evolution of stress tolerance indices in durum wheat genotypes

in order to study stress tolerance indices and identifying tolerance genotypes to drought stress condition 16 genotypes of durum wheat were assessed in a randomized complete block design with four replications under two irrigated and rainfed conditions in the research station located in west of iran ilam in 2006- 2007. results showed that variation in among durum wheat genotypes under irrigated and rainfed conditions. the highest stress yield, harmonic mean, geometric mean productivity and stress tolerant index were related to the genotype omrabi3. correlation analysis between indices, potential and yield produced under stress indicated that the most suitable criteria for identifying tolerance durum wheat genotypes under irrigated and rainfed conditions were mean productivity and geometric mean productivity. multivariate biplot indicated that the genotypes omrabi3, mrb3/mna1 and zardak were located next the vectors of drought tolerance indices, mean productivity, geometric mean productivity, stress tolerant index and harmonic mean. distribution of the genotypes in the biplot space indicated that the presence of genetic diversity among the genotypes for drought stress. cluster analysis showed the farthest genetic distance between droughts tolerance genotypes were omrabi3, mrb3/mna1, zardak and also drought susceptible genotype were 15/a/margheg and 9/a/kordestan.