Evaluation of Water stress Tolerance in Sesame Varieties Based on Tolerance Indices

In order to study drought tolerance in sesame varieties and also evaluating stress tolerance indices, an experiment conducted as a split plot based on randomized complete block design with three replications. In this experiment, irrigation as the main factor with three levels (100, 75 and 50 percent of plant water requirement) and ten sesame cultivars as the second factor were studied. In order to calculate the water needs of the sesame, the CROPWAT software (Penman- Monteith method) were used according to FAO-56. Analysis of variance showed significant differences (p≤0.01) between stress levels and cultivars in yield but interaction of tow factor were not significant. So, the tolerance indices based on cultivars yield in stress and non stress condition were calculated. Analysis of variance for indices showed significant differences between cultivars in MP, STI, GMP, and HARM. With consideration of correlation between indices and yield under stress and non-stress, these indices were identified as the best indices for isolation and selection of tolerant cultivars. The TOL and SSI indices didn’t have important role in the differentiation of cultivars. Grouping of cultivars using cluster analysis method showed that the Karaj 1, IS and Ultan were water deficit tolerant cultivars with high yield and the Moghan17 and Yellow-white cultivars were sensitive varieties to water deficit stress.