–80h with up to 4mgN; recovery from 50 or 100ml was quantitative in 3–13 days with up to 2mgN. Removal of H3BO3 for N-isotope analysis by the Rittenberg process was effected using methanol. Mason-jar diffusion methods are much simpler and more convenient than conventional steam distillations. Comparative studies showed that quantitative determinations are more accurate and precise by diffusion than by distillation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    ISSN: 1432-0789
    Keywords: Key words Intact roots ; Rhizoplane microorganisms ; Extracellular enzyme ; Barley genotypes ; Phosphorous acquisition ; Phosphatases ; Hordeum vulgare
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Genotypes of spring barley (Hordeum vulgare L. cvs. Alexis and Regatta) and winter barley (Hordeum vulgare L. cvs. Marina and Sonate) grown under sterile and non-sterile conditions were compared with regard to the activity of root- and rhizoplane-microorganism-associated and -released phosphatases. A method is described of growing plants individually under sterile and non-sterile conditions and assaying of the enzyme activities of intact roots and rhizoplane microorganisms. The results of the experiments presented in this paper indicate that all the genotypes showed significantly (P〈〉;0.01) higher actitivity of extracellular phosphomonoesterase than that of phosphodiesterase both associated with and released by their roots. There were no significant differences (P〈〉;0.05) between the sterile and non-sterile root and its surrounding solutions in the activity of extracellular phosphomonoesterase. The contribution of rhizoplane microorganisms to the root total activity of extracellular phosphomonoesterase was estimated to be 3%. Generally, the activity of the enzymes associated with the roots was 20–80 times higher than the activity of those released by the roots to the surrounding nutrient solution. However, a close correlation was found between the activity of extracellular phosphomonoesterase associated with and that released by the roots.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 24 (1997), S. 211-220 
    ISSN: 1432-0789
    Keywords: Key words Denitrification ; Fertilizer efficiency ; 15N ; Labelled dinitrogen ; Nitrification ; Nitrous oxide ; Urea ; Waterlogged soil ; Water-soluble organic carbon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A laboratory study was conducted to compare the effects of different N fertilizers on emission of N2 and N2O during denitrification of NO3 – in waterlogged soil. Field-moist samples of Drummer silty clay loam soil (fine-silty, mixed, mesic Typic Haplaquoll) were incubated under aerobic conditions for 0, 2, 4, 7, 14, 21, or 42 days with or without addition of unlabelled (NH4)2SO4, urea, NH4H2PO4, (NH4)2HPO4, NH4NO3 (200 or 1000 mg N kg–1 soil), or liquid anhydrous NH3 (1000 mg N kg–1 soil). The incubated soil samples were then treated with 15N-labelled KNO3 (250 mg N kg–1 soil, 73.7 atom% 15N), and incubation was carried out under waterlogged conditions for 5 days, followed by collection of atmospheric samples for 15N analyses to determine labelled N2 and N2O. Compared to samples incubated without addition of unlabelled N, all of the fertilizers promoted denitrification of 15NO3 –. Emission of labelled N2 and N2O decreased in the order: Anhydrous NH3〉urea〈$〉\gg〈$〉 (NH4)2HPO4〉(NH4)2SO4≃NH4NO3≃NH4H2PO4. The highest emissions observed with anhydrous NH3 or urea coincided with the presence of NO2 –, and 15N analyses indicated that these emissions originated from NO2 – rather than NO3 –. Emissions of labelled N2 and N2O were significantly correlated with fertilizer effects on soil pH and water-soluble organic C.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 20 (1995), S. 41-48 
    ISSN: 1432-0789
    Keywords: Added nitrogen interaction ; Ammonia fixation ; 15N ; Immobilization ; Fertilizer-induced solubilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Added N interactions were measured in four soil incubated with 15N-labelled urea or diammonium phosphate. The use of biologically active, γ-irradiated, or reinoculated γ-irradiated samples allowed us to separate added N interactions due to chemical and biological processes, and to distinguish real interactions from apparent effects. Real biologically mediated added N interactions were observed in one soil for both fertilizer sources and in three soils amended with urea. These real interactions increased with the N fertilizer rate, but did not differ significantly between N sources. Fertilizer-induced unlabelled organic N in soil extracts declined during incubation in both sterile and non-sterile samples, but the temporal decline was higher in biologically active soil. Changes in fertilizer-induced unlabelled organic N in the extracts of three soils attributed to biological processes were similar to the measured real biologically mediated added N interactions. The results are consistent with the hypothesis that real biologically mediated added N interactions arise from the mineralization of soil organic N solubilized by alkaline-hydrolysing N fertilizers.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 23 (1996), S. 161-165 
    ISSN: 1432-0789
    Keywords: ANI ; Baythroid ; Cyfluthrin ; Insecticide ; 15N ; Nitrification ; N uptake ; Synthetic pyrethroid ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A pot experiment was conducted to compare the uptake and dry matter production potential of NH inf4 sup+ and NO inf3 sup- and to study the effect of Baythroid, a contact poison for several insect pests of agricultural crops, on growth and N uptake of maize (Zea mays L.). Nitrogen was applied as (15NH4)2SO4, K15NO3, or 15NH4NO3 and in one treatment Baythroid was combined with 15NH4NO3. Source of N had, in general, a nonsignificant effect on dry matter and N yield, but uptake of NO inf3 sup- was significantly higher than that of NH inf4 sup+ when both N sources were applied together. Substantial loss of N occurred from both the sources, with NH inf4 sup+ showing greater losses. Baythroid was found to have a significant positive effect on dry matter yield of both root and shoot; N yield also increased significantly. Uptake of N from both the applied and native sources increased significantly in the presence of Baythroid and a substantial added nitrogen interaction (ANI) was determined. The positive effect of Baythroid was attributed to: (1) a prolonged availability of NH inf4 sup+ due to inhibition of nitrification, (2) an increased availability of native soil N through enhanced mineralization, and (3) an enhanced root proliferation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 24 (1997), S. 239-242 
    ISSN: 1432-0789
    Keywords: Key words Biologically fixed N ; Cereals ; Intercropping ; Foliar labelling ; Grasses ; Legumes ; 15N ; N transfer ; Pastures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We examined the basis for estimating the transfer of legume N to companion cereals or grasses in intercropping or pature systems using the foliar 15N-labelling technique. Published data from three pot experiments were used to illustrate different methods for estimating N transfer. Yield-dependent and yield-independent methods based on measurement of the 15N enrichment of the whole legume biomass at harvest overestimate N transfer. Estimates of N transfer using a yield-independent method based on the 15N enrichment of the legume roots at harvest were inconsistent with estimates based on the isotopic composition of the whole plant. We propose a new mathematical concept for estimating the transfer of legume N based on measurement of the ‘mean pool abundance’ of the legume biomass during the period of N transfer.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    ISSN: 1436-6215
    Keywords: Protein quality ; endogenous imbalance ; 15N ; natural abundance ; isotope discrimination ; Proteinqualität ; endogene Imbalanz ; 15N ; natürliche Häufigkeit ; Isotopendiskriminierung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Zwischen Harnstoff und Plasmaprotein besteht ein natürlicher Unterschied der15N-Häufigkeit von bis zu 10‰. Die Ursache hierfür ist der verzweigte Stickstoff-Metabolismus in der Leber. Ein Hauptzweig ist die Proteinsynthese, im zweiten Hauptzweig wird der Aminostickstoff zur Harnstoff-Synthese verwendet.15N der Vorläuferaminosäuren wird hierbei, abhängig von den Umsatzraten, im Harnstoff abgereichert und im Protein angereichert. Unter Hinzuziehung der15N-Häufigkeit der Vorläuferaminosäuren, die sich aus Jejunum-Gewebe bestimmen läßt, kann aus der Isotopendiskriminierung in den beiden Stoffwechselzweigen die Utilisierung der Aminosäuren in der Leber berechnet werden. Dies wurde an Ratten nach Fütterung mit verschiedenen Proteinen untersucht. Es zeigte sich, daß bei Verzehr von hochwertigen Proteinen die Utilisierung der Aminosäuren im Stoffwechsel der Leber bei bedarfsgerechter Fütterung besser war (Molkenprotein: 〉85%) als bei Proteinkarenz (70%). Das bedeutet, daß das Muster der aus dem metabolischen Pool verfügbaren Aminosäuren bei Proteinkarenz eine Imbalanz aufweist. Durch exogene Aminosäuren aus der Nahrung kann diese endogene Imbalanz offenbar komplementierend ausgeglichen werden, so daß die Stickstoffausscheidung bei nicht bedarfsüberschreitendem Verzehr sogar unter den Werten der sogenannten „obligaten“ oxidativen Verluste liegen kann. Die Qualität von Nahrungsproteinen spiegelt sich also nicht nur in den N-Bilanzen wider. Sie wird auch durch Bestimmung der Utilisierung der Aminosäuren im Stoffwechsel der Leber mit Hilfe der Analyse der Isotopendiskriminierung quantifizierbar. Zusätzlich wird mit dieser Methode eine Aussage über die Qualität des Musters der metabolisch verfügbaren Aminosäuren gewonnen.
    Notes: Summary Urea and plasma protein differ in natural15N abundance up to 10‰ The origin of this difference is the branched nitrogen metabolism in the liver. One main branch is the protein synthesis pathway, the other the urea synthesis pathway. By this branching15N of precursor amino acids is depleted in urea while it is enriched in protein. With the15N abundance of precursor amino acids, which may be taken from jejunum tissue, utilization of amino acids in liver metabolism can be calculated from isotope discrimination in either pathway. This was investigated by feeding different proteins to rats. When feeding high quality protein (whey protein) utilization of amino acids in liver metabolism at requirement intake was better than at zero protein intake (〉85% vs. 70%). From this we conclude that the pattern of amino acids available from the metabolic pool at zero protein intake is characterized by an imbalance. This endogenous imbalance can be complemented by exogenous dietary amino acids so that nitrogen excretion may even be smaller than the so-called „obligatory“ losses of intakes not exceeding requirement. Thus, the quality of dietary protein is reflected not only by N balance. It also may be quantified by analysis of isotope discrimination in nitrogen metabolism of the liver. In addition, the quality of amino acid pattern available from the metabolic pool is indicated by this method.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 41 (1995), S. 151-158 
    ISSN: 1573-0867
    Keywords: bicabonate-extractable-soil-phosphorus ; relative effectiveness ; residual value ; rock phosphate ; superphosphate ; Avena sativa ; Hordeum vulgare ; x Triticosecale ; Trifolium subterraneum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effectiveness of large single applications of North Carolina reactive rock phosphate, Queensland non-reactive rock phosphate, and Calciphos, were compared to the effectiveness of superphosphate in field experiments in south-western Australia for up to 11 years after application. As measured using plant yield, superphosphate was the most effective fertilizer in the year of application, and relative to freshly-applied superphosphate, the effectiveness of the superphosphate residues declined to be about 15 to 65% as effective in the year after application, and 5 to 20% as effective 9 to 10 years after application. Relative to freshly-applied superphosphate, all the rock phosphates were 10 to 30% as effective in the year of application, and the residues remained 2 to 20% as effective in the 10 years after application. The bicarbonate soil test reagent predicted a more gradual decrease in effectiveness of superphosphate of up to 70% 10 years after application. For rock phosphate, the reagent predicted effectiveness to be always lower than for superphosphate, being initially 2 to 11% as effective in the year after application, and from 10% to equally as effective 10 years later. Therefore rock phosphates are unlikely to be economic alternatives to superphosphate in the short or long term on most lateritic soils in south-western Australia.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 42 (1995), S. 139-148 
    ISSN: 1573-0867
    Keywords: denitrification ; methods ; 15N ; nitrate ; nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This paper attempts to answer the question: is denitrification a major route of N loss from tropical agro-ecosystems? This question turns out to be very difficult to answer due to a severe shortage of data on this process for tropical agro-ecosystems other than rice. Given this lack of data, I approach this question by analyzing data on denitrification and nitrous oxide flux in tropical native forest and pasture soils and attempt to make some conclusions and pose some hypotheses about the significance of denitrification in tropical agricultural soils. I also briefly review methods for measuring denitrification. The data analysis suggests that denitrification in tropical forest soils is strongly influenced by the nature and amount of soil C and N turnover. Studies to examine differences in denitrification in different tropical agricultural systems should focus on the effects of system management on C and N turnover. The data analysis also suggests that, just as in temperate regions, denitrification may not be a significant route of N loss from most tropical agricultural systems. However, field studies are necessary to determine if this is actually the case.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    ISSN: 1573-0867
    Keywords: 15N ; non-nod beans ; quantification of N2 fixation ; reference crops ; simulation technique ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A technique for the application of the15N isotope dilution technique for the quantification of plant associated biological nitrogen fixation (BNF) was tested and applied to quantify the BNF contribution to two genotypes ofPhaseolus vulgaris. The technique makes use of sequential measurements of the15N enrichment of soil mineral N, and the uptake of labelled N by the “N2-fixing” plant, to simulate its uptake of soil N (the “soil to plant simulation” technique). The test was made with two non-N2-fixing crops (non-nodulating beans and wheat) and two bean genotypes (PR 923450 and Puebla 152), at two levels of N fertilizer addition (10 and 40 kg N ha−1), to compare the actual N uptake with that simulated from the soil and crop15N data. The simulation of the soil N uptake by the non-nod bean crop using this “soil to plant simulation” technique underestimated by 20 to 30% the true N uptake, suggesting that the mineral N extracted from soil samples taken from the 0–15cm layer had a higher15N enrichment than that N sampled by the roots of this crop. In the case of the wheat crop the simulation resulted in a much greater underestimation of actual N uptake. In general the results using this technique suggested that BNF inputs to the bean cultivars was higher than would be expected from the nodulation and acetylene reduction data, except for the early PR beans in the 40 kg N ha−1 treatment. In this case the total N and simulated soil N accumulation were well matched suggesting no BNF inputs. An allied technique (the “plant to plant simulation technique”) was proposed where the15N enrichrnent of soil mineral N was simulated from the data for total N and labelled N accumulation taken from sequential harvests of either of the non-N2 -fixing control crops. This was then utilized in combination with the labelled N uptake data of the other crop to simulate its soil N uptake. However, the results using either technique indicated that the wheat and non-nod or nodulating beans exploited pools of N in the soil with completely different15N enrichments probably due to differences in exploitation of the soil N with depth.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 51 (1998), S. 35-40 
    ISSN: 1573-0867
    Keywords: ammonia emission ; ammonium ; apoplast ; Brassica napus ; compensation point ; glutamine synthetase ; Hordeum vulgare
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Barley (Hordeum vulgare L. cv. Golf) was grown in solution culture with controlled nitrogen availability in order to study the influence of nitrogen nutrition on ammonia emission from the leaves. Ammonia emission measured in cuvettes connected to an automatic NH3 monitor was close to zero for nitrate grown plants but increased to 0.9–1.3 nmol NH3 m-2 leaf area s-1 after 3–5 days of ammonium nutrition. Increasing concentrations from 0.5 to 10 mM NH4 + in the root medium increased NH3 emission from the shoots, root glutamine synthetase activity and NH4 + concentrations in apoplast, xylem sap and bulk tissue, while apoplastic pH values decreased. Inhibition of glutamine synthetase in nitrate grown barley plants by addition of 1 mM methionine sulfoximine (MSO) to the root medium caused ammonia emission to increase 5 to 10-fold after 2–3 hours. At the same time shoot tissue ammonium concentrations started to increase. Addition of an inhibitor of photorespiration, 1 mM pyrid-2-yl hydroxymethane sulfonate (HPMS) reduced this increase in ammonia emission showing a relation between NH3 emission and photorespiration. Oil seed rape (Brassica napus L. cv. Global) plants grown at 3 different nitogen levels (2N, 4N and 7N) in a sand/soil mixture showed increasing NH3 compensation points with increasing N level. This increase was highly correlated with increasing NH4 + concentrations in the leaf apoplast and total leaf tissue. The NH3 compensation points could be succesfully predicted on basis of the pH and NH4 + concentration in the leaf apoplast.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 51 (1998), S. 269-279 
    ISSN: 1573-0867
