Genetic Variability Assessment in Bread Wheat (Triticum Aestivum L.) Cultivars under Different Drought Stress Treatments using Multivariate Statistical Analysis

The improvement of tolerance to drought has been a principal goal of the majority of breeding programmes for a long time, as a water deficit in certain stages of wheat growth is common for many wheat growing regions of the world. Determination of genetic diversity is useful for plant breeding and hence production of more efficient plant species under different conditions. On the other hand, wheat (Triticum aestivum L.) is the major cereal crop in Iran on which the food security rests. Therefore, in order to evaluate and classify morphological and morphophysiological traits and tolerance indices of bread wheat genotypes, 15 cultivars were sown in randomised complete block design with three replications under two moisture treatments. Cluster analysis using ward’s method grouped these cultivars in five clusters both in stress and control conditions. Principal Component bi- plot of tolerance indices and cultivars according to PCA suggested a better understanding of each cultivar potential under drought condition. This result suggested that “Sepahan” and “Roshan” are two best cultivars under both control and stress condition. Overall, crosses among cultivars having maximum genetic distance result in higher transgressive segregation and genetic gain of selection.