QTL Mapping of Yield, Agronomic, and Nitrogen-Related Traits in Barley ( L.) under Low Nitrogen and Normal Nitrogen Treatments.

Improving low nitrogen (LN) tolerance in barley ( L.) increases global barley yield and quality. In this study, a recombinant inbred line (RIL) population crossed between "Baudin × CN4079" was used to conduct field experiments on twenty traits of barley yield, agronomy, and nitrogen(N)-related traits under LN and normal nitrogen (NN) treatments for two years. This study identified seventeen QTL, comprising eight QTL expressed under both LN and NN treatments, eight LN-specific QTL, and one NN-specific QTL. The localized C2 cluster contained QTL controlling yield, agronomic, and N-related traits. Of the four novel QTL, the expression of the N-related QTL and was unaffected by N treatment. for thousand-grain weight, for plant height, for spike length, and for awn length were identified to be the four stable expression QTL. Correlation studies revealed a significant negative correlation between grain N content and harvest index ( < 0.01). These results are essential for barley marker-assisted selection (MAS) breeding.