    Keywords: denitrification ; gas entrapment ; nitrification inhibitors ; 15N ; rice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Denitrification rates (d) in a flooded alkaline clay were measured following addition of either $$^{15} NO_3^ - or^{15} NH_4^ + $$ to the floodwater, by collecting evolved N2 + N2O in an enclosure in the absence or presence of rice plants. Similar estimates of d were obtained in the $$^{15} NO_3^ - $$ treatment when the isotopic composition of the enclosed atmosphere was determined using arc redistribution or direct mass spectrometric analysis. Approximately 90% of the gaseous products of denitrification were physically trapped in the soil five days after $$^{15} NO_3^ - $$ addition. Mechanical shaking of the soil-water system was an effective method for releasing entrapped gas. Denitrification showed a marked diurnal variation in both $$^{15} NO_3^ - $$ and $$^{15} NH_4^ + $$ treatments planted to rice, with higher rates during the day than at night. Measured rates of denitrification were higher in planted than in unplanted pots for both $$^{15} NO_3^ - $$ and $$^{15} NH_4^ + $$ treatments for normal gas sampling. However, evidence was obtained that this was not a real effect, but was due to release of entrapped gas. Denitrification losses corrected for gas entrapment were estimated at 〈5% of applied $$^{15} NH_4^ + $$ . The 15N mass balance indicated that a much larger amount of applied ammonium (15–25%) was lost by NH3 volatilisation. The rate of denitrification corrected for gas entrapment was similar to the rate of nitrification estimated by inhibition of ammonium oxidation. Although the inhibitors 2-ethynylpyridine and acetylene prevented denitrification by effectively inhibiting nitrification of $$^{15} NH_4^ + $$ , the total recovery of 15N in the soil-plant system did not increase. The total recovery of $$^{15} NH_4^ + $$ was 7–9% higher in the presence than in the absence of rice.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    ISSN: 1573-0867
    Keywords: fertilizer-N ; 15N ; soil N ; sugarcane ; vertisol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Sugarcane is one of the main economic resources of Guadeloupe (France). Cane grown on the island's vertisols shows nitrogen deficiency which is accentuated with each successive ratoon. This deficiency could partially explain the observed decrease in yield. The present study, based on the isotopic N method applied to different ratoons in the field, was aimed at: (i) diagnosing the problem in the crop environment itself; and (ii) quantifying the fertilizer-N balance. The results indicated that decrease in yield and N absorption by the cane was related to ratoon number. The real utilization coefficient for the fertilizer (RUC%) ranged from 6 and 34%, and a high proportion (30–40%) of fertilizer-N was immobilized in the soil (NiS%) after the annual crop cycle. The N absorbed by the cane was essentially derived from the soil. Rainfall at the beginning of (re)growth determined crop development and N supply to the crop. When the water requirements of the crop are satisfied, nitrogen supply and cane yield can be improved in two ways: (i) by increasing the efficiency of the applied N fertilizer (RUC% and NiS%); and (ii) by maintaining the soil's capacity to supply cane with N. This implies maintaining and, if necessary, upgrading the structural state of the vertisols.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 53 (1999), S. 249-258 
    ISSN: 1573-0867
    Keywords: added nitrogen interaction ; fertiliser efficiency ; residual fertiliser nitrogen ; microplots ; 15N ; nitrogen balance ; nitrogen recovery ; split application
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A field study using 15N was conducted on a Vertisol in semi-arid Morocco to assess the fate and efficiency of fertiliser N split applied to winter wheat (Triticum aestivum L.). Splitting of fertiliser N is highly crucial in semi-arid regions, considering the increased moisture stress towards the end of the growing season. A N fertilisation rate of 100 kg N ha-1 was split according to two schemes: i) 25% at planting, 50% at tillering and 25% at stem elongation; or ii) 50% at tillering and 50% at stem elongation. The application of 100 kg N ha-1increased the vegetative dry matter production with more than 2000 kg dry matter ha-1 in comparison with the control treatment. Nitrogen fertilisation had no significant effect on the grain yield production. Moreover, the 1000 grain weight decreased from 32 to 26 g due to N fertilisation. Total N uptake was about 50 kg N ha-1 higher for the fertilised plants in comparison with the unfertilised plants, but it was not affected by the splitting pattern of the fertiliser N. Recoveries of 15N-labelled fertiliser by the plant (above-ground plant parts plus roots from the upper 20 cm layer) were low (31% and 24% for the 3-split and 2-split application, respectively). More N in the plant was derived from fertiliser when applied early in the growing season than when applied late in the season. About 13% of the N in the plants was derived from the 50 kg N ha-1 at tillering, while only 5% was derived from the N application (50 kg N ha-1) at stem elongation. At harvest, a high residual of fertiliser-derived N was found in the 0–90 cm profile (62% and 72%, for the 3-split and 2-split application, respectively). Less than 10% of the applied N could not be accounted for, the amount being highest for the application at tillering. This N not accounted for was mainly ascribed to denitrification after an important rainfall event. The application of fertiliser N led to an increase of about 20 kg N ha-1 in soil N uptake by the crop (positive ANI). The results suggested a dominant influence of moisture availability on the fertiliser N uptake by wheat.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 55 (1999), S. 89-94 
    ISSN: 1573-0867
    Keywords: algae ; flooded soils ; N cycling ; nitrogen ; 15N ; rice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Algal N labelled with 15N added to a flooded soil in laboratory columns without plants was studied to determine the changes over time in the fate of N assimilated by algae and to study how its fate is affected by (a) exclusion of light simulating complete closure of the rice canopy, and (b) addition of fertilizer-NH4 *. In the light but with no added fertilizer-N there was little net mineralization of the added algal N during the first 4 weeks, but after 8 weeks 42% had been mineralized, of which 95% was denitrified. Exclusion of light caused net mineralization to proceed more rapidly in the first 4 weeks due to the death of algal cells and lowered reassimilation. After 8 weeks 51% had been mineralized, of which 54% was denitrified, 16% volatilized and 30% was present as KCl exchangeable NH4 +-N. Application of fertilizer-NH4 + apparently caused mineralization of 25% of the algal N within one week but the results were probably affected by pool substitution in which labelled N mineralized to NH4 +-N was diluted with fertilizer – NH+ 4 and then immobilized leaving more labelled NH4–N in the mineral pool. After 8 weeks, 42% of algal N had been mineralized, of which 69% was estimated to have been denitrified, 19% lost through NH3 volatilization and 12% remained as extracted NH4 ++NO- 3. Uptake of N by a rice crop would reduce the gaseous losses. Algal N was mineralized quickly enough to be available during the growing season of a rice crop and, depending on field conditions, algae may have a role in assimilating N and protecting it from loss as well as being a major driving force for NH3 volatilization through diurnal increases in pH.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 42 (1995), S. 33-41 
    ISSN: 1573-0867
    Keywords: acetylene ; 15N ; nodules ; reference plant ; ureide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The four commonly used methods for measuring biological nitrogen fixation (BNF) in plants are: the total nitrogen difference (TND) method, acetylene reduction assay (ARA) technique, xylem-solute (or ureide production) method and the use of15N labelled compounds. The TND method relies on a control non-N2-fixing plant to estimate the amount of N absorbed by the fixing plant from soil. It is one of the simplest and least expensive methods, but works best under low soil N conditions. The ARA technique measures the rate of acetylene conversion to ethylene by the N2-fixing enzyme, nitrogenase. The ethylene produced can then be converted into N2 fixed, using a conversion ratio, originally recommended as 3. Although the method is inexpensive and highly sensitive, its major disadvantages are, the short-term nature of the assays, the doubtful validity of always using a conversion ratio of 3 and the auto-inhibition of acetylene conversion to ethylene. The ARA technique is therefore not a method of choice for measuring BNF. The xylem-solute technique can be used to measure BNF for those species that produce significant quantities of ureide as product of BNF. Although simple and relatively inexpensive, it is an instantaneous assay and also needs to be calibrated against a known method. The most serious limitation is, that only a small proportion of N2-fixing plants examined are ureide exporters, and the method is therefore not widely applicable. The15N methods, classified into the isotope dilution and A-value methods, appear to be the most accurate, but also the most expensive. They involve labelling soil with15N fertilizer and using a non-N2-fixing reference plant to measure the15N/14N ratio in the soil. The15N isotope dilution approach is both operationally and mathematically simpler than the A-value approach. To limit potential errors in the selection of reference crops, it is recommended to use15N labelled compounds or soil labelling methods that result in the slow release of15N or the slow decline of15N/14N ratio in the soil. Additionally, the use of several reference plants rather than a single one can improve the accuracy of the results.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 42 (1995), S. 185-192 
    ISSN: 1573-0867
    Keywords: 15N ; nitrogen ; soil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The use of15N as a tracer in soil/plant research is examined. The limitations of the so-called Ndff approach are discussed to show the need to consider not just the fate of the added label but also the path that was followed and the rate of the transformation. The development of15N isotope dilution techniques to determine gross rates of nitrogen transformation in soil is reviewed with some indications as to the further development of the approach.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 42 (1995), S. 109-115 
    ISSN: 1573-0867
    Keywords: Colocasia esculenta var.esculenta ; crop uptake ; 15N ; soil management ; tropical soils ; urea ; Vertisols
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Vertisols are an important natural resource, particularly in the developing world, but a greater understanding of their chemical characteristics with special reference to the fate of applied N is needed for their greater sustainable use. The Bejucal clay (Chromic Dystraquerts, very fine, mixed, acid) is an important agricultural soil in North Trinidad and a series of studies were undertaken on it to determine the optimum rate and the best time of application and to quantify the efficiency of applied N using CO(NH2)2-15N and taro, commonly called dasheen locally, (Colocasia esculenta var.esculenta), as a test crop. The optimum rate was found to be 280 kg N ha−1 for corm production from a field experiment, laid out in a randomised incomplete block design. This corresponded to an apparent recovery at 10 per cent when CO(NH2)2 was applied at 14 days after planting (DAP). Generally, a decrease in N uptake with increasing levels and later application times was observed. Another field experiment which employed15N applied at 14, 56, and 112 DAP showed that15N applied at 112 DAP corresponded to the highest15N level in the plant tissue. A green house experiment conducted to determine the efficiency of the use of the applied N showed the highest recovery of approximately 49 per cent at a rate equilavent to 280 kg N ha−1 with efficiencies of 43 and 40 per cent at the 140 and 420 kg N ha−1 of applied N levels, respectively. A single application at 14 DAP resulted in an efficiency of 41 per cent compared to 44 and 47 per cent for the 2 split and 3 split applications, respectively. Split applications increased N uptake but without a corresponding increase in yield. These studies showed that N applied as CO(NH2)2 at 280 kg N ha−1 at 14 DAP is optimum for upland taro production under conditions of the Bejucal clay. Under normal field conditions surface washing may be the most important N loss pathway but when excessive fertilizers are used then the gaseous pathways may also contribute to N losses.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 42 (1995), S. 149-158 
    ISSN: 1573-0867
    Keywords: Micrometeorology ; N flux ; livestock waste ; NH3 ; 15N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Gaseous ammonia (NH3) transport is an important pathway in the terrestrial N cycle. In the atmosphere NH3 neutralizes airborne acids and is a major factor determining air quality and acid rain deposition patterns. Redeposition of atmospheric NH3 plays an important role in the N balance of natural ecosystems and has been implicated in forest decline, plant species change and eutrophication of surface water. Much of the N in soil-plant animal systems can be lost to the atmosphere, particularly with surface applied livestock waste, or urea and anhydrous ammonia fertilizers. Plants can have a significant impact on NH3 transport because they can both absorb and desorb atmospheric NH3. Under conditions of low soil N or high atmospheric NH3 concentrations, plants absorb NH3. Under conditions of high soil N or low atmospheric NH3 concentrations, plants volatilize NH3. This article discusses methods for evaluating NH3 transport in the filed, the rate of NH3 volatilized from fertilizer application, and the effects of plants on net NH3 transport.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 42 (1995), S. 165-174 
    ISSN: 1573-0867
    Keywords: Anabaena ; cropping systems ; fertilizer management ; integrated nitrogen management ; 15N ; nitrogen balance ; Oryza sativa ; urea ; wetlands
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract By the year 2020, an additional 300 million tons of rice are needed annually to meet the demands of a growing population. If our natural resource base is to be preserved, intensification strategies should rely on integrated nutrient management, making full use of biological nitrogen fixation. TheAzolla-Anabaena complex is amongst the most effective systems of fixing nitrogen. In this paper we present evidence from greenhouse studies on the potential ofAzolla to curb the volatilization of NH3 following the application of urea to a mixedAzolla-rice culture, providing a new incentive for developing ways of integratingAzolla in intensive rice cultivation systems. The results of a series of short term greenhouse experiments show that a full cover ofAzolla can significantly reduce losses of applied urea-N from 45 and 50% to 20 and 13% for the 30 and 60 kg N ha−1 treatments, respectively. About one-quarter of the applied N was tied up in theAzolla biomass. The applied N inhibitedAzolla growth as well as the amount of N fixed. Inoculation with smaller quantities ofAzolla allowing for more vigorousAzolla multiplication was equally effective in reducing NH3 volatilization and doubled the amount of15N tied-up byAzolla. The reduction in NH3 volatilization is largely related to the depression byAzolla of the floodwater pH, which in its absence may reach values between 9 and 10 as a result of algal activity. Early rice growth responded positively to urea as well as the large quantities of appliedAzolla and increased the yield potential of the crop. Smaller quantities ofAzolla alone were not effective in this regard. The conservation of fertilizer N byAzolla, particularly when it fully covered the water, was reflected in a synergistic effect on rice dry matter production, amounting to 9% at the 30 kg N rate and 16% at the 60 kg N rate. In all likelihood this interaction is attributable to the higher efficiency of the applied N. The benefits ofAzolla in conserving basal urea-N even in small quantities (200-500 kg fresh material ha−1), outweighed competition for the applied N and may be as important as its BNF. The most promising integratedAzolla/rice management systems emerging from our studies should be given further attention under field conditions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 42 (1995), S. 205-214 
    ISSN: 1573-0867
    Keywords: Colocasia esculenta ; fertilizer efficiency ; fertilizer management ; 15N ; urea transformations ; volatilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Urea has become the most important N carrier in many parts of the world and its reaction when added to soil is unique in many ways. Two field experiments were therefore undertaken using15N to investigate the uptake efficiency of the added urea-15N which was banded in Experiment I and broadcast in Experiment II. In both experiments the uptake efficiencies were not affected by N-rate and cropping system (Exp. I) or crop residue management (Exp. II) and averaged 17.4 and 16.9% respectively. These low values were supported by evidences of high losses; high pH increases following urea application (volatilization), downward movement of N (leaching), and cycles of waterlogged and well drained conditions in the soil (de-nitrification). Evidence of leaching at least down to 30 cm in the profile was observed in the first experiment where urea was banded but not in experiment II where it was broadcast. The proportion of N in the crop that was derived from added urea (%Ndff) was 57.7% and 36.4% in experiments I and II respectively, suggesting that band application resulted in a higher proportion of the added N in the root zone compared to that for broadcast application. The results indicate the need to investigate other management strategies, such as higher application frequencies and placement closer to the root zone, in order to improve the uptake efficiency of added urea-N in upland rainfed dasheen.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 40 (1995), S. 41-48 
    ISSN: 1573-0867
