Study of drought tolerance indices on spring wheat in Mazandaran (North of IRAN)

Fifty one spring genotypes with three check cultivars were evaluated under two post anthesis drought stress 40% (E1) and 70% (E2) and 100(E3) Water Field Capacity in GHARAKHYL station green house. Trial carried out using augmented design with three blocks that checks were replicated to block uniformity in 2009-2010. Five drought tolerance indices comprising: Stress tolerance index (STI), Tolerance (TOL), Stress susceptibility index (SSI), Mean productivity (MP), and Geometric mean productivity (GMP) were used to genotypes response in three environments. Tolerance indices had different linear regression to Ys respectively. STI and GMP in E1 and STI, TOL, MP and GMP in E2 had significant linear relationships to Ys. Analysis of variance showed that there was a significant genetic variation among genotypes for all criteria. There were significant correlations of YE3 with MP, GMP, STI, TOL, SSI, STI and YE1 with (GMP and STI) under both environments and could be conducted for high GMP and STI. Cluster analysis of genotypes by using of YE1, YE2, YE3 and five other indices categorized genotypes into four groups each of which having 27, 11, 16 members and 3 in E1 and 28, 8, 18 and 3 members in E2. Cluster analysis distinguished groups contains superior lines for both E1 and E2, considering their yield performance (YE3 and YE1& E2). In E1 and E2 tolerance and high yield were settled in Cluster 2 and Cluster 4 respectively.