Effect of deficit irrigation and kaolin clay on yield and yield components of pumpkin (Cucurbita pepo L.)

This experiment was conducted to determine the effect of kaolin clay application and deficit irrigation on quantitative characteristics of pumpkin in a field located in Siahbaz village of Khoy, Iran. In order to investigate the effect of irrigation and kaolin clay on yield and yield components of (Cucurbita pepo L.), this experimental was considered. An experiment was performed with irrigation at four levels (complete irrigation, deficit irrigation from the shoot stage, deficit irrigation from flowering stage and deficit irrigation from seed filling stage) and three levels of kaolin foliar application (control, 3% kaolin and 6% kaolin) was considered. Analysis of variance showed that deficit irrigation and kaolin had significant effect on number of seeds per fruit, fruit yield, 1000 grain weight, grain and biological yield, harvest index, oil and protein percentage, oil yield and protein yield. Maximum grain weight (294.5 gr), grain yield (807 kg ha−1), oil percentage (46.2) and oil yield (373.3 kg ha−1) were related to complete irrigation treatment. The highest grain weight (257.07 gr), grain yield (733 kg ha−1) and fruit yield (23.8 kg ha−1) were observed in the 3% kaolin. Based on the results, deficit irrigation at seed filling stage was superior to other treatments. Kaolin had no effect on grain yield and could be interrupted once without irrigation. Kaolin used in this experiment under irrigation limitation conditions could partially offset the water-deficit yield due to control treatment. Due to lack of water, yield of untreated plants was lower than kaolin-treated ones.