    Keywords: Arachis hypogaea ; intercropping ; maize ; N2 fixation ; N-transfer ; 15N ; Vigna radiata ; Vigna unguiculata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Grain legumes are used widely in intercropping systems. However, quantitative and comparative data available as to their N2 fixation and N beneficial effect on the companion crop in intercropping systems are scarce. Hence, studies were conducted to ascertain the above when cowpea (Vigna unguiculata L.), mungbean (Vigna radiata L.) and groundnut (Arachis hypogaea L.) were intercropped with maize. The study was15N-aided and made outdoors in basins (30 L) filled with 38 kg of soil.15N labelling was effected by incorporating15N-tagged plant material or applying15N-labelled fertilizer along with sucrose to stabilize15N enrichment in the soil during the experimental period. Intercropped groundnut fixed the highest amount of nitrogen from the atmosphere (i.e. 552 mg plant−1), deriving 85% of its N from the atmosphere. Intercropped cowpea and mungbean fixed 161 and 197 mg N plant−1, obtaining 81% and 78% of their N content from the atmosphere, respectively. The proportion of N derived by maize from the associated legume varied from 7-11% for mungbean, 11–20% for cowpea and 12–26% for groundnut which amounted to about 19–22, 29–45 and 33–60 mg N maize plant−1, respectively. The high nitrogen fixation potential of groundnut in dual stands and its relatively low harvest index for N have apparently contributed to greater N-benefical effect on the associated crop.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 22 (1996), S. 345-349 
    ISSN: 1432-0789
    Keywords: Key words Vertisol ; pH ; Cation exchange capacity ; Moisture ; Urea ; 15N ; Nitrogen losses ; Ammonia ; volatilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The N loss from Vertisols was estimated by measuring the loss of 15N-labelled urea N under conditions that promote NH3 volatilization. Urea granules were placed on the top of 150-mm deep soil columns (Vertisols) collected from three sites with a range in pH, electrical conductivity, and cation exchange capacity. There were two contrasting moisture treatments, one near field capacity (wet) and another with intermittent wetting of the soil surface before allowing the columns to dry (moist-dry). The results indicated that losses were influenced markedly by pH and moisture treatment, being 29.5, 33.5, and 33% from the wet soils and 37, 42, and 40.5% from the moist-dry soils with pH values of 7.7, 8.2, and 9.3, respectively. These observations clearly indicate that broadcasting of urea on the surface of Vertisols may cause substantial N losses.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 23 (1996), S. 93-98 
    ISSN: 1432-0789
    Keywords: Key words Added nitrogen interaction ; Alkaline-hydrolysing fertilizer ; Aqua ammonia ; Gross N immobilization ; Gross N mineralization ; 15N ; Soluble organic N availability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Organic N solubilized by NH3(aq) was extracted from 15N-labelled or unlabelled soil, concentrated and added to non-extracted soil, which was incubated under aerobic conditions at 27±1°C. Gross N mineralization, gross N immobilization, and nitrification in soils with or without addition of unlabelled soluble organic N were estimated by models based on the dilution of the NH4 + or NO3 – pools, which were labelled with 15N at the beginning of incubation. Mineralization of labelled organic N was measured by the appearance of label in the mineral N pool. Although gross N mineralization and gross N immobilization were increased in two soils between day 0 and day 7 following addition of unlabelled organic N solubilized by NH3(aq), there was no increase in net N mineralization. Solubilization of 15N-labelled organic N increased and the 15N enrichment of the soluble organic N decereased as the concentration of NH3(aq) added increased. A constant proportion of approximately one-quarter of the labelled organic N added at different rates to non-extracted soil was recovered in the mineral N pool after an incubation period of 14 days, and the availability ratios calculated from net N mineralization data were 1.1:1 and 2.1:1 for 111 and 186 mg added organic-N kg–1 soil, respectively, indicating that the mineralization of organic N was increased by solubilization.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 23 (1996), S. 50-56 
    ISSN: 1432-0789
    Keywords: Agroforestry ; 15N ; Nitrogen fixation ; Phenolics ; 13C ; Tree fallows
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The natural abundance of 15N and 13C, conventional soil analyses, and biomass production by maize were used to study the influence of five tropical tree species on soils and their fertility. The experiment was conducted in Morogoro, Tanzania, to compare Cassia (Senna) siamea, Eucalyptus camaldulensis, E. tereticornis (all non-N2-fixing), Leucaena leucocephala, Prosopis chilensis (both N2-fixing), and a grass fallow. Maize biomass production, which was correlated with N uptake (P=0.001), was higher on soils from plots with 5-year-old Leucaena and Prosopis spp. compared to the grass fallow, while other tree species had less favourable effects on maize growth. The per cent N was higher in soil and δ15N of soil total N was lower under Prosopis sp. compared to soil under other tree species, which suggests an input from N2 fixation by Prosopis sp. A transfer of fixed N to maize or to understorey grass species was, however, not indicated by the 15N natural abundance. Prosopis sp. contributed more C to the soil than the other four tree species; the difference in δ13C between soils from Prosopis sp. plots and from grass fallow plots showed that the tree contributed 11% to the total C of the soil over a period of 8 years. The leaves of the N2-fixing species had a low ratio of lignin+phenols to N, and maize growth was negatively correlated with this parameter. The Eucalyptus spp. had leaves with a high lignin+phenols to N ratio, contributed very little C to the soil, and lowered the soil pH.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    ISSN: 1432-0789
    Keywords: Hordeum vulgare ; Agricultural ecosystem ; Acidic soil ; Soil infectivity ; Endomycorrhizae ; Reduced tillage ; Rhizosphere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The dynamics of mycorrhizae under disturbance created by crop production is not well understood. A 3-year experiment was undertaken on a nutrient-poor and acidic land that had last been cultivated in the early 1970s. We observed the effects of cropping spring barley (Hordeum vulgare L.) under four P-fertilizer levels and four levels of lime, in a minimum (rototillage), a reduced (chisel), or a conventional tillage system, on the mycorrhizal receptiveness of the host (maximum level of mycorrhizal colonization, as measured at harvest) and soil infectivity most probable number method. The host receptiveness decreased with time, while crop yields and soil infectivity increased simultaneously with time. Liming increased mycorrhizal colonization of barley roots and soil infectivity. P additions decreased root colonization but did not significantly affect the most probable number valuse. Slightly higher soil infectivity estimates were found under reduced tillage.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 23 (1996), S. 50-56 
    ISSN: 1432-0789
    Keywords: Key words Agroforestry ; 15N ; Nitrogen fixation ; Phenolics ; 13C ; Tree fallows
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The natural abundance of 15N and 13C, conventional soil analyses, and biomass production by maize were used to study the influence of five tropical tree species on soils and their fertility. The experiment was conducted in Morogoro, Tanzania, to compare Cassia (Senna) siamea, Eucalyptus camaldulensis, E. tereticornis (all non-N2-fixing), Leucaena leucocephala, Prosopis chilensis (both N2-fixing), and a grass fallow. Maize biomass production, which was correlated with N uptake (P=0.001), was higher on soils from plots with 5-year-old Leucaena and Prosopis spp. compared to the grass fallow, while other tree species had less favourable effects on maize growth. The per cent N was higher in soil and δ15N of soil total N was lower under Prosopis sp. compared to soil under other tree species, which suggests an input from N2 fixation by Prosopis sp. A transfer of fixed N to maize or to understorey grass species was, however, not indicated by the 15N natural abundance. Prosopis sp. contributed more C to the soil than the other four tree species; the difference in δ13C between soils from Prosopis sp. plots and from grass fallow plots showed that the tree contributed 11% to the total C of the soil over a period of 8 years. The leaves of the N2-fixing species had a low ratio of lignin+phenols to N, and maize growth was negatively correlated with this parameter. The Eucalyptus spp. had leaves with a high lignin+phenols to N ratio, contributed very little C to the soil, and lowered the soil pH.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    ISSN: 1432-0789
    Keywords: 15N ; Organic N ; Net mineralization of N ; CaCl2 extraction method ; Non-exchangeable NH inf4 sup+ ; Corn-shoot tissue ; Incubation method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Management of N fertilization depends not only on the mineral N measured at the beginning of the growing season but also on the status of the low-molecular-weight organic-N fraction. Our study was conducted to analyze how much of the 15N applied in labeled cornshoot tissue would be recovered in 0.01 M CaCl2-extractable 15N fractions and wheter a decrease in the CaCl2-extractable 15N fraction quantitatively followed the trend in net mineralization of the 15N applied in corn-shoot tissue during an incubation period. The effects of adding 15N-labeled young corn-shoot tissue to a sandy soil and a clay soil were investigated for 46 days in an aerobic incubation experiment at 25°C. The application of 80 mg N kg-1 soil in the form of labeled corn-shoot tissue (24.62 mg 15N kg-1 soil) resulted in a significant initial increase, followed by a decrease the labeled organic-N fraction in comparison with the untreated soils during the incubation. The labeled organic-N fraction was significantly higher in the sandy soil than in the clay soil until the 4th day of incubation. The decrease in labeled organic N in the sandy soil resulted in a subsequent increase in 15NO inf3 sup- during the incubation. Ammonification of applied plant N resulted in a significant increase in the 1 M HCl-extractable non-exchangeable 15NH inf4 sup+ fraction in the clay soik, owing to the vermiculite content. The 15N recovery was analyzed by the 0.01 M CaCl2 extraction method; at the beginning of the incubation experiment, recovery was 37.0% in the sandy soil and 36.7% in the clay soil. After 46 days of incubation, recovery increased to 47.2 and 43.8% in the sandy and clay soils, respectively. Net mineralization of the 15N applied in corn-shoot tissue determined after the 46-day incubation was 6.60 mg 15N kg-1 soil (=34.9% of the applied organic 15N) and 4.37 mg 15N kg-1 soil (=23.1% of the applied organic 15N) in the sandy and the clay soils, respectively. The decrease in the labeled organic-N fraction extracted by 0.01 M CaCl2 over the whole incubation period was 3.14 and 2.33 mg 15N kg-1 soil in the sandy and clay soil, respectively. These results indicate that net mineralization of 15N was not consistent with the decrease in the labeled organic-N fraction. This may have been due to the inability of 0.01 M CaCl2 to extract or desorb all of the applied organic 15N that was mineralized during the incubation period.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    ISSN: 1572-9788
    Keywords: Hordeum vulgare ; malting quality ; molecular marker-assisted selection ; quantitative trait loci
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Selection for malting quality in breeding programs by micromalting and micromashing is time-consuming, and resource-intensive. More efficient and feasible approaches for identifying genotypes with good malting quality would be highly desirable. With the advent of molecular markers, it is possible to map and tag the loci affecting malting quality. The objective of this study was to assess the effectiveness of molecular marker assisted selection for malting quality traits. Two major quantitative trait loci (QTL) regions in six-row barley for malt extract percentage, α-amylase activity, diastatic power, and malt β-glucan content on chromosomes 1 (QTL1) and 4 (QTL2) have been previously identified. The flanking markers, Brz and Amy2, and WG622 and BCD402B, for these two major QTL regions were used in marker-assisted selection. Four alternative selection strategies; phenotypic selection, genotypic selection, tandem genotypic and phenotypic selection, and combined phenotypic and genotypic selection, were compared for both single and multiple trait selection in a population consisting of 92 doubled haploid lines derived from ‘Steptoe’ × ‘Morex’ crosses. Marker assisted selection for QTL1 (tandem genotypic and phenotypic selection, and combined phenotypic and genotypic selection) was more effective than phenotypic selection, but for QTL2 was not as effective as phenotypic selection due to a lack of QTL2 effects in the selection population. The effectiveness of tandem genotypic and phenotypic selection makes marker assisted selection practical for traits which are extremely difficult or expensive to measure such as most malting quality traits. It can substantially eliminate undesirable genotypes by early genotyping and keeping only desirable genotypes for later phenotypic selection.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Electronic Resource
    Electronic Resource
    Springer
    Molecular breeding 2 (1996), S. 181-183 
    ISSN: 1572-9788
    Keywords: barley ; breeding ; Hordeum vulgare ; polymerase chain reaction ; tissue
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A method for using alkali treated intact plant tissue as a DNA source for the polymerase chain reaction (PCR) was applied to barley. This method saves up to two days and more than USD 50 per 40 samples by eliminating the need for DNA extraction to produce template for PCR. The conditions were optimized for various barley tissues. Fresh leaves, freeze-dried leaves, and anthers worked well as templates while root, embryo, and endosperm tissues did not. The method was shown to work with several genotypes and different primers. The resulting PCR product could be cut with restriction enzyme to produce clear polymorphism without any interference. This method can be a practical breeding tool by providing a fast, inexpensive method for screening large populations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    ISSN: 1572-9788
    Keywords: Hordeum vulgare ; molecular marker-assisted selection ; quantitative trait loci ; genotype × environment interaction ; adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Verification of putative quantitative trait loci (QTL) is an essential step towards implementing the use of marker-assisted selection (MAS) in cultivar improvement. In a previous study with 150 doubled haploid lines derived from the 6-row cross Steptoe/Morex (S/M), four regions (QTL1–4) of the barley genome were associated with differential genotypic expression for grain yield across environments. The objectives of this study were to verify the value of these four QTL for selection and to compare the efficiency of alternative MAS strategies using these QTL vs. conventional phenotypic selection for grain yield. A total of 92 DHLs derived from the S/M cross that were not used in the original mapping efforts were used for QTL verification. Confirmation of QTL effects was first accomplished by assessing yield differences between individuals carrying alternative alleles at each putative locus in three environments. QTL1 on chromosome 3 was confirmed as the most important and consistent locus to determine yield across sites, with the S allele being favorable. The M allele at QTL3 on chromosome 6 was beneficial for grain yield across sites, but to a lesser degree than QTL1. Magnitudes of allele effects at QTL2 (chromosome 2) and QTL4 (chromosome 7) were highly influenced by the environment where the genotypes were grown. Verification of QTL effects was best achieved by comparing realized selection response. Genotypic (MAS) and tandem genotypic and phenotypic selection were at least as good as phenotypic selection. Consistent selection responses were detected for QTL1 alone and together with QTL3. Genotypic selection for lines carrying the S allele at QTL1 resulted in the identification of high-yielding genotypes. Selection responses increased when the M allele at QTL3 was combined with the S allele at QTL1. Significant qualitative QTL × environment interactions for QTL2 and QTL4 were detected through differential realized selection responses at different sites. Without a thorough understanding of the physiological and agronomic particulars of any QTL and the target environment, MAS for QTL showing qualitative interactions should be minimized
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    ISSN: 1572-9788
    Keywords: amplicon ; marker conversion ; Rpg1 ; PCR ; Hordeum vulgare ; marker-assisted selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract TheRpg1 gene in barley has provided satisfactory levels of stem rust resistance for the last 50 years. The appearance of a new race of stem rust that is virulent toRpg1 has resulted in efforts to incorporate new stem rust resistance genes into barley. Marker-assisted selection may provide the only means of combining this useful gene with resistance genes for which no virulent races have been identified. Several RFLP markers have been identified as linked to theRpg1 locus. One of these, ABG704 was converted into a post-amplification restriction polymorphism. To generate a specific PCR-amplifiable polymorphism the sequence of the ABG704 locus from four barley cultivars was determined. Primers were developed that can detect a single-base difference between resistant and susceptible cultivars. The successful conversion of an RFLP marker to an allele-specific PCR-based marker not only demonstrates that this type of conversion is possible for cereals, but also results in an immediately useful marker for application to plant breeding programmes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    ISSN: 1573-5036
