Repeatability of drought tolerance indices in chickpea genotypes over stress and non-stress environments

Abstract

To evaluate the repeatability of yield-based drought tolerance indices over years, twenty chickpea genotypes were evaluated using a randomized complete block design with three replications for four cropping seasons (2008–2012) in the experimental field of Razi University. The result of combined analysis of variance for seed yield showed significant differences for location (L) (rain-fed and irrigated), genotype (G), and LY and GL interactions, indicating the presence of genetic variability and the possibility of selection for stable, drought-tolerant genotypes. Principal component analysis (PCA) based on the Spearman's rank correlation matrix was used to visualize the relationships between different drought tolerance indices. Due to their positive significant correlation with seed yield under both conditions over four cropping seasons, the stress tolerance index (STI) and geometric mean productivity (GMP) were identified as desirable criteria for the selection of drought-tolerant genotypes under severe stress conditions. The selection of drought-tolerant chickpea genotypes using these indices in a one-year trial will mirror the results of multiple cropping season trials. According to the Spearman's rank correlation coefficients between single vs. single years and single vs. the mean of multiple years, the tolerance index (TOL), mean productivity (MP), abiotic tolerance index (ATI), stress susceptibility percentage index (SSPI) and modified stress tolerance index (K1STI) were identified as repeatable indices under severe drought conditions.