Effect of plant density and nitrogen rates on agronomic traits of Cucurbita pepo L.different sowing dates

ABRTRACT: In order to evaluate of plant density and different tempreture rates effect on agronomic traits of pumpkin, a factorial split plot experiment as randomized complete design with 3 replications was conducted. Swoing date factor in 3 levels included: 20 May, 5 June and 20 June with nitrogen factor in 2 levels included: 70 and 87.5 kg.ha-1in main plots as well as density factor in 2 levels included 10000 and 12500 plants/ha that as sub plots was considered. Results showed that sowing date had significant effect on grain yield. So that highest grian yield obtained from 5 June with mean of 875.8 kg.ha-1. Assess to sowing date and plant density showed that the highest grain yield belonged to density of 12500 plant/ha in 5 June. Results also revealed that highest 1000 grain weight and grain number gained from date of 5 June. Investigations clarified that nitrogen had not significant effect on grain yield, 1000-seed weight and grain number per plant.