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  • Essen : Verl. Glückauf
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  • Springer  (854)
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  • Essen : Verl. Glückauf
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 91 (1999), S. 403-412 
    ISSN: 1570-7458
    Keywords: aphid ; Diuraphis noxia ; Triticum aestivum ; endosymbiont ; insect-plant interactions ; phloem ; amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The feeding behavior of Diuraphis noxia Mordvilko (Homoptera: Aphididae) on susceptible hosts causes both ultrastructural and tissue level damage which may affect phloem composition. Genetic evidence suggests that endosymbiotic bacteria in most aphids overproduce limiting amino acids to benefit hosts but that D. noxia depends less on endosymbionts for these nutrients, possibly due to an enriched diet. To determine whether D. noxia feeding damage results in higher concentrations of essential amino acids, stylet exudates were analyzed from wheat (Triticum aestivum) damaged to different degrees. Comparison of samples from undamaged and damaged susceptible wheat revealed changes in amino acid composition and an increase in levels of essential amino acids, indicating a nutritionally enhanced ingesta. The changes in stylet exudates paralleled changes in leaf exudates, indicating that the effects are systemic. Feeding damage is not observed on a resistant wheat host, var. Halt, and leaf exudates from infested Halt did not show changes in amino acid composition. Mean relative growth of nymphs was significantly lower on Halt than on susceptible Arapahoe, indicating that Halt is a less suitable host. Both varieties show similar amino acid levels in non-infested samples, suggesting that D. noxia infestation does not enhance the phloem environment in Halt. This study provides evidence that aphid feeding can generate a nutritionally enhanced phloem diet.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 93 (1999), S. 227-230 
    ISSN: 1570-7458
    Keywords: Rhopalosiphum padi ; cereal aphids ; wheat ; induced responses ; feeding site
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 3
    Electronic Resource
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    Springer
    Entomologia experimentalis et applicata 92 (1999), S. 157-164 
    ISSN: 1570-7458
    Keywords: plant resistance ; antibiosis ; tolerance ; antixenosis ; Russian wheat aphid ; wheat ; Homoptera ; Aphididae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Russian wheat aphid, Diuraphis noxia (Mordvilko), is one of the most important aphid pests of wheat, Triticum aestivum L., worldwide. Among the various pest management options, plant resistance is an economical management tactic to control D. noxia in cereal crops such as wheat. Researchers have identified D. noxia resistant germplasm and it has been incorporated into wheat. This study compared D. noxia resistance between the ‘Betta’ wheat isolines Betta-Dn1, Betta-Dn2, and Betta-Dn5 and their corresponding donor gene plant introduction (PI) lines PI 137739 (Dn1), PI 262660 (Dn2), and PI 294994 (Dn5). Although the Betta isolines and PI lines showed D. noxia resistance when compared with Betta wheat, the degree of resistance in the isolines to D. noxia was different from their corresponding PI donors. Aphid number, aphid fecundity, and biomass per aphid were not different between Betta-Dn1 and PI 137739 or Betta-Dn2 and PI 262660; however, the same parameters were significantly lower on PI 294994 compared with Betta-Dn5. This indicated that aphid resistance in PI 137739 and PI 262660 was probably governed by a single dominant gene, while the resistance in PI 294994 was controlled by more than one gene. Additionally, plant biomass reduction was aphid density dependent, which suggested that use of appropriate aphid infestation level is important when using plant biomass reduction as an indicator of resistance. Plant resistance categorization showed that there was no detectable difference in antixenosis among the seven lines evaluated. However, the higher aphid fecundity observed on PI 262660 compared with PI 137739 and PI 294994, in addition to no significant differences among the three PIs in plant biomass reduction, suggested PI 262660 was a tolerant line, while PI 137739 and PI 294994 were antibiotic lines. Plant tolerance could not be elucidated among the three Betta isolines using aphid fecundity and plant biomass reduction as indicators.
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  • 4
    ISSN: 1570-7458
    Keywords: sieve element ; salivation ; aphid ; plant resistance ; wheat ; Sitobion fragariae ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Extended sieve element salivation (E1 waveform in the electrical penetration graph) is a characteristic activity during early sieve element punctures, particularly in resistant plants. In order to explore a chemically-mediated mechanism of resistance associated with sieve element salivation, we compared the pattern of feeding behaviour of the aphid, Sitobion fragariae (Walker), on two cultivars of the wheat Triticum aestivum L., with different concentrations of hydroxamic acids (Hx). During 24 h of electronic monitoring, aphids dedicated over 50% of the total time to phloem ingestion from the sieve elements. Total time allocated to E1 in the experiment, time to first E1 within the experiment, time allocated to E1 before a sustained phloem ingestion (E2) and the contribution of sieve element salivation to the phloem phase (E1/[E1+E2]) were significantly higher in the high-Hx cultivar. The increased salivation in plants with higher contents of Hx suggests the existence, at least in this system, of a chemically-mediated sieve element constraint.
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  • 5
    ISSN: 1432-1890
    Keywords: Key words Glomus mosseae ; Hydroponics ; Nitrate uptake ; Root respiration ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Oxygen and CO2 fluxes were measured in hydroponically grown mycorrhizal and non-mycorrhizal Triticum aestivum L. cv. Hano roots. The NO3 – uptake of the plants was used to estimate the amount of root respiration attributable to ion uptake. Plants were grown at 4 mM N and 10 μM P, where a total and viable mycorrhizal root colonisation of 48% and 18%, respectively, by Glomus mosseae (Nicol. and Gerd.) Gerd. and Trappe (BEG 107) was observed. The O2 consumption and NO3 – uptake rates were similar and the CO2 release was higher in mycorrhizal than in non-mycorrhizal wheat. This resulted in a significantly higher respiratory quotient (RQ, mol CO2 mol–1 O2) in mycorrhizal (1.27±0.13) than in non-mycorrhizal (0.79±0.05) wheat. As the biomass and N and P concentrations in mycorrhizal and non-mycorrhizal wheat were the same, the higher RQ resulted from the mycorrhizal colonisation and not differences in nutrition per se.
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  • 6
    ISSN: 1432-0789
    Keywords: Key words Phosphate-solubilizing microorganisms ; Mussoorie rock phosphate ; Vesicular-arbuscular mycorrhizae ; Triticum aestivum ; Nutrient-deficient soils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  The effect of inoculating wheat (Triticum aestivum L.) with the PO4 3–-solubilizing microorganisms (PSM) Bacillus circulans and Cladosporium herbarum and the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus sp. 88 with or without Mussoorie rock phosphate (MRP) amendment in a nutrient-deficient natural sandy soil was studied. In the sandy soil of low fertility root colonization by VAM fungi was low. Inoculation with Glomus sp. 88 improved root colonization. At maturity, grain and straw yields as well as N and P uptake improved significantly following inoculation with PSM or the VAM fungus. These increases were higher on combined inoculation of PSM and the VAM fungus with MRP amendment. In general, a larger population of PSM was maintained in the rhizosphere of wheat in treatments with VAM fungal inoculation and MRP amendment. The results suggest that combined inoculation with PSM and a VAM fungus along with MRP amendment can improve crop yields in nutrient-deficient soils.
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  • 7
    Electronic Resource
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    Springer
    Plant molecular biology reporter 17 (1999), S. 323-331 
    ISSN: 1572-9818
    Keywords: Agrobacterium ; modular vector ; transformation ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Wheat (cv Chinese Spring) tissues were transformed using Agrobacterium tumefasciens and a new plasmid modular vector, pMVTBP. We constructed pMVTBP with unique restriction sites connecting (1) the CaMV 35S promoter, (2) a Kozak sequence, (3) the FLAG epitope, (4) the (His)6 epitope, (5) a coding region (for wheat TATA Binding Protein, wTBP) and (6) the CaMV 35S 3′UTR. This vector thus allows easy exchange of different regulatory or coding sequences. Explants of either germinating mature seeds, or immature embryos, were induced to callus for up to two weeks, treated with virulence-induced bacteria for one hour, then regenerated into plantlets. Transient expression of a GUS reporter gene, assayed at about one week, occurred in 10–12% of calluses. Expression of the FLAG-tagged wTBP was also detected, by immunostaining. Stable expression, by selective growth on geneticin, and by GUS expression at about six weeks, occurred in 1–2% of calluses, quite comparable to that achieved by other methods.
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  • 8
    Electronic Resource
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    Nutrient cycling in agroecosystems 53 (1999), S. 139-146 
    ISSN: 1573-0867
    Keywords: critical levels of Mn ; soil extractants ; Mn-deficiency ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Seven chemical extractants were tested for their relative performance to predict the response of wheat to Mn application in coarse textured alkaline soils of semi-arid region. Five out of the seven extractants were found to be promising for the estimation of critical level of available Mn in these soils, as the amount of Mn extracted by these extractants was positively and significantly correlated with relative grain yield as well as Mn uptake. The critical deficiency level of soil available Mn with 0.005 M DTPA, 0.02% hydroquinone, 0.02 N sodium pyrophosphate, 0.1N H3PO4 and 0.05N HCl+0.025N H2SO4 was 3.1, 13.8, 23.5, 5.3 and 17.8 mg kg-1 soil, respectively. The 1N ammonium acetate and 0.01M CaCl2 were found to be unsuitable extractants for these soils. Further field trials at eight locations with varying levels of Mn deficiency showed successive increase in the grain yield of wheat with foliar Mn application, emphasizing the need for Mn fertilization when wheat is grown on Mn deficient soils.
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  • 9
    Electronic Resource
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    Nutrient cycling in agroecosystems 53 (1999), S. 157-175 
    ISSN: 1573-0867
    Keywords: Brassica napus ; Cicer arietinum ; current P ; Lens culinaris ; Lupinus albus ; Lupinus angustifolius ; P concentration response ; P content response ; Pisum sativum ; previous P ; sigmoid response ; single superphosphate ; Triticum aestivum ; Vicia faba ; yield response
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Phosphorus (P) is a major deficiency of soils of south-western Australia (WA). The fertilizer P requirements are not known for grain legumes being evaluated for neutral to alkaline, fine textured soils in WA. To rectify this, glasshouse and field experiments were undertaken to compare the responses of several grain legume species, wheat and canola to applications of single superphosphate and the results are reported in this paper. The glasshouse experiments measured responses of dried tops, harvested at 26 to 42 days after sowing, to P that was freshly-applied (current P) and previously-applied (previous P). Responses in the glasshouse were measured using yield, P concentration and P content (P concentration multiplied by yield) of oven dried tops of the following: wheat (Triticum aestivum), canola (Brassica napus), faba bean (Vicia faba), chickpea (Cicer arietinum), lentil (Lens culinaris), field pea (Pisum sativum), albus lupin (Lupinus albus) and narrow leaf lupin (Lupinus angustifolius). Field experiments in 1994 and 1995 compared seed (grain) yield responses of faba bean, chickpea, lentil, albus lupin and wheat to applications of current P. The P was banded (drilled) with the seed while sowing at 5 cm depth. Canola and wheat produced very large yield responses to increasing applications of current P. Responses were much smaller for albus lupin, faba bean and chickpea. Responses for lentil, narrow leaf lupin and field pea, fell in between responses of the small and large seeded species. Similar trends for responses were obtained as measured using yield, P concentration, or P content. For soils treated with previous P, similar trends were observed as for current P, but differences in yield responses between species were much less marked and the response curves tended to become more sigmoid. In the field experiments, grain yield responses to current P of albus lupin and chickpea were less than that for wheat. Relative to wheat, faba bean was the most responsive grain legume to applications of current P, with lentil producing similar responses to wheat in one experiment at a newly cleared, P deficient site.
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  • 10
    ISSN: 1572-9761
    Keywords: Coccinellidae ; Aphididae ; wheat ; spatial scale ; species diversity ; numerical response
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The influence of prey density, within-field vegetation, and the composition and patchiness of the surrounding landscape on the abundance of insect predators of cereal aphids was studied in wheat fields in eastern South Dakota, USA. Cereal aphids, aphid predators, and within-field vegetation were sampled in 104 fields over a three year period (1988–1990). The composition and patchiness of the landscape surrounding each field were determined from high altitude aerial photographs. Five landscape variables, aggregated at three spatial scales ranging from 2.6 km2 to 581 km2, were measured from aerial photographs. Regression models incorporating within-field and landscape variables accounted for 27–49% of the variance in aphid predator abundance in wheat fields. Aphid predator species richness and species diversity were also related to within-field and landscape variables. Some predators were strongly influenced by variability in the composition and patchiness of the landscape surrounding a field at a particular spatial scale while others responded to variability at all scales. Overall, predator abundance, species richness, and species diversity increased with increasing vegetational diversity in wheat fields and with increasing amounts of non-cultivated lands and increasing patchiness in the surrounding landscape.
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  • 11
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    Integrated pest management reviews 4 (1999), S. 127-143 
    ISSN: 1572-9745
    Keywords: wheat ; stored-grain ; integrated pest management ; aeration ; biological control ; grain sampling ; insect monitoring ; modeling ; area-wide IPM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Management of stored-grain insect pests by farmers or elevator managers should be based upon a knowledge of the grain storage environment and the ecology of insect pests. Grain storage facilities and practices, geographical location, government policies, and marketing demands for grain quality are discussed as factors influencing stored-grain insect pest management decisions in the United States. Typical practices include a small number of grain samples designed to provide grain quality information for segregation, blending and marketing. This low sampling rate results in subjective evaluation and inconsistent penalties for insect-related quality factors. Information on the efficacy of insect pest management practices in the United States, mainly for farm-stored wheat, is discussed, and stored-grain integrated pest management (IPM) is compared to field-crop IPM. The transition from traditional stored-grain insect pest control to IPM will require greater emphasis on sampling to estimate insect densities, the development of sound economic thresholds and decision-making strategies, more selective use of pesticides, and greater use of nonchemical methods such as aeration. New developments in insect monitoring, predictive computer models, grain cooling by aeration, biological control, and fumigation are reviewed, their potential for improving insect pest management is discussed, and future research needs are examined.
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  • 12
    ISSN: 1432-1890
    Keywords: Key words Arbuscular mycorrhiza ; Hordeum vulgare ; Triticum aestivum ; Glomus intraradices ; Mycorrhiza-helper bacteria ; Secondary compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Colonization of Hordeum vulgare L. cv. Salome (barley)and Triticum aestivum L. cv. Caprimus (wheat) roots by the arbuscular mycorrhizal fungus Glomus intraradices Schenck & Smith leads to de novo synthesis of isoprenoid cyclohexenone derivatives with blumenin [9-O-(2′-O-β-glucuronosyl)-β-glucopyranoside of 6-(3-hydroxybutyl)-1,1,5-trimethyl-4-cyclohexen-3-one] as the major constituent and to transient accumulation of hydroxycinnamate amides (4-coumaroylagmatine and -putrescine). Accumulation of these compounds in mycorrhizal wheat roots started 2 weeks after sowing together with the onset of arbuscule formation and proceeded with mycorrhizal progression. Highest levels were reached in 3- to 4-week-old secondary roots (root branches of first and higher order) characterized by the formation of vesicles. In the final developmental stages, the fungus produced massive amounts of spores, enclosing the stele of older root parts (older than 5 weeks) characterized by cortical death. In these root parts, the secondary compounds were detected in trace amounts only, indicating that they were located in the cortical tissues. Some rhizosphere bacteria tested, i.e. Agrobacterium rhizogenes, Pseudomonas fluorescens, and Rhizobium leguminosarum, markedly stimulated both fungal root colonization and blumenin accumulation, thus, acting as mycorrhiza-helper bacteria (MHB). Application of blumenin itself strongly inhibited fungal colonization and arbuscule formation at early stages of mycorrhiza development. This was associated with a markedly reduced accumulation of the hydroxycinnamate amides 4-coumaroylputrescine and -agmatine. The results suggest that both the isoprenoid and the phenylpropanoid metabolism are closely linked to the developmental stage and the extent of fungal colonization. Their possible involvement in the regulation of mycorrhiza development is discussed.