    Keywords: 13C ; forests ; 15N ; nitrogen saturation ; water stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Preliminary attempts to make retrospective studies of N balances and water stress in forest fertilization experiments by analyzing changes in the abundances of 15N and 13C, respectively, are discussed. Most evidence is from the Swedish Forest Optimum Nutrition Experiments, which have been running for two decades. Annual additions of N have been given either alone or in combination with other elements, notably P and K, every third year. Processes leading to loss of N, e.g. volatilization of ammonia, nitrification followed by leaching or denitrification, and denitrification alone, discriminate against the heavy isotope 15N. A correlation was found between fractional losses of added N and the change in δ15N (‰) during 19 years in current needles in a Scots pine forest, irrespective of source of N. Isotope effects were larger on urea than on ammonium nitrate plots (2 as compared to 9 δ15N (‰)) because of ammonia volatilization and higher rates of nitrification. They developed gradually over time, which opens possibilities to analyse the development of N saturation. However, the analysis may be confounded by shifts in 15N abundance of fertilizer N. In another trial, N isotope effects could be seen in both plants and soils 10 years after the last fertilization; they were smaller in soils because of a large pretreatment memory effect, but we expect them to persist there for decades. The enzyme RuBisCo discriminates strongly against the heavy isotope 13C during photosynthesis, but this effect becomes less expressed as stomata close because of water stress. The supply of N may also affect the δ13C (‰) via effects on rates of photosynthesis, and the source of N may have an influence directly via non-RubisCo carboxylations, and indirectly via effects on water use efficiency. In a trial with Norway spruce, the effect of N fertilization on the δ13C (‰) of current needles was strongly correlated with production and weakly so with foliar biomass a dry year, but not a wet year. This suggested that these variations are primarily related to induced differences in the balance between supply and demand for water. Hence, studies of {au13}C abundance can disentangle the role of water as such from its effects on mineralization of N and flow of N.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 172 (1995), S. 97-106 
    ISSN: 1573-5036
    Keywords: Atriplex hortensis ; Hordeum vulgare ; Leptochloa fusca ; root structure ; salinity ; xylem sap composition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Leptochloa fusca (L.) Kunth and Atriplex hortensis (L.) were grown on quartz sand or in liquid culture in the presence of varied concentrations of NaCl. Xylem sap was collected as (a) root pressure exudate, in L. fusca even at 100 mM NaCl, (b) by applying pressure to excised roots of L. fusca and (c) from leaves of the whole plant growing in quartz sand by pressurizing the root system. The latter procedure failed in L. fusca due to the passage of air and soil solution into the leaves. This was caused by an extensive aerenchyma in root cortex. In Atriplex hortensis remarkably high pressures were required to induce a flow of sap. The mineral cation and anion and the amino acid composition of the xylem sap obtained by the different methods was measured and is examined in view of using it for determining the flows of minerals in the whole plant and in relation to the effects of salinity. The spacious aerenchyma in roots of L. fusca has been found to persist also after prolonged exposure to dry air.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    ISSN: 1573-5036
    Keywords: Acacia raddiana ; Acacia senegal ; Acacia seyal ; Faidherbia albida ; isotope dilution ; 15N ; nitrogen fixation ; Parkia biglobosa reference tree ; Tamarindus indica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A pot experiment was conducted in a greenhouse using the 15N isotope dilution method and two reference plants, Parkia biglobosa and Tamarindus indica to estimate nitrogen fixed in four Acacia species: A raddiana, A. senegal, A. seyal and Faidherbia albida (synonym Acacia albida). For the reference plants, the 15N enrichments in leaves, stems and roots were similar. With the fixing plants, leaves and stems had similar 15N enrichments; they were higher than the 15N enrichment of roots. The amounts of nitrogen fixed at 5 months after planting were similar using either reference plant. Estimates of the percentage of N derived from fixation (%Ndfa) for the above ground parts, in contrast to %Ndfa in roots, were similar to those for the whole plant. However, none of the individual plant parts estimated accurately total N fixed in the whole plant, and excluding the roots resulted in at least 30% underestimation of the amounts of N fixed. Between species, differences in N2 fixation were observed, both for %Ndfa and total N fixed. For %Ndfa, the best were A. seyal (average, 63%) and A. raddiana (average, 62%), being at least twice the %Ndfa in A. senegal and F. albida. Because of its very high N content, A. seyal was clearly the best in total N fixed, fixing 1.62 g N plant−1 compared to an average of 0.48 g N plant−1 for the other Acacia species. Our results show the wide variability existing between Acacia species in terms of both %Ndfa and total N fixed: A. seyal was classified as having a high N2 fixing potential (NFP) while the other Acacia species had a low NFP.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    ISSN: 1573-5036
    Keywords: ammonium ; animal manure ; injection ; 15N ; N utilization ; ryegrass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effect of incorporating cattle slurry in soil, either by mixing or by simulated injection into a hollow in soil, on the ryegrass uptake of total N and 15NH4 +-N was determined in three soils of different texture. The N accumulation in Italian ryegrass (Lolium multiflorum L.) from slurry N and from an equivalent amount of NH4 +-N in (15NH4) SO4 (control) was measured during 6 months of growth in pots. After this period the total recovery of labelled N in the top soil plus herbage was similar in the slurry and the control treatments. This indicated that gaseous losses from slurry NH4 +-N were insignificant. Consequently, the availability of slurry N to plants was mainly influenced by the mineralization-immobilization processes. The apparent utilization of slurry NH4 +-N mixed into soil was 7%, 14% and 24% lower than the utilization of (NH4)2SO4-N in a sand soil, a sandy loam soil and a loam soil, respectively. Thus, the net immobilization of N due to slurry application increased with increasing soil clay content, whereas the recovery in plants of 15N-labelled NH4 +-N from slurry was similar on the three soils. A parallel incubation experiment showed that the immobilization of slurry N occurred within the first week after slurry application. The incorporation of slurry N by simulated injection increased the plant uptake of both total and labelled N compared to mixing the slurry into the soil. The apparent utilization of injected slurry NH4 +-N was 7% higher, 8% lower and 4% higher than the utilization of (NH4)2SO4-N in the sand, the sandy loam and the loam soil, respectively. It is concluded that the spatial distribution of slurry in soil influenced the net mineralization of N to the same degree as did the soil type.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 178 (1996), S. 141-152 
    ISSN: 1573-5036
    Keywords: dentrification ; leaching ; lysimeter ; 15N ; ryegrass ; white clover
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A field lysimeter experiment was conducted over 150 days to examine the fate of synthetic urinary nitrogen (N) applied to peat and mineral soils, with and without a water table. At the start of the winter season, synthetic urine labelled with 15N, was applied at 500 kg N ha−1. Plant uptake, leaching losses and nitrous oxide (N2O) fluxes were monitored. Total plant uptake ranged from 11% to 35% of the urine-N applied depending on soil type and treatment. Plant uptake of applied N was greater in the presence of a water table in the mineral soil. Nitrate-N (NO3 --N) was only detected in leachates from the mineral soil, at concentrations up to 146 μg NO3 --N mL−1. Presence of a water table in the mineral soil reduced leaching losses (as inorganic-N) from 47% to 6%, incrased plant uptake and doubled apparent denitrification losses. In the peat soils leaching losses of applied urine-N as inorganic-N were low (〈5%). Losses of N as N2O were greater in the mineral soil than in the peat soils, with losses of 3% and 〈1% of N applied respectively after 100 days. Apparent denitrification losses far exceeded N2O losses and it is postulated that the difference could be due to dinitrogen (N2) loss and soil entrapment of N2.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    ISSN: 1573-5036
    Keywords: ammonium ; heterogeneity ; inflow ; localised nutrient ; mineralisation ; 15N ; nitrate ; organic residue ; proliferation ; roots ; soil ; uptake ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract To obtain nutrients mineralised from organic matter in the soil, plants have to respond to its heterogeneous distribution. We measured the timing of nitrogen uptake by wheat from a localised, 15N labelled organic residue in soil, as well as the timing of changes in root length density. We calculated the rates of N uptake per unit root length (inflows) for roots growing through the residue and for the whole root system. A stimulated local inflow appeared to be the main mechanism of exploitation of the residue N during the first five days of exploitation. 8% of the N that the plants would ultimately obtain from the residue was captured in this period. Roots then proliferated in the residue. This, together with a rapidly declining N inflow, contributed to the capture, over the next seven days, of 63% of the N that the plants derived from the residue. After that time, massive root proliferation occurred in the residue, but relatively little further N was captured.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    ISSN: 1573-5036
    Keywords: cultivar, grazing ; 15N ; nitrogen fertilizer ; nitrogen fixation ; Trifolium repens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Forage production and N2 fixation were determined for nine cultivars of white clover (Trifolium repens L.) grown with perennial ryegrass (Lolium perenne L.) and receiving nitrogen (N) fertilizer at either 0 or 390 kg N ha-1 yr-1. The site was grazed by sheep at 3 or 6 (in winter and summer) week intervals and N fertilizer was applied at 30 kg N ha-1 after each grazing. Annual white clover production showed a 2-fold variation between cultivars and was positively correlated with total pasture production in the 0 N treatment. Nitrogen fertilizer application increased average total pasture dry matter (DM) production from 12830 to 16010 kg ha-1 yr-1, but decreased average white clover production from 3600 to 2970 kg DM ha-1 yr-1. Fertilizer N application decreased annual N2 fixation from 111 to 47 kg N ha-1 (mean for all cultivars, using 15N dilution), with the decline occurring predominantly in spring and summer. The decrease in N2 fixation in spring from 47 to 18 kg N ha-1 was due largely to a decrease in clover DM production. In contrast, N application decreased average N2 fixation in summer from 36 to 14 kg N ha-1 due mainly to a large decrease in the proportion of clover N derived from atmospheric N2 (from 49 to 24%), with clover DM production falling by only 10%. Clover cultivars showed a variation in annual N2 fixation of about 3-fold under both N regimes. During winter and spring, the amount of N fixed by the different cultivars was determined predominantly by their DM production in both N regimes. In contrast, during summer and autumn there was a marked variation between cultivars in tolerance of N2 fixation to increased soil inorganic N due to N fertilizer application. This was evident from a significant cultivar × N interaction for the proportion (PN) of clover N derived from N2 fixation. During summer/autumn, PN for Kopu was similar in the 0 and 390 N treatments, whereas PN declined by up to two-thirds for the other cultivars. Consequently, in summer/autumn the amount of N fixed by Kopu decreased by only 20% (from 65 to 52 kg N ha-1) due to N application whereas it decreased by 40–80% (to 15–34 kg N ha-1) for the other cultivars. Thus, N2 fixation during winter/spring was highest for the most productive large-leaved cultivars (Kopu, Aran and Pitau) either in the absence or presence of added N. In contrast, in summer/autumn the cultivars differed in tolerance to added N, and N2 fixation in the 390 N treatment was higher for the more tolerant cultivar Kopu than for the other cultivars.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    ISSN: 1573-5036
    Keywords: barley ; Hordeum vulgare ; microbial biomass P ; phosphatases ; soil solution P
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Organic phosphorus is often a major part of total phosphorus in soil solution. The role of this fraction as a P source for plants and the mechanism involved in its transfer from soil to plant is still unclear. We studied the utilization of organic phospharus in 0.01 M calcium chloride extracts by barley and its hydrolysis by isolated acid and alkaline phosphatases. Calcium chloride extracts were used as a nutrient solution in 24 hrs assays. Concentration of organic and inorganic P in equilibrium calcium chloride extracts was 7.8 and 1.8 µmol P L-1, respectively, which was similar to the soil solution P concentration. When soil microbial biomass was destroyed by autoclaving, organic P concentration increased to 64.8 µmol P L-1 whereas the inorganic P was hardly changed. Inoculation of the autoclaved soil with non-sterile soil and incubation for 5 days decreased the organic P concentration to 27.9 µmol P L-1 but did not change inorganic P. In this study barley plants utilized organic P from all extracts. The greatest reduction of organic P concentration occurred in fresh extracts of the autoclaved soil. Inorganic P was depleted to traces in all extracts. Organic P was hydrolyzed by isolated acid and alkaline phosphatases. We conclude that organic P in soil solution is a heterogeneous pool of organic P compounds originating from microbial biomass. Its initial availability to plants was nigh but its susceptibility to phosphatase hydrolysis was quickly reduced but not completely lost.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    ISSN: 1573-5036
    Keywords: fertilisation ; microbial immobilisation ; N nutrition ; 15N ; timing ; winter wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Previous studies on the fate of fertiliser nitrogen applied to winter wheat in temperate climates have shown that nitrogen (N) applied early, at tillering for wheat, was less efficiently taken up than N applied later in the growth cycle. We examined the extent to which the soil microbial N immobilisation varied during the wheat spring growth cycle and how microbial immobilisation and plant uptake competed for nitrogen. We set up a pulse-15N labelled field experiment in which N was applied at eight development stages from tillering (beginning of March) to anthesis (mid-June). Each application was 50 kg N ha-1 as 15N labelled urea except for the first application which was 25 kg N ha-1. The distribution of fertiliser 15N in shoots, roots, mineral and organic soil N was examined by destructive sampling 7 and 14 days after each 15N pulse. The inorganic 15N pool was almost depleted by day 14. The N uptake efficiency increased with later applications from 45% at tillering to 65% at flowering. N immobilisation was rather constant at 13–16% of N applied, whatever the date of application. The increase in plant 15N uptake resulted in an increase in the total 15N recovery in the plant-soil system (15N in soil +15N in plant), suggesting that gaseous losses were lower at the later application dates.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    ISSN: 1573-5036
    Keywords: common bean ; 15N ; Phaseolus vulgaris ; rhizobial diversity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A field experiment under rainfed conditions was conducted in Durango, México, to assess N2-fixation of three cultivars of common bean (Phaseolus vulgaris L.) using 15N-methodology. In addition, diversity of rhizobial isolates obtained from nodules of the different plant genotypes was evaluated by intrinsic antibiotic resistance (IAR), PCR using enterobacterial repetitive intergenic consensus (ERIC) primers, PCR-RFLP analysis of the 16S rRNA gene and multilocus enzyme electrophoresis (MLEE). Selected isolates were used to determine acetylene reduction and competitive ability under greenhouse conditions. The three cultivars tested did not show high variation in N2-fixation, the %Ndfa values ranged from 19 to 26%. Variability in N2-fixation efficiency among various native rhizobial isolates was very high and our results indicate that differences in competitive abilitiy exist also. PCR-RFLP of the 16S rRNA gene and MLEE revealed that most of the isolates belong to the species Rhizobium etli. Intrinsic antibiotic resistance analysis and ERIC-PCR showed high diversity among isolates. In contrast, our results using MLEE show low genetic diversity (H = 0.105).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Electronic Resource
    Electronic Resource
    Springer
    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).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Electronic Resource
    Electronic Resource
    Springer
    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.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    ISSN: 1573-5060
    Keywords: Hordeum vulgare ; barley ; Puccinia hordei ; leaf rust ; latent period ; partial resistance ; slow rusting ; minor genes ; polygenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The latent period (LP) in the barley-leaf rust relationship is an important component of the partial resistance complex. The inheritance of the host plant effect on LP was studied in five crosses between four cultivars. The LP, effectuated by the susceptible cultivars L94 and L92, were 8.0 and 8.6 days resp., those of the resistant cultivars Minerva (Mi) and Vada (Va) 16.9 and 17.1 days resp. The mean F1 and F2 values of the crosses L92×L94 and Mi x Va were intermediate between the parental ones. The variances of the F2's were slightly larger than those of the parents and the F1's indicating some segregation. In the crosses between a susceptible and a resistant cultivar the F1 value was half way between the mid-parent and susceptible parent value. The F2 mean lay approximately half way between the mid-parent and F1 value, with a distribution positively skewed and slightly bimodal. There was no transgression, in fact not even the parental values were recovered among nearly 500 F2 plants. The F3-lines of the crosses between susceptible and resistant cultivars showed within line variances from as low as the parental values to as high as or higher than those of the F2. In hte F3's the parental values could be recovered although no transgression occurred. L94 is supposed to carry no genes effecting a longer LP. The long LP of Mi and Va, assuming no linkage, is thought to be effectuated by the cumulative action of a recessive gene with a fairly large effect and some four to five minor genes with additive inheritance. One of these minor genes is supposed to be carried by L92, while Mi and Va are thought to differ for one minor gene only. In case linkage exists, the number of minor genes involved could be higher.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 25 (1976), S. 387-391 
