Genetic dissection of grain forage traits in hulless barley

To gain genetic information on forage traits for breeding new hulless barley varieties with high yield and good forage quality, we characterized the grain forage traits of 60 accessions of hulless barleys originating from the Qing-Tibet plateau. Unconditional and conditional association mapping analyses, conducted using a mixed line model as implemented in TASSEL software, and bulk sample analysis (BSA) methodology were used to identify markers significantly associated with grain forage traits. High genetic variation in grain forage traits was detected in the association mapping panel. These barley accessions were classified into three subgroups based on population genetic structure analysis, which indicated significant relationships between accession subgroups and their region of origin. Twenty-three sequence-related amplified polymorphism (SRAP) markers for grain forage traits, including crude protein content, starch content, and ash content, were determined using unconditional association analysis, whereas 20 and 24 SRAP markers significantly associated with crude protein content and starch content, respectively, were detected in the conditional association study. Additionally, a total of 37 SRAP markers associated with variation in grain forage traits were detected using the BSA methodology, among which, 2 and 4 SRAP markers associated with crude protein content and starch content, respectively, were also identified in the unconditional association study. These results provide potentially valuable information for improving grain forage traits and the cultivation of good quality, high-yielding accessions of hulless barley.