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As one of the world’s earliest domesticated crops, barley is a model species for the study of evolution and domestication. Domestication is an evolutionary process whereby a population adapts, through selection; to new environments created by human cultivation. We describe the genome-scanning of molecular diversity to assess the evolution of barley in the Tibetan Plateau. We used 667 Diversity Arrays Technology (DArT) markers to genotype 185 barley landraces and wild barley accessions from the Tibetan Plateau. Genetic diversity in wild barley was greater than in landraces at both genome and chromosome levels, except for chromosome 3H. Landraces and wild barley accessions were clearly differentiated genetically, but a limited degree of introgression was still evident. Significant differences in diversity between barley subspecies at the chromosome level were observed for genes known to be related to physiological and phenotypical traits, disease resistance, abiotic stress tolerance, malting quality and agronomic traits. Selection on the genome of six-rowed naked barley has shown clear multiple targets related to both its specific end-use and the extreme environment in Tibet. Our data provide a platform to identify the genes and genetic mechanisms that underlie phenotypic changes, and provide lists of candidate domestication genes for modified breeding strategies.

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Fungicide application is one measure available to reduce the risk of Fusarium head blight (FHB) and mycotoxin contamination in barley. The stage at or near anthesis, or at full head emergence, is generally thought to be optimal for fungicide application, regardless of cultivar. However, we have found that the most critical time for Fusarium graminearum infection and mycotoxin accumulation in barley differed among cultivars. Whereas open-flowering cultivars were most susceptible at anthesis, closed-flowering cultivars were considerably resistant at anthesis but became susceptible after ‘spent’ anther extrusion. Therefore, we evaluated the effect of the timing of fungicide application on FHB and mycotoxin (deoxynivalenol and nivalenol) accumulation in closed-flowering barley. Thiophanate-methyl fungicide was applied at different developmental stages, from before anthesis to 30 days after anthesis (DAA), under artificial inoculation conditions in the field in which inoculum spores were provided throughout the testing period. As expected, the optimal timing for chemical control of FHB and mycotoxin accumulation was the time around the beginning of spent anther extrusion, rather than at anthesis. Later application, as late as 30 DAA, was also effective in controlling mycotoxin accumulation, although it was not effective in controlling disease levels. Our results suggest that the development of control strategies that cover the late stage as well as the early stage is desirable to reduce the risk of mycotoxin contamination in barley.

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Acta Biologica Hungarica
Authors: Ivanka Fedina, Maya Velitchkova, Katya Georgieva, Dimitrina Nedeva, and H. Çakırlar

, M., Georgieva, K., Grigorova, I. (2005) UV-B induced compounds as affected by proline and NaCl in Hordeum vulgare L. cv. Alfa. Environ. Exp. Bot. 54 , 182–191. Grigorova I

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Acar, O., Türkan, İ., Özdemir, F. (2001) Superoxide dismutase and peroxidase activities in drought sensitive and resistant barley ( Hordeum vulgare L.) varieties. Acta Physiol. Plant. 3 , 351

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new hybrids of winter wheat ( Triticum aestivum ) × winter barley ( Hordeum vulgare ). Genome , 43 , 1045–1054. Sutka J. Production and meiotic pairing behavior of new hybrids of

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A study was undertaken to determine the genetics of corn leaf aphid (CLA) resistance in barley under controlled conditions with artificial inoculation at adult plant stage. Inheritance of CLA resistance was investigated in five resistant barley genotypes (EB921, EB2507, Manjula, DL529 and K144) in crosses with susceptible parent Alfa93 in F1, F2, F3 and backcross (BCF1) generations. The aphid inoculation was done using the brush method as well as the detached leaf method. Individual plants were classified in resistant, moderately resistant, susceptible and highly susceptible categories base on number per shoot as well as multiplication of CLA on any of the fresh, young leaf. The plants scored as resistant or moderately resistant were observed twice more at 10 days interval to confirm their reaction. Resistance was governed by a single dominant gene in EB921, DL529 and K144, while it was monogenic recessive in Manjula and EB2507. These diverse sources may be used in breeding for CLA resistance in barley improvement programme.

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., Cattivelli, L. (1996) Genetic analysis of the accumulation of COR14 proteins in wild (Hordeum spontaneum) and cultivated (Hordeum vulgare) barley. Theor. Appl. Genet. 93, 975-981. Genetic analysis of the accumulation of COR14

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The feeding period of the grain aphid, Sitobion avenae, an important vector of barley yellow dwarf virus (BYDV), was studied in six varieties of spring barley (Hordeum vulgare L.) in an attempt to explain the resistance mechanisms in some barley varieties to BYDV. There was no significant difference in aphid feeding period between the resistant and susceptible varieties. The mechanisms underlying BYDV resistance do not seem to involve factors related to alterations in the feeding period. Suggestions for future studies are highlighted.

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The effect of Barley stripe mosaic virus (BSMV) infection was studied on the ultrastructure of etioplasts and the greening process of barley ( Hordeum vulgare cv. Pannónia) plants infected by seed transmission. The leaves of 7–11-day old etiolated seedlings were examined with transmission electron microscopy and absorption spectroscopy. The etioplasts of infected seedlings contained smaller prolamellar bodies with less regular membrane structure while prothylakoid content was higher than in the control. Characteristic effect was observed in the process of the Shibata-shift: 40 min delay was observed in the infected leaves. The results of this work proved that BSMV infection significantly delays or inhibits the plastid development and the formation of photosynthetic apparatus.

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A field experiment was carried out to study the effect of K nutrition and genotypic variation on the dry matter (DM) accumulation, and the K concentration, accumulation, uptake and utilization efficiency in barley (Hordeum vulgare L.). Successive increases in potassium nutrition had a significant effect on the dry matter and K accumulation either in the total or in various plant parts of barley at the tillering, stem elongation, heading and maturity growth stages. K nutrition also led to significantly higher grain yield with each unit K application than without K application. The yield increase due to K application was mainly due to the improvement in spike development from tillers. Dry matter and K accumulation in various plant parts varied significantly between genotypes at the main growth stages. Among the various plant parts, the stem contained the highest K concentration, had the highest K accumulation at maturity and changed considerably with the K level, while other plant parts remained relatively unchanged. Among the eleven genotypes, genotype 98-6 had the highest grain yield and the K use efficiency of this genotype was 10.4 kg grain per kg K applied. It could thus be used as a breeding line to breed barley varieties for higher productivity under rainfed conditions with low available soil potassium.

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