Evaluation of Genetic Diversity of Spring Wheat Cultivars for Physiological and Agronomic Traits under Drought Stress

selection tolerant cultivars of wheat (as a strategic plant) under drought stress by using traits that are less affected by the environment, increases efficiencies. In this regard, in order to study some genetic parameters of physiological and agronomical traits and also genetic diversity in spring wheat cultivars under normal irrigation (control) and drought stress conditions in booting stage, a split plot experiment (two stress levels as main plots and 20 wheat cultivars as subplots) was done based on Randomized Complete Block Design with 4 replications during two cativation years 2011-12 and 2012-13 research farm of agriculture faculty, University of Tabriz, Iran. Based on the results of genetic parameters, number of tillers per plant, spike length, number of fertile tillers, number of spike per plant, seed yield, root number per plant, root diameter, leaf specific area and osmotic potential had more amounts for genetically variance, heritability and genetic improvement under control condition. While, in addition to these traits except grain yield; number of seeds per plant, root length, root volume and root dry weight under stress conditions have more genetic variance, heritability and genetic improvement. Other traits because having low amounts genetic parameters for using selection of superior cultivars under drought stress not recommended. Also dendrogram of cluster analysis based on desirable studied traits divided cultivars into four groups in terms of stress condition and non-stress conditions in the three groups that according to cluster analysis grouped under water stress, Marvdasht, Niknejhad, Moghan3, Darya and Kavir cultivars as the most tolerant and also Pishtaz, Bam, Sistan, Sepahan and Bahar identified as the most sensitive cultivars.