Abstract :
: In order to determine the performance of landraces of bread wheat under drought stress conditions and screening quantitative indices of drought tolerance, thirty bread wheat (Triticum aestivum L.) genotypes were tested in a randomized complete block design with three replications under irrigated and rainfed conditions. Significant positive correlation was found between grain yield in the stress condition (Ys) with indicators geometric mean productivity (GMP), mean productivity index (MP), stress tolerance index (STI), yield index (YI), drought response index (DRI), drought resistance index (DI) and modified stress tolerance index (MSTI) indicating that these indices are suitable criteria for screening drought tolerant genotypes. No significant correlation was observed between Ys with stress susceptibility percentage index (SSPI), tolerance index (TOL), yield stability index (YSI), stress susceptibility index (SSI), relative drought index (RDI), abiotic tolerance index (ATI) and stress non-stress production index (SNPI), hence they can be discarded as the desirable markers for identifying drought tolerant genotypes. Principal component analysis (PCA), indicated that the first and second components justified 94.60% of variations between the criteria. Screening drought tolerant genotypes using mean rank, standard deviation of ranks and biplot analysis, discriminated genotypes (17), (9) and (18) as the most drought tolerant.
