Path analysis of genotype × environment interaction in wheat-barley disomic addition lines

Abstract

In order to locate QTLs controlling the phenotypic stability and drought tolerance of yield and yield components in barley, seven disomic addition lines were sown together with their parents (donor and recipient) in a randomized complete block design with three replications under four rainfed and irrigated conditions. The descriptive diagram of yield and yield components exhibited a genotype (G) × environment (E) interaction and moderate variability over different environments, indicating the possibility of selection for stable and drought-tolerant entries. The AMMI stability value (ASV) and yield stability index (YSI) discriminated addition lines 2H and 4H as the most stable and droughttolerant.Path analysis revealed that the relative contribution of the number of seeds per plant (NSPP) (0.71) to grain yield (GY) was higher than that of the number of seeds per spike (SPS) (−0.44) and of thousand-seed weight (TSW) (−0.14). Therefore, the contribution of NSPP to the stability of GY over different environments was higher than that of other yield components. In other words, the instability of GY was caused by TSW and SPS in different environments. Path analysis on the drought susceptibility index revealed that most of the QTLs controlling drought tolerance and drought susceptibility in barley are located on chromosomes 3H and 6H, respectively.