Effect of mulch types and sowing date on morphological traits and yield of pumpkin Cucurbita pepo var. Styriaca))

Medicinal plants are the suitable subject in transition from conventional agriculture to sustainable agriculture. Pumpkin (Cucurbita pepo var. Styriaca) is one of the most important medicinal plants. Seed oil of it are used to prevent and treat prostate cancer. Sowing date is one of the effective parameters on the yield and quality of medicinal plants. Also mulch application is one of the effective parameters to achieve ecological goals of sustainable agriculture. Therefore, purpose of this study is evaluation of mulch and sowing date on agronomical traits and yield of pumpkin.

Factorial experiment was conducted based on randomized complete block design with two factors and three replications at research station of Kurdistan University during 2015 growing season. First factor was two sowing dates (20 May and 05 June) and second factor was five mulch types (transparent plastic mulch, black plastic mulch, straw mulch, live clover mulch and control treatment). Mesured traits were number of grain per fruit, number of fruit per plant, fruit diameter, fruit yield, 1000 seed weight, grain yield, biological yield and qualitative characteristics consisted of seed oil percentage and oil yield.

The results of analysis of variance showed that different treatments of mulch had significant effect on grain per fruit, number of fruit per plant, fruit diameter, fruit yield, grain yield, biological yield and qualitative characteristics consisted of seed oil percentage and oil yield of pumpkin. Sowing date significantly increased number of fruit per plant, grain yield, seed oil percentage and seed oil yield. Mulch and sowing date interaction effects was significant for fruit number per plant, grain yield, seed oil percentage and oil yield, so that the highest values of these parameters (1.82 number, 112.2 g/m2, 40.02 percentage and 44.2 g/m2) were obtained in the June sowing date and the black plastic mulch and the least of them was belonged to the control treatment and June sowing date. The factors had no significant effect on 1000 seed weight. Also, the highest number of grain per fruit, fruit yield and biological yield related to black plastic mulch, which was in a statistical group with transparent plastic. Conclosion: Results of this research revealed that sowing date and mulch application were effective on quantitative characteristics including fruit yield, seed yield and oil yield of pumpkin. In general, the date of May sowing date and black plastic mulch increased yield, yield components and qualitative traits of pumpkin.