Investigation of the Effect of Delayed Sowing Date on Some Agronomic Characteristics of Rapeseed (Brassica napus L.) Cultivars in Kermanshah

Planting date is considered an essential factor in agricultural production and it affects the growth, and yield of rapeseed .In order to investigate the effect of delayed planting dates on some phonological traits, yield, and yield components of rapeseed cultivars, a split-plot experiment based on randomized complete block design with three replications was conducted during the growing season 2014-2016 at the research station of Islamabad Gharb, Iran. Experimental treatments were two planting dates (7 and 17 October) as the main plot and five rapeseed cultivars (Nafis, Nima, Okapi, Neptune and Elvis) as subplot. The results showed that the effect of year, cultivar and planting date and their interactions were significant on most of the studied traits. The values obtained in most traits on October 7 planting date were higher than October 17. The highest number of pods per plant (214 pods), number of seed per pods (25.31 seeds), and seed yield (6793 kg.ha-1) were related to the Nima cultivar on October 7. Also, at the planting date October 7, the highest 1000 seed weight (3.61 g) was related to the Neptune cultivar. The highest plant height in both years was observed on October 7. The values of the studied traits were higher in the second year than in the first year due to climatic conditions during the experimental years. Finally, it can be reported that with increasing delay in winter rapeseed planting, the growth and yield of this plant decreases and that Nima cultivar had acceptable yield in delayed planting date.