Effect of different levels of growth retardants on growth parameters of Bougainvillea glabra var. pink beauty

Bougainvillea is a flowering plant genus which belongs to the family of Nyctaginaceae and native to South America. Because of its robust growth, regular pruning is required to maintain its plant architecture. To overcome this and to maintain the plant size consistent, application of growth retardants would be the better alternative for frequent pruning. The research work was conducted during 2022-23 at Department of Floriculture and Landscape Architecture, College of Horticulture, Bengaluru. The experiment was laid out in Randomized Complete Block Design (RCBD) with 13 treatments replicated thrice. The growth retardants viz., Paclobutrazol, Maleic Hydrazide and Alar were used and Bougainvillea glabra var. Pink Beauty was used as planting material. Where, paclobutrazol applied as soil drench and others as foliar application at thirty days interval thrice. For growth parameters viz., minimum plant height (18.93 cm), plant spread (307.60 cm²), internodal length (0.89 cm), leaf area (8.83cm²), specific leaf area (31.25 cm²/g), increased specific leaf weight (0.036g/cm²) and maximum stem girth (4.02 mm) noticed with the soil drenching of Paclobutrazol at 45 ppm. Whereas, foliar application of Alar at 1250 ppm resulted with increased number of primary branches (2.33). However, increased number of secondary branches per plant (2.07) noticed with foliar application of Maleic Hydrazide at 1000 ppm. Therefore, soil drenching of Paclobutrazol at 45 ppm can effectively retard the plant growth and also makes the plant photosynthetically active and draught tolerant.