Growth and yield response of tomato cv. Hisar Arun to micronutrients and plant growth regulators

Vegetable crops play a vital role in global nutrition and food security; however, achieving optimal productivity is often constrained by biotic and abiotic stresses. Plant growth regulators (PGRs) and micronutrients have emerged as effective tools for enhancing growth, development, and stress resilience in vegetable crops. The present study evaluated the effects of foliar applications of borax, zinc sulphate, gibberellic acid (GA₃), and naphthalene acetic acid (NAA) on the growth, flowering, and yield attributes of the tomato cultivar Hisar Arun during the Rabi season of 2023-2024 at the Vegetable Research Farm, CCS Haryana Agricultural University, Hisar, under semi-arid conditions. The experiment was conducted in a Randomized Block Design with three replications, comprising fifteen treatment combinations involving individual and combined applications of micronutrients and PGRs. Growth, reproductive, and yield parameters were recorded at critical growth stages. Among the treatments, GA₃ @ 50 ppm + Borax @ 0.25% (T₇) consistently outperformed all others, producing significant improvements in plant height, branching, flowering behavior, fruit set, fruit size, and overall yield. The superior performance of T₇ is attributed to the synergistic effects of GA₃-induced cell elongation and enhanced photosynthate translocation facilitated by boron. These outcomes align with earlier findings on the beneficial interaction of PGRs with micronutrients in improving tomato productivity. Based on the results, foliar application of GA₃ @ 50 ppm + Borax @ 0.25% can be recommended for farmers cultivating tomato under semi-arid and late-winter conditions similar to Hisar, as it provides a reliable and sustainable strategy to maximize growth and yield. The treatment also shows potential to partially substitute chemical fertilizers under fluctuating temperature and humidity conditions.