Effect of silica and calcium contents and harvest dates on yield and components function of canola (Brassica napus L.)

In order to investigate the effect of silica and calcium content and harvest dates on yield and yield components of rapeseed as a factorial split in a randomized complete block design with three replications in experimental farms in Aftab region of Tehran province in two cropping years 2018-2019 and 2019-2020 were implemented. Experimental factors include harvest date in three levels one week after the start of yellowing of pods, two weeks after the beginning of yellowing of pods and time of complete yellowing of pods, silica in three levels of zero (control), 3 and 6% of the source was sodium and calcium silicate at three levels of 2, 4 and 6% of the source of calcium sulfate. The results showed that the effect of year on plant height, number of pods per plant, number of seeds per pod and anthocyanin was significant and the second year had the highest amount of these traits. It was observed that the best grain yield of 2477.02 kg / ha and harvest index of 24.83% was related to harvest one week after the start of yellowing of pods and with delay in harvest, 1000-seed weight, grain yield, Biological yield and harvest index decreased and anthocyanins increased. According to the results, silica foliar application with 32.81% increase in plant height, 11.8% number of pods per plant, 31.48% number of seeds per pod, 17.2% weight per thousand seeds, 24.31% grain yield, Biological yield and harvest index and reduction of anthocyanin and electrolyte leakage were associated. The most positive effect on physiological characteristics and yield and yield components was obtained in 6% silica spray. With increasing calcium concentration, plant height, number of pods per plant, number of seeds per pod, 1000-seed weight, grain yield, biological yield and harvest index decreased and anthocyanin and electrolyte leakage decreased, the maximum positive effect on these traits in foliar application 6% calcium was observed. The results showed that silica and calcium had an additive effect on yield and yield components and the best grain yield was obtained by consuming 6% silica with 6% calcium and harvesting one week after the start of yellowing of pods.