evaluation of wheat toleranc indices to moisthre stress condition

breeding for environmental stress is one of the most important goals in plant breeding. among stresses, drought stress has high influencing on limitation of wheat production. so, in order to find the best drought tolerant genotypes, 24 genotypes were planted in three separate experiments in ardebil: one with optimum irrigation (control), another with water stress at pre-anthesis stage and the other with water stress at post-anthesis stage. rbcd experiment design with four replications was used. stress susceptibility index (ssi), mean productivity (mp), tolerance (tol), geometric mean productivity (gmp), stress tolerance index (sti), modified stress tolerance index for optimum condition (k1sti) and modified stress tolerance index for water stress condition (k2sti) indices were used to evaluate susceptibility and tolerance of the genotypes. results showed that, genotypes number 15 and 21 had higher grain yield than mean in all irrigation conditions. these genotypes had the highest sti and located at part of high yield potential and low sensitivity to drought in the biplot. according to tol and sti, genotype number 15 had the highest water stress tolerant and highest yield in all studied conditions. also, results of biplot analysis and correlation drought tolerant indices with ys and yp showed that sti, gmp and mp were the best indices for yield predicting. k1sti and k2sti along with sti were important indices to select genotype for control and stress conditions.