Evaluation of Tolerance to Drought Stress in Some Bread Wheat Cultivars Using Old and New Indices

In order to evaluation the effect of terminal drought stress on 5 bread wheat cultivars and for determining their relative tolerance using old (SSI، TOL، MP، GMP، STI، HARM، RDI) and new (SSPI and SNPI) indices, two separate experiments bases on randomized complete block design (RCBD) with 3 replications, were conducted. The results showed positive and significant correlation among stress and non-stress yield (Y_S and Y_p) and indices of SNPI, STI, MP, GMP and HARM. Therefore, the above-mentioned indices are the best and suitable index for relative resistance selection. These results indicated that, Pishgam and Tous were relatively resistant, Sayson was semi-resistant and Alvand and Navid were semi-sensitive cultivars. The results of principal component analysis demonstrated that SNPI and RDI were the best indices and SNPI could select resistant cultivars better than the other ones.