Effects Of Brassinosteroids And Jasmonates On Seed Yield And Quality Of Oilseed Rape

Oilseed rape is an important oil crop, which plays an important role in the protection of the safety of China’s edible oil supply, In the main winter rapeseed production areas of the middle and lower reaches of the Yangtze River, the long rainy and sunless, which often occur during the period of blooming and seeding, restrict severely the promotion of seed yield and quality in oilseed rape production. In this study, we applied different concentrations of brassinosteroids and jasmonates-like substances and their combinations with inorganic fertilizer at the end of full-bloom stage, to explore technical ways to regulate seed yield and quality of oilseed rape. The main results are as follows:1. Suitable concentration of brassinosteroid compounds treatment could improve seed yield per plant. Compared to the control, the treatment of0.2μmol/L brassinolide (domestic product), Yunda120(epi-Homobrassinolide, BR120) and TS-303(brassinolide, Japanese product) increased seed yield by14.87%,6.04%and5.27%, repectively. The treatment of inorganic fertilizer could also improve seed yield per plant by12.58%. Tests showed that, the above regulators increased pod number, total pod surface area per plant and chlorophyll content in pod. Correlation analysis showed that, the seed yield per plant was significantly positively correlated with plant aboveground biomass and total pod surface area per plant.2. Treatments with brassinosteroids compounds reduced oil content of rape seed to varying degrees, among which, the maximum reduce was6.85%less than the contron when treated with0.2μmol/L TS-303treatment.Seed phosphorus absorption was positively correlated with seed yield per plant (r=0.7574, P=0.0112), but negatively with oil content of seed (r=-0.6332, P=0.0494)3. Treatment with proyl dihydro jasmonate (PDJ) separately had a certain inhibition on seed yield, and the inhibition increased along with increasing treatment concentration. While, treatments of appropriate concentration of PDJ with brassionosteroid and inorganic fertilizer could increase seed yield. Under the treatments of0.4μmol/L PDJ combining with inorganic fertilizer, or with brassinolide and inorganic fertilizer, seed yield increased by9.70%and8.83%, respectively, compared to the control. The treatments of0.4μmol/L PDJ with inorganic fertilizer was shown to increase pod number per plant, chlorophyll content in pods, aboveground biomass and total pod surface area per plant, but have little effect on seed number per pod and thousand seed weight. Correlation analysis showed that, seed yield per plant was significantly positively correlated with plant aboveground biomass and total pod surface area per plant, with correlation coefficients of0.9612(P<0.0001) and0.7981(P=0.0099), respectively.4. PDJ treatments had little effect on the oil content of seed, but the treatment of0.4μmol/L PDJ with inorganic fertilizer decreased the oil content of seed by6.57%, compared to the control. Seed potassium absorption was positively correlated with seed yield per plant (r=0.7245, P=0.0273), while seed phosporus absorption negatively with the oil content of seed (r=-0.6760, P=0.0456).