Studies on Bio-efficacy of Plant Growth Regulators and bio-stimulant on Growth, Yield and Biochemical Attributes of Mango cv. Kesar under Deficit Irrigation Regimes

Abstract

The present investigation entitled Effect of plant growth regulators and biostimulant on growth, yield and quality attributes of mango cv. Kesar under deficit irrigation regimes was conducted in two consecutive years (2023- 2024 and 2024-2025). Experimental site falls under the agro-ecological region of Deccan Plateau (AER-6) and agro-climatic zone AZ-95 which is the scarcity zone of Maharashtra. It is characterized by a hot and semi-arid climate with long-term average annual rainfall of 576 mm. The trial was laid out in a split plot design with three replications. Fourteen treatment combinations were evaluated, comprising two irrigation regimes (I1- 100% ETc and I2-75% ETc) in which 100% ETc (full irrigation at 100% ETc applied on both sides of the tree) and 75% ETc (fixed irrigation at 75% ETc applied on both sides) as main plot factor and including individual and combined applications of two plant growth regulators i.e., Salicylic acid (200 ppm) and CPPU (2.5 ppm) along with one biostimulant, Seaweed extract (4 ml/lit) and a control, as sub-plot factor. Sub plot treatment combinations were B1- Salicylic acid (200 ppm), B2- CPPU (2.5 ppm), B3- Seaweed extract (4 ml/lit), B4- Salicylic acid (200 ppm) + CPPU (2.5 ppm), B5- Salicylic acid (200 ppm) + Seaweed extract (4ml/lit), B6- 100% ETc + Seaweed extract (4ml/lit) + CPPU (2.5 ppm), B7- Control. The foliar applications of the plant growth regulators and biostimulant were carried out at three phenological stages viz., flowering (December–January), fruit development (February–March), and maturity (April–May). The result indicated that, among different irrigation levels, 100% ETc significantly enhanced vegetative growth and yield, while 75% ETc improved fruit quality parameters. In case of growth parameters, T3- 100% ETc + Seaweed extract (4 ml/l) recorded the maximum plant height (3.33 m) and T5- 100% ETc + Salicylic acid + Seaweed extract observed highest canopy spread (East–West: 3.64 m²) and leaf area (106.92 cm²) whereas T6- 100% ETc + Seaweed extract + CPPU found the maximum canopy spread (North–South: 3.58 m²) and canopy volume (179.49 m³). By considering the yield parameters treatment T4-100% ETc + Salicylic acid (200 ppm) + CPPU (2.5 ppm) recording the highest number of fruits per plant (145.38) and maximum fruit yield per plant (35.15 kg) and biochemical parameters the like TSS (19.38%) and ascorbic acid content (48.96 mg 100 g⁻¹ pulp) were recorded highest under T11- 75% ETc + Salicylic acid + CPPU and highest titrable acidity found in T₁₄- 75% ETc + Control.