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  • 13
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    Theoretical and applied genetics 98 (1999), S. 472-477 
    ISSN: 1432-2242
    Keywords: Key words QTL ; Ear emergence time ; Plant height ; Recombinant substitution line ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Chromosome 5A of wheat carries major gene loci for agronomic traits including the vernalization requirement (Vrn-A1) and ear morphology (Q). To determine whether the genetic variation for ear emergence time and plant height is attributable to either of these major genes as pleiotropic effects or independent QTL, we combined a RFLP map constructed from 120 recombinant substitution lines derived from a cross between ‘Chinese Spring’ (Cappelle-Desprez 5A) and CS(Triticum spelta 5A) with data collected from field trials over 3 years. For ear emergence time the main effects on flowering time were by Vrn-A1 and QEet.ocs-5A.1, the latter a QTL in the 28.6-cM Xcdo584/Q interval linked to Q by less than 10 cM. The CS(T. spelta 5A) allele at QEet.ocs-5A.1 contributed to an earlier ear emergence time by 2.7–6.0 days, which was approximately equal to the effects of Vrn-A1. For plant height, three QTLs were identified on the long arm and linked in repulsion. The CS(T. spelta 5A) allele at Vrn-A1 or closely linked to Xfba068 contributed to a height reduction of 3.5–6.1 cm, whereas both the Q allele and Qt.ocs-5A.1 allele within the Xcdo1088/Xbcd9 interval from CS(Cappelle-Desprez 5A) produced a shorter plant. When plant height was partitioned into culm length and ear length, the Vrn-A1 allele and CS(Cappelle-Desprez 5A) allele at QCl.ocs-5A.1 within the Xcd1088/Xbcd9 interval were found to contribute to a shorter culm. CS(T. spelta 5A) allele at q was a major determinant of a long ear, together with minor effects at QEl.ocs-5A.1 within the Xcdo1088/Xbcd9 interval.
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  • 14
    ISSN: 1432-2242
    Keywords: Key words Erysiphe graminis ; Powdery mildew resistance ; QTL ; Triticum aestivum ; Triticum spelta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Powdery mildew is one of the major diseases of wheat in regions with a maritime or semi-continental climate and can strongly affect grain yield. The attempt to control powdery mildew with major resistance genes (Pm genes) has not provided a durable resistance. Breeding for quantitative resistance to powdery mildew is more promising, but is difficult to select on a phenotypic basis. In this study, we mapped and characterised quantitative trait loci (QTLs) for adult-plant powdery mildew resistance in a segregating population of 226 recombinant inbred lines derived from the cross of the Swiss wheat variety Forno with the Swiss spelt variety Oberkulmer. Forno possibly contains the Pm5 gene and showed good adult-plant resistance in the field. Oberkulmer does not have any known Pm gene and showed a moderate susceptible reaction. Powdery mildew resistance was assessed in field trials at two locations in 1995 and at three locations in 1996. The high heritability (h2=0.97) for powdery mildew resistance suggests that the environmental influence did not affect the resistance phenotype to a great extent. QTL analysis was based on a genetic map containing 182 loci with 23 linkage groups (2469 cM). With the method of composite interval mapping 18 QTLs for powdery mildew resistance were detected, explaining 77% of the phenotypic variance in a simultaneous fit. Two QTLs with major effects were consistent over all five environments. One of them corresponds to the Pm5 locus derived from Forno on chromosome 7B. The other QTL on 5A, was derived from the spelt variety Oberkulmer and did not correspond to any known Pm gene. In addition, five QTLs were consistent over three environments, and six QTLs over two environments. The QTL at the Pm5 locus showed a large effect, although virulent races for Pm5 were present in the mixture of isolates. Molecular markers linked with QTLs for adult-plant resistance offer the possibility of simultaneous marker-assisted selection for major and minor genes.
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  • 15
    ISSN: 1432-2242
    Keywords: Key words Aegilops tauschii ; Triticum aestivum ; Genetic mapping ; Molecular markers ; Agronomically important genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Aegilops tauschii is the diploid D-genome progenitor of bread wheat (Triticum aestivum L. em Thell, 2n=6x=42, AABBDD). A genetic linkage map of the Ae. tauschii genome was constructed, composed of 546 loci. One hundred and thirty two loci (24%) gave distorted segregation ratios. Sixty nine probes (13%) detected multiple copies in the genome. One hundred and twenty three of the 157 markers shared between the Ae. tauschii genetic and T. aestivum physical maps were colinear. The discrepancy in the order of five markers on the Ae. tauschii 3DS genetic map versus the T. aestivum 3D physical map indicated a possible inversion. Further work is needed to verify the discrepancies in the order of markers on the 4D, 5D and 7D Ae. tauschii genetic maps versus the physical and genetic maps of T. aestivum. Using common markers, 164 agronomically important genes were assigned to specific regions on Ae. tauschii linkage, and T. aestivum physical, maps. This information may be useful for map-based cloning and marker-assisted plant breeding.
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  • 16
    ISSN: 1432-2242
    Keywords: Key words Lodging ; Morphological traits ; QTL ; Triticum aestivum ; Triticum spelta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Lodging can strongly affect both the grain yield and the quality of wheat. Lodging represents a quantitative trait and is difficult to assess on a phenotypic basis. Marker-assisted selection (MAS) could therefore become an important tool in breeding for lodging resistance. In this study, we mapped and characterised quantitative trait loci (QTLs) for lodging resistance, as well as morphological traits correlated with lodging, in a segregating population of 226 recombinant inbred lines derived from the cross of the lodging-resistant wheat variety Forno with the susceptible spelt variety Oberkulmer. Lodging, plant height, leaf width, leaf-growth habit, culm stiffness, culm swinging, culm thickness, days to ear emergence and days to flowering were assessed in field trials at two locations in 1996 and at one location in 1997. Additionally, at one location weight and length parameters were also assessed. Plant height and culm stiffness explained 77% of the phenotypic variance of lodging in a multiple regression model over all three environments. QTL analysis of lodging and morphological parameters was based on a genetic map containing 230 loci with 23 linkage groups (2469 cM). With the method of composite interval mapping nine QTLs for lodging resistance were detected, explaining 63% of the phenotypic variance in a simultaneous fit. Seven of these QTLs coincided with QTLs for morphological traits, reflecting the correlations between these traits and lodging. In our population the most efficient way to improve lodging resistance would be by a combination of indirect selection on plant height and culm stiffness together with MAS on the two QTLs for lodging resistance which did not coincide with QTLs for morphological traits.
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  • 17
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    Theoretical and applied genetics 98 (1999), S. 1248-1252 
    ISSN: 1432-2242
    Keywords: Key words Wheat ; Chromosome sorting ; Chromosome isolation ; Aneuploids ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We are reporting the successful isolation of wheat chromosome arm 1DS by flow cytometry. A chromosome suspension was prepared for the 1DS ditelosomic line and the normal ‘Chinese Spring’ (CS) by chopping 2-day-old root tip meristems, synchronized by hydroxyurea, in HEPES-magnesium sulfate buffer containing propidium iodide. Chromosomes were analyzed and sorted with a FACS Vantage flow cytometer and cell sorter. An extra peak was observed in the flow karyotype of the ditelosomic line that was absent in ‘CS’. The estimated size of chromosomes from the extra peak matched with the expected size of chromosome 1DS. Chromosomes from the putative 1DS peak were analyzed by both fluorescent microscopy and N-banding analysis. A total of 571 chromosomes from two separate experiments were analyzed, and all were observed to be telosomics except for 2 which were broken. About 82% of these telosomics showed the diagnostic N-band of 1DS, the remaining were unbanded and are probably also 1DS. This strategy can also be used to sort other wheat arms.
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  • 18
    ISSN: 1432-2242
    Keywords: Key words Transgenic wheat ; Triticum aestivum ; Tritordeum ; Transgene inheritance ; Marker gene stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The stability and heritability of three marker genes was investigated in a population of twelve independent transgenic cereal lines (six wheat and six tritordeum). Integration patterns, inheritance of structural transgenes and inheritance of expression were analysed in the T0 and T1 generations for all 12 lines. Transmission and expression were analysed in the T2 generation for 9 lines and in the T3 generation for the six wheat lines. Inheritance of integration patterns was highly stable, and transmission of the transgenes and inheritance of their expression followed Mendelian ratios in the majority of lines. A gradual reduction in uidA expression was observed over three generations, which was not accompanied by a similar reduction in bar expression. Some unexpected phenomena associated with transgene inheritance were also observed and are discussed.
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  • 19
    ISSN: 1573-9368
    Keywords: low molecular weight glutenin promoter ; particle bombardment ; transgene expression ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transgenic wheat plants from specific cultivars can now be routinely engineered in many laboratories. However, our understanding of the factors controlling transgene expression and stability in wheat compared to other cereals is rather limited. Only a few promoters have been tested in transgenic wheat, and relatively little is known of their relative activities and expression parameters. In the present study, the spatial and temporal properties of one heterologous constitutive promoter and one seed‐specific wheat promoter were investigated. We generated constructs with the reporter gene gusA (β‐glucuronidase) driven by: (a) the constitutive maize ubiquitin‐1 (ubi‐1) promoter, and (b) two different‐sized fragments of the seed‐specific low molecular weight glutenin (LMWG1D1) promoter from wheat. The activities of all three promoter constructs were comparable in endosperm tissue. A detailed analysis of spatial and temporal properties of the promoters is described. Heat shock treatment of transgenic plants carrying the ubi‐1: gusA construct resulted in a significant elevation in the levels of GUS activity. The inheritance of transgene expression levels and stability was evaluated over four generations, as a function of transgene integration patterns and copy number.
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  • 20
    ISSN: 1618-2545
    Keywords: BLB light ; conidiogenesis ; Fusarium globosum ; subtropical Japan ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The second report ofFusarium globosum is based on strains isolated from wheat in Ishigaki Island, Okinawa, in subtropical Japan. Morphological features of the Japanese isolates are described. These strains show different reactions in conidiogenesis to light conditions. Under continuous BLB light, falcate sporodochial conidia are typically induced, but production of aerial globose conidia is suppressed. In two of the strains, clavate conidia became longer under BLB light. Application of both, complete darkness and continuous BLB light, is recommended as standard light conditions to cultureFusarium isolates.
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  • 21
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    Molecular breeding 5 (1999), S. 561-568 
    ISSN: 1572-9788
    Keywords: wheat ; milling yield ; QTL mapping ; RFLP ; microsatellite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A partial genetic linkage map constructed using 150 single seed descent (SSD) lines generated from a cross between the hexaploid wheat varieties ‘Schomburgk’ and ‘Yarralinka’ was used to identify loci controlling milling yield. Milling yield data were obtained using seed collected from field trials conducted at different sites over two seasons. The estimated broad-sense heritability of milling yield in this population was calculated as 0.48. In the preliminary analysis, two regions were identified on chromosomes 3A and 7D, which were significantly associated with milling yield and accounted for 22% and 19% of the genetic variation, respectively. Bulked segregant analysis in combination with AFLP identified other markers linked to these loci, as well as an additional region on chromosome 5A, which accounted for 19% of the genetic variation. The applicability of these markers as selection tools for breeding purposes is discussed.
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  • 22
    ISSN: 1572-9788
    Keywords: insect resistance ; aphids ; GNA ; lectins ; transgenic plants ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Transgenic wheat plants containing the gene encoding snowdrop lectin (Galanthus nivalis agglutinin; GNA) under the control of constitutive and phloem-specific promoters were generated through the particle bombardment method. Thirty-two independently derived plants were subjected to molecular and biochemical analyses. Transgene integration varied from one to twelve estimated copies per haploid genome, and levels of GNA expression from 0 to ca. 0.2% of total soluble protein were observed in different transgenic plants. Seven transgenic plants were selected for further study. Progeny plants from these parental transformants were selected for transgene expression, and tested for enhanced resistance to the grain aphid (Sitobion avenae) by exposing the plants to nymphal insects under glasshouse conditions. Bioassay results show that transgenic wheat plants from lines expressing GNA at levels greater than ca. 0.04% of total soluble protein decrease the fecundity, but not the survival, of grain aphids. We propose that transgenic approaches using insecticidal genes such as gna in combination with integrated pest management present promising opportunities for the control of damaging wheat pests.
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  • 23
    ISSN: 1572-9788
    Keywords: wheat ; DNA markers ; yellow rust resistance ; Yr17
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The Yr17 gene, which is present in many European wheat cultivars, displays yellow rust resistance at the seedling stage. The gene introduced into chromosome 2A from Aegilops ventricosa was previously found to be closely linked (0.5 cM) to leaf and stem rust resistance genes Lr37 and Sr38, respectively. The objective of this study was to identify molecular markers linked to the Yr17 gene. We screened with RAPD primers, for polymorphism, the DNAs of cv. Thatcher and the leaf rust-resistant near-isogenic line (NIL) RL 6081 of cv. Thatcher carrying the Lr37 gene. Using a F2 progeny of the cross between VPM1 (resistant) and Thésée (susceptible), the RAPD marker OP-Y15580 was found to be closely linked to the Yr17 gene. We converted the OP- Y15580 RAPD marker into a sequence characterized amplified region (SCAR). This SCAR marker (SC-Y15) was linked at 0.8 ± 0.7 cM to the Yr17 resistance gene. We tested the SC-Y15 marker over a survey of 37 wheat cultivars in order to verify its consistency in different genetic backgrounds and to explain the resistance of some cultivars against yellow rust. Moreover, we showed that the Xpsr150-2Mv locus marker of Lr gene described by Bonhomme et al. [6] which possesses A. ventricosa introgression on the 2A chromosome was also closely linked to the Yr17 gene. Both the SCAR SC-Y15 and Xpsr150-2Mv markers should be used in breeding programmes in order to detect the cluster of the three genes Yr17, Lr37 and Sr38 in cross progenies.
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  • 24
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    European journal of plant pathology 105 (1999), S. 629-641 
    ISSN: 1573-8469
    Keywords: wheat ; Triticum spp. ; Septoria tritici ; septoria tritici blotch of wheat Stagonospora nodorum ; stagonospora nodorum blotch of wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 25
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    Plant molecular biology 39 (1999), S. 915-926 
    ISSN: 1573-5028
    Keywords: programmed cell death ; wheat ; endosperm ; ethylene ; nucleases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Although maize endosperm undergoes programmed cell death during its development, it is not known whether this developmental feature is common to cereals or whether it arose inadvertently from the selection process that resulted in the enlarged endosperm of modern maize. Examination of wheat endosperm during its development revealed that this tissue undergoes a programmed cell death that shares features with the maize program but differs in some aspects of its execution. Cell death initiated and progressed stochastically in wheat endosperm in contrast to maize where cell death initiates within the upper central endosperm and expands outward. After a peak of ethylene production during early development, wheat endosperm DNA underwent internucleosomal fragmentation that was detectable from mid to late development. The developmental onset and progression of DNA degradation was regulated by the level of ethylene production and perception. These observations suggest that programmed cell death of the endosperm and regulation of this program by ethylene is not unique to maize but that differences in the execution of the program appear to exist among cereals.
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  • 26
    ISSN: 1573-5036
    Keywords: genotypic variation ; Secale cereale ; Triticum aestivum ; Triticum durum ; zinc efficiency ; zinc deficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Effect of zinc (Zn) nutritional status on uptake of inorganic 65Zn was studied in rye (Secale cereale, cv. Aslim), three bread wheat (Triticum aestivum, cvs. Dagdas, Bezostaja, BDME-10) and durum wheat (Triticum durum, cv. Kunduru-1149) cultivars grown for 13 days in nutrient solution under controlled environmental conditions. The cultivars were selected based on their response to Zn deficiency and to Zn fertilization in calcareous soils under field conditions. When grown in Zn-deficient calcareous soil in the field, the rye cultivar had the highest, and the durum wheat the lowest Zn efficiency. Among the bread wheats, BDME-10 showed higher susceptibility to Zn deficiency and Bezostaja and Dagdas were less affected by Zn deficiency. Similarly to field conditions, in nutrient solution visual Zn deficiency symptoms (i.e. necrotic lesions on leaf blade) appeared to be more severe in Kunduru-1149 and BDME-10 and less severe in rye cultivar Aslim. Under Zn deficiency, shoot concentrations of Zn were similar between all cultivars. Cultivars with adequate Zn supply did not differ in uptake and root-to-shoot translocation rate of 65Zn, but under Zn deficiency there were distinct differences; rye showed the highest rate of Zn uptake and the durum wheat the lowest. In the case of bread wheat cultivars, 65Zn uptake rate was about the same and not related to their differential Zn efficiency. Under Zn deficiency, rye had the highest rate of root-to-shoot translocation of 65Zn, while all bread and durum wheat cultivars were similar in their capacity to translocate 65Zn from roots to shoots. When Zn2+ activity in uptake solution ranged between 117 p M and 34550 pM, Zn-efficient and Zn-inefficient bread wheat genotypes were again similar in uptake and root-to-shoot translocation rate of 65Zn. The results indicate that high Zn efficiency of rye can be attributed to its greater Zn uptake capacity from soils. The inability of the durum wheat cultivar Kunduru-1149 to have a high Zn uptake capacity seems to be an important reason for its Zn inefficiency. Differential Zn efficiency between the bread wheat cultivars used in this study is not related to their capacity to take up inorganic Zn.
