Effects of Nitrogen Fertilizer on Growth, Seed Yield and Oil Seed Content of Naked Seed Pumpkin (Cucurbita pepo subsp. pepo var. styriaca)

Naked (Styrian, Green Gold, Medicinal) pumpkin (Cucurbita pepo L. subsp. pepo var. styriaca Greb.) is one of the valuable medicinal plants in pharmaceutical industries of developed countries. Nitrogen influenced on the growth, development and productivity of the plants. In this study, nitrogen applied at four levels (0, 50, 100 and 150 Kgha^-1) with three replicates in each treatments. Nitrogen fertilization were applied at three different stages of the plant growth: seed sowing time, fourth leaves and flowering stage. In order to study the effects of increasing nitrogen level on leaf total chlorophylls content, leaf dry matter, fruit and seed yield and oil seed content of the medicinal pumpkin determined. The results indicated that nitrogen fertilization increased the amount of total leaves chlorophyll content in comparison to the check. The highest rate of chlorophylls content of the leaves obtained when nitrogen applied at 150. There were significant different between some treatments on fruit and seed yields, seed dry matter and oil seed content of the plants. The highest oil levels obtained at 100 and 150 Kgha^-1 of nitrogen fertilization.