    ISSN: 1573-5060
    Keywords: Triticum aestivum ; wheat ; Hordeum vulgare ; barley ; screening nursery ; distance between control plots ; protein content ; correlation coefficient
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Correlation coefficients were calculated in two seasons, between protein content of control plots of ‘Kyperounda’ durum wheat and ‘Athenais’ barley sown at distances of from 0.6 m to 68.4 m. Simple correlation coefficients were high (0.737, 0.710 and 0.311) and significant at the 1% level of probability for plots 0.6 m apart, but decreased rapidly with increasing distances between plots. The correlation in four nurseries was significant for plots 7.2 m, 4.2m, 4.2 m and 1.8 m apart. It was concluded that a control plot provides a fairly good measure of the protein content of adjacent plots.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 25 (1976), S. 621-631 
    ISSN: 1573-5060
    Keywords: Hordeum vulgare ; Hordeum bulbosum ; barley ; bulbous barley grass ; interspecific hybrids ; colchicine treatments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary To produce hexaploid (or other polyploid) hybrids, diploid or tetraploid Hordeum vulgare was crossed with hexaploid or octoploid H. bulbosum, and perennial triploid hybrids between the two species were treated with colchicine. The crosses did not yield viable plants: seedset was low, the seed aborted and embryo culture was unsuccessful. The colchicine treatments geve rise to plants in which hexaploid chromosome numbers were observed. At the hexaploid level chromosomal instability occurred, resulting in chromosome elimination. The colchicine-treated triploid hybrids showed in the first years after the treatment better fertility after open flowering than untreated plants, but the level of fertility remained very low. The offspring consisted of haploid, diploid and approximately triploid plants like H. vulgare, tetraploid and approximately tetraploid plants like H. bulbosum, and plants with hybrid morphology and unstable chromosome number, which were highly sterile. Thus the crossing barrier between H. vulgare and H. bulbosum could not be broken down at higher ploidy level.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 25 (1976), S. 249-254 
    ISSN: 1573-5060
    Keywords: Hordeum vulgare ; barley ; Puccinia hordei ; leaf rust ; seedling resistance ; hypersensitivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The three Dutch isolates studied carried virulence genes against the resistance genes Pa, Pa-2, Pa-4 and Pa-5, substantiating the widespread occurrence of these virulences in Western Europe as reported by others. The cultivars Cebada Capa, La Estanzuela, Gondar and Dabat carry the same dominant to semi-dominant gene, which is also found in Forrajera Klein and H2212. It is proposed to designate this gene Pa-7. This gene segregated independently from the Pa-3 gene in Rika x (Baladi x Rika) substantiating the data of Johnson (1968), but disagreeing with those of Roane & Starling (1970). EP 75 seems to carry a single dominant or semi-dominant gene conferring an intermediate resistance to the isolates used. This gene, tentatively designated as Pa-z, is different from the Pa, Pa-2, Pa-4, Pa-5 and Pa-7 genes. The intermediate resistance of Monte Christo is probably based on gene(s) different from EP 75.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    ISSN: 1573-5060
    Keywords: Hordeum vulgare ; barley ; fertility restoration ; genetic male sterility ; gibberellic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary We propose that research be increased on chemical restoration of fertility to the genetic male steriles of barley. Seed harvested from male-sterile plants restored to fertility can then be planted as the female for hybrid barley production. Male fertility has been resotred in male-sterile or gynoecious plants by chemicals in many species, but a satisfactory method has not been developed in barley. Male-sterile mutants that self and mutant-chemical combinations with fertility persisting into the second generation should be avoided.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 27 (1978), S. 117-126 
    ISSN: 1573-5060
    Keywords: Hordeum vulgare ; barley ; Triticum aestivum ; Triticum durum ; wheat ; genotypic variance ; environmental variance ; protein content ; nitrogen fertilizer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effects of N fertilizer, irrigation and location on genotypic and environmental variances of barley and wheat varieties were studied in a series of trials. Genotypic variance for crude protein content, as well as for grain yield, tended to be higher under high N fertilizer rate (80 kg N/ha). The effect of N fertilizer rate on environmental variance varied with variety and location. Increase in crude protein content resulted in decrease in environmental variance for only a few of the varieties tested. The effect of quantity of irrigation water on genotypic and environmental variance for crude protein content was small.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    ISSN: 1573-5060
    Keywords: Hordeum vulgare ; barley ; Puccinia hordii ; leaf rust ; cultivars ; infection frequencies ; latent period ; partial resistance ; non-hypersensitive resistance ; slow rusting resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The cultivar effect on infection frequency (IF) was studied in the seedling and adult plant stages of 15 spring barley cultivars. In both stages the cultivar effects were highly significant. The cultivars L94 and Vada represented the extremes. Vada having about 2 1/2 times fewer uredosori than L94. Between cultivars and development stage clear interactions occurred. Pauline f.i. had the same low IF as Vada in the seedling stage, but in the adult plant stage its IF was about 70% higher. Also other effects could influence the cultivar effects. Increasing leaf age appears to increase IF. The cultivar effect also seemed to depend on the level of IF. At high levels the cultivars differed far less than at low levels of IF. The cultivar effect on IF appeared correlated with partial resistance in the field (r=0.7) through a high correlation with the cultivar effect on latent period (r=0.8).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    ISSN: 1573-5060
    Keywords: barley landraces ; drought ; Hordeum vulgare ; leaf colour ; photosynthesis ; photosystem I and II ; thylakoid chlorophyll-proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Barley breeders at ICARDA have observed that genotypes adapted to dry regions have leaves which are lighter in colour than those of unadapted ones. We measured photosynthesis, chlorophyll content and chlorophyll a:b ratios in two sets of genotypes which had previously been observed to have either light green or dark green leaves when grown in the field. Thylakoid membranes were also extracted and the proteins analysed on SDS-PAGE gels. The light leaf colour was associated with a higher chlorophyll a:b ratio. This was a measure of a reduction in the amount of antenna chlorophyll compared to that in the core complex of PSII. Genotypes with light green leaves had consistently less chlorophyll per unit leaf area and lower photosynthetic rates per unit area than those with dark green leaves. It is suggested that these features of light green leaves may confer the ability to adapt to high levels of irradiance under drought conditions. This ability may result from a high rate of photosynthetic electron transport through each PSII reaction centre, thus reducing the risk of damage from the overexcitation of these centres.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    ISSN: 1573-5060
    Keywords: heading character ; Hordeum vulgare ; Triticum aestivum ; wheat-barley chromosome addition line
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Heading time in cereals is a composite character determined by vernalization requirement, photoperiodic sensitivity and narrow-sense earliness. To study the effects of added barley chromosomes on the heading characters in wheat, two sets of wheat-barley chromosome addition lines, i.e., ‘Betzes’ barley chromosomes 2H to 7H added to ’Chinese Spring‘ wheat (CS-Be2H to CS-Be7H) and ‘New Golden’ barley chromosomes 5H and 6H added to ‘Shinchunaga’ wheat (Shi-NG5H, Shi-NG6H), were examined for their heading characters. All barley chromosomes except Be6H affected vernalization requirement and/or narrow-sense earliness in CS or Shi. Be5H chromosome also slightly increased the photoperiodic sensitivity of CS. Shi-NG5H addition line showed significantly decreased vernalization requirement in comparison with Shi, whereas CS-Be5H did not show any difference from CS. The F1 hybrid of the cross, Shi-NG5H × CS-Be5H, exhibited the same level of vernalization insensitivity as the Shi-NG5H addition line, and plants with and without a vernalization requirement segregated in a 1 : 3 ratio in the F2 generation. These observations, together with previous reports, suggest that the decreased vernalization requirement in the Shi-NG5H addition line was caused by the presence of a major dominant gene for spring habit, Sh2, located on the NG5H barley chromosome. Furthermore, this study revealed that the Sh2 gene in barley has a similar but weaker effect than the wheat vernalization insensitive gene, Vrn1, on the vernalization response in wheat.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    ISSN: 1573-5060
    Keywords: epistasis ; Hordeum vulgare ; QTL ; RFLP ; barley ; grain yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The positions of quantitative trait loci (QTL) for yield and yield components were estimated using a 85-point linkage map and phenotype data from a F1-derived doubled haploid (DH) population of barley. Yield and its components were recorded in two growing seasons. Highly significant QTL effects were found for all traits at several sites in the genome. A major portion of the QTL was found on chromosome 2. The effect of the alleles in locus v on thousand grain weight and kernels per ear explained 70–80% of the genetic variation in the traits. QTL × year interaction was found for grain yield. Several different QTL were found within the two-rowed DH lines compared to those found in the six-rowed DH lines. Epistasis between locus v and several loci for yield and yield components indicates that genes are expressed differently in the two ear types. This may explain the difficulties of selecting high yielding lines from crosses between two-rowed and six-rowed barley.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    ISSN: 1573-5060
    Keywords: Hordeum vulgare ; barley ; tissue culture ; chromosomal variation ; plant regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Chromosome number of morphogenic and non-morphogenic calli and regenerated plants of barley were determined. Cultures were obtained from two kinds of explants, immature embryos and seedling leaves from three cultivars, Ingrid, Dissa and Golden Promise. Callus chromosome analyses were carried out during a 12 month period in a medium containing 2 mg/l of 2,4-D. Diploid cells were predominant in all cases; although in leaf-derived cultures, retraploid cells (2n=4x=28) showed a tendency to increase as time in culture increased and after more than six months in culture, diploid cells decreased to percentages of almost 70%. Aneuploid cells were generally infrequent in all cases. The source of explant has been more important than the genotype (cultivar) and the type of callus (morphogenic vs. non-morphogenic) in the chromosomal stability of cultures as time increases. From short term cultures, only 1.85% of the regenerated plants were tetraploid, the remaining were diploids. The ability of morphogenic calli to regenerate plants decreased before any significant reduction of diploid cells were observed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    ISSN: 1573-5060
    Keywords: gene mapping ; germination ; Hordeum vulgare ; quantitative trait loci ; salt tolerance ; seedling test
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Quantitative trait loci (QTLs) controlling salt tolerance at germination and the seedling stage in barley (Hordeum vulgare L.) were identified by interval mapping analysis using marker information from two doubled haploid (DH) populations derived from the crosses, Steptoe/Morex and Harrington/TR306. Interval mapping analysis revealed that the QTLs for salt tolerance at germination in the DH lines of Steptoe/Morex were located on chromosomes 4 (4H), 6(6H), and 7(5H), and in the DH lines of Harrington/TR306 on chromosomes 5(1H) and 7(5H). In both DH populations, the most effective QTLs were found at different loci on chromosome 7(5H). Genetic linkage between salt tolerance at germination and abscisic acid (ABA) response was found from QTL mapping. The QTLs for the most effective ABA response at germination were located very close to those for salt tolerance on chromosome 7 (5H) in both crosses. The QTLs for salt tolerance at the seedling stage were located on chromosomes 2(2H), 5(1H), 6(6H), and 7(5H) in the DH lines of Steptoe/Morex, and on chromosome 7(5H) in the DH lines of Harrington/TR 306. Their positions were different from those of QTLs controlling salt tolerance at germination, indicating that salt tolerance at germination and at the seedling stage were controlled by different loci.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    ISSN: 1573-5036
    Keywords: Helianthus annuus L. ; 15N ; nitrogen supply ; redistribution ; remobilization ; seed N ; sunflower ; total N ; vegetative organs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A glasshouse study was made of the distribution of 15N among vegetative organs of sunflower and its later remobilization and redistribution to seeds, as influenced by the developmental stage at which 15N was provided, and by the N status of the plants. Plants of Hysun 30 sunflower were grown in sand culture and provided with K15NO3 for a 3-day period at: (a) 3 days before the end of floret initiation; (b) 3 days before anthesis; (c) the start of anthesis; (d) full anthesis; and (e) 8 days after full anthesis. The plants were grown on a range of N supply rates, from severely deficient to more than adequate for maximum growth. Nitrogen-15 was distributed to all parts of the plant at the end of the 15N uptake periods. With the exception of the most N-stressed plants, subsequent remobilization of 15N from roots, stems and leaves occurred irrespective of the time the 15N was taken up. However, the percentage redistribution to seeds of 15N taken up at the end of floret initiation was less than for 15N taken up at anthesis. Remobilization of 15N from leaves and roots was higher (70%) for 15N taken up during and after anthesis than for 15N taken up at the end of floret initiation (45%), except for plants grown on the lowest N supply. By contrast, remobilization of 15N from the stem was lower for 15N taken up after full anthesis (40%) than before or during anthesis (〉70%). The proportion of 15N remobilized from the top third of the stem was less than that from the bottom third, and decreased with increasing plant N status. Nitrogen-15 taken up over the 3-day supply periods during anthesis contributed from 2 to 11% of the total seed N at maturity; the contribution to seeds was greatest for plants grown on the highest N supply. Nitrogen taken up just before and during anthesis contributed most of the N accumulated in mature seeds of plants grown on an adequate N supply, but N taken up between the end of floret initiation and just before anthesis, or after full anthesis seemed to make an equally important contribution to mature seeds as N taken up during anthesis for plants grown on a very low N supply. It was concluded that the development of florets and seeds of sunflower is supported by N taken up by the plant between the end of floret initiation and anthesis, and by N redistributed from vegetative organs. Unless soil N is so low as to impair early growth, split applications of N fertilizer would be best made just before the end of floret initiation (‘star stage’) and just before anthesis.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 183 (1996), S. 137-148 
    ISSN: 1573-5036
    Keywords: barley ; legume ; mixed crop ; monocrop ; N2 fixation ; 15N ; vetch
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A field experiment on vetch and barley grown in monoculture and in mixed culture was conducted under rain-fed conditions throughout two growing seasons. Plants were either subjected to three sequential harvests, or were harvested only once, at physiological maturity. Our results showed the advantage of a mixed cropping system of vetch and barley over sole cropping under rainfed conditions in terms of dry matter production, total nitrogen content, and land use efficiency expressed as land equivalent ratio (LER). This advantage was more pronounced in the plants harvested once at the end of the season than those subjected to the three successive harvests. Based on this result, a single seasonal rather than several harvests would be recommended under similar rainfed conditions. Nitrogen fixation in vetch measured by the15N-isotope dilution method, varied with the number of harvests and with cropping system. The percentage of N derived from the atmosphere (%Ndfa) of vetch in mixed culture was in most cases higher than in monoculture. The poor competitiveness of vetch for soil N uptake was responsible for the higher soil N uptake by barley and therefore, a higher %Ndfa in vetch. Positive and high final nitrogen balance was observed in the mixture. We excluded, under the current experimental conditions, the possibility of N-transfer from vetch to barley.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    ISSN: 1573-5036
