Response of Rainfed Wheat Genotypes to Drought Stress Using Drought Tolerance Indices

Abstract

Ten wheat genotypes were tested in a randomized complete block design with three replications under two irrigated and rainfed conditions to identify drought tolerant genotypes. Indices of drought tolerance were calculated based on the potential (Yp) and under stress (Ys) yield. Analysis of variance of indices exhibited highly significant differences among the geometric mean productivity (GMP), mean productivity (MP) and stress tolerance index (STI) and non-significant differences between the stress susceptibility index (SSI) and stress tolerance (TOL) indices. This indicates the existence of genetic variation for the attributes studied and the possibility of selection for drought tolerance genotypes. The highest significant positive correlations were found among GMP, MP and STI indices and potential and under rainfed yield. The highest GMP, MP, and STI were related to the TV2 genotypes. Principal component analysis reduced five indices down to two components with 99.49% proportional cumulative variance. Correlation and principal component analysis indicated that the most suitable criteria for the identification of genotypes under irrigated and rainfed conditions were GMP, MP and STI indices. Three dimensional plots exhibited that TV2 was the best drought tolerance genotype. Results of biplot analysis also identified the same genotype as the highest yielding one in both conditions.