Effects of head pruning and different nutritional systems (chemical, biological and integrated) on seed yield and oil content in medicinal pumpkin (Cucurbita pepo L.)

To evaluate the effect of head pruning and different nutritional systems (chemical, biological and integrated) on yield and seed oil content in medicinal pumpkin (Cucurbita pepo L.), an experiment was conducted in Kermanshah/Iran during the 2013 growing season. The experimental treatments consisted of two levels - no head pruning, control (Co) and head pruning (C1) allocated to the main plots. Four levels of different fertilizing systems - control (without fertilizer) (T0), chemical (T1), biological (a combination of nitrogen fixing bacteria, Azospirillum brasilense and Glomus mosseae) (T2), and integrated fertilizing system (biological fertilizer + 50% chemical fertilizer) (T3) were assigned to the sub-plots. The experimental treatments were arranged as a split plot based on a randomized complete block design with three replications. The results showed that the highest percentage of seed oil was obtained (37%) in the integrated nutritional system along with the head pruning treatment. The highest grain yields of 53 and 50 g per square meter were obtained in integrated and chemical fertilizing systems, respectively while no pruning was applied. The highest fruit yields of 3,710 and 3,668 kg per hectare were produced by chemical and integrated fertilizing systems, respectively. The biological nutrition system required more time to demonstrate its positive effect on the growth and yield of medicinal pumpkin