    Keywords: crop residues ; isotope dilution ; 15N ; nitrogen ; organic matter ; pool substitution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Experiments were carried out to compare the direct approach for estimating crop N uptake from 15N labelled organic inputs, to two indirect approaches, 15N isotope dilution and A value. In the first experiment soils received 25, 50, 75, or 100 mg N kg soil−1 in the form of Casuarina equisitifolia residues in addition to ammonium sulphate fertiliser, to give a total of 100 mg N kg soil−1 added. This was a cross labelling design, thus two matching sets of treatments, were set up, identical in all but the position of the 15N label. Maize (Zea mays L.) plants were grown in the soils amended with residues for 11 weeks and N derived from residues (Ndfr) estimated using the A-value or the direct approach. The A-value approach appeared to significantly overestimate %Ndfr compared to the direct method. In the second experiment contrasting residues were added to soil, fababean (Vicia faba L. var. minor), alfalfa (Medicago sativa L.), soyabean fixing, (Glycine max (L.) Merrill), soyabean non-fixing, barley (Hordeum vulgare L.) and maize. This was also cross-labelling design, labelled and unlabelled residues were used. Maize plants were grown in these soils for 11 weeks and %Ndfr in the maize plants estimated using 15 N isotope dilution and the direct approach. The 15 N isotope dilution approach also overestimated %Ndfr compared to the direct method in this experiment. Pool substitution appeared to be responsible for the discrepancy between the direct and indirect techniques. It was concluded that 15N isotope dilution and A-value approaches as used in these experiments (i.e where residues and 15N label are added simultaneously) were not appropriate techniques for estimating N derived from organic residues in soils.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    ISSN: 1573-5036
    Keywords: carbon mineralization ; microbial biomass ; 15N ; nitrogen mineralization ; temperature effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of temperature on N mineralization were studied in two organic surface horizons (LF and H) of soil from a boreal forest. The soil was incubated at 5 °C and 15 °C after adding 15 N and gross N fluxes were calculated using a numerical simulation model. The model was calibrated on microbial C and N, basal respiration, and KCl-extractable NH4 +, NO3 −, 15NH4 + and 15 NO3 −. In the LF layer, increased temperature resulted in a faster turnover of all N pools. In both layers net N mineralization did not increase at elevated temperature because both gross NH4 + mineralization and NH4 + immobilization increased. In the H layer, however, both gross NH4 + mineralization and NH4 + immobilization were lower at 15 °C than at 5 °C and the model predicted a decrease in microbial turnover rate at higher temperature although measured microbial activity was higher. The decrease in gross N fluxes in spite of increased microbial activity in the H layer at elevated temperature may have been caused by uptake of organic N. The model predicted a decrease in pool size of labile organic matter and microbial biomass at elevated temperature whereas the amount of refractory organic matter increased. Temperature averaged microbial C/N ratio was 14.7 in the LF layer suggesting a fungi-dominated decomposer community whereas it was 7.3 in the H layer, probably due to predominance of bacteria. Respiration and microbial C were difficult to fit using the model if the microbial C/N ratio was kept constant with time. A separate 15N-enrichment study with the addition of glucose showed that glucose was metabolized faster in the LF than in the H layer. In both layers, decomposition of organic matter appeared to be limited by C availability.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Electronic Resource
    Electronic Resource
    Springer
    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.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    ISSN: 1573-5036
    Keywords: nitrogen ; 13N ; 15N ; phloem sap ; positron-emitting tracer imaging system ; rice ; xylem
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Nitrogen movement through the xylem vessels and sieve tubes in rice plants was studied using xylem and phloem sap analysis in combination with stable and radioactive nitrogen isotope techniques. More than 90% of nitrogen was translocated in the sieve tubes of rice plants as amino acids. When 15N (99.6 atom%) was applied as a nitrate to the root, 15N first appeared in phloem sap of the leaf sheath within 10 minutes and increased to 37 atom% excess 5 hours after the experiment had started. In long-term experiments, 63% of nitrogen in the phloem sap of the leaf sheath and 15% in that of the uppermost internode came from nitrogen absorbed within the last 24 hours and 50 hours, respectively. To obtain information about the more rapid circulation of nitrogen in the plant, radioactive 13N was used as a tracer. A positron-emitting tracer imaging system was used to show that 13N was transferred to the leaf sheath within 8 minutes of its application to the roots. Analysis of the xylem sap of the leaf sheath showed that when the nitrate was applied to the roots, most of the nitrogen in the xylem was transported as a nitrate. These data showed that phloem and xylem sap analysis together with the stable and radioactive nitrogen techniques provide a good method for the detection of nitrogen cycles in plants.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 173 (1995), S. 205-210 
    ISSN: 1573-5036
    Keywords: citrus ; N mobilization ; N translocation ; 15N ; reserves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The mobilization of N from reserve organs (leaves, roots, branches and trunk) to developing new organs was studied at different moments of the growth cycle. Three-year-old Valencia Late orange trees (Citrus sinensis (L.) Osbeck) were grown individually outdoors in 150 L containers filled with siliceous sand. Trees were irrigated with a nutrient solution labelled with potassium nitrate with an enrichment of 4 atom 15N % excess during a complete growth cycle. At the following year, plants were irrigated with unlabelled nutrient solution, and harvested throughout the growth cycle (flowering, fruit set, second flush, third flush, and dormancy). Total N and 15N analyses were carried out in the different organs of the plants. The highest amounts of N were found in leaves and roots (33–42% and 30–38%, respectively). Distribution of 15N was similar to that obtained for total N (42 and 39% of total 15N in leaves and roots, respectively) as is expected after a long period of labelling. Old leaves were the main reserve organs, contributing a 40–50% of the total N exported. Roots and aerial woody tissues exported between 30–35% and 15–25% of total reserve N, respectively. N exported by old leaves was approximately 57% of the N accumulated during the preceding year, while roots translocated 40% and trunk plus branches 35%. More than 70% of N accumulated in new organs during spring came from N stored in old organs.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    ISSN: 1573-5036
    Keywords: decomposition ; isotope dilution ; 15N ; mineralization ; nodulation ; N use efficiency ; residue management
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Alley cropping is being widely tested in the tropics for its potential to sustain adequate food production with low agricultural inputs, while conserving the resource base. Fast growth and N yield of most trees used as hedgerows in alley cropping is due greatly to their ability to fix N2 symbiotically with Rhizobium. Measurements of biological N2 fixation (BNF) in alley cropping systems show that some tree species such as Leucaena leucocephala, Gliricidia sepium and Acacia mangium can derive between 100 and 300 kg N ha-1 yr−1 from atmospheric N2, while species such as Faidherbia albida and Acacia senegal might fix less than 20 kg N ha-1 yr-1. Other tree species such as Senna siamea and S. spectabilis are also used in alley cropping, although they do not nodulate and therefore do not fix N2. The long-term evaluation of the potential or actual amounts of N2 fixed in trees however, poses problems that are associated with their perennial nature and massive size, the great difficulty in obtaining representative samples and applying reliable methodologies for measuring N2 fixed. Strategies for obtaining representative samples (as against the whole tree or destructive plant sampling), the application of 15N procedures and the selection criteria for appropriate reference plants have been discussed. Little is known about the effect of environmental factors and management practices such as tree cutting or pruning and residue management on BNF and eventually their N contribution in alley cropping. Data using the 15N labelling techniques have indicated that up to 50% or more of the tree's N may be below ground after pruning. In this case, quantification of N2 fixed that disregards roots, nodules and crowns would result in serious errors and the amount of N2 fixed may be largely underestimated. Large quantities of N are harvested with hedgerow prunings (〉300 kg N ha-1 yr-1) but N contribution to crops is commonly in the range of 40–70 kg N ha-1 season. This represents about 30% of N applied as prunings; however, N recoveries as low as 5–10% have been reported. The low N recovery in maize (Zea mays) is partly caused by lack of synchronization between the hedgerow trees N release and the associated food crop N demand. The N not taken up by the associated crop can be immobilized in soil organic matter or assimilated by the hedgerow trees and thus remain in the system. This N can also be lost from the system through denitrification, volatilization or is leached beyond the rooting zone. Below ground contribution (from root turnover and nodule decay) to an associated food crop in alley cropping is estimated at about 25–102 kg N ha-1 season-1. Timing and severity of pruning may allow for some management of underground transfer of fixed N2 to associated crops. However many aspects of root dynamics in alley cropping systems are poorly understood. Current research projects based on 15N labelling techniques or 15N natural abundance measurements are outlined. These would lead to estimates of N2 fixation and N saving resulting from the management of N2 fixation in alley cropping systems.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 177 (1995), S. 111-126 
    ISSN: 1573-5036
    Keywords: added nitrogen interactions ; Aeschynomene afraspera ; cowpea ; groundnut ; 15N ; nitrogen recovery ; Sesbania rostrata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two field experiments were conducted on farmers' fields in Northeast Thailand to examine the potential of several green manure and short-duration grain legume species as pre-rice green manures. The performance of species mixtures was also investigated. Experiments were conducted under rainfed conditions both with and without recommended applications of lime, P and K fertilizers. 15N-isotope methods were used to estimate N2-fixation in the legumes and N supplied by the legume residues to a following rice crop. When provided with lime, P and K fertilizer, all legumes grew well and fixed 65–85% of their N, amounting to 59–102 kg N ha-1 wihin 90 days. The short-duration groundnut and a mixed Sesbania rostrata and multi-purpose cowpea treatment produced over 4 tonnes ha-1 residue dry weight which contained 135–150 kg N ha-1. In addition groundnut yielded almost 2 tonnes ha-1 of grain, whilst the intercrop yielded 1 t ha-1 of fresh pods of MCP, only 35% less than the sole MCP which only produced 41 kg N ha-1 in its stover. Rice dry weight increases of over 50% were found after several of the legume treatments, and 15N-based estimates indicated up to 18 kg N ha-1 was directly supplied by the legume stover to the rice. Without fertilizer application residue yields of the S. rostrata + multi-purpose cowpea mixed crop were poor (580 kg ha-1) and N2-fixation contributed only 57% of the N accumulated (20 kg N ha-1 fixed). The application of P and K fertilizers was found to approximately double residue yields with the combined addition of lime more than doubling these yields again, resulting in 88% of the legume N derived from N2-fixation (84 kg N ha-1). The following rice recovered 9–17% of the added legume N and the yield response in rice reflected the differences in legume yield. Application of P,K and lime resulted in a fivefold increase in the amount of legume N recovered by rice, indicating the importance of alleviating nutrient deficiencies through fertilizer application if green manures are to be used successfully in Northeast Thailand.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    ISSN: 1573-5036
    Keywords: Acacia caven ; agroforestry ; Chamaecytisus proliferus subsp. palmensis ; isotope dilution ; 15N ; nitrogen fixation ; nodule efficiency ; Prosopis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Initial results of a long-term field experiment are presented for the above and below-ground biomass accumulation after two years, as well as root nodulation, nodule efficiency (g N fixed/g nodules) and biological N2 fixation (using the 15N isotope dilution method) of four N2-fixing tree species (NFTs) grown in the subhumid mediterranean-climate zone of central Chile. Two non-legume tree species, Fraxinus excelsior and Schinus polygamus, were used as reference plants for the isotope dilution calculations. Over two years, Tagasaste (Chamaecytisus proliferus subsp. palmensis, a Papilionoideae from the Canary Islands), produced 10 to 20 times more biomass than the other three NFTS (Acacia caven, Prosopis alba and P. chilensis); all Mimosoideae native to Chile, and nodulation and nitrogen fixed were an order of magnitude higher as well. At the end of the second year, the percentage of N derived from N2 fixation (%Ndfa) in Tagasate averaged 85.6, equivalent to ca. 49.1 g N fixed per tree. For all four NFTs, however, %Ndfa, nodule efficiency, and total N accumulation varied from one year to the next; caution is thus required in interpreting or predicting NFT performance over the long term, even if Tagasaste can already be considered a highly promising NFT for central Chile.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    ISSN: 1573-5036
    Keywords: inhibition ; 15N ; nitrate ; nitrogen fixation ; Trifolium repens ; uptake ; white clover
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The impact of sustained low external concentrations of NO 3 − (0, 10, 100 and 1000 mmol m−3) on plant growth and the relative acquisition of N through N2 fixation and NO 3 − uptake by established, nodulated white clover (Trifolium repens L. cv. Blanca) was studied over 28 days in flowing solution culture. Nitrogen fixation was measured by N difference and 15N dilution methods. Plants supplied with NO 3 − achieved higher relative growth rates (% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmiEayaara% aaaa!3702!\[\bar x\]=0.091 d−1) compared with ‘control’ plants dependent on N2 fixation (0.073 d−1). Nitrate plants showed progressive increases in shoot: root d.w. ratios from 4 to 6.5–7.6 between days 0–28, compared with 5.1 on day 28 for control plants. Increases in both nodule d.w. and numbers per plant were inhibited after day seven at all concentrations of NO 3 − . The severity of inhibition of N2 fixation increased with increasing NO 3 − concentration and with time. The total amounts of N2 fixed per plant between days 0–7 after supplying 10, 100 and 1000 mmol m−3 NO 3 − , respectively, were 37–39, 28–30 and 0–13%, of the total N acquired. Between days 7–28 the proportional contributions of N2 fixation to total N acquisition declined to 3, 0.5 and 0%, respectively, in these treatments. The corresponding mean specific rates of N2 fixation between days 0–7 were, respectively, 5.4, 3.2, and 2.0 mmol N d−1 g−1 nodule d.w., compared with 7.9 mmol N d−1 g−1 nodule d.w. for zero NO 3 − plants. There was no evidence of a transitory increase in N2 fixation following the addition of NO 3 − , even at the lowest supply concentration.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 182 (1996), S. 25-38 
    ISSN: 1573-5036
    Keywords: Hordeum vulgare ; intercropping ; 15N-isotope dilution technique ; N transfer ; Pisum sativum ; Relative Yield Total (RYT)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effect of mixed intercropping of field pea (Pisum sativum L.) and spring barley (Hordeum vulgare L.), compared to monocrop cultivation, on the yield and crop-N dynamics was studied in a 4-yr field experiment using 15N-isotope dilution technique. Crops were grown with or without the supply of 5 g 15N-labeled N m-2. The effect of intercropping on the dry matter and N yields, competition for inorganic N among the intercrop components, symbiotic fixation in pea and N transfer from pea to barley were determined. As an average of four years the grain yields were similar in monocropped pea, monocropped and fertilized barley and the intercrop without N fertilizer supply. Nitrogen fertilization did not influence the intercrop yield, but decreased the proportion of pea in the yield. Relative yield totals (RYT) showed that the environmental sources for plant growth were used from 12 to 31% more efficiently by the intercrop than by the monocrops, and N fertilization decreased RYT-values. Intercrop yields were less stable than monocrop barley yields, but more stable than the yield of monocropped pea. Barley competed strongly for soil and fertilizer N in the intercrop, and was up to 30 times more competitive than pea for inorganic N. Consequently, barley obtained a more than proportionate share of the inorganic N in the intercrop. At maturity the total recovery of fertilizer N was not significantly different between crops, averaging 65% of the supplied N. The fertilizer N recovered in pea constituted only 9% of total fertilizer-N recovery in the intercrop. The amount of symbiotic N2 fixation in the intercrop was less than expected from its composition and the fixation in monocrop. This indicates that the competition from barley had a negative effect on the fixation, perhaps via shading. At maturity, the average amount of N2 fixation was 17.7 g N m-2 in the monocrop and 5.1 g N m-2 in the intercropped pea. A higher proportion of total N in pea was derived from N2 fixation in the intercrop than in the monocrop, on average 82% and 62%, respectively. The 15N enrichment of intercropped barley tended to be slightly lower than of monocropped barley, although not significantly. Consequently, there was no evidence for pea N being transferred to barley. The intercropping advantage in the pea-barley intercrop is mainly due to the complimentary use of soil inorganic and atmospheric N sources by the intercrop components, resulting in reduced competition for inorganic N, rather than a facilitative effect, in which symbiotically fixed N2 is made available to barley.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    ISSN: 1573-5036
