Vol. 9, Issue 6, Part A (2025)

A field experiment was conducted during 2023 and 2024 to study the effect of plant growth regulators (PGRs) on seed characters of rambutan (Nephelium lappaceum L) variety N-18. The study was carried out on six-year-old, healthy and uniformly maintained trees at the Plant Propagation and Nursery Management Unit, College of Agriculture, Vellanikkara, Thrissur, and Kerala. The experiment followed a Randomized Block Design (RBD) with seven treatments which include NAA @ 20 and 40 ppm, GA₃ @ 25 and 50 ppm, 2, 4, 5-T @ 25 and 50 ppm, and water spray as control, each replicated thrice. The seed parameters recorded seed length, width, weight, colour and shape. The results revealed significant variation among the treatments. GA₃ @ 50 ppm (T4) showed the most promising performance with the highest seed length (3.41 cm), width (1.52 cm), and weight (2.54 g) on a pooled basis. This was followed by NAA @ 40 ppm and 2, 4, 5-T @ 50 ppm, which also showed improvement over the control. In contrast, the control treatment recorded the lowest values for all seed parameters, with pooled values of 1.25 cm, 0.28 cm, and 1.31 g for seed length, width and weight respectively. The seed colour and shape remained consistent across all treatments and years, with all seeds displaying a creamish hue and an obovoid, elongated form. The results suggest that GA₃ at 50 ppm, plays a key role in enhancing seed development in rambutan, likely through its influence on cell elongation and nutrient translocation. Overall, the study highlights the potential of growth regulator application in improving seed quality traits, which could contribute to enhanced seedling vigor and better propagation outcomes in rambutan cultivation.