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  • 27
    ISSN: 1573-5036
    Keywords: 2 ; 4-D ; germination ; growth ; salinity-tolerance ; seed treatment ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Experiments were conducted under laboratory and greenhouse conditions to study the effect of 2,4-D on rooting and salinity tolerance of wheat. Seeds of one commercial wheat (Inqalab-91) and three salt-tolerant wheat lines (WL-41, WL-359, and WL-1073 developed through wide hybridization) were included in the study. Preliminary and short-term experiments were conducted to determine the level of 2,4-D (administered through seed soaking for 24.5 h. at 25 °C in the dark) at which the maximum number of roots emerged. Under hydroponic conditions, 2,4-D treatment of seeds caused an increase of 60 to 100% in the number of primary roots. The maximum increase in the number of roots was observed in one of the salt tolerant wheat lines (WL-41). The roots appeared in bunches but showed stunted growth at higher levels of 2,4-D. Dry matter accumulation decreased markedly; the effect was more pronounced in Inqalab-91 which is less tolerant to stress than other wheat lines. In all wheat types, allocation of dry matter to roots relative to shoot increased due to 2,4-D treatment. In soil, seeds treated with different levels of 2,4-D showed a germination delay of 1–3 days. Although the number of primary roots increased, 2,4-D treatment caused a decrease in total dry matter accumulation by plants grown for 40 days. In another experiment, conducted under greenhouse conditions, seed germination and growth of seedlings was significantly retarded in saline compared to that in non-saline (normal) soil. Initially, the pace of germination of treated seeds as well as seedling growth was slower in both soils, but after six weeks, the leaf area of seedlings raised from treated seeds was greater than those raised from untreated seeds. Towards maturity, plants arising from treated seeds developed wider and longer flag leaves leading to enhanced yield. Root biomass decreased in saline soil as compared to normal soil. However, 2,4-D treatment caused a substantial increase in root biomass in saline soil and the roots were harder in texture in wheats other than Inqalab-91. Seed treatment with 2,4-D led to a significant improvement in the number of productive tillers, yield of straw and grain, and grain protein content of all wheats grown in saline soil. Plants grown in normal soil did not show any marked effect of seed treatment on grain yield and other agronomic parameters. The four wheats showed substantial differences for different parameters but the salt tolerant wheat lines performed better compared to the commercial variety Inqalab-91.
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  • 28
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    Plant and soil 209 (1999), S. 283-295 
    ISSN: 1573-5036
    Keywords: leaf emergence ; phosphorus ; photosynthesis ; tillering ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Phosphorus (P) deficiency limits the yield of wheat, particularly by reducing the number of ears per unit of area because of a poor tiller emergence. The objectives of this work were to (i) determine whether tiller emergence under low phosphorus availability is a function of the availability of assimilates for growth or a direct result of low P availability, (ii) attempt to establish a quantitative relation between an index of the availability of P in the plant and the effects of P deficiency on tiller emergence, and (iii) to provide a better understanding of the mechanisms involved in tiller emergence in field-grown wheat. Wheat (Triticum aestivum L., cv. INTA Oasis), was grown in the field under drip irrigation on a typic Argiudol, low in P (5.5 μg P g-1 soil Bray & Kurtz I) in Balcarce, Argentina. Treatments consisted of the combination of three levels of P fertilization 0, 60 and 200 kg P2O5 ha-1, and two levels of assimilate availability, a control (non-shaded) and 65% of reduction in incident irradiance from seedling emergence until the end of tillering (shaded). Phosphorus treatments significantly modified the pattern of growth and development of the plants. Shading reduced the growth and concentration of water-soluble carbohydrates in leaves and stems. Leaf photosynthetic rate at saturating irradiance was reduced by P deficiency, but was not affected by shading. At shoot P concentrations less than 4.2 g P kg-1 the heterogeneity in the plant population increased with respect to the number of plants bearing a certain tiller. At a shoot P concentration of 1.7 g P kg-1 tillering ceased completely. Phosphorus deficiency directly altered the normal pattern of tiller emergence by slowing the emergence of leaves on the main stem (i.e. increasing the phyllochron), and by reducing the maximum rate of tiller emergence for each tiller.
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  • 29
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    Euphytica 107 (1999), S. 51-59 
    ISSN: 1573-5060
    Keywords: wheat ; plant breeding ; yield stability ; environmental index
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effect of plant breeding on yield and their physiological determinants has been widely studied in wheat. However, it is poorly understood how, and to what extent, yield stability has been modified. To attempt a direct analysis of changes in absolute and relative yield stability, data of yield of cultivars released in different eras in different environments were obtained from records from our lab and from the literature. Depending on the availability of data, effects of plant breeding on yield stability of cultivars released in Argentina, Australia, Italy and the United Kingdom were evaluated using a quantitative approach. In this paper it was assumed that the slope of yield vs. environmental index estimates the instability of the cultivars. In addition, a more qualitative approach for Mexico, and the former USSR complemented this analysis. There was a clear decrease in yield stability assessed in absolute terms as a consequence of wheat breeding. In Argentina, Australia, Italy and the UK this decrease was related to the magnitude of yield increases. However, the decrease in yield stability in Argentina and Australia was less than for Italy and the UK, particularly so during the last 30 years. Modern cultivars released in Argentina and Australia showed a trend to maintain yield stability as a percentage of their yield similar to that of their predecessors, while the two European countries analysed tended to a slight decrease in yield stability even in relative terms. The complementary, less quantitative evaluation of Mexico and the former USSR appeared to confirm the quantitative trends described for the other countries, i.e. a general decrease in yield stability (assessed in absolute terms) with genetic gains in yield potential.
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  • 30
    ISSN: 1573-5060
    Keywords: chromatin ; breeding ; gel electrophoresis ; in situ hybridization ; rye ; rye-specific probes ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Chromosome arm 1RS of rye ( Secale cereale L.), when transferred to wheat ( Triticum sp.), significantly influences variety performance, because it carries genes for resistance to disease and insect pathogens. Inserted into wheat, 1RS also promotes haploid production, affects end-product quality, and sometimes affects yield. Therefore, its detection by breeders and geneticists is important. The entire 1RS arm is present in chromosome substitutions and in Robertsonian translocations involving chromosomes 1A, 1B, or 1D of wheat. In recombinant lines, a segment of 1RS has been exchanged with a segment of a group-1 wheat chromosome. Determining the wheat chromosome arm involved in a translocation, the source of rye chromatin, and the amount of 1RS chromatin introduced is necessary for a complete characterization of the introgressed segment. Biochemical, molecular, and cytogenetic technologies are described which enable such a characterization of 1RS in wheat. Examples of using gel electrophoresis, high-performance liquid chromatography, monoclonal antibodies, rye-specific molecular probes, RFLP and PCR assays, chromosome banding, in situ hybridization, and flow cytometry are provided. A comparison of these technologies is made and the advantages and disadvantages of each technology are discussed relative to modern wheat breeding efforts.
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  • 31
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    Plant molecular biology 40 (1999), S. 921-933 
    ISSN: 1573-5028
    Keywords: A23187 ; calcium ; elicitor ; MAP kinase ; Typhula ishikariensis ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Wheat cultured cells were used to study the role of Ca2+ in regulating protein kinases during the induction of defense-related genes by fungal elicitor treatments. Manipulation of intracellular Ca2+ concentrations by treatment with calcium ionophore A23187 in the presence of high extracellular Ca2+ resulted in the induction of mRNA expression of WCK-1, a gene encoding mitogen-activated protein (MAP) kinase. The induction of WCK-1 mRNA by A23187 did not occur when extracellular Ca2+ was chelated by 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA). The WCK-1 mRNA was also induced by Typhula ishikariensis-derived elicitors, suggesting a possible involvement of WCK-1 in the plant defense response against pathogens. BAPTA and a calcium channel blocker, La3+, inhibited the elicitor-induced expression of the WCK-1 mRNA. A recombinant fusion protein of WCK-1 (GST-WCK-1) autophosphorylated at the Tyr residue and exhibited an autophosphorylation-dependent protein kinase activity towards myelin basic protein. Alteration of Tyr-196 in the conserved ‘TEY’ motif in GST-WCK-1 to Phe by site-directed mutagenesis abolished the autophosphorylation. The GST-WCK-1 protein was activated by elicitor-treated wheat cell extracts but not by the control extract. These results suggest that fungal elicitors activate WCK-1, a specific MAP kinase in wheat. Furthermore, the results suggest a possible involvement of Ca2+ in enhancing the MAP kinase signaling cascade in plants by controlling the levels of the MAP kinase transcripts.
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  • 32
    ISSN: 1573-5028
    Keywords: alternative splicing ; starch biosynthesis ; starch-branching enzyme ; transit peptide ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A wheat gene, denoted Sbe1, encoding a type I starch-branching enzyme (SBEI) was isolated from a genomic library and shown to comprise 14 exons distributed over a 5.7 kb DNA region. Analyses of kernel RNA by 5′ rapid amplification of cDNA ends (5′-RACE) and reverse transcription-polymerase chain reaction (RT-PCR) demonstrated a considerable sequence variation at the 5′ ends of SBEI gene transcripts. DNA sequence alignments between the 5′-RACE products and the Sbe1 genomic DNA indicated that the first two exons and first intron were differentially processed to generate three classes of the mature transcript. One form of the SBEI gene transcript in 12-day old kernels contained the exon I+II+III combination at the 5′ end, whereas other forms differed by inclusion of intron 1 or exclusion of exon II sequences. RT-PCR analysis of Sbe1-uidA::nptII chimeric mRNA produced in transgenic wheat cultured cells confirmed that the isolated Sbe1 was able to produce all three forms of SBEI gene transcripts by alternative splicing of the primary mRNA. The variants of processed Sbe1 mRNA were potentially translated into N-terminal variants of the SBEI precursor with different transit peptide sequences.
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  • 33
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    Plant and soil 208 (1999), S. 149-159 
    ISSN: 1573-5036
    Keywords: abscisic acid ; drought ; soil water content ; water potential ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In order to investigate the effects of soil texture on possible non-hydraulic signals under field conditions, spring wheat plants (Triticum aestivum L. cv. Cadensa) grown in sand and loam soils and with a well developed root system were exposed to slow soil drying in the late vegetative stage of growth. Soil water potential and content were measured daily at different depths and plant responses were measured in flag leaves. When the average soil water potential in the top soil layers (0–25 cm depth in sand and 0–45 cm depth in loam) dropped to –60 or –70 kPa and the lower soil layers were still at field capacity, morning xylem [ABA] (0.03–0.04 vs. 0.06–0.08 mmol m-3) and midday leaf ABA concentration increased (250–300 vs. 400–450 ng/g DW) and leaf conductance decreased relatively to well-watered (control) plants (0.75–0.88 vs. 0.64–0.70 mol m-2 s-1). These responses took place before any decrease in leaf water potential occurred as compared with control plants, indicating that they were triggered by root-borne signals due to reduced root water status in the top soil layers. At this stage the soil water content was as low as 6% by volume, the fraction of roots in ‘wet’ soil was 0.12 and relative available soil water was 45% in sand and still high 20%, 0.48 and 70%, respectively, in loam of the whole soil profile indicating that roots were responding to soil water availability and not soil water content at a certain evaporative demand. In addition, similar responses occurred at high and low evaporative demands (3.4–5.2 vs. 0.6–4.0 mm/day of potential evapotranspiration).
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  • 34
    ISSN: 1573-5036
    Keywords: macropores ; rhizosphere ; roots ; root-soil interplay ; soil properties ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Under certain soil conditions, e.g. hardsetting clay B-horizons of South-Eastern Australia, wheat plants do not perform as well as would be expected given measurements of bulk soil attributes. In such soils, measurement indicates that a large proportion (80%) of roots are preferentially located in the soil within 1 mm of macropores. This paper addresses the question of whether there are biological and soil chemical effects concomitant with this observed spatial relationship. The properties of soil manually dissected from the 1–3 mm wide region surrounding macropores, the macropore sheath, were compared to those that are measured in a conventional manner on the bulk soil. Field specimens of two different soil materials were dissected to examine biological differentiation. To ascertain whether the macropore sheath soil differs from rhizosphere soil, wheat was grown in structured and repacked cores under laboratory conditions. The macropore sheath soil contained more microbial biomass per unit mass than both the bulk soil and the rhizosphere. The bacterial population in the macropore sheath was able to utilise a wider range of carbon substrates and to a greater extent than the bacterial population in the corresponding bulk soil. These differences between the macropore sheath and bulk soil were almost non-existent in the repacked cores. Evidence for larger numbers of propagules of the broad host range fungus Pythium in the macropore sheath soil were also obtained.
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  • 35
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    Plant and soil 215 (1999), S. 65-72 
    ISSN: 1573-5036
    Keywords: barley ; boron deficiency ; Hordeum vulgare ; Triticum aestivum ; variation ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Responses of a range of barley (Hordeum vulgare L.) genotypes to boron (B) deficiency were studied in two experiments carried out in sand culture and in the field at Chiang Mai, Thailand. In experiment 1, two barley genotypes, Stirling (two-row) and BRB 2 (six-row) and one wheat (Triticum aestivum L.) genotype, SW 41, were evaluated in sand culture with three levels of applied B (0, 0.1 and 1.0 μM B) to the nutrient solution. It was found that B deficiency depressed flag leaf B concentration at booting, grain number and grain yield of all genotypes. In barley Stirling, B deficiency also depressed number of spikes plant-1, spikelets spike-1 and straw yield. However, no significant difference between genotypes in flag leaf B concentration was found under low B treatments. Flag leaf B concentration below 4 mg kg-1 was associated with grain set reduction and could, therefore, be used as a general indicator for B status in barley. In experiment 2, nine barley and two wheat genotypes were evaluated in the field on a low B soil with three levels of B. Boron levels were varied by applying either 2 t of lime ha-1 (BL), no B (B0) or 10 kg Borax ha-1 (B+) to the soil prior to sowing. Genotypes differed in their B response for grain spike-1, grain spikelet-1 and grain set index (GSI). The GSI of the B efficient wheat, Fang 60, exceeded 90% in all B treatments. The B inefficient wheat SW 41 and most of the barley genotypes set grain normally (GSI 〉80%) only at the B+. In B0 GSI of the barley genotypes ranged from 23% to 84%, and in BL from 19% to 65%. Three of the barley with severely depressed GSI in B0 and BL also had a decreased number of spikelets spike-1. In experiment 3, 21 advanced barley lines from the Barley Thailand Yield Nursery 1997/98 (BTYN 1997/98) were screened for B response in sand culture with no added B. Grain Set Index of the Fang 60 and SW 41 checks were 98 and 65%, respectively, and GSI of barley lines ranged between 5 and 90%. One advanced line was identified as B efficient and two as moderately B efficient. The remaining lines ranked between moderately inefficient to inefficient. These experiments have established that there is a range of responses to B in barley genotypes. This variation in the B response was observed in vegetative as well as reproductive growth. Boron efficiency should be considered in breeding and selection of barley in low B soils.
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  • 36
    ISSN: 1573-5036
    Keywords: chelator ; genotypic differences ; HEDTA ; ion speciation ; micronutrient ; tolerance to zinc deficiency ; wheat ; zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The chelator-buffered nutrient solutions containing excess chelator have been used frequently in the micronutrient research, but potential toxicity of the excess chelator has not been ascertained. The present study was conducted to test effects of four concentrations of excess HEDTA [ N-(2-hydroxyethyl)ethylenedinitrilotriacetic acid] and two levels of total Zn on growth, root exudation, and nutrient uptake and transport by Triticum aestivum L. (cv. Aroona) and Triticum turgidum L. conv. durum (Desf.) MacKey (cv. Durati) genotypes differing in tolerance to Zn deficiency. Excess HEDTA at 50 μM reduced root and shoot growth and caused visual toxicity symptoms (necrotic lesions) on leaves; these effects were generally absent at lower concentrations of excess HEDTA. Root exudation of phytosiderophores increased with increasing concentrations of excess HEDTA at deficient and sufficient Zn levels, and was higher in Zn-deficiency-tolerant Aroona than in Zn-deficiency-sensitive Durati wheat. Shoot and root Zn concentrations showed a saturable response to increasing Zn2+ activities in solution. Excess HEDTA at 50 μM caused an increase in shoot concentrations of Fe and a decrease in concentrations of Mn and Cu. An average rate of Zn uptake increased with an increase in Zn2+ ionic activity in solution, with Zn-deficiency-tolerant Aroona having a higher rate of Zn uptake than Zn-deficiency-sensitive Durati in the deficiency range of Zn2+ activities. Average uptake rates of Mn and Cu decreased with an increase in concentration of excess HEDTA. Similar observations were noted for transport of Mn and Cu to shoots, while Zn transport to shoots was proportional to Zn2+ activities in solution. It was concluded that excess HEDTA at 50 μM adversely affects wheat growth and physiology, while excess of 25 μM or less does not cause measurable toxicity.
