EVALUATING THE RESPONSE OF SOME CANOLA (Brassica napus L.) CULTIVARS TO SALINITY STRESS AT SEEDLING STAGE

The current study reports salt tolerance of eleven cultivars of canola from diverse backgrounds. Ten days old seedlings were transplanted in an aerated hydroponic system containing Hoagland’s solution.Salinity levels (100, 140 and 180 mM NaCl) were developed by dissolving NaCl in nutrient solution. Nutrient solution without salt was used as control. The blade of 3rd fully expanded leaf was sampled to determine Na^+, K^+ and K^+/Na^+ ratio on day 28 of salt stress. Shoot fresh and dry biomass, root fresh and dry weight and leaf area were recorded on day 42 of salt stress. The KS-75, Rainbow, DGL and Shiralee were found most efficient among cultivars in maintaining low Na^+, while high K^+ and K^+/Na^+ ratio in leaves under salt stress. Based on plant growth and ionic regulation, cultivars KS-75 and Rainbow were placed in salt tolerant group, whereas Shiralee, DGL, Westar, KH-65 and Legend in moderately tolerant group. The Con-II, Con-III, Dunkeld and Oscar were categorized as fairly salt tolerant cultivars. Results express useful variation for salt tolerance among canola cultivars which may be exploited through selection and breeding forfurther improvement of salt tolerance in canola.