Salicylic acid promotes sunflower production under normal and water deficit conditions

Water insufficiency affects agriculture productivity and quality of crops. Applying antioxidants such as salicylic acid (SA) can enhance plant resistivity against drought stress. The current experiment was performed to check the concentration and mode of application of salicylic acid (S.A) under normal and drought stress. A completely randomized design (CRD) with factorial arrangement, one factor being the moisture condition (i.e., normal and drought) and the second one being the application method (foliar spray and seed soaking) was used. The treatments included T1 (control), T2-T4 (0.5mM, 1.0mM, and 1.5mM SA by foliar spray) respectively, and T5-T7 (0.5mM, 1.0mM, and 1.5mM SA by seed soaking), respectively). Under the normal irrigation i.e., at 75% of Water Holding Capacity (WHC), T4 had the highest percentage increase in plant height (56.28%), head diameter (45.65%), shoot fresh weight (56.30%), shoot dry weight (164.94%), root fresh weight (184.66%), root dry weight (159.42%), No. of achene/plant (35.74%), thousand grain weight (65.03%) and seed yield/plant (124.15%), NPK concentration (125%, 61.30% and 28.41%), proline contents (59.18%), chlorophyll contents (41.25%) and oil contents (34.88%) compared to T1. Under the drought (40%WHC), T4 performed better and increased plant height (55.67%), head diameter (44.26%), shoot fresh weight (114.87%), shoot dry weight (179.38%), root fresh weight (134.27%), root dry weight (133.90%, No. of achene/plant (20.49%), thousand grain weight (62.58%) and seed yield/plant (96.02%), NPK concentration (221.30%, 78.16% and 11.91%), proline contents (55.43%), chlorophyll contents (43.68%) and oil contents% (35.04%) compared to T1. The electrolyte leakage (EL%) was reduced by 47.18% at 75WHC and 50.41% at 40%WHC. The results predicted that the application of SA at the 1.5mM(T4) concentration in both moisture conditions and drought showed better performance. The agronomic and biochemical parameters were enhanced by foliar application of SA except the electrolyte leakage which reduces significantly by SA foliar spray. Similarly, the macronutrients (NPK) were enhanced by the foliar application of S.A at 1.5mM dose. Therefore, the foliar application of adequate quantity of SA could be a better strategy to cope with water stress in dry areas where rainfall in low.