Efficacy of Foliar Application of Potassium Nitrate in the Regulation of Photosynthetic Pigments, Sex expression, Yield and Quality Attributes of Sweet Lime ( Citrus limmetoids)

Sweet lime is one of the famous Citrus species however, its shy bearing habit, poor yield and quality adversely affects its production in Pakistan. Potassium nitrate is known to affect sex expression, yield and quality of different fruit species. Therefore effect of different KNO3 concentrations (0, 3.5, 4.0, and 4.5 %) and their time of application (5, 10 and 15 days after bud break, DABB) on sweet lime was evaluated during 2020 in Rustam, Mardan, Pakistan. The experiment was laid out in randomized complete block design with split plot arrangement having three replications. Results of the current study indicated that 4.0 % KNO3 significantly increased Ch a, Ch b Ch a+b carotenoids content, perfect flowers, fruit weight, number of fruits per tree, fruit yield per tree, TSS, total sugars and reduced staminate flowers. Potassium nitrate at 3.5 % produced maximum fruit juice content and vitamin C, while the highest fruit firmness was recorded with 4.5 % KNO3 application. Spray application done on 10 days after bud break increased perfect flowers, fruit weight, number of fruits per tree, fruit yield per tree, fruit firmness, vitamin C, TSS, total sugars and decreased staminate flowers. Chlorophyll a, Ch a+b and carotenoid content were highest on 15 DABB application. Our single year findings indicate that KNO3 at 4.0 % should be applied after 10 days of bud break for improved yield and fruit quality of sweet lime.