Evaluation of Bread Wheat (Triticum aestivum L.) Genotypes for Drought Tolerance through Selection Indices

The current study was planned to identify drought tolerant bread wheat genotypes based on physiological and yield traits. In this context, a set of 12 genotypes (Sarsabz, NIA-Sundar, NIA-Amber, Sassui, Khirman, Marvi-2000, NIA-Sarang, Kiran-95, NIA-Sunheri, Bhittai, Bathoor-08 and Tatara) were evaluated under normal and water stress conditions. Mean squares from analysis of variance exhibited that genotypes, treatments and genotype x treatment interaction showed significant differences (P<0.05) for majority of the studied traits, indicating that there is significant variations are existed for physio-yield traits; therefore these genotypes may be preferred for further breeding programs in respect to drought stress. Regarding reduction percentage of genotypes under drought stress against normal water conditions, the minimum reduction was observed in Bathoor-08 for spike length and flag leaf area, Kiran-95 for grain yield plant, NIA-Sundar for seed index, Marvi-2000 for relative water content, Sarsabz for grains spike, whereas maximum but desirable reduction of stomatal dimension and density was displayed by Sarsabz and Tatara under water stress conditions, respectively. On the basis of drought tolerant indices, the genotypes Kiran-95, NIA-Sundar and Sarsabz showed lower values for tolerance index (TOL), trait stability index (TSI) and stress susceptibility (SSI), nevertheless it is believed that lower values of these indices show the less reduction in yield and its related traits due to water stress conditions hence can be tagged as tolerant genotypes for drought. Correlation results revealed that MP, SSI, TOL and TSI indices were correlated with grain yield under two conditions and they can be the appropriate indices for screening wheat genotypes.