Effect of different concentrations of gibberellic acid and naphthalene acetic acid on growth, yield and post harvest quality of tomato

Abstract

A field experiment was carried out in Rukum West, Nepal, from March to June 2025 in order to assess the impact of various concentrations of gibberellic acid (GA3) and naphthalene acetic acid (NAA) on the growth, yield, fruit quality, and postharvest quality of "Monoprecos" tomato. The experiment was conducted using a randomized complete block design (RCBD) with seven treatments and three replications. Plant height, flowering traits, fruit length, fruit diameter, fruit yield, total soluble solids (TSS), titratable acidity (TA), pH, physiological loss in weight (PLW), and decay loss of tomato were recorded during the experiment. GA3 @ 75 ppm treatment produced the maximum plant height (165.21 cm) of tomato, whereas GA3 @ 50 ppm recorded the highest number of flowers per plant (104.29), fruit length (4.42 cm), and fruit yield (24.07 mt ha⁻¹) of tomato. NAA @ 30 ppm treatment produced the highest number of flowers per cluster (10.34) and fruit diameter (4.94 cm) of tomato. GA3 @ 50 ppm also recorded higher TSS (4.88 °Brix) and pH, while titratable acidity was highest in the control. After 12 days of storage, GA3 @ 50 ppm showed lower PLW (11.92%), whereas GA3 @ 25 ppm recorded the lowest decay loss (70.83%). Therefore, GA3 @ 50 ppm can be recommended as an optimum concentration for growth, yield, and postharvest quality of tomato in the mid-hill region of Nepal.