Evaluation of the reaction of durum wheat genotypes (Triticum durum Desf.) to drought conditions using various stress tolerance indices

In this study, 40 genotypes of durum wheat (Triticum durum) originating from Iran and Azerbaijan Republic were evaluated in both water-stressed and well-watered environments in 3 years 2008 to 2011 cropping years. In each environment, the genotypes were evaluated using a randomized complete block design with three replications. From the grain yield data, drought tolerance indices comprising of stability tolerance index (STI), mean productivity (MP), geometric mean productivity (GMP), stress susceptibility index (SSI), tolerance index (TOL), yield index (YI) and yield stability index (YSI) were calculated for every genotype. The resulting data were analyzed as obtained from a randomized complete block design. Significant differences among genotypes were observed for all drought tolerance indices. High yield value in non-stress and stress environments was exhibited by genotypes '40 (4411.22 kg ha (-1)) and '32' (4256.34 kg ha (-1)) respectively. The maximum value of STI (1.07), MP (3642.11) and GMP (3590.85) indices was by genotype '35'. The highest value for YI (1.24) was from genotypes '39' and '21'. Correlation coefficients revealed that TOL, MP, GMP, STI, HM, and YI indices could effectively be used for screening of drought tolerant genotypes. Using MP, GMP, TOL, YI and STI indices, genotypes UPGMA classification was done and three clusters were established that is paralleled to biplot analysis results. According to results in this study, G10 and G35 were the most drought tolerant genotypes which were clustered as group A. We suggest that tolerance indices including MP, GMP and STI are suitable for durum wheat drought tolerant genotypes selection.