Improvement of Drought Tolerance in Sunflower (Helianthus annuus L.) By Foliar Application of Abscisic Acid and Potassium Chloride

Abstract

A field experiment was carried out at the Research area, College of Agriculture, Dera Ghazi Khan to measure the response of spring sowing sunflower to foliar application of abscisic acid (ABA) and potassium chloride under drought. In the experiment four irrigations by flooding (25 days after sowing, at bud initiation, at anthesis and at achene formation stage) were applied in control. Foliar application of 2µM ABA and 1% KCl was made at anthesis stage of sunflower hybrids (NK-265 and SF-187) after skipping the irrigation. Foliar application of 2µM ABA and 1% solution of KCl under drought at anthesis stage significantly increased achene yield and oil yield over skipping irrigation with no ABA and no KCl at anthesis stage. Sunflower hybrid NK-265 showed better drought tolerance compared with SF-187 with foliar application of ABA as well as KCl because it showed improvement in growth and yield. Sunflower hybrids NK-265 had significantly increased achene yield and oil yield than SF-187. Drought stress at anthesis stage to sunflower hybrids showed decrease in agronomic parameters and foliar application of ABA as well as KCl under water deficits improved them. ABA as well as KCl application to sunflower hybrids at anthesis under drought improved achene oil content but decreased achene protein content. Exogenous application of ABA or KCl to NK-265 under drought showed more percent increased in achene yield and oil yield than SF-187 over no ABA and no KCl application. Foliar application of ABA as well as KCl on leaf score at anthesis stage was non-significant. It is, therefore, suggested that foliar application of 2µM ABA and 1% solution of KCl under drought at anthesis stage significantly increased achene yield and oil yield over skipping irrigation, no ABA and no KCl at anthesis stage. Sunflower hybrid NK-265 showed better improvement of drought tolerance by foliar application of ABA as well as KCl than SF-187 because it showed more improvement in growth and yield.