Evaluation of Biosaka Spray for Enhancing Physiological Traits and Improving Fruit Quality in Inodorus Melon

Melon is an economically important horticultural crop, yet its productivity and fruit quality are often constrained by suboptimal cultivation practices. Biosaka, a biostimulant containing natural elicitors, has the potential to enhance physiological performance and fruit traits, but its effective concentration remains unclear. This study evaluated the optimal concentration of biosaka spray for improving physiological traits and fruit quality of Inodorus melon. A non-factorial completely randomized design was applied with six concentrations (0, 10, 20, 30, 40, and 50 mL L^-1), each with four plants and replications, totaling 96 experimental units. Biosaka application did not have significant effect on chlorophyll content, chlorophyll a/b ratio, stomatal density, biomass, net assimilation rate, or harvest index. In contrast, it significantly increased leaf area index (LAI) and fruit quality attributes. Polynomial regression predicted an optimal concentration of 26.5 mL L^-1 for LAI (0.845). Concentrations between 31.0 and 50.7 mL L^-1 produced optimal fruit traits, including fruit weight, diameter, total soluble solids, and edible portion. Correlation analysis indicated weak relationships between LAI and physiological parameters, while strong positive associations were found between biomass and NAR, and negative associations between HI and biomass. Overall, biosaka at 26.5 - 50.7 mL L^-1 is optimal for enhancing melon fruit quality, though further studies are required to characterize its elicitor compounds.