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  • 37
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    Plant molecular biology 40 (1999), S. 567-578 
    ISSN: 1573-5028
    Keywords: wheat ; mitochondria ; RNA polymerase ; transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Using PCR-based methods, we assembled two wheat cDNA sequences, wheat-G and wheat-C, that encode T3/T7 bacteriophage-like RNA polymerases (RNAPs) sharing 45% amino acid identity. In phylogenetic analyses using maximum likelihood, parsimony and distance methods, the predicted protein sequence of wheat-G (1005 amino acids, 113 kDa) clusters with sequences of previously assigned mitochondrial RNAPs from dicotyledonous plants (Arabidopsis thaliana, Chenopodium album); likewise, in such analyses, the wheat-C sequence (949 amino acids, 107 kDa) affiliates specifically with the Arabidopsis sequence that encodes a phage-like RNAP thought to function in chloroplasts. To confirm biochemically the assignment of the gene encoding the putative wheat mitochondrial RNAP, we isolated a ca. 100 kDa wheat mitochondrial protein that is enriched in fractions displaying specific in vitro transcription activity and that reacts with an antibody raised against a recombinant maize phage-type RNAP. Internal peptide sequence information obtained from the 100-kDa polypeptide revealed that it corresponds to the predicted wheat-G cDNA sequence, providing direct evidence that the wheat-G gene (which we propose to call RpoTm) encodes the wheat mitochondrial RNAP.
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  • 38
    ISSN: 1573-5036
    Keywords: agriculture ; fertilisation ; nitric oxide flux ; nitrification ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The surface flux of nitric oxide from a wheat field was investigated from 23 March to 29 May 1997 in the Kerzersmoos, Switzerland. A plot fertilised with 19 kg N ha-1 in cattle slurry and 40 kg N ha-1 in mineral NH4NO3 fertiliser and a plot receiving no nitrogen containing fertiliser were compared. The flux was calculated based on hourly measurements of the NO soil–atmosphere concentration gradient using the one-dimensional soil diffusion model of Galbally and Johansson (1989). The soil bulk diffusion coefficient was determined from measurements of the 222Rn surface flux and the activity gradient between 10 cm depth and the surface. It ranged between 79% and 0.3% of the NO diffusion coefficient in air and was parameterised by air filled soil pore space. The indirectly determined NO flux agreed well with standard flux measurements using dynamic chambers. The largest NO emission was found following fertiliser application and irrigation. The emission occurred in pulses, which lasted for 4 days up to 3 weeks coinciding with elevated soil ammonium concentrations. Nitric oxide emission in 5 days following application of cattle slurry were 31 g NO-N ha-1 and 5 g NO-N ha-1 from the non-fertilised plot, respectively. Nitric oxide emission in 15 days following application of NH4NO3 was 95 g NO-N ha-1 and 10 g NO-N ha-1 from the non-fertilised plot, respectively. NO emission in 4 days following irrigation on 21 April were 36 g N ha-1 from the fertilised and 39 g N ha-1 from the non-fertilised plot. The daily NO emission before and after fertiliser and irrigation pulses was between 0.3 and 0.7 g NO-N ha-1 d-1. NO production and NO uptake of the soil was measured regularly. No systematic influence of management or climate on NO uptake was found. NO production was strongly stimulated by fertiliser input and soil moisture content. The simulation of NO production could be reproduced using a nitrification algorithm (Riedo et al., 1998) driven by soil temperature, moisture and ammonium concentration. A NO production rate constant of 1.1ċ10-3 h-1 at 15 °C was derived from a linear regression between nitrification and NO production. Introducing the parameterisation of NO production into the model of Galbally and Johansson (1989) the duration and the strength of the NO emission pulses could be reproduced and the total NO emission during the experiment was approximated within a factor of two.
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  • 39
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    Plant and soil 211 (1999), S. 223-230 
    ISSN: 1573-5036
    Keywords: silicon absorption ; transport ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Although silicon (Si) is a quantitatively major inorganic constituent of higher plants the element is not considered generally essential for them. Therefore it is not included in the formulation of any of the solution cultures widely used in plant physiological research. One consequence of this state of affairs is that the absorption and transport of Si have not been investigated nearly as much as those of the elements accorded 'essential' status. In this paper we report experiments showing that Si is rapidly absorbed by wheat (Triticum aestivum L.) plants from solution cultures initially containing Si at 0.5 mM, a concentration realistic in terms of the concentrations of the element in soil solutions. Nearly mature plants (headed out) 'preloaded' with Si absorbed it at virtually the same rate as did plants grown previously in solutions to which Si had not been added. The rate of Si absorption increased by more than an order of magnitude between the 2-leaf and the 7-8 leaf stage, with little change thereafter.
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  • 40
    ISSN: 1573-5060
    Keywords: barley ; embryogenesis ; medium ; regeneration ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Media have been developed for somatic embryogenesis and plant regeneration from immature inflorescences and immature scutella of elite cultivars of wheat, barley and tritordeum. For wheat and tritordeum inflorescences, regeneration from embryogenic calluses induced on medium with picloram was almost twice as efficient as regeneration from cultures induced on 2,4-dichlorophenoxyacetic acid (2,4-D). The addition of zeatin at 5 or 10 mg l−1 to regeneration media had a positive effect on regeneration. For scutella, the highest frequencies of embryogenesis (85%) and regeneration (50%) was obtained using an induction medium containing 2 mg l−1 of 2,4-D and half concentration of aminoacids. The morphogenetic capacities of 19 different cultivars of wheat, barley and tritordeum were compared, and clear differences were found both between explants and genotypes. In wheat, embryogenic capacity from inflorescences (average of 92%) was higher than from immature scutella (average of 62%). However, shoot regeneration from scutella was clearly higher than from inflorescences (averages of 63%, and 18% respectively). Frequencies of regeneration in wheat and barley varied widely among the cultivars tested and in both species no difference was found between spring and winter varieties.
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  • 41
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    Euphytica 108 (1999), S. 193-198 
    ISSN: 1573-5060
    Keywords: K+/Na+ selectivity ; Lophopyrum elongatum ; salt-stress ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Accumulation of potassium ions (K+) in expanding or most recently expanded leaves and exclusion of sodium ions (Na+) from them (K+/Na+ selectivity) have been shown to be associated with salt stress tolerance in wheat and Lophopyrum elongatum, a highly salt stress tolerant relative of wheat. This physiological trait is expressed in an amphiploid from the cross of wheat (cv. Chinese Spring) × L. elongatum and the chromosomes controlling it have been identified in field studies employing Chinese Spring disomic substitution lines with individual L. elongatum chromosomes. In this paper the arm location of these genes was investigated by assessing K+/Na+ selectivity in lines harboring individual chromosomes and chromosome arms of L. elongatum. Lophopyrum elongatum chromosome arms 1ES, 7ES, and 7EL, were shown to enhance K+/Na+ selectivity in wheat.
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  • 42
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    Euphytica 108 (1999), S. 91-95 
    ISSN: 1573-5060
    Keywords: amylose content ; granule-bound starch synthase ; null alleles ; Triticum aestivum ; Wx loci
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The Wx locus controls amylose synthesis in the cereal endosperm. Hexaploid wheat (Triticum aestivum L.) has the three Wx loci on chromosomes 7A ( Wx-A1), 4A (Wx-B1) and 7D (Wx-D1). To verify the effects of null alleles on reducing amylose content and determine the amylose synthesis capacity of each Wx gene independently and accurately, we produced eight possible types of recombinant lines carrying different null alleles at the Wx loci under the ‘Chinese Spring’ genetic background. Amylose content varied from 0% of the waxy ‘Chinese Spring’ to 25% of the ‘Chinese Spring’ normal type. The reducing effect of the single null alleles was the largest in Wx-B1b, and there was no significant difference between Wx-A1b and Wx-D1b. More than 3% reductions in amylose content were detected in the double null types. The results of the double null lines further demonstrated that for the capacity of amylose synthesis, Wx-B1a predominates and produces 21–22% amylose, followed by Wx-D1a (20–21%) and Wx-A1a (15–18%). These significant differences were partly correlated with variation in the amounts of the Wx proteins produced by different Wx genes. However, comparisons of the double null lines with the single null or normal lines indicated that amylose content was not linearly proportional to the number of the Wx genes, suggesting that the Wx genes act in an epistatic manner.
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  • 43
    ISSN: 1573-5060
    Keywords: diallel analysis ; Fusarium culmorum ; heterosis ; resistance ; scab ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Fusarium head blight (FHB, scab) caused by Fusarium spp. is a widespread disease of cereals causing relevant yield and quality losses and contaminating cereal products with mycotoxins. Breeding resistant cultivars is the method of choice for controlling the disease. Resistance to FHB is a quantitative trait and is most likely governed by several genes. We present the results of an F1 diallel analysis of FHB resistance involving six resistant and one susceptible European winter wheat genotypes of diverse origin in order to identify promising combinations for the selection of improved cultivars. Parents and F1s including reciprocals were evaluated for FHB resistance in an artificially inoculated field trial. Two traits were assessed: visual disease symptoms on the heads and the percentage of Fusarium damaged kernels in a harvested sample. General combining ability (GCA) and specific combining ability (SCA) effects were statistically significant for visual symptoms and kernel damage, whereas reciprocal effects were small or not significant. Heterosis for resistance was common, indicating that the parental genotypes possess different resistance genes. Selection of transgressive segregates should be feasible from such heterotic combinations.
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  • 44
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    Plant growth regulation 28 (1999), S. 129-132 
    ISSN: 1573-5087
    Keywords: dormancy ; Lactuca sativa ; lettuce seeds ; Brassica napus ; rapeseed ; combustion products ; Salix viminalis ; Themeda triandra ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In darkness, dormancy was imposed on seeds of lettuce (Lactuca sativa L. cv. Grand rapids) by high temperature and on seeds of oilseed rape (Brassica napus L. cv. Apex) by osmotic stress using polyethylene glycol (PEG 8000). In both cases, dormancy was broken by incubating the seeds in aqueous extracts of combustion products from Salix viminalis wood chips or Themeda triandra leaves. Dormancy of rapeseed, but not lettuce, was also broken by a solution of smoke from burnt straw of Triticum aestivum. The greatest stimulation from burnt vegetation was achieved with an aqueous extract of pyrolysed willow wood chips, which had been subjected to temperatures of up to 800 °C during combustion in a down-draught gasifier. This suggests that some biologically active substances obtained from combustion of plant tissues are highly heat-stable.
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  • 45
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    Plant growth regulation 28 (1999), S. 187-197 
    ISSN: 1573-5087
    Keywords: ABA ; grain filling ; water stress ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effect of in situ water stress on the endogenous abscisic acid (ABA) content of the endosperm and the in vitro application of ABA on some important yield regulating processes in wheat have been studied. Water stress resulted in a marked increase in the ABA content of the endosperm at the time close to cessation of growth. Application of ABA to the culture medium of detached ears reduced grain weight. Exogenously applied ABA, at the highest concentration (0.1 mM) reduced transport of sucrose into the grains and lowered the starch synthesis ability of intact grains. In vitro sucrose uptake and conversion by isolated grains was stimulated by low ABA concentrations (0.001 mM) in the medium but was inhibited by higher concentrations. ABA application had no effect on sucrose synthase (SS) and uridine diphosphate glucose pyrophosphorylase (UDP-Gppase) activities, whereas adenosine diphosphate glucose pyrophosphorylase (ADP-Gppase), soluble starch synthase (SSS), and granule-bound starch synthase (GBSS) activities were reduced. These results raise the possibility that water stress-induced elevated levels of endogenous ABA contribute to reduced grain growth.
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  • 46
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    Plant growth regulation 29 (1999), S. 1-21 
    ISSN: 1573-5087
    Keywords: drought resistance ; wheat ; small grains ; genetic analysis ; yield stability ; traits
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Drought is a serious problem in many parts of the world where wheat, barley and other small-grained cereals are part of the staple diets. Even in parts of South-eastern Europe, seasonal rainfall for winter cereals has been falling gradually for many years. Thus, since 1981 across three sites in Yugoslavia (Novi Sad, Kragujevac and Zaječar), rainfall fell from a mean of 511 mm for October to July in 1981--1982 to about 453 mm during the same period for the 1995--1996 season. Nevertheless, average wheat yields for new varieties in Yugoslav Commission trials during this period have shown a steady increase from 7.6 to 8.8 t ha−1. This is due to increasing the yield potential of the new varieties, even in trials giving low average yields, caused largely by drought. Thus, breeders in Yugoslavia are succeeding in improving drought resistance in new wheat varieties. However, future progress in improving drought resistance may be helped by focusing on specific traits which will help to improve either crop water use, water-use efficiency or harvest index. Thus, for example, rapid early leaf area development not only improves subsequent crop growth rates, but increases competition with weeds for water and nutrients. The rate of leaf area development is closely associated with embryo size, so selection for large embryo size should improve early growth rates. Osmotic adjustment in wheat in response to drought appears to be important for maintaining yields, and selection for high osmotic adjustment has improved drought yields. Carbon 13 discrimination (Δ) is an integral measure of plant water-use efficiency. Selecting for low Δ has also resulted in increased yield under drought conditions. Other constitutive and induced traits, such as phenology, leaf xeromorphy, excised-leaf water loss, rooting behaviour, senescence and stored assimilates are also discussed in relation to improving yields in small-grain crops. Opportunities for marker-assisted selection are also considered. Incorporating specific drought resistance traits in breeding programmes should facilitate more rapid improvement in the drought resistance of wheat and other small-grained cereals.
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  • 47
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    Genetic resources and crop evolution 46 (1999), S. 81-85 
    ISSN: 1573-5109
    Keywords: aluminum tolerance ; germplasm ; rye ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Regional rye populations and wheat cultivars/lines were screened for aluminum tolerance using the hematoxylin staining method. Portuguese regional rye populations showed better tolerance than the Polish cv. Dank. Zlote, used as tolerant tester. In the group of bread wheats, EPM 305/81, a Barbela reselection, was the most tolerant genotype with the same behaviour as the cv. BH 1146, a tolerant tester. In a study with lines selected from a local Barbela landrace, aluminum tolerance variability was detected. Some lines were as tolerant, or higher, as wheat tester. As Portuguese rye populations and the Barbela wheat landrace have grown for centuries on an acid soil region, the data supports the idea that natural biotic or abiotic stresses associated to man selection, lead to the adaptation of genotypes to specific regional conditions and, in this case, to acid soils where aluminum toxicity occurs.
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  • 48
    ISSN: 1573-5087
    Keywords: cortical fibre cell ; gibberellic acid ; spring wheat ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The role of gibberellic acid (GA) in differentiation and secondary cell-wall deposition of fibre cells of spring wheat (Triticum aestivum) culms was studied using applications of GA and chlormequat (a GA biosynthesis inhibitor). In certain genotypes, higher GA levels may increase the number of cortical fibre cell files by changing cell fate from parenchyma to fibre, and induce thicker secondary cell-walls.
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    Genetic resources and crop evolution 46 (1999), S. 469-475 
    ISSN: 1573-5109
    Keywords: foliar blight ; germplasm ; resistance ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract One thousand three hundred and eighty-seven spring wheat germplasm (Triticum aestivum L.) lines belonging to the Indian and CIMMYT wheat programmes were evaluated for their tolerance to foliar blight disease for three consecutive years i.e., from 1994 to 1997. Disease severity at six different growth stages, beginning from tillering to late milk stage, was recorded. None of the genotypes showed immunity to the disease. Of 43 lines showing resistant reaction, a major proportion (25) was represented by CIMMYT material. Comparatively, Indian germplasm lines tended to be more susceptible at more advanced growth stages. Area Under Disease Progress Curve (AUDPC) and Apparent Infection Rate (r) values of resistant lines were much lower than those of susceptible ones, but lower AUDPC in some of the resistant lines did not correspond to a lower 'r' value. Most of the resistant lines were derived from Seri, Myna, Bau, kauz, Hork 's' and Aegilops tauschii Coss.
