Association Mapping of Grain Weight, Length and Width in Barley (Hordeum vulgare) Breeding Germplasm

Grain weight, grain length and grain width are important target traits in the malting barley breeding, due to their attributes for determining the market value of barley grain. In this study, a diversity collection of 112 accessions was used to identify quantitative trait loci (QTLs) for them by association mapping approach with simple sequence repeat (SSR) markers and detect elite alleles related to the improvement of grain size. The heritability calculated for grain weight over multi-environment experiments was 83.6%, while the values of grain length and width were 70.0% and 69.9%, respectively. Population structure analysis showed that all the accessions were divided into two subgroups that originated from East Asia and North America. A total of five QTLs for grain weight were identified on chromosomes 1H, 2H, 5H and 6H, respectively, and the QTLs on 5HS and 6HS were detected in more than one environment. The A4 allele of GBM1215 on 6HS increased grain weight significantly in all three environments. Four and two QTLs were detected for grain length and width, respectively. QTL for grain width on 2HS was detected in two environments and the A1 allele produced wider grain. These findings might be valuable for marker-assisted selection of breeding lines to improve grain weight and width. (C) 2017 Friends Science Publishers