Evaluation of Some Physiological Characteristics of Spring Rapeseed Genotypes under Drought Stress

This experiment was conducted in 2010 in order to study the effect of drought stress on proline, soluble carbohydrates, relative water content, concentration of potassium and sodium of leaf, electrolytes leakage from leaves and grain yield of spring rapeseed cultivars in Research Greenhouse of Yasouj University, Yasouj, Iran. The experiment was factorial, based on completely randomized design with three replications. In this research, six genotypes of spring rapeseed (CR3189, CR3250, Kosa Kroko, Marnoo and Regent) and irrigation treatment at three levels (irrigation after 10, 40 and 70% depletion of soil moisture) were studied. Results showed that interaction of irrigation and genotype had significant effect on all traits, except potassium concentration. Comparison of average values of treatments showed that in all genotypes, the proline content, soluble carbohydrates, sodium concentration and electrolytes leakage from leaves were increased due to drought stress, but potassium concentration, relative water content and grain yield were decreased. Among the genotypes, at all three levels of irrigation, the maximum grain yield (0.86, 0.58 and 0.34 g/plant, respectively) was related to Kosa cultivar, which had less electrolyte leakage and sodium concentration, but higher proline content, potassium concentration and relative water content. Regent cultivar had the lowest potassium concentration, proline, relative water content and grain yield and also had the highest electrolytes leakage and sodium concentration. The lowest grain yield at 10% irrigation level (0.47 g/plant) was in CR3250 genotype and at 40% and 70% irrigation levels (0.33 and 0.19 g/plant, respectively) was observed in Regent genotype. Overall, based on the obtained results, Kosa and Regent cultivars were identified as tolerant and susceptible to drought stress, respectively.