Impact of Spacing and Fertilizer Levels on Quality Attributes of Pinwheel Flower (Tabernaemontana Divaricata L.)

The present experiment was carried out at the Department of Floriculture and Landscaping, College of Horticulture, Bagalkot during the year 2023–2024. The study tested three fertilizer levels (F₁: 20:40:40 g NPK/plant/year, F₂: 30:60:60 g NPK/plant/year and F₃: 40:80:80 g NPK/plant/year) and three spacing configurations (S₁: 1.5 × 1.2 m, S₂: 2.0 × 1.5 m and S₃: 2.5 × 1.8 m), resulting in nine treatment combinations, each replicated thrice in a Factorial Randomized Complete Block Design (RCBD). Fertilizers were applied at four intervals (May, July, September and November) using urea, diammonium phosphate and muriate of potash as sources of nitrogen, phosphorus and potash respectively. Quality attributes were measured at 240 days after treatment imposition. The results indicated that the combination of S₂ and F₃ (spacing of 2.0 × 1.5 m and fertilizer level of 40:80:80 g NPK/plant/year) resulted in the highest flower diameter (17.00 mm), bud diameter (11.32 mm), corolla tube length (2.44 cm), single (1.10 g), ten (11.0 g), fifty (50.0 g) and 100-flower bud weight (100.01 g) and flower bud shelf life (2.90 days). On the other hand, the lowest values for these traits were observed in the S₁ F₁ treatment combination (spacing of 1.5 × 1.2 m and fertilizer level of 20:40:40 g NPK/plant/year), with flower diameter (13.41 mm), bud diameter (7.98 mm), corolla tube length (1.94 cm), single (0.79 g), ten (7.9 g), fifty (46.1 g) and 100-flower bud weight (92.11 g) and flower bud shelf life (1.70 days). The study concluded that the ideal combination of spacing S₂ and F₃ proved to be highly beneficial for producing top-quality flower buds in Pinwheel flowers. Hence, can be recommended to the growers for ensuring superior flower quality.