Medicinal pumpkin (Cucurbita pepo convar. pepo var. styriaca) is an annual plant belonging to the family of Cucurbitaceae. It bears a sprawling prickly stem, about 300-500 cm long. Tropical and sub-tropical regions of America are reported as origin of medicinal pumpkin. The seeds contain fatty oil, ?-sitostrol and E-vitamin as active substances that are used to cure prostatic hypertrophy as well as urinary tract irritation. In this study that was carried out in College of Agriculture at Tarbiat Modarres University, the effect of five pruning treatments at different developmental stages (no pruning, 3-5 nodes, 6-8 nodes, after appearance of the first flower and after 8-10 flowers appearance) on the number and weight of fruit, some characteristics of seed fatty oil and its fatty acids were studied. The results showed that pruning at 6-8 node stage significantly effected the number of fruits, fresh and dry weight of seed in the fruit as well as in the plot. The control (no pruning) and 6-8 node stage of pruning treatment had a significant effect on the number of seeds per fruit, fresh and dry seed weight per fruit, and per plot. The greatest 1000 seed weight was obtained from control. Pruning was demonstrated to have no effect on fatty oil content but fatty acids content was affected by pruning operations.
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