Study of Tolerance Indices of Different Cultivars of Canola under Salinity Stress

In order to investigate the effect of four salinity levels of irrigation water (1.15, 4, 7 and 10 dS.m-1) on four cultivars of canola (Hyola 4815, 308 and 401 and RGS 003), an experiment was designed as factorial based on complete randomized blocks with 3 replications. Tolerance of Canola cultivars related to salinity stress in aspect of seed and oil yields and seed and oil water use efficiencies were evaluated based on 12 tolerance indices. The results showed that in aspect of seed yield and water use efficiency, Hyola 308 cultivar had significant difference with other cultivars. However, there was not significant difference in aspect of oil percent, yield and water use efficiency between all cultivars. Salinity led to reduction of seed yield and water use efficiency and of oil yield and water use efficiency, although it was not significant up to 4 dS.m-1. The result of tolerance indices on seed yield and water use efficiency traits showed that Hyola 308 cultivar selected as the most salinity tolerant cultivar on the base of all indices. Also, in aspect of seed oil yield and water use efficiency traits, Hyola 4815 and RGS 003 were most tolerant cultivars, although their differences was not significant with Hyola 308 cultivar. Results of correlation analysis on seed yield under stress and non-stress conditions with 12 tolerance indices showed that highest correlation was observed between Yield Stability Index, Yield Index, Stress Index, Stress Susceptibility Percentage, Stress Susceptibility Index and Modified Stress Tolerance Index.