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  • 50
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    Genetic resources and crop evolution 46 (1999), S. 521-528 
    ISSN: 1573-5109
    Keywords: glutenin ; homogeneity ; landrace ; obsolete cultivars ; storage proteins ; Triticum aestivum L. ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Identity and present degree of genetic homogeneity and heterogeneity, respectively of 52 European wheat accessions, maintained in the collection of wheat genetic resources, have been characterized using analyses of glutenins by sodiumdodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE). Six of the analyzed wheat accessions were observed to be homogeneous, while 46 (88.5%) of them were heterogeneous in protein profiles. Heterogeneous accessions possessed 2 to 13 different protein lanes. Together, 17 high molecular weight glutenin subunit (HMW-GS) alleles have been found. The most frequent HMW-GS alleles at the Glu-A1, Glu-B1, and Glu-D1 complex loci were 1, 7+9, and 2+12, respectively. However, also low frequented HMW-GS alleles or allelic combinations, such as 7+15, 13+16, 20, 6, 7, and 9 were observed. Furthermore, another new allele encoding HMW glutenin subunit with relative molecular weight 98.6 kDa has been found in one of the lines of the cultivar Eritrospermum 917. The Glu-score in the examined accessions varied in broad range, some of the lines reached the maximum value 10.
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  • 51
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    Photosynthesis research 59 (1999), S. 1-7 
    ISSN: 1573-5079
    Keywords: leaf gas exchange ; ozone ; Pisum sativum ; Rubisco ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Previous studies have shown that short exposure of plants to high doses of ozone decreases subsequent photosynthesis; initially by reducing carboxylation capacity. This study tests the hypothesis that this is also the primary cause of loss of photosynthetic capacity in leaves affected by development under a low level of ozone. Triticum aestivum and Pisum sativum plants were exposed from germination to ozone in air (80 nmol mol-1 for 7 hours per day, for 18 days. Leaves that had completed lamina expansion at this time were free of visible injury and light absorptance was unaffected. However, some significant changes in photosynthetic gas exchange were evident. Photosynthetic CO2 uptake at light saturation was decreased significantly by 35% in T. aestivum but was unchanged in P. sativum. The reduction in photosynthesis of T. aestivum was accompanied by a 31% decline in the maximum velocity of carboxylation measured in vivo. Decreased stomatal conductance did not contribute to this reduction of photosynthesis because there was no significant change in the stomatal limitation to CO2. Processes directly dependent upon photochemical reactions; that is, the quantum yield of CO2 uptake and capacity for regeneration of ribulose 1,5-bisphosphate were not affected by O3 fumigation in either species. This suggests that for wheat, the quantitative cause of decreased photosynthetic rate in vivo is a decrease in the quantity of active ribulose-1,5- bisphosphate carboxylase-oxygenase.
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  • 52
    ISSN: 1573-1561
    Keywords: Aphid ; experience ; probing behavior ; sieve elements ; salivation ; cell punctures ; hydroxamic acids ; EPG ; Sitobion fragariae ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We hypothesized that aphids after previous exposure to hydroxamic acids (Hx), a family of secondary plant compounds deleterious to aphids, are able to reduce their subsequent exposure to them. This hypothesis was tested by evaluating the time to produce salivation into a sieve element (SSE) by the aphid Sitobion fragariae on seedlings of two wheat cultivars of Triticum aestivum differing in their concentration of Hx. The total time to produce a first SSE was significantly longer in the high-Hx cultivar; however, the subsequent, second SSE (first SSE after interruption of probing) in this cultivar was significantly reduced, reaching the level observed in the low-Hx plants. Therefore, a strategy to reduce the exposure to secondary compounds was observed only in the second SSE in high-Hx plants. When the experimental plant was replaced by a new unattacked plant after the first SSE, aphids did not change the behavior described, thus excluding an aphid-induced plant susceptibility. The number of cell punctures and accumulated duration was not affected by previous exposure to Hx, either in low or high Hx cultivars. Total time and pathway time but not cell punctures, seem to be the variables affected by previous exposure to Hx.
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  • 53
    ISSN: 1573-1618
    Keywords: CERES ; wheat ; soil moisture ; nitrogen ; variability ; precision agriculture ; spatial
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Crop growth modelling techniques were used to investigate the performance of a wheat crop over a range of weather conditions, nitrogen application rates and soil types. The data were used to predict long term benefits of using spatially variable fertilizer application strategies where fertilizer application rate was matched to the soil type, against a strategy of uniform fertilizer application. The model was also run with modified soil properties to determine the importance of soil moisture holding capacity in the variability of crop yield. It was found that the benefits of spatially variable nitrogen management when fertilizer was applied at the beginning of the season were modest on average. The range of results for different weather conditions was much greater than the average benefit. A large proportion of the variability of crop performance between soil types could be explained by differing soil moisture holding capacity. Devising techniques for managing this variability was concluded to be important for precision farming of cereals.
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  • 54
    ISSN: 1573-0867
    Keywords: bicarbonate-extractable soil phosphorus ; Lupinus angustifolius ; residual value ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Decreases in Colwell bicarbonate soil test P in the years after applying single (ordinary) superphosphate, and the residual value of superphosphate, was measured in a long-term field experiment on a duplex (texture contrast) soil (sand over lateritic ironstone gravel clay sand at 10–15 cm), at Wongan Hills, Western Australia, typical of many soils used to grow crops in Western Australia. Ten levels of P (0–91 kg P ha-1) were applied once only in late May to different plots in different years from 1988 to 1993. Wheat (Triticum aestivum), or lupin ( Lupinus angustifolius)) were sown in late May of each year, when the P treatments applied that year were banded (drilled) with the seed. Soil samples were collected each June to measure soil test P. Seed (grain) yields of the crops were measured each December. The residual value (RV) of P applied in previous years was calculated relative to P applied in the current year, using grain yields (RVyield) and soil test P (RVsoil). Soil test P measured on soil samples collected in June was related to yields measured in December that year to provide soil P test calibrations. Relative to P applied in the current year, soil test P decreased by between 15 to 30% for P applied one year previously, by 25 to 30% for P applied three years previously, and by 60 to 70% for P applied six years previously. Soil test P was affected by spatial variation, and it also varied in the different years, for P applied in the current year, one year previously, two years previously, etc. Compared with P applied in the current year, mean RVyield determined in the different years decreased by about 40% one year after P application, followed by a further 20% decrease for P applied two years previously, followed by a further 20% decrease for P applied three to five years previously. Relative to current P, RVsoil decreased by about 25% one year after P application, followed by a further 20% for P applied two years previously, followed by a further 10% for P applied three years ago, and followed by a further 6% for P applied four and five years ago. As measured in the different years, the soil P test calibration varied between years for P applied one, two etc. years previously. This was so even when the same cultivar of wheat was grown at the same site in different years.
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    Nutrient cycling in agroecosystems 54 (1999), S. 41-48 
    ISSN: 1573-0867
    Keywords: wheat ; potassium ; nutrition ; genotypic variability ; utilization efficiency ; uptake efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Pot and field experiments were carried out in order to study the genotypic variation in potassium uptake and utilization by winter wheat (T. aestivum L). Fifty-eight genotypes showed variation in K concentration, accumulation and potassium efficiency ratio (KER) in a field experiment. KER had significant positive correlation with grain weight per spike and harvest index (HI), and significantly negative correlation with stem K concentration at maturity. In a subsequent field experiment, three out of four genotypes, Yunmei 5, 94-18 and 94-6 differed in their KER, and had significantly higher grain yield with K application (K1) than without K application (K0). The 4th genotype Zhemei 1 showed no response to K. The yield increase due to K application was mainly due to the improvement in spike development from tillers. K concentration and accumulation in the plant varied between genotypes, K levels and plant parts. Among various plant parts, stem contained the highest K concentration and had the highest K accumulation at maturity, and changed considerably with the K level, while other plant parts remained relatively unchanged. All four genotypes had smaller KER in K1, as compared to K0, but there existed some difference in KER reduction among genotypes.
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  • 56
    ISSN: 1573-5087
    Keywords: flooding ; kinetin ; leaf relative water content ; membrane stability ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Wheat plants, 22d. old, were exposed to wide range of soil water osmotic potential (Ψs = 0 to −1.2 MPa) induced by NaCl and CaCl2 treatments in combination with roots maintained under aerobic (drained at field capacity) or nonaerobic (flooded) conditions in the soil, and sprayed with 10 mg L−1 kinetin solution. In drained plants, not receiving kinetin, increased soil salinity resulted in appreciable inhibition of shoot growth and reduction in chlorophyll (Ch1.), soluble sugars (SS) contents and grain yield. Shoot growth, Ch1. content, soluble sugars and grain yield were significantly lower for flooded plants than unflooded analogues over the entire Ψs range. Both salinity and waterlogging synergize to increase Na+, Ca+ and Cl− accumulation in shoot tissues and to decrease the stability of leaf membranes to either dehydration (40% polyethylene glycol 6000) or heat (51 °C) stress. The ratio of K+/Na+ transported to shoots under aerobic and anaerobic conditions decreased progressively on salinization. The association between the internal mineral element concentrations was largely affected by kinetin treatment. Kinetin application ameliorated the deleterious effects of salinity and oxygen deficiency. It reduced Na+, Ca2+ and Cl− accumulation and improved K+ uptake under salinity and waterlogging stresses. Increased K+/Na+ ratio helped the plants to avoid Na+ toxicity and enhanced shoot growth and grain yield. Kinetin also reduced membrane injury by dehydration and heat stresses and improved the water status of plants under both aerobic and anaerobic conditions. The effects of single factors (Soil salinity ‘Ψs’, soil waterlogging ‘WL’ and Kinetin ‘Kin’) and their interactions (Ψs × WL, Ψs × Kin, WL × Kin and Ψs × WL × Kin) were shown by analysis of variance to be statistically significant for most parameters tested. Calculation of the coefficient of determination (η+) led to three important findings. (1) Salinity (Ψs) was dominant in affecting leaf relative water content (RWC), shoot dry mass, grain yield, stability of leaf membranes to dehydration stress and the contents of Na+, Ca2+, Mg2+ and Cl−. (2) Kinetin (Kin) had a dominant effect on the stability of leaf membranes to heat stress as well as on chlorophyll and soluble sugars contents. (3) The share of waterlogging (WL) was dominant for K+ content. It can be concluded that kinetin application helped wheat plants to grow successfully in the areas subjected to combined effects of salinity and oxygen deficiency, such as in salt marshes.
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  • 57
    ISSN: 1573-5109
    Keywords: Aegilops tauschii ; hairy auricles ; hairy leaf sheath ; inheritance ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Inheritance of genes for hairy auricles and hairy leaf sheath of Ae. tauschii in hexaploid wheat backgrounds (synthetic hexaploid wheat and common wheat varieties) was analyzed. The results indicated that hairy auricles and hairy leaf sheath of Ae. tauschii can be transferred and are expressed in hexaploid wheat. In a synthetic hexaploid wheat ('Ae. tauschii' 188) hairy auricles was proved to be controlled by a single dominant gene derived from Ae. tauschii, which was different from the Pa gene located on chromosome 4BS of common wheat. The hairy leaf sheath phenotype of 'Altar 84/Ae. tauschii 188' was also controlled by a single dominant gene derived from Ae. tauschii, which is obviously different from the Hls gene in T. dicoccoides. We suggest to designate the Ae. tauschii genes for hairy auricles and hairy leaf sheath as Pa2 and Hls2, respectively; such genes could be used as useful genetic markers in common wheat.
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  • 58
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    Plant cell, tissue and organ culture 59 (1999), S. 151-154 
    ISSN: 1573-5044
    Keywords: Ne1 ; Ne2 ; necrotic hybrid ; Triticum aestivum ; viable seeds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Hybrid necrosis in wheat is a problem for gene transfer in wheat breeding. Hybrid necrosis occurs due to dominant complementary interaction of two genes, Ne1 and Ne2. A cross between wheat (Triticum aestivum L.) varieties C306 (drought tolerant, Ne1 carrier) and WL711(high yielding, Ne2 carrier) produced necrotic F1 hybrids, which died before ear emergence and produced no seeds. To overcome the problem of hybrid necrosis, ears enclosed in the leaf sheath were taken and cultured to maturity in liquid medium containing 5% sucrose and 0.04% glutamine. The necrotic hybrids produced only a few seeds per ear compared to parents, but individual grain weight was similar in the hybrid and the parents. The F1 ear culture study has been repeated for three years and F2 seeds obtained. In 1996–97, the cultured ears of F1 hybrids produced 62 seeds, of which only 52 showed germination and were grown under normal field conditions. Out of the 52 seeds, 50% were non-necrotic and showed segregation for various physiological traits. The results reveal that hybrids ears had the potential to form viable seeds. Culturing of wheat ears before ear emergence and production of viable F2 seeds from necrotic hybrids is a simple and efficient method for overcoming the problem of hybrid necrosis.
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  • 59
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    Euphytica 105 (1999), S. 125-131 
    ISSN: 1573-5060
    Keywords: disease resistance ; inheritance ; Karnal bunt ; Neovossia ; Tilletia indica ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Inheritance of resistance to Neovossia indica was studied in a Triticum aestivum line HD 29. To overcome the influence of environment on disease expression, the study was conducted by extensive evaluation of advanced generation (F8) recombinant inbred lines (RILs) developed by single seed descent from the cross WL 711 (susceptible) × HD 29 (resistant. The results suggested that HD 29 possesses three major genes for resistance to isolated Ni7 and two genes for resistance to isolate Ni8. One of the two genes controlling resistance to Ni8 is common with one of the genes conferring resistance to Ni7. These observations have important implications in breeding for Karnal bunt resistance.
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  • 60
    ISSN: 1573-5060
    Keywords: capillary electrophoresis ; cultivar identification ; gliadins ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Gliadin proteins extracted from fifteen Chinese and Yugoslav winter wheat cultivars were fractionated using a new separation technique – Capillary Zone Electrophoresis (CZE). Different CZE conditions were defined to optimize resolution and reproducibility of gliadin separations. Excellent resolution and high reproducibility of gliadin CZE patterns were obtained by using 47 cm length, 50 μm i.d. capillaries at 15 kV and 30° C in sodium borate buffer system with acetonitrile (ACN) and sodium dodecyl sulfate. By using these CZE conditions, gliadin proteins from each cultivar were easily separated into more than 35 components. This resolution is generally superior to that of one- and two-dimensional electrophoresis and RH-HPLC. Analysis of reproducibility of gliadin CZE patterns from Chinese cultivar ‘Lumai 6’ showed that the average relative standard deviation (RSD) for peak migration times and heights was 0.21% and 4.06%, respectively. Gliadin electrophoregrams of all cultivars studied showed clear qualitative and quantitative differences, including presence or absence of some major peak, migration times and heights of peaks. Specifically, some closely related cultivars that were not differentiable by A-PAGE, were readily differentiated by CZE. In addition, winter wheat cultivars from China and Yugoslavia showed greater differences in gliadin compositions revealed by CZE.
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  • 61
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    Euphytica 107 (1999), S. 71-78 
    ISSN: 1573-5060
    Keywords: Russian wheat aphid ; resistance ; inheritance ; allelism ; segregation ratio ; wheat ; Triticum aestivum L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), is an important pest of wheat (Triticum aestivum L.) in the United States of America. Developing adapted wheat cultivars with genetic resistance to RWA is an effective control strategy. Genetic studies were conducted to determine the mode of inheritance of gene(s) conferring resistance to RWA in an Iranian landrace wheat line, G 5864. For the inheritance study, G 5864 was crossed with the susceptible wheats ‘Yecora Rojo’ and ND 2375. Seedlings of F1, reciprocal F1, F2, BC1 to the susceptible parent (BCS), and BC1 to the resistant parent (BCR) were screened for RWA reaction. Several phenotypic segregation ratios were tested in the F2 populations for goodness of fit; the 9:3:3:1 ratio (resistant: rolled leaves: stunted plants: susceptible) was an acceptable fit in all cases. Thus, resistance in G 5864 seemed to be controlled by two independent dominant genes with additive gene effects. The allelic relationships of gene(s) in this line with genes in other resistant lines, PI 137739 (Dn1), PI 262660 (Dn2), PI 372129 (Dn4), PI 294994 (Dn5), and PI 243781 (Dn6), were also studied. Segregation patterns observed in G 5864 × resistant (R × R) F2 populations were inconclusive. However, no susceptible plants were observed in these F2 populations. If previous reports concerning the number of resistance genes present in the other resistant lines are correct, then given the high manifestation of resistance observed in G 5864, and given the absence of susceptible plants in the R × R F2 populations, it is indicated that RWA resistance in G 5864 is either controlled by different alleles at the same loci as the other resistance genes, or that G 5864 shares a resistance gene with each of the other resistant lines.
