Genetic analysis reveals four interacting loci underlying awn trait diversity in barley (Hordeum vulgare)

Barley ( Hordeum vulgare ) awns contribute to grain yield, but the genetic basis of awn development remains largely unclear. Five barley lines differing in awn traits and row types were used to create four F 2 populations. Genetic analyses revealed that four pairs of genes were involved in awn development: A / a (awnless/awned), B / b (awnless/awned), H / h (hooded/straight), and L / l (long/short). Of these four loci, A , H and L functioned on both central rows (CR) and lateral rows (LR) of the barley spikes, while B exhibited effect only on LR. A and B had duplicate effects on LR, and both showed dominant epistasis to loci H and L, whereas H was epistatic to L. Meanwhile, A and B were found to be genetically linked, with a row-type locus V located between them. The genetic distances of A - V and B - V were estimated to be 9.6 and 7.7 cM, respectively. Literature search suggested that A , H and V may correspond to the reported Lks1 , Kap1 and Vrs1 , respectively, whereas B is a novel gene specifically controlling awn development on LR, designated as Lsa1 for lateral spikelet awnless 1 . The only barley homolog of wheat awn inhibitor gene B1 , HORVU2Hr1G077570 , is a potential candidate of Lsa1 .