Effects of Planting Date on Spring Rapeseed (Brassica napus L.) Cultivars under Different Irrigation Regimes

Two field studies were conducted during 2011-2013 years using factorial split plot experiment laid out in RCBD with three replications, to assess the effects of planting date on some qualitative and quantitative traits of three spring rapeseed (Brassica napus L.) cultivars under different irrigation regimes. Planting date in three levels as February 24, March 6, and March 16 and Irrigation in two levels as normal irrigation and interruption of irrigation from the pod formation stage (water stress) were randomized in the main plots and spring cultivars including V1: RGS003, V2: Sarigol, and V3: Zarfam were randomized in subplots. The results of experiments showed that water stress and delayed planting date negatively affected yield components of seed and oil yield of rapeseed cultivars as the highest means of all assessed traits (plant height, stem diameter, number of branches per plant, pod length, number of pods per plant, number of seeds per pod, 1000 seeds weight, seed yield, seed oil content, seed oil yield, total chlorophyll content and oleic acid content) obtained in first planting date and under normal irrigation by RGS003. RGS003 showed superiority in comparison to other cultivars in all planting dates and irrigation regimes