Effect of Phosphate Solubilizer Biofertilizer and Phosphorus Fertilizer on Response of Agronomic Traits, Yield and Yield Components of Pumpkin (Cucurbita pepo L.)

This research was carried out to investigate the response of agronomic traits, yield and yield components of pumpkin (Cucurbita pepo L.) to phosphate solubilizer biofertilizer at different levels of phosphorus (P) fertilizer. The experiment was factorial, based on randomized complete blocks design with three replications. Treatments included two levels of phosphate solubilizer biofertilizer (inoculation of seeds and non-inoculation) and P fertilizer at four levels (25, 50, 75 and 100% of recommended level based on soil test), which were performed at Educational and Research Farm of Bu-Ali Sina University, Hamadan, Iran, in 2011. Results of the flowering stage showed that application of 75% P fertilizer produced maximum number of leaves per plant (21.86), leaf dry weight (27.75 g/plant) and plant dry weight (49.66 g). At the stage of fruit production, maximum number of branches and leaf dry weight per plant were achieved in inoculation treatment. With increasing P fertilizer application, the number of fruits per plant was increased. Application of P fertilizer up to 50% of recommended level along with using biofertilizer increased seed yield. This result could be due to increased efficiency of bacteria, which dissolve phosphate in lower rates of P fertilizer.