Effect of Gibberellic Acid Application on growth, yield and oil quality of Sunflower (Helianthus annuus L.) under water stress

Field experiment was carried out at Hartha Station in Basrah University during the spring of 2021 to study the effect of four concentrates Gibberellic Acid (0,100,200,300 ppm) with three levels from water stress (% 100, % 75, % 50 from field capacity) in Sunflower. Included growth, yield and oil quality characters. Results showed that Gibberellic Acid concentrates were significant different in growth, yield and quality characters. The Gibberellic Acid (100 ppm) was superior in all growth, yield and oil quality characters. Furthermore, plant height, LAI, number of seeds in disc, 1000 seeds weight, seeds yield, and oil present (144.17 cm; 2.77; 1277.26 seeds; 51.83 gm; 3481.9 kg h-1 and % 38.72). The water stress (% 100 from field capacity) has been exceeding in most growth, yield, quality characters while, furthermore, plant height , LAI , number of seeds in disc, weight of 1000 seeds, seeds yield and oil present (137.96 cm ; 2.78 ; 1173.55 seeds ; 50.98 gm ; 3191..2 kg h-1 and % 39.42). Interaction between Gibberellic Acid and water stress affected significantly all growth, yield characters but insignificant in oil present. Interaction between water stress (% 100 from field capacity) with Gibberellic Acid (100 ppm) gave highest rate of plant height, LAI , number of seeds in disc, weight of 1000 seeds and seeds yield (154.30 cm ; 3.24 ; 1355.10 seeds ; 57.48 gm and 3946.1 kg h-1) respectively.