Effect of growth retardants (Cycocel and Paclobutrazol) on flowering, yield and quality of Nagpur mandarin under heavy black cotton soil

Résumé fourni par la source

Aims: To study the effect of the growth retardants cycocel (chlormequat chloride) and paclobutrazol on flowering, fruiting, yield and quality of Nagpur mandarin grown under heavy black cotton soil, and to identify the most suitable growth retardant and concentration for regulating Mrig bahar cropping. Study Design: Randomized Block Design (RBD) with seven treatments replicated thrice. Place and Duration of Study: A farmer's orchard at Shirajgaon Ardak, Tehsil Chandurbazar, District Amravati, Maharashtra, India, with analytical work at the Department of Fruit Science, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola, during 2025-2026. Methodology: Ten- to twelve-year-old bearing Nagpur mandarin trees spaced at 6 × 6 m were subjected to seven treatments cycocel as foliar spray at 1000, 1500 and 2000 ppm; paclobutrazol as soil (collar) drench at 3, 6 and 9 g a.i. per plant; and an untreated control each replicated thrice with three plants per replication. Observations were recorded on plant growth, flowering, fruit physical characters, yield attributes and fruit physico-chemical quality, and the data were analysed following Randomized Block Design procedures. Results: Paclobutrazol at 9 g a.i. per plant produced the earliest flower bud initiation (47.00 days) and flower opening (53.67 days), the shortest period to fruiting (59.67 days) and maturity (271.33 days), the largest canopy volume (4.81 m³), the maximum number of harvested fruits per plant (590.67), and the highest total soluble solids (10.73 °Brix) and ascorbic acid content (56.33 mg 100 ml⁻¹). Paclobutrazol at 3 g a.i. gave the highest fruit yield (75.37 kg plant⁻¹; 20.87 t ha⁻¹) and the greatest fruit volume (135.00 cm³). Among cycocel concentrations, 1500 ppm was consistently superior, recording the highest fruit set (56.15%), fruit weight (122.33 g), equatorial breadth (74.97 mm), juice content (51.26%), reducing sugars (4.67%), non-reducing sugars (3.24%), total sugars (7.92%) and TSS:acid ratio (12.65), together with a fruit yield of 69.05 kg plant⁻¹ (19.12 t ha⁻¹). Conclusion: Paclobutrazol (9 g a.i. plant⁻¹, soil-applied) and cycocel (1500 ppm, foliar-applied) are effective, complementary treatments for regulating flowering and enhancing yield and quality of Nagpur mandarin grown on heavy black cotton soil, offering growers a practical means of achieving more predictable Mrig bahar cropping.

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