Effect of Ethephon application and harvesting date on yield, seed losses and oil percent of Rapeseed

In order to eliminate the overlapping time of rapeseed harvesting and rice transplantation in Guilan province, and to provide appropriate solutions to reduce yield losses through seed loss, the present experiment was conducted as a factorial plots in a completely randomized blocks design with three replications at the Rice Research Institute of Iran in Rasht. The main plots in the present experiment consisted of the interaction of two ethephon foliar application factors at two levels (non-consuming and consuming 280 gram per hectare) and foliar application time at three levels ( podding, early grain filling, grain filling completion) and subplot including harvesting time in three phases, physiological maturation, 10 and 20 days after the physiological maturity. The results showed that ethephon foliar application with a mean time of 192 days reduced 8 days growth period compared to control treatment with an average time of 200 days. Also, erosion time (194.6 days) was higher than early grain filling (196.3 days) and seed filling completion with 197.1 days for early maturity traits. The effect of harvest time on number of pods per plant, one-thousand grain weight, grain yield, oil percentage was significant. According to the results, ethephon foliar application caused 12 percent increase in grain yield and 0.7 percent increase in oil in later harvestings. The interaction effect of foliar application, foliar application time and harvest time on seed yield was significant. Ethethenol soluble foliar application at the time of podding, with the lowest grain loss, was 202.8 kilogram per hectare as the best experimental treatment.