Investigation of Water Stress Tolerance in Some Sesame (Sesamum indicum L.) Genotypes using Tolerance and Sensitivity Indices

This experiment was conducted at the Research Farm of Isfahan University of Technology, Najafabad, Iran in 2014 and 2015 to evaluate drought tolerance indices of some sesame (Sesamum indicum L.) genotypes. In this study, 21 sesame genotypes isolated from different local populations along with seven exotic cultivars were evaluated at two irrigation regimes, using a randomized complete block design with two and three replications in the first and second years, respectively. The normal and water deficit irrigation regimes were determined based upon the depletion of 60% and 90% of soil moisture content, respectively. The results showed that the effect of irrigation regimes was significant (p<0.01) on seed yield. Averaged over two-years, mean of seed yield was 2186 kg ha-1 and 1231 kg ha-1 in normal and water deficit irrigation conditions, respectively. Based upon the data of two years, the genotype Shiraz 5 had the highest seed yield in normal irrigation conditions, however, genotypes Markazi 1 and Shiraz 5 had higher seed yield in water deficit condition. Investigation of different indices of tolerance and sensitivity to drought stress (TOL, SSI, STI, MP, GMP, HARM, DRI, SNPI, SSPI and ATI) showed that STI, MP, GMP, HARM and SNPI were more suitable indices to recognize drought tolerant sesame genotypes. Based upon these indices obtained from the data of two years, genotype Shiraz 5 had the highest tolerance and more productivity and genotype China had the highest sensitivity to drought stress with less potential of productivity.