Influence of Growth Regulators and Boron on Growth, Flowering and Yield Characters on Tomato (Solanum lycopersicum L.)

Abstract

A field experiment was conducted from August 2019 to March 2020 at the Vegetable Seed Farm, Department of Horticulture (Vegetable and Floriculture), Bihar Agricultural University, Sabour, to assess the effects of plant growth regulators (PGRs) and boron on growth, flowering, and yield traits of tomato cv. Kashi Vishesh. The study was arranged in a factorial randomized block design with three replications, including three boron levels (0, 0.3%, and 0.4% borax) and ten PGR treatments consisting of different concentrations of NAA, GA₃, and ethephon. Observations were recorded for growth parameters, flowering characteristics, fruit traits, and yield attributes. The results showed that both PGRs and boron significantly influenced most of the measured parameters. Among PGR treatments, GA₃ at 75 ppm produced the highest plant height (81.47 cm), number of branches (10.84), fruits per plant (50.64), and yield per plant (1.58 kg), while control plants recorded the lowest values. Boron application at 0.3% was found most effective, resulting in maximum plant height (77.08 cm), branches (11.52), fruits per plant (53.70), fruit weight (82.67 g), and yield per plant (1.63 kg). Significant interaction effects were observed for several traits. The combination of GA₃ at 75 ppm with borax at 0.3% gave the highest plant height (86.85 cm), branches (13.38), fruit length (7.01 cm), and yield per plant (1.85 kg). For fruit weight, the treatment NAA at 75 ppm combined with borax at 0.3% recorded the highest value (85.71 g). However, interaction effects were generally non-significant for days to 50% flowering and days to first harvest. Overall, the study indicates that foliar application of PGRs, particularly GA₃, along with boron at 0.3%, significantly enhances vegetative growth, reproductive performance, and yield of tomato. The combined effect of hormonal regulation and micronutrient supplementation improves plant physiological efficiency, resulting in increased vigor and productivity. Therefore, the application of GA₃ at 75 ppm together with borax at 0.3% is recommended for maximizing tomato growth and yield under similar agro-climatic conditions.