THE STUDY OF THE DROUGHT TOLERANCE OF CANOLA (Brassica napus L.) CULTIVARS BY USING STRESS TOLERANCE INDICES

To study the drought tolerance of the different canola cultivars by the evaluation of drought tolerance indices, fourteen canola cultivars were planted and studied in the research farm of Karaj area under both normal and stress conditions. For this purpose, the randomized complete block design (RCBD) with three replications was employed. The results indicate that SML046 and Sarigol cultivars have the mean seed yield respectively. The results of the combined analysis of variance showed that seed yield had had significant difference. The analysis of correlation between drought tolerance indices showed that there is a positive significant correlation between most indices. In addition, the analysis of the components shows that the first two factors explain approximately 99.93% of the variance. The cultivars were studied by the analysis of the data using drought tolerance indices. According to the indices TOL and SSI, the cultivars Talaye 13 and Hyola401 were the most tolerant cultivars to drought stress. According to the indices GMP and MP, the cultivars Licord and SLM046 were the most tolerant ones. Based on Harm index, the genotypes Sarigol and SLM046 were the most tolerant ones and finally, according to the STI index, the cultivar Sarigol had the highest tolerance for drought stress. The results of the study of correlation between the indices of drought stress tolerance indicate that there is a positive significant correlation between most indices. According to the results obtained from the bi-plot depicted from the two main components, the indices MP, GMP, and TOL are the best indices.