Evaluation of drought tolerant genotypes in bread wheat using yield based screening techniques

In order to evaluate drought tolerance in bread wheat genotypes, a factorial experiment based on completely randomized block design with three replications under two water stress and irrigated conditions was used. The experiment was carried out in the greenhouse of Campus of Agriculture and Natural Resources of Razi University in crop season 2011. The results obtained from correlation analysis between drought resistance indices (based on grain yield under stress and non-stress environments) showed positive significant correlation between geometric mean productivity (GMP), mean productivity (MP), harmonic mean (HARM) and stress tolerance index (STI) with grain yield . A significant positive correlation was also observed between these indices indicating their similar pattern for identification of drought tolerant genotypes. Genotypes no 4, 7 and 8 had the highest STI values, therefore they are suitable for stress and non-stress conditions with high grain yield. The genotypes no 3 and 7 exhibited the lowest TOL and SSI values and no. 4 and 8 revealed the highest HARM index hence they are desirable for drought prone condition. Screening drought tolerant genotypes based on all indices using mean rank, standard deviation of ranks and rank sum (RS) distinguished genotypes 7, 8 and 3 as the most drought tolerant