تعیین مهم ترین جزء عملکرد کلزا در تاریخ های کشت و سطوح نیتروژن

To evaluate the effects of sowing date and nitrogen on seed yield by stepwise regression, a field experiment was conducted in the 2011-2012 growing season at the experimental farm of the College of Agriculture, Shiraz University, Shiraz, Iran. Treatments includes: three sowing dates (23 September, 2 October, and 12 October 2011) and four levels of nitrogen (0, 50, 100 and150 kg N ha-). In early sowing date (23 September) seed weight in main pod was the most important variables contributing seed yield, but in delayed sowing dates (2 October, and 12 October) branch number and seed weight in secondary branches with partial R2 0.87 and 0.91 were the most effective components, respectively. As, with increasing nitrogen, variables contributing seed yield, were changed. Stepwise regression analysis showed that with increasing nitrogen from 0 to 50 and 100 to 150 kg Nha-1, seed weight per main pod, number of seed per sub pod and seed weight per sub pod explained 87%, 91% and 89% variations of seed yield, respectively. It means that, with increasing of nitrogen from 0 to 50 kg Nha-1 the role of seed weight per main pod decreased.