Effect of Deficit Irrigation on Grain Yield and Quality Characteristics of Oil content of Sunflower (Helianthus annus L.)

In order to evaluate the grain yield and the quality characteristics of sunflower grain oil in response to deficit irrigation (DI), a split plot experiment based on randomized complete block design with three replications and two factors was carried out at experimental farm of Safiabad agricultural and natural resources research and education center in 2019–2020 growing seasons. The factors were DI as the main factor (including control, moderate DI, and severe DI- based on the discharge of 50, 70, and 90% of field capacity) and cultivar as sub-factor (including Oscar, Felix, Shakira, Savana, Labad, and Monaliza). The results showed that deficit irrigation caused a significant difference in grain yield, grain number per head, grain weight per head, oil quality characteristics compared to the control. Deficit irrigation caused a significant reduction in grain yield, grain number per head, and oil yield by 49.94, 49.94, and 26.67%, respectively, compared to control. In addition, deficit irrigation increased iodine index, peroxide value, phosphorus, chlorophyll content, carotenoid content, and oil acidity; hence, impurity in oil and oil corruption was increased. In conclusion, Felix and Labad cultivars are recommend for cultivation in Dezful and similar regions due to having high grain yield and maintaining yield under deficit irrigation conditions.