Evaluation of sowing date and plant density on growth and seed yield of two canola (Brassica napus L.) cultivars in Gorgan's climatic condition

In order to study agronomic traits on sowing date and plant density of canola cultivars (B. napus L.), field experiments were carried out in Gorgan Agriculture experimental Station during 2002-2003 and 2003- 2004 cropping seasons. The experimental design was spilt plot factorial in a randomized complete block design with four replications. Four sowing date (Oct. 15th, Oct. 30th, Nov. 15th and Nov. 30th) were assigned to main plots and combination of canola cultivars (Hayola420 and R.G.S003) and plant densities (Including 80 and 120 plants/m2) were randomized to subplots. Late sowing date had negative effect on canola yield and yield components were the number of pod per plant, grain per pod, 1000 seed weight and seed oil content were reduced. Canola density have significant effect on seed yield and the highest canola seed yield was obtained at 80 plant/m2 (3012 kg/ha). The agronomic traits of sowing date and plant density only affected seed yield where the highest seed yield belonged to 15 Oct, 30 Oct and 15 Nov sowing date and 80 plants/m2 density and 30 Nov. sowing date with 120 plants/m2 density.