Genomic analysis of pre-harvest sprouting resistance in barley

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Kaur, Gurkamal
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Pre-harvest sprouting (PHS), which refers to the germination of seeds before harvest due to humid conditions, is one of the major factors that negatively affects the production of barley. The incidence of PHS is primarily associated with the level of seed dormancy, which refers to the failure of seeds to germinate under favourable conditions. The lack of sufficient level of dormancy leads to PHS whereas high dormancy level is responsible for non-uniform germination and delayed seedling establishment. It is therefore critical to have intermediate level of dormancy. Since seed dormancy and PHS are quantitatively inherited traits, identification of genomic regions/genes associated with dormancy has a paramount significance in breeding barley cultivars that are resistant to PHS. This study carried out genome wide association analysis to detect dormancy/PHS associated loci by using an association mapping panel consisting of diverse barley genotypes grown over multiple environments. The phenotypic data of the mapping panel was recorded as germination index (GI) while their genotypic data was derived using 50k Illumina Infinium iSelect genotyping single nucleotide polymorphism (SNP) array. The findings of the project showed association between the genotypic and phenotypic characteristics of the different barley genotypes exhibiting considerable variation in dormancy, leading to the detection of significant markers and closely linked genomic regions/genes associated with dormancy and PHS resistance. Furthermore, the expression patterns of the candidate genes were studied in two genotypes possessing contrasting dormancy levels, and most of the candidate genes showed differential expression between the two genotypes, indicating their role in dormancy regulation.
Pre-harvest sprouting, Barley, GWAS