QTL analysis of forage quality traits in barley (Hordeum vulgare L.)

Despite the importance of barley as an animal feed, its forage quality has usually been neglected in breeding programs. In order to map the genomic regions, which modify barley forage quality, a population of 72 F1-derived doubled haploid lines (DH) from the cross “Steptoe/Morex” and their two parents were sown in Karaj and Zabol provinces of Iran, in each under a randomized complete block arrangement with two replications. Forage samples were oven-dried and ground and dry matter digestibility (DMD), acid detergent fiber (ADF), neutral detergent fiber (NDF), acid detergent lignin (ADL), crude fiber (CF), crude protein (CP), water-soluble carbohydrates and ash content were measured by NIRS. Analysis of variance showed that genotype, environment and genotype-environment interaction have significant effects on almost all studied traits. Several QTLs were resolved for each studied trait in both environments. Highest LOD scores were obtained for CF, ADF and DMD on chromosome 2H and for ash and CP on chromosomes 3H and 5H, respectively. QTLs for NDF were present on all chromosomes except 4H and 7H. QTL × environment interaction and the specificity of the QTLs are discussed.