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Barley Cultivars (barley + cultivar)
Selected AbstractsScreening for Barley yellow dwarf virus -Resistant Barley Genotypes by Assessment of Virus Content in Inoculated SeedlingsJOURNAL OF PHYTOPATHOLOGY, Issue 6 2006Abstract The content of Barley yellow dwarf virus (BYDV) in roots and leaves of barley seedling plants differing in their level of resistance was assessed by quantitative ELISA 1,42 days after inoculation with the strain of BYDV (PAV). High virus accumulation in roots and low concentration in leaves was characteristic of the period 9,15 days after inoculation. In leaves, the differences in virus content between resistant and susceptible genotypes became significant after 15 days and resistance to virus accumulation was better expressed 30,39 days after inoculation. Roots of resistant materials exhibited evident retardation of virus accumulation and the greatest difference in virus content between resistant and susceptible plants was detected 9 days after inoculation. By these criteria, the selected winter and spring barley cultivars and lines (in total 44 materials) fell in to five groups according to field reactions and the presence or absence of the Yd2 resistance gene. There were highly significant and positive relations between ELISA values and 5-year field data on symptomatic reactions and grain-yield reductions due to infection. Using the described method, resistant and moderately resistant genotypes (both Yd2 and non- Yd2) were significantly differentiated from susceptible genotypes. The possible use of this method in screening for BYDV resistance is discussed. [source] Identification of Cochliobolus sativus (Spot Blotch) Isolates Expressing Differential Virulence on Barley Genotypes in SyriaJOURNAL OF PHYTOPATHOLOGY, Issue 8-9 2004M. I. E. Arabi Abstract Spot blotch, caused by Cochliobolus sativus, is a common foliar disease of barley. Information on the variability of virulence in C. sativus is essential for the production of spot-resistant barley cultivars. The virulence variability of isolates of this pathogen collected from different regions of Syria was evaluated using 10 differential barley genotypes originating from widely dispersed areas. Genotypes showed a continuous range of response from very susceptible to moderately resistant but none was immune to the disease. A cluster analysis indicated that the isolates had distinct differential virulence patterns within the three groups. A mean disease rating of 3.71 was the separation point between avirulent and virulent reactions. The data demonstrated that variation occurred in the virulence of and the resistance level to isolates and among genotypes, respectively. Isolate C41 exhibited distinct differential virulence patterns, high frequency and low variance in all genotypes. To incorporate adequate levels of resistance into future barley genotypes, disease evaluations should be made with C. sativus isolates that express the full spectrum of virulence found in Syria. [source] Yield Responses of Barley to Leaf Stripe (Pyrenophora graminea) under Experimental Conditions in Southern SyriaJOURNAL OF PHYTOPATHOLOGY, Issue 8-9 2004M. I. E. Arabi Abstract The seed-borne pathogen, Pyrenophora graminea is the causal agent of barley leaf stripe disease. Field trials were undertaken to investigate the impact of leaf stripe on barley yield in two growing seasons in Southern Syria, by comparing plots with and without artificial inoculation. Ten barley cultivars originating from widely dispersed areas were used. The overall response to leaf stripe differed with the differences in susceptibility levels of the cultivars. Grain yield, the number of tillers, kernel weight and plant biomass decreased as disease severity increased. Diseased plants had fewer tillers, and as a consequence a reduced grain yield per plant. High yield losses resulted from leaf stripe in susceptible cultivars in Arrivate, Furat 1, WI2291 and Arabi Abiad with 44%, 50%, 73% and 92%, respectively. The cultivar Banteng had the best level of resistance to the disease, and is a candidate donor for resistance in future breeding programmes. As leaf stripe can dramatically reduce barley yields under favourable conditions, the disease should be considered by crop improvement programmes in Mediterranean and similar environments. [source] Isolation, structural features and rheological properties of water-extractable ,-glucans from different Greek barley cultivarsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2004Maria Irakli Abstract ,-Glucans were isolated from six Greek barley cultivars (Persefoni, Kos, Thessaloniki, Athinaida, Dimitra and Triptolemos) by water extraction at 47 °C, enzymatic removal of starch and protein and subsequent precipitation of the water-soluble ,-glucans with 37% (w/v) ammonium sulfate