62 research outputs found

    Mapping adaptation of barley to droughted environments

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    Identifying barley genomic regions influencing the response of yield and its components to water deficits will aid in our understanding of the genetics of drought tolerance and the development of more drought tolerant cultivars. We assembled a population of 192 genotypes that represented landraces, old, and contemporary cultivars sampling key regions around the Mediterranean basin and the rest of Europe. The population was genotyped with a stratified set of 50 genomic and EST derived molecular markers, 49 of which were Simple Sequence Repeats (SSRs), which revealed an underlying population sub-structure that corresponded closely to the geographic regions in which the genotypes were grown. A more dense whole genome scan was generated by using Diversity Array Technology (DArTÂź) to generate 1130 biallelic markers for the population. The population was grown at two contrasting sites in each of seven Mediterranean countries for harvest 2004 and 2005 and grain yield data collected. Mean yield levels ranged from 0.3 to 6.2 t/ha, with highly significant genetic variation in low-yielding environments. Associations of yield with barley genomic regions were then detected by combining the DArT marker data with the yield data in mixed model analyses for the individual trials, followed by multiple regression of yield on markers to identify a multi-locus subset of significant markers/QTLs. QTLs exhibiting a pre-defined consistency across environments were detected in bins 4, 6, 6 and 7 on barley chromosomes 3H, 4H, 5H and 7H respectivel

    Relativistic Laser-Matter Interaction and Relativistic Laboratory Astrophysics

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    The paper is devoted to the prospects of using the laser radiation interaction with plasmas in the laboratory relativistic astrophysics context. We discuss the dimensionless parameters characterizing the processes in the laser and astrophysical plasmas and emphasize a similarity between the laser and astrophysical plasmas in the ultrarelativistic energy limit. In particular, we address basic mechanisms of the charged particle acceleration, the collisionless shock wave and magnetic reconnection and vortex dynamics properties relevant to the problem of ultrarelativistic particle acceleration.Comment: 58 pages, 19 figure

    Throughput-Optimal Distributed Probabilistic Medium-Access in MPR-Capable Networks

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    Genome wide association analyses for drought tolerance related traits in barley (Hordeum vulgare L.)

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    Genome wide association (GWA) analysis of yield, yield components, developmental, physiological and anatomical traits was conducted for a barley germplasm collection consisting of 185 cultivated (Hordeum vulgare L.) and 38 wild (Hordeum spontaneum L.) genotypes, originating from 30 countries of four continents. Phenotypic evaluations were performed at a dry (Breda) and wet (Tel Hadya) location in Syria. Genome wide association study was done with 816 markers comprised of 710 diversity array technology (DArT), 61 single nucleotide polymorphism (SNP) and 45 microsatellite or simple sequence repeat (SSR) markers. Diversity analysis revealed 5 groups of germplasm, related to origin (Middle East, North Africa), structural information (two-rows), and domestication (wild versus domesticated). Linkage disequilibrium (LD) decayed after 3 cM with a few exceptions at 10 and 15 cM. Although a few QTLs were identified that differed between the dry and wet site, these QTLs explained low phenotypic variation and could not unequivocally be related to drought tolerance when compared to earlier linkage mapping based QTL analysis studies. Therefore, GWA analysis seems to be not very effective for identification of major QTLs for complex traits like drought tolerance in highly structured germplasm collections
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