Evaluation of Drought Tolerance in Canola (Brassica napus L.) Genotypes, using Biplot Analysis

Drought is one of the major environmental stresses that adversely affect crop growth and productivity worldwide. For evaluation of drought stress on grain yield, yield components and drought tolerance indices, 20 genotype of rapeseed (Brassica napus L.) was studied in an experiment based on a randomized complete blocks design with three replications in two different conditions (stress and non-stress). Result of mean comparision showed significant difference among all genotypes for all traits. Losses in grain yield, thousand grain weight and water use efficiency due to drought stress was more than other traits. In this study, geometric mean productivity index (GMP), mean productivity index (MP), harmonic mean index (HAM) and stress tolerance index (STI) showed high correlation with grain yield in normal and drought stress conditions. In present research, GT-biplot approach was applied for grouping and detection drought-tolerant and drought-sensitive genotypes. Biplot diagram based on interaction of genotype × trait (tolerance index) indicated that genotype Zarfam is the most stable genotype for non-stress and drought stress conditions, and in other hand Talent and Talye genotypes were identified as the most sensitive genotypes to drought stress condition. Hence, the statistical model of GT-biplot could provide useful information for evaluation of drought-tolerance canola genotypes in water deficit stress condion.