حمیدرضا نوریزدان

In order to assessment the genetic diversity, screening the quantitative Tolerance Indices and identify the drought tolerant varieties among 12 sesame genotypes, an experiment was conducted in a Randomized Complete Block design with three repetitions. The experiment was carried out in 2014-2015 crop year, at Agriculture and Natural Resources College of Persian Gulf University in Bushehr. Seven drought tolerance indices such as stress susceptibility index (SSI), stress tolerance index (STI), mean productivity (MP), geometric mean productivity (GMP ), tolerance (TOL), yield index (YI) and yield stability index (YSI) were calculated based on the yield optimal (Yp) and yield under drought (Ys) conditions. The results showed the significant difference between the varieties for all the indices measured. It showed the existence of genetic among genotypes and thus the possibility of selecting drought tolerance genotypes which can be used to hybrid for later breeding studies. In the non-stress conditions, the greatest difference was observed between the yield of the Behbahan and Arak land varieties. In water stress conditions, Borazjan, Behbahan and Dezful land varieties possed the highest yield. The most GMP, HARM and YI belonged to Borazjan and Behbahan land varieties. By considering all the drought tolerance indices, at the same time based on ranks mean of drought tolerance Dezful, Borazjan and Behbahan land varieties were introduced as the best tolerant genotypes to water stress. According the correlation analysisthe ,GMP had positive significant correlation with yield in both conditions. Therefore it was the best indice for screening the sesame genotypes in experimental conditions. This index was able to separate and to detect A Fernandez Group from the others. According to three-dimensional graph, Borazjan and Behbahan land varieties were indicated as the tolerant drought and R?mhormoz, Abadan and Arak genotypes were introduced as the most sensitive varieties . Accordi