    Keywords: extractable organic N ; fertilizer N ; mineral N ; 15N ; N loss ; oilseed rape ; soil microbial biomass N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We studied the fate of 15N-labelled fertilizer nitrogen in a sandy loam soil after harvest of winter oilseed rape (Brassica napus L. cv. Ceres) given 100 or 200 kg N ha-1 in spring, with or without irrigation. Our main objective was to quantify the temporal variations of the soil mineral N, the extractable soil organic N and soil microbial biomass N, and fertilizer derived N in these pools during autumn and winter. Nitrogen use efficiency of the oilseed rape crop varied from 47% of applied N in the 100N, irrigated treatment to 34% in the 200N, non-irrigated treatment. However, only in the latter treatment did we find significantly higher fertilizer derived soil mineral N than in the three other treatments which all had low soil mineral N contents at the first sampling after harvest (8 days after stubble tillage). Between 31% and 42% of the applied N could not be accounted for in the harvested plants or 0-15 cm soil layer at this first sampling. Over the following autumn and winter none of the remaining fertilizer derived soil N was lost from the 0–5 cm depth, but from the 5–15 cm depth a marked proportion of N derived from fertilizer was lost, probably by leaching. Negligible amounts of fertilizer derived extractable soil organic and mineral N (〈1 kg N ha-1, 0-15 cm) were found in all treatments after the first sampling. Soil microbial biomass N was not significantly affected by treatments and showed only small temporal variability (±11% of the mean 76 kg N ha-1, 0- 15 cm depth). Surprisingly, the average amount of soil microbial biomass N derived from fertilizer was significantly affected by the treatments, with the extremes being 5.5 and 3.1 kg N ha-1 in the 200N, non-irrigated and 100N, irrigated treatments, respectively. Also, the estimated exponential decay rate of microbial biomass N derived from fertilizer, differed greatly (2 fold) between these two treatments, indicating highly different microbial turnover rates in spite of the similar total microbial biomass N values. In studies utilising 15N labelling to estimate turnover rates of different soil organic matter pools this finding is of great importance, because it may question the assumption that turnover rates are not affected by the insertion of the label.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    ISSN: 1573-5036
    Keywords: diurnal variation ; 15N ; net nitrate uptake rate ; nitrate efflux ; nitrate influx ; specific respiratory costs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In this paper we address the question why slow-growing grass species appear to take up nitrate with greater respiratory costs than do fast-growing grasses when all plants are grown with free access to nutrients. Specific costs for nitrate transport, expressed as moles of ATP per net mole of nitrate taken up, were 1.5 to 4 times higher in slow-growing grasses than in fast-growing ones (Scheurwater et al., 1998, Plant, Cell & Environ. 21, 995–1005). The net rate of nitrate uptake is determined by two opposing nitrate fluxes across the plasma membrane: influx and efflux. To test whether differences in specific costs for nitrate transport are due to differences in the ratio of nitrate influx to net rate of nitrate uptake, nitrate influx and the net rate of nitrate uptake were measured in the roots of two fast-growing ( Dactylis glomerata L. and Holcus lanatus L.) and two slow-growing (Deschampsia flexuosa L. and Festuca ovina L.) grass species at four points during the diurnal cycle, using 15NO3 -. Efflux was calculated by subtraction of net uptake from influx; it was assumed that efflux of nitrogen represents the flux of nitrate. Transfer of the plants to the solution containing the labelled nitrate did not significantly affect nitrate uptake in the present grass species. The net rate of nitrate uptake was highest during the middle of the light period in all species. Diurnal variation in the net rate of nitrate uptake was mostly due to variation in nitrate influx. Variation in nitrate efflux did not occur in all species, but efflux per net mole of nitrate taken up was higher during darkness than in the light in the slow-growing grasses. The two fast-growing species, however, did not show diurnal variation in the ratio of efflux to net nitrate uptake. Integrated over 24 hours, the slow-growing grasses clearly exhibited higher ratios of influx to net uptake than the fast-growing grass species. Our results indicate that the higher ratio of nitrate influx to net nitrate uptake can account for higher specific costs for nitrate transport in slow-growing grass species compared with those in their fast-growing counterparts, possibly in combination with greater activity of the non-phosphorylating alternative respiratory path. Therefore, under our experimental conditions with plants grown at a non-limiting nitrate supply, nitrate uptake is less efficient (from the point of ATP consumption) in slow-growing grasses than in fast-growing grass species.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    ISSN: 1573-5036
    Keywords: Acacia saligna ; nutrient competition ; 15N ; resin core ; soil solution ; Sorghum bicolor ; Sr
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In a runoff irrigation system in Northern Kenya, we studied the nutrient interactions of sole cropped and alley cropped Sorghum bicolor (L.) Moench and Acacia saligna (Labill.) H.L. Wendl. The trees were pruned once before the cropping season and the biomass was used as fodder for animals. The nutrient contents in leaf tissue, soil and soil solution were monitored and the uptake of applied tracers (15N, Sr) was followed. The grain yield of alley cropped sorghum was similar to or slightly higher than in monoculture and did not decrease near the tree-crop interface. Foliar N and Ca contents of the crop were higher in the agroforestry combination than in monoculture, corresponding to higher soil N and Ca contents. Soil solution and soil mineral N dynamics indicate an increase of N under the tree row and unused soil N at the topsoil in the alley of the sole cropped trees as well as below 60 cm depth in the crop monoculture. The N use efficiency of the tree+crop combination was higher than the sole cropped trees or crops. Competition was observed for Zn and Mn of both tree and crop whereas for Ca only the tree contents decreased. P, K, Mg and Fe dynamics were not affected by alley cropping at our site. The lower uptake of applied Sr by trees in alley cropping compared to those of the monoculture stand suggested a lower competitiveness of the acacia than sorghum, which did not show lower Sr contents when intercropped. The study showed the usefulness of combining soil and plant analyses together with tracer techniques identifying nutrient competition, nutrient transfer processes and the complementary use of soil nutrients, as the main features of the tree-crop combination.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    ISSN: 1573-5060
    Keywords: alcohol dehydrogenase 1 ; duplication ; Hordeum vulgare ; microsatellite ; partial DNA sequences ; sequence diversity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Partial sequences (appr. 900bp) spanning from exon 2 to 4 of the gene encoding alcohol dehydrogenase 1 were obtained from four varieties of cultivated barley, Hordeum vulgare ssp. vulgare, and from 21 accessions of its wild progenitor, H. vulgare ssp. spontaneum. Sequence diversity was low and restricted to the non-coding intron sequences. In the 648–660bp long intron 3 both a microsatellite locus and a major duplication (153/156bp) were found. Sequence diversity in H. vulgare ssp. spontaneum was slightly higher than in cultivated barley. In general the Adh1 gene displays only limited polymorphism and is not appropriate for seeking correlations between molecular and eco-geographical data.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 26 (1977), S. 67-73 
    ISSN: 1573-5060
    Keywords: Hordeum vulgare ; barley ; F1 hybrids ; genotype-environment interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Genotype-environment interactions in F1 hybrids between a selection of current commereial varicties as male parents and a balanced tertiary trisomic male-sterile female were investigated. Sixteen environments were employed, comprising eight treatments in each of two seasons. Hybrid stabilities in terms of yield response to changing environments, were found to be very similar to those of the parents, however hybrid yields exceeded parental yields in all but one instance. A heterotic effect for plant height was also observed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 26 (1977), S. 797-804 
    ISSN: 1573-5060
    Keywords: Hordeum vulgare ; barley ; aleurone color ; fitness ; yield ; isolines ; population dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Genotypic frequency data at two loci governing blue vs. white aleurone color in barley showed that composite cross (CC) populations grown at Davis varied in the changes in allelic frequencies as well as heterozygosity levels. The blue class increased steadily over 20 generations in CC V and CC XXI along with an excess of heterozygotes over expected under high selfing rates, fluctuated without a directional shift in CC XIV, and declined in CC XVI. Utilizing the xenia feature of this character, nearly 100 Bl/bl Bl2/bl2 individuals were randomly drawn from the CC XVI and CC XXI populations and used in a paired-plot study of some yield components for comparing the blue and white isogenic classes within lines in the varied genetic backgrounds of different lines. For seed number blue vs. white isogenic class differences were significant only in one out of four populations (CC XXI-F8) whereas differences among the lines were significant in CC XVI-F12, CC XXI-F3 and CC XXI-F8. Thus, specific locus effects were relatively much smaller than the genetic background component although overall the genotypic frequency changes at the aleurone color loci were found to be consistent with the relative average seed output per plant in the three genotypic classes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 26 (1977), S. 521-526 
    ISSN: 1573-5060
    Keywords: Hordeum vulgare ; barley ; haploid barley ; yield components ; hill plots
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Twenty homozygous barley lines were grown in row and hill plots at two locations in Ontario in 1973. The hill plots were of two spacings −30×30 cm and 45×45 cm between hills. Within each spacing, three seeding rates were used i.e. 15, 25 and 35 seeds per hill. Grain yield and three of its components, namely; number of seeds per spike (NSS), number of spikes per plot (NSP) and seed weight (SW) were studied. It was concluded that both NSS and SW could be evaluated in hill plots. NSS was found to be an important component of grain yield and its relationship with grain yield was unaffected by plot types and locations. SW also remained unaffected by plot types and seeding rates but as a component of grain yield it was the least important of the three components measured. The correlation between SW and grain yield could be changed by locations. NSP was as important as NSS as a component of grain yield, and was highly correlated with grain yield. Unlike NSS, NSP could not be efficiently evaluated in hill plots since its correlation between row and hill plots was generally lower.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 26 (1977), S. 55-62 
    ISSN: 1573-5060
    Keywords: barely ; Hordeum vulgare ; powdery mildew ; Erysiphe graminis f. sp. hordei ; resistance ; resistance genes ; genes for resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Ten barley mutants and five Ethiopian barley lines representing 11 independently arisen powdery mildew resistance genes in the ml-o locus were tested at the seedling stage to cultures of the powdery mildew fungus from Europe, Israel, USA. Canada, and Japan. They were resistant with infection type 0/(4) in all tests. They were also resistant to field populations of the pathogen when scored in disease nurseries at more than 78 locations in 29 countries in Europe, the Near East, North and South America. New Zealand, and Japan. This indicates that the 11 genes confer the same, world-wide spectrum of powdery mildew resistance. They have no effect on several other barley diseases such as stripe rust and leaf rust.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    ISSN: 1573-5060
    Keywords: Hordeum vulgare ; barley ; Puccinia hordei ; leaf rust ; cultivars ; component analysis ; infection frequency ; intectious period ; lateht period ; partial resistance ; spore production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Eight spring barley cultivars, respresenting the known range in partial or slow rusting resistance to leaf rust, Puccinia hordei, were investigated for their effects on the components of partial resistance; infection frequency, latent period, infectious period and spore production per uredosorus per day. Considerable variation was observed among the cultivars for each of the components. The cultivar effects on the components tend to be associated. Cultivar L94 for instance, shows the highest infection frequency, the shortest latent period and a long infectious period. Julia and Vada both have a low infection frequency, a long latent period and a low spore production per sorus per day. This association, though, is only a partial one. The total spore production per unit leaf area (the combined result of the four components) appeared highly correlated with the partial resistance in the field (r=0.85). Only a relatively small portion of the variation in partial resistance cannot be explained by the four components studied. Several other aspects, which might affect the rate of epidemic development, are discussed. Latent period, measuring the onset of the new spore production, estimated partial resistance as well as total spore production did (r=−0.85). In order to evaluate the partial resistance of barley genotypes in the greenhouse the latent period is preferred above total spore production as it is measured more easily, more accurately and sooner after inoculation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 27 (1978), S. 865-868 
    ISSN: 1573-5060
    Keywords: Hordeum vulgare ; barley ; male sterility genes ; male gametocide ; ethrel ; recurrent selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The use of ethrel for hand crossing in recurrent selection programs with barley is advocated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 27 (1978), S. 369-379 
    ISSN: 1573-5060
    Keywords: Hordeum vulgare ; barley ; Puccinia hordei ; leaf rust ; gene-for-gene relationship ; latent period ; minor genes ; partial resistance ; polygenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The latent period (LP) is a crucial component of partial resistance. Five cultivars, L94, Sultan (Su), Volla (Vl), Julia (Ju) and Vada (Va), representing the known range in partial resistance and LP were crossed in a diallel, and the F1, F2 and F3 tested. The LP effectuated by the five cultivars is about 9, 101/2, 101/2, 13 and 151/2 days, respectively. The crosses Su×L94, Vl×L94 and Ju×L94 had an F2 positively skewed. Their F2 means were similar or only slightly larger than the F1 means. The F2 frequency distributions in the crosses Vl×Su, Ju×Su and Ju×Vl were normal or nearly so with F1 and F2 means similar to each other and to the mid-parent value. The crosses involving Va as a parent again showed a positive skewness but with F2 means considerably larger than the F1 moans. Most F2's ranged from the low parent to the high parent values without transgression. In the crosses Va×L94 (reported earlier) and Ju×L94 the parental values were not recovered among 216 and 154 F2 plants, respectively. The cross Ju×Va showed transgression beyond the low parent, Ju. From these data it is concluded, assuming no linkage, that seven loci are involved. The + alleles (governing a longer LP) are thought to be distributed over the parents as follows: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGceaqabeaacaqGmb% GaaeyoaiaabsdacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabcca% caqGGaGaaeiiaiaab2cacaqGTaGaaeiiaiaabccacaqGGaGaaeiiai% aabccacaqGGaGaaeiiaiaabccacaqGTaGaaeylaiaabccacaqGGaGa% aeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeylaiaab2caca% qGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaa% b2cacaqGTaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaae% iiaiaabccacaqGTaGaaeylaiaabccacaqGGaGaaeiiaiaabccacaqG% GaGaaeiiaiaabccacaqGGaGaaeylaiaab2cacaqGGaGaaeiiaiaabc% cacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGTaGaaeyl% aiaabccaaeaacaqGtbGaaeyDaiaabccacaqGGaGaaeiiaiaabccaca% qGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGRaGaae4kaiaa% bccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGRaGaae% 4kaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabUcacaqG% RaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaab2% cacaqGTaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeii% aiaabccacaqGTaGaaeylaiaabccacaqGGaGaaeiiaiaabccacaqGGa% GaaeiiaiaabccacaqGGaGaaeylaiaab2cacaqGGaGaaeiiaiaabcca% caqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGTaGaaeylaa% qaaiaabAfacaqGSbGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqG% GaGaaeiiaiaabccacaqGGaGaaeiiaiaabUcacaqGRaGaaeiiaiaabc% cacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabUcacaqGRaGaaeii% aiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeylaiaab2cacaqGGa% GaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabUca% caqGRaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiai% aab2cacaqGTaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGa% aeiiaiaabccacaqGTaGaaeylaiaabccacaqGGaGaaeiiaiaabccaca% qGGaGaaeiiaiaabccacaqGGaGaaeiiaiaab2cacaqGTaaabaGaaeOs% aiaabwhacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGa% GaaeiiaiaabccacaqGGaGaae4kaiaabUcacaqGGaGaaeiiaiaabcca% caqGGaGaaeiiaiaabccacaqGGaGaae4kaiaabUcacaqGGaGaaeiiai% aabccacaqGGaGaaeiiaiaabccacaqGRaGaae4kaiaabccacaqGGaGa% aeiiaiaabccacaqGGaGaaeiiaiaabccacaqGRaGaae4kaiaabccaca% qGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGRaGaae4kaiaa% bccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaab2cacaqGTaGaae% iiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqG% GaGaaeylaiaab2caaeaacaqGwbGaaeyyaiaabccacaqGGaGaaeiiai% aabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabUcacaqGRaGa% aeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabUcaca% qGRaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaae4kaiaa% bUcacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaae% 4kaiaabUcacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqG% GaGaaeylaiaab2cacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabc% cacaqGGaGaae4kaiaabUcacaqGGaGaaeiiaiaabccacaqGGaGaaeii% aiaabccacaqGGaGaaeiiaiaabUcacaqGRaaaaaa!1BBA!\[\begin{gathered} {\text{L94 - - - - - - - - - - - - - - }} \hfill \\ {\text{Su + + + + + + - - - - - - - - }} \hfill \\ {\text{Vl + + + + - - + + - - - - - - }} \hfill \\ {\text{Ju + + + + + + + + + + - - - - }} \hfill \\ {\text{Va + + + + + + + + - - + + + + }} \hfill \\ \end{gathered} \] The genes are supposed to act additively (intermediate inheritance) with the exception of one locus (the 6th or 7th locus) which shows dominance for the shorter LP (for the-alleles). The effect of this locus on LP seems considerably larger than that of the other loci. There are indications of physiological barriers, which means that LP's shorter than the one of L94 or much longer than that of Va are not possible. The effect of + genes in genotypes governing LP's close to these barriers (with very few or very many + alleles respectively) is smaller than in genotypes governing intermediate LP's.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 28 (1979), S. 47-56 
