GENETIC EVALUATION OF 80 IRRIGATED BREAD WHEAT GENOTYPES FOR DROUGHT TOLERANCE INDICES

M. Ghobadi, S. Bahraminejad, Sh. Sasani, R. Amiri

Abstract: Drought stress is one of the most important problems for crop production in arid and semi-arid areas such as Iran. In order to select drought-tolerant bread wheat genotypes, an experiment was conducted on 80 genotypes in a Randomized Complete Blocks Design (RCBD) with three replicates under normal and terminal drought stress conditions in Kermanshah, Iran during 2011-2012 cropping season. Based on the potential (Yp) and stress (Ys) yields, 15 quantitative criteria of drought tolerance including: stress susceptibility index (SSI), tolerance index (TOL), mean productivity (MP), geometric mean productivity (GMP), stress tolerance index (STI), yield index (YI), yield stability index (YSI), harmonic mean (HAM), sensitivity drought index (SDI ), drought response index (DRI), drought resistance index (DI ), relative drought index (RDI ), stress susceptibility percentage index (SSPI) and modified stress tolerance index (MSTI) were calculated. A positive and significant correlation was observed between Ys and Yp with MP, GMP, STI, YI, HAM, SDI , K1STI and K2STI indicated that these indices are the most suitable indices to screen genotypes in drought stress conditions. Principal component analysis (PCA) introduced two components.
First vector showed 65.39% of variations and the second PCA explained 32.20% of the total variability. It separated the stress–tolerant from non-stress tolerant genotypes. According to all statistical procedures, Ghods, DN -11, Sepahan and Tajan were known as superior genotypes under both stressed and non-stressed conditions with high stability to drought stress.

Keywords: biplot diagram; bread wheat; drought tolerance indices; principal component analysis

Date published: 2017-10-16