EFFECT OF DEFOLIATION AND SILIQUE REMOVAL ON CARBOHYDRATES ACCUMULATION, SEED QUALITY, AND YIELD OF RAPESEED (BRASSICA NAPUS L.)

Rapeseed is one of the important oil seed crop and it has many studies related to its yield and oil quality. There is a lack of quantitative information on the effect of rapeseed yield and quality by management measures (Defoliation and silique removal). This study was designed to investigate defoliation and silique removal treatments effect on the physiological process at the flowering stage, the quality and quantity of crops. A field trial was carried out at the Experimental Research Station of Sichuan Agricultural University in Sichuan province of China, in 2020. The split-plot field experiment was designed with treatments as the main plot and variety as a subplot with three replicates. The leaf and silique removal treatments were applied to investigate their seed yield and quality behaviors at the flowering stage. This experiment was conducted by using two high-yielding varieties, V-1=JYJS01: medium height variety and V-2=CY36: tall height variety to investigate the impact of different leaf and silique removal treatments, T-1=control; T-2=50% branch silique removal; T-3=50% defoliation; T-4=100% branch silique removal and T-5=100% defoliation. Our results have revealed that the effect of defoliation and silique removal treatments affected the N uptake of rapeseed plants. During the physiological maturity stage of rapeseed, treatment T-4 significantly amplified the protein content by 9%, while the seed oil content was decreased by 3.95% compared to T-1. Moreover, in contrast, the stem sucrose and reducing sugar content were decreased at T-4 by 26.70% and 42.80 % compared to T-1, respectively. The seed yield and plant biomass was also decreased at T-4 compared to T-1. Our findings revealed that higher stem nitrogen percentage and sugars metabolism was possible during the seed filling stage of rapeseed by defoliation and silique removal treatments. Further research is required to investigate the involvement of molecular mechanisms in the fatty acid metabolism of rapeseed.