Evaluation of Terminal Drought Tolerance in Spring Rapeseed (Brassica napus L.) Promising Lines

To evaluate terminal drought tolerance in promising lines of spring rapeseed, using stress tolerance indices, this research was conducted in 2008-09 and 2009-2010 growing seasons in Safiabad Agricultural Research Center, Dezfoul, Iran. Eleven promising lines of spring rapeseed as well as Hyola401 (check) were evaluated in two separate field experiments using randomized complete block design with three replications in non-stress and terminal drought stress conditions. Results revealed that L5 and L4 were more tolerant than other lines using Stress Susceptibility Index (SSI) and Tolerance Index (TOL). However, Stress Tolerance Index (STI) and Geometric Mean Productivity identified Hyola401 and L1 line as genotypes with higher yield in both non-stress and drought stress conditions. Considering all drought tolerance indices, Hyola401 and L1 were suitable and adapted genotypes in terminal drought stress conditions. Study of correlation coefficients between seed yield in non-stress and terminal drought stress conditions and STI, GMP and MP showed that these indices are suitable for identification of terminal drought tolerant promising lines of spring rapeseed.