The <i>SD1</i> locus affects primary seed dormancy in winter malting barley

Preharvest sprouting (PHS) resistance and seed dormancy are key targets for malting barley (Hordeum vulgare L.) in environments with a high probability of rain events at harvest. Characterization has been limited in winter malting barley compared to spring malting barley in the United States. We used a modified half-sibling winter malting barley breeding population to map PHS at maturity and germination traits during after-ripening to identify marker associations with dormancy and rate of dormancy loss. Seed dormancy locus 1 (SD1) on chromosome 5H has been identified as an H. vulgare L. alanine aminotransferase (HvAlaAT) gene. The SD1 locus was significantly associated with the rate of primary seed dormancy loss in the winter malting barley population, and additional quantitative trait loci (QTLs) for PHS resistance and seed dormancy were identified. Identified markers for HvAlaAT alleles and other QTL for seed dormancy can provide greater precision for selecting lines that have high PHS resistance but short dormancy periods to produce high-quality malt.