Study of Genetic diversity among spring wheat genotypes in drought stress by advanced statistical analysis

20 wheat genotypes with check cultivar were evaluated under two post anthesis drought stress 30% (E1), 70% (E2) and 100% (E3) in greenhouse water field capacity in greenhouse of research center in 2010-2011. Trial carried out using split plot design with three blocks that humidity levels and genotypes were as main and sub plots respectively. The Analysis of variance showed that all traits except of seeds per spike had different significant but almost interaction effects between genotypes and drought levels became non significant. Correlation analysis in drought conditions recognized positive role flag leaf and stem length, spike weight and spikes per square meter to yield in E1 similar E2 but the relationships of traits changed in E3. Stepwise regression analysis showed that harvest index and Biomass traits were entered in regression equation in all environments but spikes per m2 and spike weight were additional and important in E1 and E2. The traits that distinguished clusters were difference in environments. Either statistical method or variance analysis showed that genotypes 9 and 11 were introduced as tolerance genotypes.