LAUSR

Abstract Drought is one of the most important abiotic stresses limiting yield production in cereal crops which deleteriously affects food security worldwide. The study aimed to identify marker-trait associations (MTAs) and putative candidate genes underlying agronomic and seed related traits under post-anthesis drought stress in a set of 183 spring barley gene bank accessions from 23 countries that were genotyped with a 9 K SNP chip. Plants were grown in the field in two consecutive years and post-anthesis drought stress was simulated by spraying 1% KI ten days after anthesis. The treatment caused a significant reduction in total biomass by 10.7 %, in kernel number by 2.5 %, in kernel weight per spike by 21.4 % and in thousand kernel weight (TKW) by 16.7 %, whereby most tolerant accessions were HOR 5970, HOR 6606 and HOR 6560. GWAS analysis of best linear unbiased estimators (BLUEs) revealed 97 significant MTAs associated with kernel number and kernel weight per spike and confirmed prominent regions such as 2H (18.9 cM), 6H (54.8 cM) and 7H (70.5-71.0 cM) for drought response and were co-localized with ten putative candidate genes. Gene annotation indicates that genes for the plant respiratory burst oxidase homologs (rboh) family, the carotenoid cleavage dioxygenase 1 (CCD1) and RNA-binding proteins (RBPs) might be involved in tolerance and stress response mechanisms during post-anthesis drought stress. In conclusion, the study provides essential information about significant MTAs and candidate genes related to drought tolerance which can be further used for marker-assisted selection. More drought tolerant barley accessions may be used as pre-bred material to widen the genetic diversity of cultivated barley and to meet the demands for cultivars in world’s areas which suffer post-anthesis drought stress.