Interactive Role of Fungicides and Plant Growth Regulator (Trinexapac) on Seed Yield and Oil Quality of Winter Rapeseed

This study was designed to evaluate the role of growth regulator trinexapac and fungicides on growth, yield, and quality of winter rapeseed (Brassica napus L.). The experiment was conducted simultaneously at different locations in Germany using two cultivars of rapeseed. Five different fungicides belonging to the triazole and strobilurin groups, as well as a growth regulator trinexapac, were tested in this study. A total of seven combinations of these fungicides and growth regulator trinexapac were applied at two growth stages of rapeseed. These two stages include green floral bud stage (BBCH 53) and the course of pod development stage (BBCH 65). The results showed that plant height and leaf area index were affected significantly by the application of fungicides. Treatments exhibited induced photosynthetic ability and delayed senescence, which improved the morphological characters and yield components of rape plants at both locations. Triazole, in combination with strobilurin, led to the highest seed yield over other treatments at both experimental locations. Significant effects of fungicides on unsaturated fatty acids of rapeseed oil were observed. Fungicides did not cause any apparent variation in the values of free fatty acids and peroxide of rapeseed oil. Results of our study demonstrate that judicious use of fungicides in rapeseed may help to achieve sustainable farming to obtain higher yield and better quality of rapeseed.