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  • 62
    ISSN: 1573-5060
    Keywords: C-banding ; chromosome additions ; chromosome substitution ; Elymus tsukushiense ; homoeology ; in situ hybridization ; RFLP ; Roegneria kamoji ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Elymus tsukushiense Honda (syn. Roegneria kamoji C. Koch) (2n = 6x = 42, StsStsHtsHtsYtsYts) is a hexaploid species, distantly related to bread wheat Triticum aestivum L. em Thell (2n = 6x = 42, AABBDD). Apart from the delineation of evolutionary relationships, this species is a potential source of resistance to scab, a devastating disease of wheat caused by Fusarium graminearum Schw. A standard C-banded karyotype was established identifying all 21 chromosome pairs of E. tsukushiense. By using C-banding and genomic in situ hybridization analyses, three wheat-E. tsukushiense chromosome addition lines, one ditelosomic addition line, and one disomic substitution line were identified in BC2 progenies from wheat × E. tsukushiense hybrids. Twenty DNA markers specific for the seven homoeologous groups of the Triticeae were used to determine the homoeology of the added E. tsukushiense chromosomes. The E. tsukushiense chromosomes in the addition lines NAU702, NAU703, and NAU701 were identified as belonging to homoeologous groups 1, 3, and 5, and thus, were designated as 1Ets#1, 3Ets#1, and 5Ets#1, respectively. NAU751 was identified as a disomic substitution line with chromosome 3A of wheat replaced by chromosome 3Ets#1. Line NAU702 has a high level of resistance to scab and will be used in chromosomal engineering and development of improved wheat germplasm for scab resistance breeding.
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  • 63
    ISSN: 1573-5060
    Keywords: 1BL/1RS ; bread-making quality ; prolamins ; wheat-rye translocations ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The allelic variation of prolamin loci was studied in three F2 progenies from three crosses between the 1BL/1RS cultivar Triana and Yécora Rojo, Pavón and Florence Aurora, cultivars without the translocation. According to the 1:2:1 theoretical proportions observed in the allelic variants of the Glu-B3/Gli-B1 loci of the parent without the translocation, the inheritance as a block of the rye chromosome arm was confirmed. A group of F3-F4 recombinant lines, developed from these crosses was evaluated using the SDS-sedimentation test and the mixograph and alveograph tests. The presence of the 1BL/1RS translocation was not associated with significantly lower grain protein content values or with the optimum mixing time in the mixograph of the genotypes. The effect of the 1BL/1RS translocation on most of the quality parameters was highly dependent on the genetic pool. Significant increases in gluten strength and better mixing properties associated with the presence of some alleles of the Glu-A1, Glu-A3/ Gli-A1 and Gli-D2 loci were detected. The additivity and the interaction of prolamin gene effects with the rye translocation in the 1BL/1RS lines and its possible use in plant breeding are discussed.
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  • 64
    ISSN: 1573-5060
    Keywords: Blumeria graminis ; powdery mildew ; QTL ; RFLPs ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A segregating population of doubled-haploid lines issued from the cross between the wheat (Triticum aestivum L. em. Thell) cultivars Courtot, resistant to several isolates of powdery mildew (Blumeria graminis DC. f. sp. tritici Em. Marchal), and Chinese Spring (susceptible) was used to map Mlar, a gene carried by Courtot and conferring resistance to this pathogen. The assignation of Mlar using monosomic lines of Courtot was confirmed by the mapping analysis. Mlar was located on the short arm of the chromosome 1A, in the vicinity of the locus XGli-A5 coding for storage proteins. This result was in accordance with those demonstrating that Mlar was an allele of the Pm3 locus (Pm3g), a gene also involved in the resistance to powdery mildew.
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  • 65
    ISSN: 1573-5060
    Keywords: disease assessment ; maturity ; resistance ; Septoria tritici ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Nineteen cultivars, with large differences in heading date, were evaluated for their response to septoria tritici blotch in two experimental setups in Njoro, Kenya. Due to the more or less constant temperatures during the growing season and the overhead irrigation applied the epidemic conditions were similar over the whole observation period for the early and late cultivars. In experiment 1 the cultivars were assessed for disease severity at the same moment irrespective of the developmental stage, while in experiment 2 the cultivars were assessed at the same developmental stage. Measured at the same time, the disease severity was highest in the early maturing cultivars and lowest in the late maturing cultivars (r = –0.78). When assessed at the same development stage the disease build up was independent of heading date (r = –0.10) but strongly dependent on resistance level. There were no indications that early heading cultivars were more susceptible than late heading cultivars.
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  • 66
    ISSN: 1573-5060
    Keywords: allelic variation ; glutenin subunit ; Japanese Norin variety ; seed storage protein ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Seed storage proteins of 131 Japanese Norin wheat (Triticum aestivum) varieties were fractionated by sodium dodecyl sulfate polyacrylamide gel electrophoresis to determine allelic make-up in varieties at each of three loci that control high-molecular-weight (HMW) glutenin subunits. Three alleles were identified at the Glu-A1 locus, six at the Glu-B1 locus and five at the Glu-D1 locus. Twenty-four different, major glutenin HMW subunits were identified and each contained three to five subunits and seventeen different glutenin subunit patterns were observed for 19 subunits in the 131 Japanese Norin varieties. Fourteen alleles were identified by comparison of subunit mobility with that previously found in hexaploid wheat. Japanese Norin varieties showed a specific pattern of allelic variation in glutenin HMW subunits, different from that of Chinese and other country common wheats in allelic frequency at Glu-1 loci.
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  • 67
    ISSN: 1573-5028
    Keywords: promoter analysis ; puroindoline gene ; seed ; tissue-specific expression ; transgenic rice ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A genomic DNA fragment containing the 5′-upstream sequence and part of the open reading frame corresponding to Triticum aestivum puroindoline-b cDNA, was isolated by inverse PCR. Promoter fragments extending to −1068, −388, −210 or −124 upstream of the translation initiation ATG codon and the sequence coding for the first 13 amino acids of the puroindoline-b, were translationally fused to the uidA reporter gene encoding β-glucuronidase and transferred to rice calli via particle bombardment-mediated transformation. The 1068 bp and 124 bp promoters were also transcriptionally fused to the uidA reporter gene. Out of the 196 plants regenerated from transformed rice calli, 118 plants set seeds. No GUS activity was detectable in the stems, roots, leaves or pollen of the transgenic rice which had integrated the puroindoline-b promoter or its deletions; GUS activity was detected only in seeds, except in those having integrated the 124 bp promoter. Within seeds, histological localisation showed GUS activity as being restricted to the endosperm, aleurone cells and pericarp cell layers; no GUS activity was detected in the embryonic axis. Analysis of 5′ promoter deletions identified the region between −388 and −210 as essential for endosperm expression, and the region between −210 and −124 as essential for expression in the epithelium of the scutellum. No difference of expression was observed between the translational and transcriptional fusion genes.
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  • 68
    ISSN: 1573-5036
    Keywords: barley ; genetic variation ; phosphate uptake ; rhizosphere ; root hairs ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Low phosphorus (P) availability in soils and diminishing P reserves emphasize the need to create plants that are more efficient P users. Knowledge of P efficient germplasm among the existing cereal varieties may serve as the basis for improving soil P use by selection and breeding. We had identified some cereal cultivars (winter wheat: Kosack and Kraka; winter barley: Hamu and Angora; spring barley: Canut, Alexis, Salka, Zita;) which differed (p〈0.05) in P depletion from thin slices (0.2 mm) of the rhizosphere soil under controlled conditions. In the present study, the same cultivars were studied under field conditions at three levels of P supply (no-P, 10 and 20 kg P ha-1) and the differences in P uptake as found in the previous work were confirmed. Under both conditions, the variation between the cultivars was greatest in soil without P fertilizers (no-P) for about 30 years. The variation in P uptake with most cultivars disappeared when 10 kg P ha-1 was applied. Root development did not differ between the cultivars much, but there was wide, consistent variation in their root hairs, regardless of growth media (solution, soil column and field). Increase in soil P level reduced the length of root hairs. The variation in root hairs between the cultivars was largest in no-P soil. When 10 kg P ha-1 was applied, the root hair lengths did not differ between the cultivars. Barley cultivars with longer root hairs depleted more P from the rhizosphere soil and also absorbed more P in the field. The relationship between root hairs and phosphorus uptake of the wheat cultivars was less clear. The wide variation in P uptake among the barley cultivars in the field and its relationship to the root hair development confirms that root hair length may be a suitable plant characteristic to use as criterion for selecting barley cultivars for P efficiency, especially in low-P soils.
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  • 69
    ISSN: 1573-5036
    Keywords: banded wetting agent ; furrow sowing ; lupins ; press wheels ; water repellent soils ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The rates of emergence of wheat and lupin were measured in 13 field experiments on water repellent sands. Conventional sowing was compared with furrow sowing either with or without the use of a press wheel and several rates of banded wetting agent. Measurements included, severity of water repellence, plant emergence, rainfall, soil temperature at sowing and, at one site, the area of wet soil after sowing. All ameliorative techniques improved emergence, with responses being greatest when seeds were sown into dry soil. Compared with conventional sowing, furrow sowing increased wheat and lupin emergence by an overall average of 16 and 41%, respectively. The benefits were greater at the drier sites. Increases in emergence due to the use of a press wheel were sometimes small, although they always occurred (1–19%). It was visually observed that press wheel use gave more uniform seeding depth, reduced clods and ensured more accurate placement of banded wetting agent. Banded wetting agent consistently improved wheat and lupin emergence, particularly where early rains were light and press wheels were used. The wetting agent increased the cross-sectional area of wet topsoil (0–10 cm) which was positively related with increased wheat emergence (R2 = 0.91). At 0.5 L ha−1 of banded wetting agent, the soil along the furrow was four times wetter than without wetting agent. Wetting agent at 0.5 and 1 L ha−1 (with press wheels) increased wheat emergence by 6 and 11% and lupin emergence by 13 and 11%, respectively. The high rates of banded wetting agent gave highest plant densities. Grain yield was only measured at three sites. Furrow sowing did not increase grain yield, however, press wheels use with furrow sowing increased grain yield by 30%. Banded wetting agent increased grain yield and they were positively correlated. The highest rate increased grain yields by a further 9% above press wheels and furrow sowing.
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  • 70
    ISSN: 1573-5036
    Keywords: boron ; genotypic difference ; sterility ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two pot experiments at the Plant Environment Laboratory (PEL), Reading, UK investigated sterility, boron (B) accumulation and B partitioning of wheat cultivars grown with limited B in the growing medium. The first experiment evaluated nine cultivars of spring wheat with diverse field responses to low available soil B, supplied with or without 20 μM B. A second experiment examined the response of a susceptible (SW-41) and a tolerant (Fang-60) cultivar to B-deficiency. These cultivars were supplied with either 20 μM B from sowing to flag leaf emergence and no added B thereafter, or 20 μM B from sowing to maturity. When B was not supplied in the nutrient solution, the number of grains ranged from 4 per ear (cv. BL-1135) to 32 per ear (cv. BL-1249) and sterility of competent florets ranged from 39% to 93%. Boron concentration in the flag leaf at anthesis did not differ greatly when the growing medium contained limited B, but differences between cultivars were evident when B was unlimited. Tolerance of B-deficiency was not related to the B concentration in the flag leaf. Some cultivars produced viable pollen and set grains while others failed to do so at similar B concentrations in the flag leaf. The two contrasting cultivars did not differ much in their pattern of B partitioning when B supply was restricted from flag leaf emergence onwards. Similarly, little evidence was found that the tolerant cultivars translocated B from their leaves, roots or stems when the supply in the growing medium was restricted. The proportion of total B partitioned in different organs was the same irrespective of B supply and cultivar. On average, leaves contained 68% of the total B content in the whole plant compared to 16% in the roots, 10% in the ears and only 6% in the stems. Tolerant or susceptible cultivars of wheat could not be distinguished based on the B concentration and B content of the flag leaf.
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  • 71
    ISSN: 1573-5036
    Keywords: hydraulic conductivity ; leaf growth ; phosphorus ; Rhizoctonia ; water status ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Wheat seedlings infected with a pure inoculum of the root-rotting fungus Rhizoctonia solani were grown in pots designed to fit in pressure chambers, to allow the effects of the Rhizoctonia infection on leaf growth to be studied while maintaining the leaves at elevated water status. Wheat was grown to the third leaf stage in soil inoculated with three different levels of Rhizoctonia, and the pots were then pressurised for seven days to maintain the leaf xylem at the point of bleeding (ie. the leaves were at full turgor). The reduction in leaf expansion caused by Rhizoctonia was not overcome by pressurisation, indicating that a reduced supply of water to the leaves was not responsible for reduced leaf growth. The addition of phosphorus to pots marginally deficient in P did not increase the leaf growth of Rhizoctonia-infected plants, despite increased P uptake to the leaves. These results indicate that a reduced supply of water to the leaves and a supply of phosphorus that was bordering on deficient was not the cause of the growth reduction in seedlings with Rhizoctonia infection. The nature of this reduced growth remains uncertain but may involve growth regulators produced by the fungus, or by the plant as a result of the infection process. The mechanism of these growth reductions is of interest as it may provide a key to the development of plant resistance mechanisms.
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  • 72
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    Plant cell, tissue and organ culture 57 (1999), S. 207-210 
    ISSN: 1573-5044
    Keywords: biolistics ; gene expression ; haploid ; transformation ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Using the PDS-1000/He Biolistic® Particle Delivery System, the microprojectile travel distance, rupture disk pressure and DNA/gold particle concentrations were assessed in order to optimise short and longer-term β-glucuronidase reporter gene expression in microspore-derived embryos of wheat. The effects were also evaluated of using sterile filter paper to support explants and treatment with a high osmoticum medium (0.2 M mannitol/0.2 M sorbitol or 0.4 M maltose). In the optimised procedure, wheat microspore-derived embryos (MDEs), were placed on filter paper and incubated on medium containing 0.4 M maltose, for 4 h pre- and 45 h post-bombardment. Five μl pAHC25 (0.75 mg ml-1 in TE buffer) was precipitated onto 25 μl gold particles (60 mg ml-1 in sterile water), using 20 μl spermidine (0.1 M) and 50 μl CaCl2 (2.5 M). The particles were centrifuged and resuspended in 75 μl absolute ethanol prior to the preparation of 6 macrocarriers. A microprojectile travel distance of 70 mm, a rupture pressure of 1300 p.s.i., and a vacuum of 29′′ Hg were employed. Maltose at 0.4 M in the support medium was the most important factor influencing GUS activity in bombarded tissues. GUS activity, 1 day post-bombardment, reached 52 ± 17 GUS-positive foci/MDE (mean ± s.e.m, n=3), with 17 ± 4 foci/MDE at 15 days, giving a 3.0-fold increase (p〈0.05) compared to expression in MDEs bombarded on medium without a high osmoticum treatment.
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  • 73
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    Plant cell, tissue and organ culture 58 (1999), S. 119-125 
    ISSN: 1573-5044
    Keywords: plant regeneration ; protoplast ; suspension culture ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A fast-growing, small, granular, embryogenic callus was selected from primary calli induced from the Japanese wheat cultivar Nakasoushu and the Australian wheat cultivar Bodallin. Regenerable and fine suspension cultures were induced three to six months after liquid culture was initiated and were characterized by dense cytoplasm and active division. These suspension cultures routinely provided high yields of protoplasts with about 90% viability when incubated in a modified KMP (Kao and Michayluk, 1975) medium containing 1 mg l-1 2,4-D (2,4-dichlorophenoxyacetic acid), and 1 mg l-1 zeatin. Nakasoushu and Bodallin protoplasts divided at frequencies of 8.6% and 11.1%, respectively, in agarose-solidified media. When Nakasoushu protoplasts were cultured with effective nurse cells of sorghum and wheat, protoplast division increased to 16.9% and 12.6%, respectively. Plating efficiencies varied from 0.03% to 2.5%. After subculture, protocolonies yielded embryogenic calli and somatic embryos, from which green plants were eventually regenerated. Whole plants obtained from Nakasoushu protoplasts were fertile, demonstrating the first report of Japanese cultivars in wheat protoplast cultures.
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  • 74
    ISSN: 1573-5060
    Keywords: diallel cross ; genotype-environment interaction ; marginal environments ; wheat ; yellow rust ; yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Complete F1 and F2 diallel crosses were used to investigate the inheritance of yield among eight Ugandan bread wheat lines grown in two low-yielding environments; one marginal because of the high incidence of yellow rust normally experienced there, the other a low-rust site. In the marginal, high-rust environment, mainly additive genetic variation was present, though in one season, when disease incidence was unusually low, non-additive variation due to dominance was also detected. Although yield was significantly higher at the low-rust site, no clear pattern of inheritance was apparent there. The results indicated that the low rust site was an intermediate environment, just below the crossover point of a crossover genotype-environment interaction. The implications of these results for wheat breeding in low-yielding and marginal environments in Uganda and elsewhere are discussed.
