Role of Triple Intercropping System in Weeds Control and Naked-Pumpkin (Cucurbita pepo L.) Yield

In order to study of maize، pinto bean and naked-pumpkin triple intercropping system effects on weeds suppression and optimal yield of naked pumpkin، an experiment was conducted as factorial based on randomized complete block design with three replications in both sites (Rasht and Roudsar) in Guilan at 2013. Treatments consisted of naked pumpkin sole crops (60 and 90 cm on row)، maize – naked pumpkin double crops (30-60 cm and 40-90 cm on row) and maize-pinto bean-naked pumpkin triple crops (30-20-60 cm and 60-30-90 cm on row) and hand-weeding and no-weeding. The result showed that place had significant effect on yield and yield component of pumpkin and the best results observed in Roudsar. Interaction between cropping systems and weeding treatment was significant in Rasht. The highest and lowest seeds per fruit number، mean weight of fresh fruit، weight of 1000 seeds and fruit and seed yield were obtained in sole cropping (hand-weeding) and triple cropping (no-weeding)، respectively. But، in Rasht، weeding treatments hadn’t significant effect on measured traits and the maximum of them observed in sole cropping systems. Based on results، triple cropping systems suppressed weeds (broadleaf and grassy leaf) more than double and sole cropping systems. The reduction of yield in triple and double cropping in no-weeding was lower than sole cropping that showed better control of weeds in intercropping systems.