Selection for Drought Tolerance in Bread Wheat Genotypes with Drought Tolerance and Susceptibility Indices

To evaluate and selection the wheat genotypes regarding their response to drought stress, 10 genotypes were studied in a randomized complete block design with three replications in normal and stress conditions in two separate experiments in 2010 year in the farm of Moghan agricultural education center. The results showed that there were significant differences the between genotypes regarding grain yield in non-stress (normal) conditions. The highest mean grain yield under stress conditions was observed in Koohdasht genotypes (3160 kg/ha) while the highest mean grain yield under non-stress conditions was observed in Chamran genotypes (7100 kg/ha). MP, GMP, HAR, STI, TOL and SSI indices were used to investigate the tolerance of the genotypes under study. The results obtained from this investigation showed that STI, MP, SSI, and TOL indices had higher heritability than other indices. In addition, TOL, MP, GMP, HAR and grain yield indices had the highest coefficients of genetic variation. Based on MP, GMP, HAR, STI and grain yield indices under stress and non-stress conditions, Chamran, Kuhdasht, N-81-18, N83-3 and N-84-10 genotypes were identified as the tolerant genotypes with the highest grain yield. Based on the method used to select the genotypes as well as the heritability coefficients, MP and STI indices had better performance in cultivar selection compared to other indices. Using cluster analysis, the genotypes were classified into two groups. The tolerant genotypes were included in the first cluster while the susceptible genotypes were included in the second cluster. Assigning the genotypes to the different groups using cluster analysis had appropriate compliance with the drought tolerance of the genotypes.