Delay cropping effect on yield, yield component, grain oil content of two canola (Brassica napus L.) cultivars

In order to evaluate the delay cropping on yield and yield component of two canola cultivars and selecting the best genotype and row spacing, an experiment was conducted at three years (2007, 2008 and 2009) in Gorgan Research Station. This experiment was arranged in spilt-factorial based on randomized complete block design with four sowing dates (28 Oct., 12 and 28 Nov. and 12 Dec.) as main plot and row spacing (12 and 24 cm) and cultivar ( RGS and Hayola 401) as subplot in three replications. Growth stage, number of sillique per plant, number of seed per sillique, seed yield and grain oil content (%) was recorded. Results showed that delay cropping had different effect in three years and delay planting had higher risk during dry years. In normal years seed yield reduced 27 Kg ha-1 per one day delay in sowing. Average seed yield of three years at different sowing date showed that Hayola produced higher yield (3287 Kg ha-1). Seed yield of Hayola and RGS reduced 379 and 410 Kg ha-1 per ten days delay in sowing date. Relationship between mean air temperature during flowering and maturity showed that the effect of increasing temperature on seed number (351 Kg ha-1 loss) was more than seed weight (100 Kg ha-1 loss). Ten days in planting date increased oil percent (1%). In general, in delay planting Hayola cultivar is recommended and increasing row spacing did not have significant effect.