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  • 75
    ISSN: 1573-9058
    Keywords: diurnal variation ; photoinhibition ; photosystem 2 reaction centres ; state transition ; trans-thylakoid membrane proton gradient ; Triticum aestivum ; xanthophyll cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Non-photochemical quenching of chlorophyll fluorescence (qN) and its three components (qNf, qNm, and qNs) in the flag leaves of wheat grown in the field were studied by a fluorometer PAM-2000 on clear days. The diurnal variation patterns of qN in just fully extended (JFEL) and aging leaves (AL) were similar, but qNm declined markedly in JFEL while it remained at a relatively high level in AL under strong sunlight at noon. Furthermore, at midday qNf was higher than qNs in JFEL, but much lower in AL. The results show the relative contributions of different mechanisms in preventing the photosynthetic apparatus from photodamage change during leaf development.
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  • 76
    ISSN: 1573-9058
    Keywords: D1 protein ; diphenylcarbazide ; oxygen evolving complex ; scavengers ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Irradiation of thylakoid membranes at 40 °C resulted in complete inhibition of photosystem (PS) 2 activity measured as 2,6-dichlorophenol indophenol (DCIP) photoreduction either in the absence or presence of 1,5-diphenylcarbazide (DPC). Concomitant with the inactivation of PS2 activity, several thylakoid proteins were lost and high molecular mass cross-linking products appeared that cross-reacted with antibodies against proteins of PS2 but not with antibodies against proteins of other three complexes PS1, ATP synthase, and cytochrome b6f. Irradiation of thylakoid membranes suspended in buffer of basic pH or high concentration of Tris at 25 °C resulted in the formation of cross-linking products similar to those in thylakoid membranes irradiated at 40 °C. Presence of radical scavengers and DPC during the high temperature treatment prevented the formation of cross-linking products. These results suggest the involvement of oxygen evolving co mplex (OEC) in the formation of cross-linking between PS2 proteins in thylakoid membrane irradiated at high temperature.
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  • 77
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    Photosynthetica 36 (1999), S. 433-440 
    ISSN: 1573-9058
    Keywords: antibody ; polyacrylamide gel electrophoresis ; protease ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Exposure of thylakoid membranes to high temperature in dark leads to the degradation of D1 protein. Maximum degradation of D1 protein occurred at 45 °C. Using N-terminal specific D1 antibody, a 23 kDa fragment of D1 protein was detected. The degradation of D1 protein could be prevented both by radical scavengers and inhibitors of serine protease and metallo-protease. These results suggest that degradation of D1 protein during exposure of thylakoid membranes to high temperature in dark is catalyzed by protease.
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  • 78
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    World journal of microbiology and biotechnology 15 (1999), S. 417-423 
    ISSN: 1573-0972
    Keywords: 15N ; nitrogen mineralization ; Pseudomonas fluorescens ; rhizosphere ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The effects of an antibiotic-producing Pseudomonas fluorescens strain (F113) carrying the marker gene cassette lacZY and a marked, non-producing strain (F113G22) on the uptake of nitrogen from 15N-enriched organic residues incorporated into a sandy soil were investigated in microcosm studies. Strain F113 produces the antibiotic 2,4-diacetylphloroglucinol (DAPG), whilst its modified derivative strain F113G22 has DAPG production deleted by Tn5 mutagenesis. Uptake of nitrogen by wheat (Triticum aestivum) from 15N-enriched organic residues was estimated using stable isotope-ratio mass spectrometry of shoot and root material of 17-day-old plants. In addition, plant growth and active microbial biomass in soil were monitored. In contrast to results obtained in our previous study on pea (Pisum sativum), it was found that in wheat, inoculation with either strain F113 or F113G22 decreased the proportion of nitrogen derived from 15N-labelled organic residues incorporated into soil as compared to non-inoculated controls. It is therefore suggested that these strains decreased mineralization of organic residues in the rhizosphere of wheat, making less inorganic N (15N) available for plant uptake. The results of this study indicate that the effects of introduced Pseudomonas fluorescens strains on nitrogen mineralization in the rhizosphere are plant-species dependent, and highlight the importance of testing microbial inocula on a range of plant species.
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  • 79
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    European journal of plant pathology 105 (1999), S. 363-372 
    ISSN: 1573-8469
    Keywords: Microdochium nivale ; Fusarium ear blight ; in vitro bioassay ; disease resistance breeding ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A novel in vitro bioassay is described for screening Fusarium ear blight (FEB) resistance in adult winter wheat plants. Seven winter wheat cultivars were assessed for components of partial disease resistance as 28 day-old detached leaf segments in the laboratory using isolates of Microdochium nivale var. nivale and M. nivale var. majus. Results were compared with disease data obtained at anthesis using the same cultivars as whole plants and the same isolates under glasshouse conditions. Significant cultivar differences were observed using detached leaves, with cv. Avalon (a Fusarium culmorum ear susceptible cultivar) having the shortest leaf incubation period, greatest leaf lesion development and shortest leaf latent period compared to cv. Spark (a Fusarium culmorum ear resistant cultivar), which had the longest leaf incubation period, least leaf lesion development and longest leaf latent period. Using whole plants, cv. Avalon had the shortest ear incubation period and greatest ear disease severity, whilst cv. Spark had the longest incubation period and least ear disease severity. Overall, cultivars of intermediate F. culmorum ear resistance expressed intermediate responses to M. nivale isolates, using both detached leaves and whole plants. Significant correlations were found with ear disease severity and ear incubation period in whole plants and components of partial disease resistance in detached leaves, with significant correlations obtained between leaf incubation period and ear disease parameters using the M. nivale var. nivale isolate. In addition, leaf latent period and leaf lesion size showed significant correlations with whole plant reactions using M. nivale var. nivale and var. majus isolates. The in vitro screening of cultivars as detached leaves using M. nivale isolates may offer a real possibility of a rapid bioassay for the early screening of FEB resistance in wheat and other cereals.
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  • 80
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    European journal of plant pathology 105 (1999), S. 917-925 
    ISSN: 1573-8469
    Keywords: ergosterol ; detached glumes ; interaction ; Mycosphaerella graminicola ; Phaeosphaeria nodorum ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Interactions between Stagonospora nodorum and Septoria tritici were studied. Results from a detached glume experiment indicated that the interaction may be isolate-dependent, as it was shown that the interaction between the two pathogens may be beneficial or antagonistic depending on the isolate of each pathogen present. The number of spores produced by both pathogens was significantly greater when an aggressive isolate of S. tritici was mixed with a non-aggressive isolate of S. nodorum, whereas the number of spores produced by both pathogens was significantly less when two non-aggressive isolates were mixed. There was a significant reduction in disease level when S. tritici was applied prior to S. nodorum, compared to vice versa in the growth chamber. Results from growth chamber and field studies showed that S. nodorum produced significantly more spores when both pathogens were present together. It is concluded that S. tritici has a stimulatory effect on spore production by S. nodorum. However, there was a reduction of S. tritici spores observed in the dual inoculation treatments, suggesting that S. nodorum inhibits S. tritici.
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  • 81
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    Biologia plantarum 42 (1999), S. 217-222 
    ISSN: 1573-8264
    Keywords: chlorophyll ; photochemical activity ; photosystem 2 ; ribulose-1,5-bisphosphate carboxylase/oxygenase ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chlorophyll (Chl) a and b content, ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO) content and activity, and electron transport rate were measured in flag leaves of wheat genotypes Uniculm and Kalyansona, grown at suboptimal and optimal supply of nitrogen. The Chl content, RuBPCO activity, and electron transport rate were decreased due to suboptimal nitrogen supply only in Kalyansona. There was no change in the ratio of RuBPCO and photosystem 2 (PS2) activity at various stages which suggests that there was no alteration in distribution of N due to additional N supply.
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  • 82
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    Biologia plantarum 42 (1999), S. 119-123 
    ISSN: 1573-8264
    Keywords: anatomy ; epidermis ; heavy metals ; mesophyll ; Triticum aestivum ; vascular bundles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of 1 mM cadmium, lead and nickel on dry mass, Cd, Pb, and Ni contents, and changes in leaf structure in young wheat plants were studied. In leaves, Cd content was highest, followed by Pb and Ni, in roots Cd content was also highest, but followed by Ni and Pb. Roots accumulated considerably larger amounts of the three heavy metals than leaves. Largest reductions of leaf and root mass were obtained with Cd. Pb and Ni effects were almost equal. Ni excess had a strong negative effect on mesophyll thickness, while Cd mostly reduced the number and size of vascular bundles and vessel diameter. High Pb reduced the diameter of vessels causing their different deformations.
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  • 83
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    Entomologia experimentalis et applicata 89 (1998), S. 111-118 
    ISSN: 1570-7458
    Keywords: leaf surface wax ; probing behavior ; nymphoposition ; Russian wheat aphid ; wheat ; barley ; oat ; Homoptera ; Aphididae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of cereal leaf surface wax on Diuraphis noxia (Mordvilko), the Russian wheat aphid, probing behavior and nymphoposition was evaluated. Ultrastructure of leaf epicuticular wax from wheat (Triticum aestivum L.) c.v. ‘Arapahoe’ and ‘Halt’ was different from barley (Hordeum vulgare L.) c.v. ‘Morex’, and oat (Avena sativa L.) c.v. ‘Border’. Both wheat cultivars had similar rod-shaped epicuticular wax, while barley and oat plants had flakes. The chemical composition comparison of gas chromatograms also indicated that the extract of the two wheat cultivars had similar pattern of peaks, while the barley and oat leaves had similar peaks. Cereal variety significantly affected aphid probing behavior (P 〈 0.05), but wax removal using ethyl ether swab did not (P 〈 0.05). Aphids initiated significantly more probes on Border oat leaves than on Morex barley irrespective of wax removal, although total probing duration per aphid was not significantly different among the four cereals examined. Accumulative salivation duration per aphid on oat leaves with wax was significantly longer than other cereal leaves with wax, while accumulative ingestion duration per aphid on Arapahoe wheat and Morex barley was significantly longer than on oat. Nymphoposition of D. noxia on cereal leaves maintained on the benzimidazole-agar medium showed that aphids produced a greater number of nymphs on Morex barley and less on Border oat leaves, although wax removal did not affect aphid nymphoposition. Removal of leaf epicuticular waxes from the 4 cereal genotypes using ethyl ether swab indicated that the influence of wax on plant resistance to D. noxia probing and reproduction was limited. Morex barley was the most favorable, while Border oat was the least favorable cereal host of D. noxia.
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  • 84
    ISSN: 1573-0832
    Keywords: deoxynivalenol ; enzyme immunoassay ; feed ; maize ; mycotoxins ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Samples of wheat (n = 25) and maize (n = 30) for animal consumption, collected in 1997 after harvest from western Romania, were analyzed by enzyme immunoassays for mycotoxin contamination. Toxins analyses included deoxynivalenol (DON), 3-acetylDON, 15- acetylDON, fusarenone X (FX), T-2 Toxin (T-2), diacetoxyscirpenol (DAS), zearalenone (ZEA), fumonisin B1 (FB1), aflatoxin B1 (AFB1), ochratoxin A (OA), and citrinin (CT). DON and acetylDONs were the major contaminants in wheat (100%) and maize (46%). Median values for DON, 3-acetylDON, and 15-acetylDON were 880 μg kg-1, 66 μg kg- 1, and 150 μg kg-1 in wheat, and 890 μg kg-1, 180 μg kg-1, and 620 μg kg- 1 in maize, respectively. Additionally, 3,15-diacetylDON was detected in some samples by HPLC-EIA analysis. All samples were negative for FX (〈150 μg kg-1). T-2 was found in wheat (n = 6) and maize (n = 1) at levels between 13 and 63 μg kg- 1. DAS (2.6 μg kg-1) was found in one maize sample. ZEA occurred in all wheat and in four maize samples, median values were 10 μg kg-1 and 250 μg kg-1, respectively. One maize sample contained FB1 (140 μg kg-1). All samples were AFB1-negative (〈4 μg kg-1). OA was found in one wheat sample (37 μg kg- 1), CT was found in one maize sample (580 μg kg- 1). This first reported natural occurrence of a range of mycotoxins in Romanian feeding stuff shows that DON and acetyl DONs may be present at levels which may affect animal production.
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  • 85
    ISSN: 1432-203X
    Keywords: Key words Bread wheat ; Triticum aestivum ; Tritordeum ; Tissue electroporation ; Transient gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Wheat scutella and tritordeum inflorescences were transformed by tissue electroporation with plasmid DNA containing a β-glucuronidase (GUS) gene (gus A) under the control of the rice actin1 promoter. Factors affecting electroporation efficiency were analysed. Important factors were electroporation voltage and pulse length, the volume of electroporation buffer, the osmoticum of electroporation buffer and medium, the osmoticum of pre-electroporation culture medium, and pre-electroporation incubation time and temperature. Maximum transient gene expression was obtained with a single pulse of 550 V/cm from a 960-μF capacitor, using 200 μl of electroporation buffer, after 2–3 h culture on media with 357 mOsm for wheat scutella or 1 day on media with 222 mOsm for tritordeum inflorescences, and 0.5–1 h pre-electroporation incubation with DNA at 24 °C. Under these conditions, up to 90% of the explants showed GUS expression, and up to 149 expression signals were recorded per replicate. Electroporated explants showed high rates of survival and retained the ability to regenerate plants via somatic embryogenesis.
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  • 86
    ISSN: 1432-2242
    Keywords: Key words Aegilops markgrafii ; Triticum aestivum ; Addition lines ; Chromosome markers ; Homoeology ; Wheat ; Wheat microsatellites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We describe the use of wheat microsatellites for the discrimination of Aegilops markgrafii chromosomes. Twenty out of eighty eight wheat microsatellites (WMS) tested were able to distinguish Triticum aestivum-Ae. markgrafii addition lines. Six, three, three, one and six of 18 WMS can be used as markers for single Ae. markgrafii chromosomes B, C, D, F and G, respectively. Addition line A is not available but additional bands, appearing only in Ae. markgrafii and the T. aestivum-Ae. markgrafii amphiploid and not in any of the available addition lines, indicate that three WMS detect markers for Ae. markgrafii chromosomes A. Addition line E could not be detected by any of the WMS markers applied, although the 20 WMS represented all the homologous groups of wheat. All three WMS located on the short arm of group-2 chromosomes were located on Ae. markgrafii chromosome B; three of four WMS, located on the long arm of wheat group-2 chromosomes, were specific to Ae. markgrafii chromosome G and three of four WMS, specific to group-5 chromosomes, were markers for Ae. markgrafii chromosome C, indicating the homoeology of these wheat chromosome arms with the respective Ae. markgrafii chromosomes.
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  • 87
    ISSN: 1432-2242
    Keywords: Key words RFLP analysis ; Triticum aestivum ; Genetic diversity ; Genetic similarity estimates ; Cluster analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Restriction fragment length polymorphisms (RFLPs) have been used to characterise the genetic diversity of wheat (Triticum aestivum) germplasm. One hundred and twenty-four accessions comprising all major Australian wheat varieties and lines important for breeding purposes were assayed for RFLPs with clones of known genetic location and selected to give uniform genome coverage. The objectives of this study were to determine RFLP-based genetic similarity between accessions and to derive associations between agronomically significant traits and RFLP phenotypes. Ninety-eight probes screened against genomic DNA digested with five restriction endonucleases detected a total of 1968 polymorphic fragments. Genetic similarity (GS) calculated from the RFLP data ranged from 0.004 to 0.409 between accessions, with a mean of 0.18. Cluster analysis based on GS estimates produced four groupings that were generally consistent with available pedigree information. Comparisons of the RFLP phenotypes of accessions containing disease resistance genes present on introgressed alien segments enabled the identification of specific alleles characteristic of these regions. Associations were derived for a range of stem-rust, leaf-rust and yellow-rust resistance genes. These results suggest that RFLP analysis can be used for the characterisation and grouping of elite breeding material of wheat and RFLP profiling can identify chromosome segments associated with agronomic traits.
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  • 88
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    Theoretical and applied genetics 96 (1998), S. 69-75 
    ISSN: 1432-2242
    Keywords: Key words Aegilops umbellulata ; Co-linearity ; Comparative mapping ; Translocations ; Triticum aestivum ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  A comparative genetic map of Aegilops umbellulata with wheat was constructed using RFLP probes that detect homoeoloci previously mapped in hexaploid bread wheat. All seven Ae. umbellulata chromosomes display one or more rearrangements relative to wheat. These structural changes are consistent with the sub-terminal morphology of chromosomes 2 U, 3 U, 6 U and 7 U. Comparison of the chromosomal locations assigned by mapping and those obtained by hybridization to wheat/Ae. umbellulata single chromosome addition lines verified the composition of the added Ae. umbellulata chromosomes and indicated that no further cytological rearrangements had taken place during the production of the alien-wheat aneuploid lines. Relationships between Ae. umbellulata and wheat chromosomes were confirmed, based on homoeology of the centromeric regions, for 1 U, 2 U, 3 U, 5 U and 7 U. However, homoeology of the centromeric regions of 4 U with wheat group-6 chromosomes and of 6 U with wheat group-4 chromosomes was also confirmed, suggesting that a re-naming of these chromosomes may be pertinent. The consequences of the rearrangements of the Ae. umbellulata genome relative to wheat for gene introgression are discussed.
