Effects of irrigation interval and quantity on the yield and quality of confectionary pumpkin grown under field conditions

Confectionary pumpkin (Cucurbita pepo L) is one of the important snacks preferred by consumers in Turkey due to its higher nutrient contents. However, there is no comprehensive study on water management in pumpkin cultivation in many countries including Turkey. Therefore, a 2-year study (2013-2014) was conducted to determine the effects of different irrigation intervals (S) and irrigation levels (I) on the seed yield and yield components of drip-irrigated confectionary pumpkin under the Middle Anatolian climatic conditions in Konya, Turkey. The experimental design was made in randomized blocks, in a 3 x 5 factorial scheme, with three replications. Treatments consisted of three irrigation intervals (S-7: 7 days, S-14: 14 days, and S-21: 21 days) and five irrigation levels (I-100: 100% irrigation or full irrigation, I-75: 75% of full irrigation, I-50: 50% of full irrigation, I-25: 25% of full irrigation, and I-0: no irrigation). Seasonal plant water consumption or actual evapotranspiration (ETa) of irrigation treatments varied from 194.2 to 660.2 mm in 2013 and from 208.6 to 629.6 mm in 2014. The irrigation interval (S) and the irrigation level (I) significantly affected the seed yield and quality of pumpkin in both the years. Typically, no significant differences were found among S7I-(100), S7I75, and S14I100 treatments in both the years although S7I100 treatment produced the highest seed yield (1274 kg ha(-1)). In 2013, except for 1000-seed weight, interaction between the irrigation interval and the irrigation level significantly affected the seed yield, the number of fruits per plant, seed yield per fruit, and mean fruit weight; however, in 2014, the effects of S x interaction on the seed yield and yield components were not significant. Seed yields were significantly affected in a linear relationship by the amount of irrigation water and evapotranspiration in both the years. Seasonal yield response factors (k(y)) were 0.92 and 1.27 in 2013 and 2014, respectively. In conclusion, I-100 with a 7-day irrigation interval is recommended for pumpkin grown under field conditions to maximize the yield. However, if the irrigation water is scarce, it will be suitable to irrigate pumpkin with either 25% water deficit (7-day interval) or full irrigation (14-day interval) in semiarid conditions. (C) 2015 Elsevier B.V. All rights reserved.