Pumpkin (Cucurbita pepo L.) is an important and valuable medicinal plant for its seeds. Phosphorus is a major nutrient which its deficiency limits plant growth. This investigation was aimed at studying sources integrated application of phosphorus supply on growth and production of Pumpkin. Co-inoculation of phosphate solubilizing microorganisms (PSM) (mycorrhiza and bacteria) with and without seed inoculations, and P chemical fertilizer at 0, 25%, 50%, 75% and 100% of recommended fertilizer were applied. Hence, a factorial experiment was done based on randomized complete block design with three replications. Data indicate that PSM and P fertilizer show significant effects on all traits. Maximum oil yield (41.80 g m-2) and linoleic acid (68.30 %) were obtained with applying PSM and consuming 50% of the recommended P fertilizer. Seed yield was significantly increased in response to inoculation of PSM in the presence of low levels of P fertilizer. However, maximum mycorrhizal colonization obtained in 25% recommended P fertilizer. A high level of P fertilizer has a negative effect on the activity of PSM. On the other hand, a low level of phosphorus with PSM has a simulative impact on root colonization and productivity of Pumpkin and favors the activities of PSM.
