Assessing the interplay of paclobutrazol and micronutrients for enhanced litchi production

Climate variability has increasingly disrupted the natural vegetative dormancy of litchi (Litchi chinensis), negatively impacting flowering, fruit set, and quality. This study evaluates the combined effect of paclobutrazol (PBZ) and micronutrients (Zinc Sulphate and Boric Acid) on the physical and biochemical quality of litchi fruits in a subtropical agro-climatic region. A factorial randomized block design was employed on 20-year-old litchi trees (cv. Dehradun) with 27 treatment combinations. Results revealed that PBZ @ 50 ppm followed by ZnSO₄ @ 1.0% significantly improved fruit length, weight, pulp percentage, and juice content. The same treatment also enhanced reducing sugars, total soluble solids (TSS), and ascorbic acid content, while optimizing the TSS: acid ratio. Zinc's role as a cofactor in carbohydrate metabolism and antioxidant enzyme activity, along with PBZ's vegetative growth suppression, synergistically improved nutrient allocation and fruit quality. Use of 50 ppm PBZ in month of October with 1% zinc sulphate at time of panicle emergence is an integrated approach for mitigating climate-related disruptions and improving litchi productivity and nutritional value.