The effect of chlormequat chloride spraying and different level of nitrogen fertilizer on yield and yield components of rapeseed (Brassica napus L.)

To evaluate the effect of varied concentrations of chlormequat chloride (CCC) on yield, yield components and grain quality of rapeseed under different nitrogen (N) levels, a field study was conducted as factorial experiment based on randomized complete block design with three replications during 2014-2015 growing season in Marvdasht. The treatments were consisted of nitrogen fertilizer at four levels: 50, 100, 150 and 200 kg ha-1 and CCC spraying at three concentrations: 0, 1.5 and 3 g.L-1. IThe results of analysis of variance showed that the effect of N on all traits, the effect of CCC on all traits except hundred grain weight and the effect of N and CCC interaction on all traits except hundred grain weight and protein percentage were significant. Nitrogen and CCC had positive and significant effect on yield, yield components as well as protein and oil percentage of seed. In general, increasing N up to 150 kg ha-1 was associated with enhanced quantity and quality of rapeseed crop, whereas more amount of N had no significant effect on yield components but reduced oil percentage of seed. There is no significant difference between 1.5 and 3 g.L-1 CCC spraying. Under no CCC application, N up to 150 kg.ha-1 and under CCC foliar application N up to 200 kg.ha-1 increased grain yield. Exceeded amount of N stimulate tillering and increase infertile tillers and reduce N efficiency, while CCC as a growth retardant increased uniformity intra plants and increased fertile tillers via prolong of development during.