Enhancement in Plant Water Relations and Fatty Acid Profile in Sunflower (Helianthus Annuus L.) Through Application of Abscisic Acid Under Varied Water Levels

Abstract

Enhancement in yield and quality of sunflower by foliar spray of abscisic acid (ABA) under water deficit condition was studied during 2016 and 2017. Three irrigation treatments were applied. Four irrigations (at 4-6 leaf, at vegetative, at flowering and at grain formation stage), three irrigations (at 4-6 leaf, at pre flowering and at grain formation stage), three irrigations (at 4-6 leaf, at vegetative and at grain formation stage). Sunflower hybrid (S-278) was sprayed with different ABA concentrations (0, 10 µm and 20 µm) at 4-6 leaf, vegetative, flowering and grain formation stage. Foliar application of 10 µM ABA under water stress at vegetative stage significantly enhanced plant height, head diameter, achene yield and biological yield. It also enhanced sunflower water relations by increasing water potential. ABA application and water deficit showed opposite results for yield and oil quality. Water deficit at vegetative or at flowering stage maximized stearic and oleic acid contents and minimized palmitic and linoleic acid contents, whereas foliar spray of ABA under water stress at both stages reduced stearic and oleic acid but maximized palmitic and linoleic acid.