saturation. The purity of barley ,-glucans was high (>93% dry basis) with some small contamination by protein (<3.84%). The molecular size of the ,-glucan isolates was determined by high-performance size-exclusion chromatography (HPSEC); the weight-average molecular weights and the intrinsic viscosities ranged between 0.45 × 106 and 1.32 × 106 and 2.77 and 4.11 dl g,1, respectively. Structural features of barley ,-glucans were revealed by 13C NMR spectroscopy and high-performance anion-exchange chromatography (HPAEC) of the oligomers released by the hydrolytic action of lichenase. Lichenase degradation showed that ,-glucans from all barley cultivars consisted of blocks of cellotriosyl and cellotetraosyl units, accounting for 90.6,92.3% of the total oligomers released, with a molar proportion of these units between 2.31 and 2.77. Rheological measurements of aqueous solutions/dispersions of ,-glucans showed the behaviour of non-interacting polysaccharides and a transition from the typical viscoelastic response to gel-like properties after a time period that depended on the molecular size of the polysaccharide. The lowest molecular size ,-glucans from the Triptolemos cultivar showed shorter gelation times than their higher molecular weight counterparts. The effect of sugar incorporation (glucose, fructose, sucrose, xylose and ribose), at a concentration of 30% (w/v), to the ,-glucans gels (6% w/v) on compression parameters seemed to be related to the type of sugar used; the pentose sugars substantially reduced gel firming. Copyright © 2004 Society of Chemical Industry [source] Genetic control over grain damage in a spring barley mapping populationPLANT BREEDING, Issue 1 2004P. Rajasekaran Abstract A genetic map was constructed using DNA-based markers in a barley mapping population derived from the cross ,Tankard'×,Livet', that was developed to explore the genetic control over grain damage in spring barley cultivars. Quantitative trait loci (QTL) were located for husk skinning, gape between the lemma and palea and splitting of the fused pericarp/testa/aleurone tissues. The QTL accounted for 70% of the genetic variation in Split and 60% of the genetic variation in Gape and Skinning. The QTL were clustered on chromosomes 1H, 4H, 5H, 6H and 7H. QTL analysis indicates the possibility of transgressive segregation for grain splitting and so the breeding of lines with more extreme splitting. This is of concern to the malting industry as, without extensive phenotypic assessment, such lines could be commercialized, as was the case of Landlord, and put malting barley supplies at risk. These findings are discussed in relation to the genetic control over traits including grain length and width. [source] Inheritance of agronomic traits from the Chinese barley dwarfing gene donors ,Xiaoshan Lixiahuang' and ,Cangzhou Luodama'PLANT BREEDING, Issue 6 2000Zhang Jing Abstract The inheritance of agronomic traits from the barley dwarfing gene donors ,Xiaoshan Lixiahuang' and ,Cangzhou Luodamai' was studied. The results indicated that dwarf plants, six-row and short spikes, dense spikelets and naked kernels, respectively, were controlled by one pair of recessive genes, but a toothed awn was determined by one pair of dominant genes in both barley cultivars. The genes for the six characters in ,Xiaoshan Lixiahuang' were allelic to those in ,Cangzhou Luodamai'. Genetic linkage was found among the genes for plant height, spike length and spikelet density. They were located on the long arm of chromosome 3 (3HL) in the order: plant height, spikelet density, spike length. The genes for naked kernels, six-row spikes and tooth awns were independent of each other, and carried on the long arms of chromosomes 1(7H), 2(H) and 7(5H), respectively. The dwarfing genes were the same as the gene uz in Japanese and Korean barley cultivars. [source] Powdery mildew resistance in Czech and Slovak barley cultivarsPLANT BREEDING, Issue 3 2000A. Dreiseitl Abstract Fifteen powdery mildew resistance genes and the gene MlaN81 derived from ,Nepal 81'were found in 76 Czech and Slovak spring and winter barley cultivars when tested for reaction to a set of powdery mildew isolates. Nine cultivars (,Donum', ,Expres', ,Jubilant', ,Orbit', ,Primus', ,Progres', ,Stabil', ,Vladan' and ,Zlatan') are composed of lines with different resistance genes. The Mlat gene is present in nine cultivars and was transferred from the Anatolian landrace ,A-516,. The resistances derived from ,KM-1192'and ,CI 7672'were identical and designated Ml(Kr). Five winter barley cultivars possess the Ml(Bw) resistance. The winter barley line ,KM-2099'carries the mlo gene. The parental cultivar ,Palestine 10'was also tested in which the genes Mlk1, MlLa were identified. The German cultivar ,Salome', a parent of seven cultivars tested, probably carries the gene MlLa in addition to mlo and