Genetic evaluation of physiological Traits related to drought tolerance in some bread wheat genotypes under rain-fed conditions

In order to investigate phenotypic and genotypic correlations between physiological characteristics related to drought tolerance and genetic variation and estimating the genetic parameters of these indices in rain-fed condition, 19 genotypes of bread wheat were cultivated in a randomized complete block design with three replications in the research field of Agricultural Research Campus Natural Resources of Razi University of Kermanshah, Iran during 2014-15. analysis of variance (ANOVA) showed significant differences for the grain yield (YS), the cell membrane stability )CMS), the relative water loss )RWL(, the leaf water loss (LWL), the relative water protective (RWP), the water use efficiency )WUE( and the leaf greenish value )LGV( under rain-fed condition. The polygon view of GT biplot showed that genotype no. 12 (wc-4931) was the best genotype compared to other genotypes due to YS, WUE, ELWR and LGV. A high positive genetic and phenotypic relation was observed between WUE and Ys, FV/FM and LWL and, ELWR and LGV. In other hand, High heritability and genetic gain were observed for YS, CMS and WUE that reflect the additive gene action. Accordingly, due to the high propotion of additive effects in CMS, YS and WUE, it was suggested that the evaluation of genotypes must be done at erarly generarion of inbreeding.