Assessment of quantitative and qualitative traits in the pumpkin (Cucurbita pepo L.) under water deficit stress induction and nitrogen fertilizer

To study some quantitative and qualitative traits of Cucurbita pepo L. under fertilizer and water deficit stress, a trial was conducted in the research field of Tarbiat Modares University in 2011 and 2012 cropping years. In this study, the experiment was performed in factorial randomized completely block design with three replications. and water deficit at three levels (normal irrigation, withholdingirrigation at milk stage, withholdingirrigation and spraying sodium chlorate at milk stage). Results showed that nitrogen fertilizer treatment significantly affected all traits studied except seed number and stress treatment had significant effects on all traits except seed number, seed length, and stearic acid content at 1% level of significance. In this study, increasing water stress reduced the content of all traits studied except linoleic acid content. In addition, increased levels of nitrogen fertilizer led to the decreased content of all traits studied. The highest values for fruit and seed weight, seed width, seed diameter, oil, linoleic, oleic, palmetic, and stearic acid were obtained at a nitrogen fertilizer level of 60kg.ha-1. Totally, nitrogen fertilizer (60kg.ha-1) and control irrigation treatments are recommended as the most suitable treatments to gain maximum seed yield.