Effect of Late Sowing Date on Agronomic and Quality Traits of Four Winter Oilseed Rape (Brassica napus) Cultivars in Hamedan, Iran

Appropriate planting date is directly related to the geographical situation and climatic conditions of the region. Due to the declining trend of rainfall and lack of soil moisture in most parts of Iran, applying the maximum possible delay in planting is essential due to less autumn irrigation and getting closer to autumn rainfall. Therefore, to investigate the effect of delay in planting on quality traits, yield, and yield components of rapeseed, an experiment was conducted in 2012 as split plots in a randomized complete block design with three replications in Hamedan province, Iran. The main factor was planting date in 4 levels, including 10 September, 20 September, 30 September, and 10 October. The second factor was four genotypes of Okapi cultivar and hybrids of Tassilo, Octans-NK, and Elite. The results showed that the number of pods per plant, biological yield, seed yield, harvest index, and oil yield at 1% probability level and the number of seeds per pod and Thousand seed Weight (TSW) at 5% probability level were affected by the interaction of planting date and genotype. Also, the simple effect of genotype on the percentage of seed oil was significant at the level of 1% probability. The highest seed yield in the first planting date with 5083.3 kg/ha belonged to the Octans-NK genotype and the lowest yield in the last planting date (1244.4 kg/ha) belonged to the Okapi genotype.