A Study of Grain Yield, Yield Components in some Promising Bread Wheat (Triticum aestivum L.) Genotypes under Normal Irrigation and Terminal Drought Stress Conditions

To study the tolerance of genotypes under terminal drought stress, 20 promising winter and facultative bread wheat genotypes were evaluated at Karadj, Ardebil, Arak and Hamedan Agricultural Research Stations during 2001-02 cropping season. The experimental design in all the locations was randomized complete block of three replications. Grain yield (YLD), Harvest Index (HI), Grain Number per Spike (GNS) and Thousand Kernel Weight (TKW) were the traits evaluated in the study. Combined ANOVA showed significant effect for irrigation, genotype and genotype × location interaction on YLD, HI, GNS and TKW. Comparison of the genotypes using TOL, SSI, MP, GMP and STI showed genotypes 20 (1-27-6275/ Cf1770/ 5/ Gds/ 4/ Anza/ 3/ Pi/ Nar/ Hys) and 13 (Darunk) as the superior ones under terminal drought for YLD and HI, respectively. For GNS and TKW, genotype 6 (1-60-1//Emu”s”/Tjb84/3/1-12638) was identified as the superior genotype under terminal drought stress condition. All in all, MP, GMP and STI were identified as better means than TOL and SSI for a determination of the tolerant and high yielding genotypes.