EFFECT OF IRRIGATION CUT-OFF AND PLANTING DATE ON YIELD AND YIELD COMPONENTS OF RAPESEED CULTIVARS
An experiment was performed as a factorial split plot and in the form of a randomized complete block design with three replications for two cropping years (2015-2016 and 2016-2017) in Pars water and soil field located in Karaj(Iran) to investigate the effect of irrigation cut-off and planting date on yield and yield components of rapeseed cultivars. Irrigation treatment included regular irrigation (irrigation after 80 mm of evaporation from Class A pan) and irrigation cut-off from the silique formation stage onwards in the main plots, planting date including September 27 and October 27 and winter rapeseed cultivars including Tassilo, Elvise, Neptune, and Okapi were evaluated in a factorial form in sub-plots. The results revealed that irrigation cut-off and delay in planting date had a significant effect on reducing plant height, number of sub-branches per plant, number of siliques per plant, number of grains per pod, and 1000-grain weight. The studied cultivars were significantly different in terms of all evaluated traits. Elvise and Neptune cultivars had the highest grain yield with 3346 and 3220 kg / ha, respectively, under normal irrigation conditions and with a mean of 3211 and 3081 kg / ha, respectively, under irrigation cut-off conditions. This advantage was mainly due to an increase in the tank capacity of the yield components. Therefore, Elvise and Neptune cultivars can be introduced with acceptable production stability under normal irrigation conditions and water stress conditions after silique formation.