تأثیر تاریخ کاشت بر فیزیولوژی عملکرد ارقام مختلف کلزا در منطقه ورامین

    Abstract:   This research was conducted to investigate the effect of sowing date on growth and yield of five rapeseed (Brassica napus L.) cultivars. The experimental design consisted of four randomized complete blocks (CRDB) in a split-plot arrangement. Four convetional sowing dates (11 September, 27 September, 12 October and 27 October) as main plots and five rapeseed cultivars (RGS003, HAYOLA401, OKAPI, SARIGOL and ZARFAM) as sub-plots were evaluated. Traits evaluated included number of silique per main and secondary stems, grain yield, number of seed per silique, 1000-grain weight, biological yield, oil yield, oil content and harvest index. Sowing date had significant effect on all of the characteristics except for number of silique per secondary stem and harvest index. Cultivar also had significant effect on all of the characteristics except for 1000-grain weight and harvest index. Results showed that delayed sowing date left significant negative impacts on all of the characteristics except for number of seed per silique. Among the cultivars investigated, the highest and the lowest grain yield belonged to RGS003 and HAYOLA401, respectively. Results showed that the optimum sowing date for fall cropping of rapeseed in Varamin region was September. Also the best yielding cultivar for this area was RGS003.