Assessment of Genetic Variability of Bread Wheat (Triticum aestivum L.) Genotypes for Salinity using Salt Tolerance Indices

In India about 6.73 million hectare land area is salt affected. Wheat is the second most important crop after rice in India and occupies approximately 28.5 million hectare area. In this investigation, we calculate several tolerance indices for salinity and its ability to understand which one or more predictor among studied indices based on correlation, principal component analysis and cluster analysis. Ten wheat genotypes were evaluated two successive growing seasons (2012-2014), with complete randomized design with three replications under both salinity stress and non-salinity to identify salt tolerant genotypes to the target environment. Multiple indices for salt tolerance were calculated based on the potential yield (Yp) under non-stress and yield (Ys) under stress conditions. The Ys and Yp showed highest significant and positive correlations with GMP, MP and STI among indices studied. Therefore, these indices were considered as a better predictor of Ys and Yp than TOL, SSI and YSI. Principal component (PCs) analysis classified the genotypes into two groups. The first two PCs with eigen values > 1 contributed 99.73% of the variability amongst genotypes. PC1 accounted for about 4.85% of the variation in salt tolerance indices and PC2 for 4.12%. The first PC was related to Ys, Yp, MP, GMP, STI and YI whereas the second PC related to Yp, TOL and SSI. The cluster analysis sequestrated ten genotypes into three clusters based on Ward’s method. According to results, salinity significantly reduced the yield of some genotypes while some were found to tolerant to stress indicating that sufficient genetic variability for salinity tolerance among the studied genotypes were present and the genotypes K72 and HUW570 can be recommended for cultivation in salt affected areas.