Evaluation of Drought Tolerance in wheat Genotypes under Drought Stress at Germination Stage

In order to assess tolerance to drought and resistant and susceptible genotypes, 86 genotypes of native and commercial wheats were evaluated in germination stage with a factorial experiment in a completely randomized design with three replications. Two levels of osmotic potential of zero (control) and -4 bar. PEG 6000 were used to create the tension of the material. Different morphological traits were studied 8 days after planting the seeds on the seedlings. All the studied traits had significant differences in the level of one percent except the number of roots between the two levels of osmotic potential. In other words, the number of roots in different genotypes, were not affected by the drought stress. The effects of genotype and genotype × environment for all examined characteristics were significant at the one percent level. Stress decreased all germination index but this decline was not equally in all the traits, such as decline in the shoot was more noticeable than the root length. Stepwise regression analysis based on regression model with six variables were fitted to control circumstances and bivariate regression models were fitted to experimental data for stress. The genotypes were classified based on all traits using cluster analysis in the stage of germination in both environments. Genotypes in each environment (stress and control) were clustred separately that resistant and sensitive genotypes. Biplot analysis based on two main components were used on tolerance and susceptibility indices that resistant and susceptible genotypes were classified in two differenti groups based on the dry weight of biomass in both the stress and control condtion. According to the result of this research, the genotypes including Khazar 1, Khoi, Chamran and mahdavai have been identified as sensitive and also the genotypes of Bolani, Simineh and Golestan were drought tolerance.