Effect of cycocel on safflower seed yield and oil at different levels of nitrogen and plant density

High nitrogen and plant density cause increasing vegetative growth and reducing harvest index. The objective of this study was to evaluate the effect of cycocel at high nitrogen and plant density on safflower yield and yield components. For this purpose a field experiment was carried out as a factorial-split plot based on randomized complete block design with three replications with Esfahan 14 safflower variety in 2010 in Yasouj, Iran. Main plots were three nitrogen levels (50, 100 and 150 kg ha-1) and two cycocel levels (0 and 10-6 M) as factorial and subplots were three plant densities (20, 25 and 33.3 plant m-2). Results showed that the interaction of cycocel, nitrogen and plant density were statistically significant for yield and yield components. The highest seed yield (3146.4 kg ha-1) was obtained from 10-6 M cycocel, lowest nitrogen level and 25 plant m-2. The interaction of nitrogen and plant density and the interaction of cycocel and nitrogen were statistically significant for seed oil percent. The most seed oil percent (27.75%) was obtained from the lowest nitrogen and 25 plant m-2. The greatest seed yield and quality was obtained from high plant density and cycocel, and the effect of nitrogen due to excessive soil fertility was low.