Effect of delayed planting and foliar application of nitrogen on canola seed and oil yield in Ahvaz conditions

To investigate the effect of delayed plantine date and timing of foliar application of nitrogen on seed yield، yield components and quality of canola، a field experiment was conducted as split plot using randomized complete blocks design with three replications at research farm of Agriculture and Natural Resource University of Ramin، Iran، in autumn of 2013-2014 growing season. The experimental treatment consisted of three sowing date; 27 November، 17 December، 30 December which were assigned to main plots and the timing of of nitrogen foliar application in four levels; control، rosette، budding، flowering، were randomized in sub-plots. Results showed that the highest seed yield (3406. 6 kg. ha-1) and oil yield (1481 kg. ha-1) were obtained from the first sowing date. With delay in sowing date، seed yield، pod per unit area، 1000 seed weight، oil yield، growing degree days (GDD)، day to flowering and duration of flowering to maturity decreased significantly. Moreover، with delaying sowing date seed oil content decreased، but the canopy temperature increased. The effect of nitrogen foliar application on seed yield، yield components and oil yield of canola was significant. The highest seed yield، pod per unit area، 1000 seed weight and dry mater were obtained from nitrogen foliar application in budding stage، however، with nitrogen foliar application oil content significantly decreased. In conclusion، the first sowing date and nitrogen foliar application in budding stage produced the maximum seed and oil yield، therefore it was considered the most suitable treatment. In general، results showed that nitrogen foliar application in budding stage could compensate for the reduction in seed yield and oil content، due to delay in planting date and heat stress، by 31% and 34%، respectively.