Assessment of genetic diversity for drought tolerance and determination of the best resistance indices for some common wheat (Triticum aestivumL.) genotypes

Abstract

In order to evaluate genetic diversity of common wheat (Triticum aestivum L.) to identify the most drought resistant genotypes and also finding the best drought tolerance indices, an experiment was carried out in research center of Kabotarbad, Isfahan, Iran, using randomized complete block design in three replications. Twenty wheat genotypes were selected for this study. The experiment was done under normal (Yp) and water stress (Ys) conditions. The stress was applied after heading stage. The results showed that stress tolerance index (STI), geometric mean productivity (GMP) and mean productivity (MP) indices had the most correlation with the yield, therefore, they were used for screening drought tolerant varieties. Biplot analysis also showed that genotypes 10, 18, 19 and 20 had the highest grain yield under both the conditions. Genotypes 3, 6, 14 and 15 were also suitable for the stress condition. The principal component analysis (PCA) showed that two first components accounted for 99.945% of the variance for the observed genotypes. The first component had the most positive coefficients in both irrigated and stress conditions and also the highest GMP and STI values, therefore, it can be named as the yield potential component under drought condition and also the tolerance index. The second one had the most positive and highest correlation with tolerance index (TOL) and SSI and it can be referred as the drought susceptibility component.