Mla7. The gene mlo6 may be present in the cultivar ,Heris'. Most of the results were confirmed by the pedigrees of the cultivars. [source] Postulation of leaf-rust resistance genes in Czech and Slovak barley cultivars and breeding linesPLANT BREEDING, Issue 3 2000A. Dreiseitl Abstract Leaf-rust resistance (Rph) genes in 61 Czech and Slovak barley cultivars and 32 breeding lines from registration trials of the Czech Republic were postulated based on their reaction to 12 isolates of Puccinia hordei with different combinations of virulence genes. Five known Rph genes (Rph2, Rph3, Rph4, Rph7, and Rph12) and one unknown Rph gene were postulated to be present in this germplasm. To corroborate this result, the pedigree of the barley accessions was analysed. Gene Rph2, as well as Rph4, originated from old European cultivars. The donor of Rph3, which has been mainly used by Czech and Slovak breeders, is ,Ribari' (,Baladi 16'). Rph12 originates from barley cultivars developed in the former East Germany. Rph7 in the registered cultivar ,Heris' originates from ,Forrajera'. A combination of two genes was found in 10 cultivars. Nine heterogeneous cultivars were identified; they were composed of one component with an identified Rph gene and a second component without any resistance gene. No gene for leaf rust resistance was found in 17 of the accessions tested. This study demonstrates the utility of using selected pathotypes of P. hordei for postulating Rph genes in barley. [source] Economic Returns to Feed Barley Yield-increasing and Disease Resistance Research at the Alberta Field Crop Development CentreCANADIAN JOURNAL OF AGRICULTURAL ECONOMICS, Issue 3 2003Joseph G. Nagy The Alberta Field Crop Development Centre (FCDC) at Lacombe has carried out an extensive research and development program on feed barley since 1973. Prior to 2002, FCDC released 11 hulled and six hull-less barley varieties that have been adopted by farmers. The primary objective of this study is to estimate an economic rate of return to the FCDC barley research and development program from 1973 to 2001. A secondary objective is to include benefits arising from research that improved feed barley disease resistance in new cultivars in addition to benefits from purely higher-yielding cultivar research. The analysis uses an ex post economic surplus methodology. Benefits are identified and empirically investigated for three separate FCDC feed barley research thrusts: , benefits arising from FCDC research that developed new, higher-yielding feed barley cultivars that give a yield advantage , benefits arising from FCDC research that improved feed barley disease resistance in new cultivars that result in yield loss avoidance from disease , benefits arising from FCDC research that developed new feed barley cultivars that yield higher silage production. Of the total benefits from research on feed grain varieties, 52% can be attributed to yield advantage research and 48% to yield loss avoidance research. The overall internal rate of return with base elasticity parameters is estimated at 27%, ranging between 23% and 31%, depending on the assumptions made about the yield advantage and base variety. The IRR was sensitive to changes in supply elasticities and ranges from 20% (,= 1.5) to 54% (,= 0.1). L'Alberta Field Crop Development Center (FCDC) de Lacombe poursuit un vaste programme de recherche et de dáveloppement sur l'orge fourragàre depuis 1973. Avant 2002, le FCDC a homologuá onze variátás d'orge ordinaire et six à grains nus que les agriculteurs ont par la suite adoptáes. La prásente átude devait estimer la rentabilitá du programme entre 1973 et 2001. Un objectif secondaire consistait à inclure les retombáes rásultant des cultivars plus rásistants à la maladie à celles dérivant uniquement de l'amélioration du rendement. L'analyse reposait sur la méthode ex-post des excédents économiques. L'auteur a identifié les retombées et les a examinées en fonction de trois courants distincts de la recherche entreprise au FCDC: (1) les retombées issues des cultivars d'orge fourragère à rendement plus élevé; (2) celles venant des travaux sur la résistance des variétés qui ont abouti à un meilleur rendement grâce à de moins grandes pertes attribuables à la maladie; (3) celles résultant de la création de cultivars d'orge fourragère produisant plus d'ensilage. Sur les retombées totales de la recherche, 52 % résultaient de l'amélioration du rendement et 48 % de la réduction des pertes associées à la maladie. On situe le taux de rentabilité interne global à 27 % avec les élasticités de base, soit entre 23 et 31 % selon les hypothèses sur l'amélioration du rendement et la variété de départ. Le taux de rentabilité interne est sensible à la variation des élasticités de l'offre et fluctue de 20 ,= 1, 5) à 54% (,= 0,1). 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