    ISSN: 1573-5060
    Keywords: Hordeum vulgare ; barley ; alleles ; centimorgan ; centromere ; chromosome ; DDT ; embryo ; endosperm ; highlysine ; linkage ; loci ; lysine ; mutant ; protein ; recombination ; shrunken seeds ; turbidity test
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    ISSN: 1573-5060
    Keywords: Triticum aestivum ; Hordeum vulgare ; wheat ; barley ; chromosome addition lines ; translocation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two disomic barley chromosome addition lines and five translocated chromosome addition lines of common wheat cultivar Shinchunaga were isolated. They were derived from a hybrid plant between Shinchunaga and cultivated barley Nyugoruden (New Golden) by backcrossing with wheat and self pollination. Barley chromosomes added to chromosome arms involved in the translocated chromosomes were identified by C-banding method and by crossing these lines with Chinese Spring/Betzes addition lines. Two disomic addition lines were identified to have chromosome 6 and 7 of barley, respectively. Two of the five translocated chromosome addition lines were clarified to have same chromosome constitution, 42 wheat chromosomes and a pair of translocated chromosomes constituted with a long arm of chromosome 5B of wheat and a short arm of chromosome 7 of barley. The other three lines could not be identified due to chromosome rearrangement. Performances of these seven lines on agronomic characters were examined. Addition of barley chromosome 7 induced early heading, and chromosome 6 showed lated heading. Almost all of the lines except that of chromosome 6 showed short culm length and all showed reduced number of tillers, spikelets and grains per ear, and low seed fertility. These lines would be useful for genetic analyses in wheat and barley and for induction of useful genes of barley into wheat.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 92 (1996), S. 81-87 
    ISSN: 1573-5060
    Keywords: barley ; net blotch ; Pyrenophora teres ; resistance ; Hordeum vulgare
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Seedlings of a differential barley (Hordeum vulgare L.) series (21 genotypes) and of six check genotypes were used in the greenhouse to assess variation in virulence among 20 single-spore isolates of the net blotch pathogen. Pyrenophora teres Drechs. f.teres Smedeg., collected from various sites in Finland. The experiment was run twice and symptom expression was recorded on the first three leaves. Analysis of second leaf symptom scores from Run 1 indicated differences in virulence between isolates, all of which were pathogenic, and differential resistance among the barleys. The virulence of P. teres isolates appeared to be conditioned by the host barley from which the isolate derived; the average virulence of isolates collected from a susceptible host was greater than that of isolates collected from a less susceptible host. Results from Run 2 were similar regarding resistance within the barleys, but variation in virulence among the P. teres isolates was not consistent with that from Run 1. CI 9819 caries duplicate genes for resistance to P. teres (Rpt1b and Rpt1c), and CI 7548 possesses Rpt3d. Both genotypes were highly resistant to all isolates. The Rpt1a gene of Tifang (CI4407) conferred resistance to all isolates in Run 2, but only to about half of the isolates in Run 1. The checks, including two of the symptomatically most resistant Nordic barley genotypes, were universally susceptible during these stringent tests. No selective pressure has been placed on Finnish isolates of P. teres through previous deployment of major resistance genes, and it is speculated that any variation in virulence among isolates is likely to be due to a combination of evolutionary forces including, natural selection, random genetic drift and gene flow.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 92 (1996), S. 203-214 
    ISSN: 1573-5060
    Keywords: Hordeum vulgare ; barley ; genotype by environment interaction ; landraces ; low-input agriculture ; specific adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Many aeas of world, particular those where agriculture is largely practiced by resource-poor farmers with little or no use of external inputs, have not benefitted from the spectacular yield increases achieved by the combination of modern breeding technologies and use of inputs. The paper argues that because breeding is mostly conducted in presence of high inputs, it has systematically missed the opportunity to exploit genetic differences at low levels of inputs. Many studies show that these differences do exist, particularly in the case of fertilizers, and that these differences can only be identified is selection is conducted under the target level of inputs. Although this was predicted by theory more than 40 years ago, and has been supported by a large body of experimental data, very few breeders select in sub-optimal or stress conditions. The most common justification is the high environmental variation, and hence the lower heritability expected in low input conditions. While this is not supported by experimental evidence, the paper shows that in the case of a typical crop grown in low-input and climatically marginal conditions such as barley, genetic gains are possible by using locally adapted germplasm and by selecting in the target environment. Similar conclusions, in relation to the use of a low-input selection environment, have been reached recently in maize. It is concluded that the best avenue to a sustainable increase of agricultural production in low-input agricultural systems is through locally based breeding programs.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    Electronic Resource
    Electronic Resource
    Springer
    Genetic resources and crop evolution 42 (1995), S. 1-6 
    ISSN: 1573-5109
    Keywords: Barley ; Hordeum vulgare ; Hordeum spontaneum ; leaf rust ; Puccinia hordei ; resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract An isolate ofPuccinia hordei (ND89-3) originally collected in Morocco is virulent on most barley genotypes reported to possess resistance, except cultivar Estate (CI 3410), which possesses theRph3 gene and exhibits a low to intermediate level of resistance (infection type 12). Isolate ND89-3 possesses one of the widest virulence spectrums reported forP. hordei. Accessions ofHordeum vulgare (1,997 in total) andH. spontaneum (885 in total), mostly originating from the Mediterranean region and parts of North Africa, were evaluated with isolate ND89-3 at the seedling stage to identify new sources of leaf rust resistance. Fifty-eight accessions ofH. vulgare, and 222 accessions ofH. spontaneum exhibited low infection types to this isolate. Further evaluations of these resistant accessions with isolates ofP. hordei virulent forRph3,Rph7, andRph12 suggested that most of the resistantH. vulgare accessions possess theRph3 gene. Data suggested additional sources of effective resistance inH. vulgare are rather limited. FiveH. vulgare accessions and 167H. spontaneum accessions were identified as possible sources of new genes for leaf rust resistance. These accessions likely possess resistance genes that are different fromRph1 toRph12, or gene combinations thereof based on their reaction to four leaf rust isolates. Utilization of these accessions in barley breeding will broaden the germplasm resources available for genetic control ofP. hordei.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    Electronic Resource
    Electronic Resource
    Springer
    Genetic resources and crop evolution 46 (1999), S. 193-205 
    ISSN: 1573-5109
    Keywords: Hordeum vulgare ; diversity ; germplasm ; RAPD analysis ; geographical distribution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Random amplified polymorphic DNA (RAPD) analysis was used to characterize barley germplasm genetic diversity. For the analysis 303 morphologically distinctive accessions were selected from the VIR germplasm collection, St. Petersburg, Russia and the MAFF Genebank, Tsukuba, Japan to represent the principal regions of barley cultivation. A total of 93 polymorphic bands scored from RAPD patterns were used to generate a genetic distance matrix, which was used in both cluster and principal coordinate analysis. Both analysis clearly separated barley cultivars and local populations into three distinctive groups, which evidently reflect different directions in evolution and geographical distribution of barley. The hierarchy of accessions clustering in the first group indicates the westward distribution of barley from West Asia to Europe and New World across Ethiopia and then Mediterranean region. The principal breeding trends based on spike morphology are also observed in this group. The second group is associated with eastward distribution of the crop and represents a unified genetic group, which consists of East Asian and Central Asian accessions. The third distinctive group identified is connected with the evolution and dissemination of hulless forms in Central Asia and the Caucasus region. The conformity of identified genetic groups and clusters with the global centers of crops diversity (gene centers) determined by Vavilov (1926) and modern ecogeographical classification of barley is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    Electronic Resource
    Electronic Resource
    Springer
    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.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    ISSN: 1573-0867
    Keywords: China ; Loess Plateau ; maize ; 15N ; Nitrogen ; urea ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Field trials were carried out to study the fate of15N-labelled urea applied to summer maize and winter wheat in loess soils in Shaanxi Province, north-west China. In the maize experiment, nitrogen was applied at rates of 0 or 210 kg N ha−1, either as a surface application, mixed uniformly with the top 0.15 m of soil, or placed in holes 0.1 m deep adjacent to each plant and then covered with soil. In the wheat experiment, nitrogen was applied at rates of 0, 75 or 150 kg N ha−1, either to the surface, or incorporated by mixing with the top 0.15 m, or placed in a band at 0.15 m depth. Measurements were made of crop N uptake, residual fertilizer N and soil mineral N. The total above-ground dry matter yield of maize varied between 7.6 and 11.9 t ha−1. The crop recovery of fertilizer N following point placement was 25% of that applied, which was higher than that from the surface application (18%) or incorporation by mixing (18%). The total grain yield of wheat varied between 4.3 and 4.7 t ha−1. In the surface applications, the recovery of fertilizer-derived nitrogen (25%) was considerably lower than that from the mixing treatments and banded placements (33 and 36%). The fertilizer N application rate had a significant effect on grain and total dry matter yield, as well as on total N uptake and grain N contents. The main mechanism for loss of N appeared to be by ammonia volatilization, rather than leaching. High mineral N concentrations remained in the soil at harvest, following both crops, demonstrating a potential for significant reductions in N application rates without associated loss in yield.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 52 (1998), S. 131-139 
    ISSN: 1573-0867
    Keywords: denitrification ; di-nitrogen ; mass spectrometry ; nitrification ; 15N ; nitrous oxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Nitrous oxide can be produced during nitrification, denitrification, dissimilatory reduction of NO 3 - to NH 4 + and chemo-denitrification. Since soils are a mosaic of aerobic and anaerobic zones, it is likely that multiple processes are contributing simultaneously to N2O production in a soil profile. The N2O produced by all processes may mix to form one pool before being reduced to N2 by denitrification. Reliable methods are needed for measuring the fluxes of N2O and N2 simultaneously from agricultural soils. The C2H2 inhibition and 15N gas-flux methods are suitable for use in undisturbed soils in the field. The main disadvantage of C2H2 is that as well as blocking N2O reductase, it also blocks nitrification and dissimilatory reduction of NO 3 - to NH 4 + . Potentially the 15 N gas-flux method can give reliable measurements of the fluxes of N2O and N2 when all N transformation processes proceed naturally. The analysis of 15N in N2 and N2O is now fully automated by continuous-flow isotope-ratio mass spectrometry for 12-ml gas samples contained in septum-capped vials. Depending on the methodology, the limit of detection ranges from 4 to 11 g N ha-1day-1 for N2 and 4 to 15 g N ha-1day-1 for N2O. By measuring the 15N content and distribution of 15N atoms in the N2O molecules, information can also be obtained to help diagnose the sources of N2O and the processes producing it. Only a limited number of field studies have been done using the 15N gas-flux method on agricultural soils. The measured flux rates and mole fractions of N2O have been highly variable. In rain-fed agricultural soils, soil temperature and water-filled pore space change with the weather and so are difficult to modify. Soil organic C, NO 3 - and pH should be amenable to more control. The effect of organic C depends on the degree of anaerobiosis generated as a result of its metabolism. If conditions for denitrification are not limiting, split applications of organic C will produce more N2O than a single application because of the time lag in the synthesis of N2O reductase. Increasing the NO 3 - concentration above the K m value for NO 3 - reductase, or decreasing soil pH from 7 to 5, will have little effect on denitrification rate but will increase the mole fraction of N2O. The effect of NO 3 - concentration on the mole fraction of N2O is enhanced at low pH. Manipulating the interaction between NO 3 - supply and soil pH offers the best hope for minimising N2O and N2 fluxes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    ISSN: 1572-9680
    Keywords: woody legumes ; screening ; Alfisol ; Ultisol ; N2-fixation ; 15N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In order to identify for alley cropping new candidate species with high biomass and nitrogen-fixing potential, a screening study was conducted on ten woody and shrub legumes (Acacia auriculiformis, Albizia lebbeck, Gliricidia sepium, Leucaena diversifolia, L. leucocephala cv. K28 and cv. K636, Lonchocarpus sericeus, Cajanus cajan, Crotalaria juncea and Tephorsia candida) for 6 months using an acid Ultisol and a non-acid Alfisol. A wide interspecific variability of legumes appeared within soil types, and there were significant species-by-soil interactions for many parameters in this study. In the acid Ultisol, plant growth in height and grith, nodule numbers, nitrogen yield and N2-fixing potential were significantly (P = 0.05) lower than those in the Alfisol. While Albizia lebbeck was outstanding in both acid and non-acid soil conditions for most performance criteria, L. leucocephala cv. K28 was most sensitive to soil acidity with 41.7% of total nitrogen yield in the Ultisol relative to that accumulated in the Alfisol. In addition to L. leucocephala cv. K28 and G. sepium, the most common hedgerow species, A. lebbeck, L. leucocephala cv. K636, L. diversifolia on Alfisol, and A. lebbeck, L. leucocephala cv. K636, L. diversifolia, Tephrosia candida and Cajanus cajan on acid Ultisol, could be considered promising and thus, worthy of further site adaptability trials.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    ISSN: 1572-9680
    Keywords: nitrogen fixation ; 15N ; %Ndfa ; ryegrass+clover pasture ; silvopastoral system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Quantitative field measurements of biological nitrogen fixation (BNF) and biomass production by four different understorey pastures in a Pinus radiata-pasture agroforestry system were determined over a period of one year. The trees were two years old at the beginning of this study and the understorey pastures were being cut and removed for silage. The BNF was determined using the 15N dilution technique. Pastures of ryegrass+clover, cocksfoot+clover, phalaris+clover and lucerne were used. Substantial amounts of BNF were found (71 to 230 kg N ha−1 year−1) with lucerne showing the highest N fixation. However, lucerne derived only 71 to 72% of its N from the atmosphere (%Ndfa) during the spring/summer period compared to 83–97% with clovers, thus the net N demand from the soil was substantially higher with lucerne. This caused increased N stress to the trees. Clover in ryegrass+clover pasture fixed more N than the other grass+clover pastures. Although pasture position in relation to trees did not affect annual pasture total DMY and %Ndfa, pastures north of tree row grew better than those in other positions. Trees significantly affected the BNF of legumes and the botanical composition of pastures with highest BNF and legume production occurring in pastures midway between two rows of trees. These results suggest that it would be advantageous to evaluate different legumes and grasses for tolerance of shade and moisture stress in future studies. As the trees studied were only 1.5 to 3 m in height, their effects on BNF, seasonal pasture biomass production and botanical composition are expected to increase with tree dominance in the ecosystem with time. Amounts of N fixed were related to the productivity (i.e. dry matter and N yield) and seasonal persistence of the legumes. The productivity was high in spring and summer and low in autumn and winter.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...