Effect of UV radiation and evaluated CO2 on morphological traits, yield and yield components of canola (Brassica napus L.) grown under water deficit stress

Abstract

In this study, we studied the combined effects of UV radiation, CO2 and water stress on the morphological traits, yield and yield components of canola (Brassica napus cv. 'Okapi' and 'Talaye') under twelve growth conditions: complete irrigation with ambient CO2 with UV-A (control), complete irrigation with ambient CO2 with UV-B, complete irrigation with ambient CO2 with UV-C, limited irrigation with ambient CO2 with UV-A, limited irrigation with ambient CO2 with UV-B, limited irrigation with ambient CO2 with UV-C, complete irrigation with elevated CO2 with UV-A, complete irrigation with elevated CO2 with UV-B, complete irrigation with elevated CO2 with UV-C, limited irrigation with elevated CO2 with UV-A, limited irrigation with elevated CO2 with UV-B and limited irrigation with elevated CO2 with UV-C. The results showed that water stress significantly decreased all of traits except for the oil percentage. Additionally, an elevated level of CO2 significantly increased the final yield, 1000-seed weight, oil yield, plant height, specific leaf area and number of branches per plant, whereas UV radiation decreased all of the traits in this experiment. Elevated CO2 ameliorated the adverse effects of UV radiation in the final yield, seed weight, oil percentage, oil yield, plant height, specific leaf area and number of branches per plant. This study showed that elevated CO2 can partially ameliorate some of the adverse effects of UV radiation in canola plants. Furthermore, in this study, we observed that the increase in the yield was due to the increase in the seed weight and number of branches caused by elevated CO2 in canola plants. In addition, the maximum yield was obtained from the 'Talaye' cultivar under conditions of sunlight, full irrigation and elevated CO2.