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  • 89
    ISSN: 1432-2242
    Keywords: Key words Fluorescence in situ hybridization ; Translocation ; WSMV resistance ; Thinopyrum intermedium ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract   Thinopyrum intermedium is a promising source of resistance to wheat streak mosaic virus (WSMV), a devastating disease of wheat. Three wheat germplasm lines possessing resistance to WSMV, derived from Triticum aestivum×Th. intermedium crosses, are analyzed by C-banding and genomic in situ hybridization (GISH) to determine the amount and location of alien chromatin in the transfer lines. Line CI15092 was confirmed as a disomic substitution line in which wheat chromosome 4A was replaced by Th. intermedium chromosome 4Ai?2. The other two lines, CI17766 and A29-13-3, carry an identical Robertsonian translocation chromosome in which the complete short arm of chromosome 4Ai?2 was transferred to the long arm of wheat chromosome 4A. Fluorescence in situ hybridization (FISH) using ABD genomic DNA from wheat as a probe and S genomic DNA from Pseudoroegneria stipifolia as the blocker, and vice versa, revealed that the entire short arm of the translocation was derived from the short arm of chromosome 4Ai?2 and the breakpoint was located at the centromere. Chromosomal arm ratios (L/S) of 2.12 in CI17766 and 2.15 in A29-13-3 showed that the translocated chromosome is submetacentric. This translocated chromosome is designated as T4AL ⋅ 4Ai?2S as suggested by Friebe et al. (1991).
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  • 90
    ISSN: 1432-2242
    Keywords: Key words Triticum spelta ; Triticum aestivum ; SDS-PAGE ; Acid-PAGE ; Seed storage proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Seed storage proteins of a few selected spelt forms and crosses have already been electrophoretically analysed by SDS-PAGE and acid-PAGE and compared with a few winter wheat cultivars. In the analyses presented here further important Central European spelt varieties were included, as well as modern winter wheat cultivars which were chosen as standards. In this study gliadin and glutenin band patterns of modern Central European winter wheat cultivars were analysed, in particular for a comparison with spelt varieties. An improved differentiation within and between the two species was obtained.
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  • 91
    ISSN: 1432-2242
    Keywords: Key words Genetic diversity ; Triticum tauschii ; Triticum aestivum ; RFLP ; Landrace wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Chinese accessions of Triticum tauschii and T. aestivum L. from the Sichuan white (SW), Yunnan hulled (YH), Tibetan weedrace (TW), and Xinjiang rice (XR) wheat groups were subjected to RFLP analysis. T. tauschii and landraces of T. aestivum from countries in Southwest Asia were also evaluated. For T. tauschii, a west to east gradient was apparent where the Chinese accessions exhibited less diversity than those from Southwest Asia. Compared to the Southwest Asian gene pool, the Chinese T. tauschii was highly homogeneous giving a low frequency of polymorphic bands (16%) and banding patterns (1.33 per probe) with 75 RFLP probe-HindIII combinations. Accessions of T. tauschii from Afghanistan and Pakistan were genetically more similar to the Chinese T. tauschii than those from Iran. Of 368 bands found for 39 Chinese hexaploid wheat accessions with 63 RFLP probe-HindIII combinations, 28.3% were polymorphic with an average of 2.6 banding patterns per probe and 5.0 bands per genotype. The individual Chinese landrace wheat groups revealed less variation than those from Afghanistan, Iran, and Turkey. When classified into country based groups, however, the diversity level over all Chinese landraces was greater than that of some Southwest Asian landraces, especially those from Afghanistan and Iran . The XR wheat group was genetically distinct from the other three Chinese landrace groups and was more related to the Southwest Asian landraces. The TW group was genetically similar to, but more diverse than, the SW and YH groups. The Chinese landraces had a higher degree of genetic relatedness to the Southwest Asian T. tauschii, particularly to accessions from Iran, rather than to the Chinese T. tauschii. ‘Chinese Spring’ was most related to ‘Chengdu-guang-tou’, a cultivar from the SW wheat group.
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  • 92
    ISSN: 1432-2242
    Keywords: Key words Aegilops triuncialis ; Triticum aestivum ; Heterodera avenae ; Cereal cyst nematode ; Resistance gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The cereal cyst nematode (Heterodera avenae) is an important root parasite of common wheat. A high level of resistance was transferred to wheat from Aegilops triuncialis (TR lines) using the cross [(T. turgidum×Ae. triuncialis)×T. aestivum]. Low fertility (3–5 viable kernels per plant) was observed during the process but the surviving hybrid plants were highly vigorous. To obtain stable resistant lines further crosses to T. aestivum were performed. The resistance in TR lines seems to be transferred from the C genome of Ae. triuncialis (genomes CCUU). Ae. triuncialis was highly resistant to the two Spanish populations of H. avenae tested, as well as to four French races and two Swedish populations. The histological analysis showed a hypersensitive reaction in the roots of a resistant TR line inoculated with the Ha71 pathotype of H. avenae, whereas well-formed syncytia were observed in the roots of the susceptible control. Resistance to the H. avenae Ha71 pathotype seemed to be inherited as determined by a single dominant factor in the crosses between resistant TR lines and susceptible cultivars.
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  • 93
    ISSN: 1573-9368
    Keywords: particle bombardment ; transgene expression ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A population of R0 transgenic wheat plants, generated by particle bombardment, was analyzed to define molecular, genetic and phenotypic properties resulting from transformation with a cointegrate vector, or cotransformation with two separate plasmids. By evaluating the progeny of 70 independently-derived transgenic plants, we also identified rare events such as chimerism and transgene elimination, which provide valuable information concerning the development of transgenic cereal plants following bombardment experiments. The frequency of chimerism in our transgenic wheat plants was very low. Furthermore, while transgene elimination did occur, this was also a very rare event. We determined the copy numbers of integrated transgenes and the levels of transgene expression. Comparisons to transgenic rice plants generated in the same manner demonstrated some similarities, but also important differences in transgene behavior. Whereas in rice there is no evidence for any direct relationship between transgene copy number and transgene expression or stability, multicopy populations in wheat demonstrated a bias towards higher levels of expression for the two genes and the maize ubiquitin promoter evaluated in the present study.
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  • 94
    ISSN: 1573-8469
    Keywords: Central Europe ; powdery mildew ; wheat ; complexity of pathotypes ; Erysiphe graminis f.sp. tritici ; stabilizing selection ; survey ; virulence analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In 1993–1996, the virulence of regional populations of the wheat powdery mildew pathogen (Erysiphe graminis DC f. sp. tritici Marchal) from the Czech Republic, Austria, Hungary and Slovakia against 13 resistance genes was investigated. The populations differed mainly at the regional level. Populations from the Czech Republic, mainly from the western regions, showed higher values of virulence against the Pm4b gene. Lower frequency of virulence against Pm4b was found in Austria, and the lowest value was observed in Hungary. The differences in frequencies of virulence against Pm4a and Pm4b showed a similar geographic pattern across the four countries: a continuous decline from west to east and from north to south. Virulence against Pm2 decreased in all countries considered; virulence to pm5, Pm6, Pm8 and Mli was high throughout. Genes and gene combinations that can ensure a relatively effective biological protection against this pathogen across Central Europe at present are Pm3b, Pm2+Mld and Pm1+2+9. Czech and Slovak populations were the most complex: virulence complexity reached a maximum in Slovakia in 1994. A similar evolution, though less significant, was observed in the Czech Republic. Data on complexity of isolates suggest that Central European populations of wheat powdery mildew tend to reach an intermediate level representing the optimal number of virulence genes. This process is probably a consequence of stabilizing selection.
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  • 95
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    Chromosome research 6 (1998), S. 339-344 
    ISSN: 1573-6849
    Keywords: Leymus ; meiosis ; molecular cytogenetics ; wheat ; wide-hybrids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Meiosis was examined in pollen mother cells of F1 hybrids made from crosses between wheat (Triticum aestivum) and lymegrass (Leymus arenarius and L. mollis). Fluorescence genomic in situ hybridization detected pairing between wheat and lymegrass chromosomes during prophase I and metaphase I. Such pairing, when resulting in bivalent formation, was likely to yield correct disjunction, and hence intergenomic recombination could be incorporated into the gametes. Bivalents in these hybrids, however, were more frequently formed between chromosomes of the same parental origin. Univalents were common, whereas multivalents were not clearly detected. Meiotic behaviour in some cells was not totally aberrant, and this may have accounted for the presence of normal pollen. The results are discussed in relation to intergenomic pairing, meiotic behaviour in wide-hybrids and genome relationships, including the Leymus genome origin.
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  • 96
    ISSN: 1573-5028
    Keywords: barley ; kinase ; leaf rust ; receptor-like kinase ; resistance ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In plants, several types of receptor-like kinases (RLK) have been isolated and characterized based on the sequence of their extracellular domains. Some of these RLKs have been demonstrated to be involved in plant development or in the reaction to environmental signals. Here, we describe a RLK gene family in wheat (wlrk, wheat leaf rust kinase) with a new type of extracellular domain. A member of this new gene family has previously been shown to cosegregate with the leaf rust resistance gene Lr10. The diversity of the wlrk gene family was studied by cloning the extracellular domain of different members of the family. Sequence comparisons demonstrated that the extracellular domain consists of three very conserved regions interrupted by three variable regions. Linkage analysis indicated that the wlrk genes are specifically located on chromosome group 1 in wheat and on the corresponding chromosomes of other members of the Triticeae family. The wlrk genes are constitutively expressed in the aerial parts of the plant whereas no expression was detected in roots. Protein immunoblots demonstrated that the WLRK protein coded by the Lrk10 gene is an intrinsic plasma membrane protein. This is consistent with the hypothesis that WLRK proteins are receptor protein kinases localized to the cell surface. In addition, we present preliminary evidence that other disease resistance loci in wheat contain genes which are related to wlrk.
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  • 97
    ISSN: 1573-5028
    Keywords: calcium ; in situ hybridization ; multigene family ; polyploid ; signal transduction ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Recently, we reported on the characterization of the calmodulin (CaM) gene family in wheat [44]. We classified wheat CaM genes into four subfamilies (SFs) designated SF-1 to SF-4, each representing a series of homoeoallelic loci on the homoeologous chromosomes of the three genomes of common wheat. Here we studied the expression of these wheat CaM genes in the course of wheat development. Northern blot analysis using SF-specific probes revealed differences in SF expression levels in different organs and stages of development. Subsequently, cell-specific expression of CaM SFs was investigated by in situ RNA hybridization. In developing seeds, all CaM SFs showed highest expression in the embryo and less in the aleurone and in the starchy endosperm. In primary roots, all four CaM SFs were expressed in the root cap, meristematic regions and in differentiating cells. During development of the roots, expression gradually decreased. The wheat glutenin gene, which was used as a control throughout our experiments, was found to be expressed in the starchy endosperm but not in the aleurone, embryos or vegetative tissues. In stems, at advanced stages of growth, differences in cell-specific expression of CaM SFs were found. For example, SF-2 was highly expressed in differentiating phloem fibers. Thus, CaM genes in common wheat exhibit a developmentally regulated organ-, tissue-, cell- and SF-specific expression patterns.
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  • 98
    ISSN: 1573-8469
    Keywords: Bacillus thuringiensis ; biological control ; Helicotylenchus multicinctus ; nematicide ; numerical response ; Paecilomyces marquandii ; Radopholus similis ; Streptomyces costaricanus ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effect of 24 treatment combinations of cultures of Streptomyces costaricanus sp. nov. (ATCC55274), Bacillus thuringiensis (ATCC55273) and a strain of Paecilomyces marquandii, nematicide (cadusaphos), and/or wheat mash on growth and response of potted banana plants (Musa AAA) and populations of Radopholus similis, Helicotylenchus multicinctus and free living nematodes were studied in Río Frío, Costa Rica. The best plant responses (height, leaf numbers, healthy root weight), lowest numbers of plant parasitic nematodes and highest numbers of free living nematodes were observed for treatments containing wheat as a component. Two treatments, viz. wheat + Streptomyces costaricanus (200-ml culture) and wheat + P. marquandii (200-ml culture), gave the overall best results. Numbers of free living nematodes increased up to 1500-fold only for treatments containing wheat. Significant positive correlations existed between numbers of free living nematodes and shoot weight, healthy root biomass, plant height, and leaf numbers. Non-wheat treatments, including nematicide only, gave the poorest responses in general. Observations of nematodes sampled 50 days following planting in wheat-containing treatments showed most of the free-living nematodes (≈ 90%) to be infected by nematophagous fungi (species not recorded). The results show that an organic amendment to soil, with or without a microbial component, can be an effective inducer of processes that regulate plant-parasitic nematode populations in soil.
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  • 99
    ISSN: 1615-6102
    Keywords: Cucumis sativus ; Ethylene ; Ferric-reducing capacity ; Iron deficiency ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Dicotyledonous plants respond to Fe deficiency by enhancing the capacity of their roots to reduce Fe(III) to Fe(II). It has been suggested that there are two different ferric redox systems in the roots: the standard reductase, active with ferricyanide and not inducible by Fe deficiency, and the turbo reductase, active with both ferricyanide and ferric chelates and inducible by Fe deficiency. We have used different experimental approaches to test whether or not the Fe(III)-reducing capacity of cucumber (Cucumis sativus L. cv. Ashley) roots can be explained by considering the standard and the turbo reductase as the same enzyme. For this, we used both Fe-sufficient and Fe-deficient plants, which were treated with ethylene inhibitors (cobalt or silver thiosulfate; found to inhibit the turbo reductase in a previous work), a protein synthesis inhibitor (cycloheximide), or an mRNA polyadenylation inhibitor (cordycepin). At different times after application of these inhibitors, reduction of both ferricyanide and Fe(III)-EDTA were determined. In addition, we studied the effects of pH and temperature on the reduction of ferricyanide and Fe(III)-EDTA by both Fe-sufficient and Fe-deficient plants. Results suggest that there are, at least, two different ferric redox systems in the roots. Enhancement of Fe(III)-reducing capacity (turbo reductase) by Fe-deficient plants probably requires the de novo synthesis of a (or several) protein(s), which has a high turnover rate and whose expression is presumably regulated by ethylene.
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  • 100
    ISSN: 1573-5036
    Keywords: canola ; oilseed rape ; root ; subsoil residual Zn ; wheat ; Zn loading ; Zn uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The residual effects of Zn supplied (+Zn: 1 mg kg−1 soil, -Zn: no Zn added) in subsoil to four oilseed rape genotypes (Zhongyou 821, Xinza 2 and Narendra: Brassica napus type, and CSIRO-1: Brassica juncea type) were studied on the following wheat in a glasshouse experiment in pots (100 cm long, 10.5 cm diameter). The topsoil (upper 20 cm soil in pots) was supplied with Zn (0.5 mg kg−1 soil) in all treatments whereas Zn (1 mg Zn kg−1 dry soil) was either supplied or omitted from the subsoil at time of sowing of oilseed rape genotypes. Oilseed rape plants were harvested at maturity and wheat (variety Songlen) was grown to evaluate the residual effects of subsoil Zn and oilseed rape genotypes. Subsoil residual Zn significantly improved the root growth, yield attributes, grain and straw yield of wheat. Wheat grain Zn concentration was 4 times higher in +Zn subsoil residual than under -Zn subsoil residual. Oilseed rape genotypes did not vary in their residual effect on grain and straw yield of wheat, but reflected a differential effect on Zn concentration and Zn content of wheat grain. Zinc uptake per wheat plant (grain + shoot + root Zn uptake) was about 4 times higher in +Zn subsoil residual than -Zn subsoil residual. Out of total Zn uptake per plant, 77%, 15% and 8% of Zn was loaded in wheat grains, shoots and roots respectively in +Zn subsoil residual. However in -Zn subsoil residual, distribution of Zn in grains, shoots and roots was 55%, 29% and 16% respectively. Zinc loading in grains of wheat was significantly higher in wheat grown after Narendra and Xinza 2 compared with wheat grown after Zhongyou 821 (Zn-inefficient genotype). These results indicate that subsoil residual Zn and Zn-efficient genotypes of oilseed rape have the potential to increase the Zn loading in wheat grains.
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