Morphophysiological and Nutritional Responses of Melon Genotypes Under Water Deficit Conditions

Water scarcity limits melon (Cucumis melo L.) productivity in the Brazilian semi-arid region. In this context, the morphophysiological, nutritional, and fruit quality responses of five genotypes (A-09, A-52, Nantais Oblong, PMR6, and PI 234607) subjected to three water replacement levels (50%, 75%, and 100% of field capacity) were evaluated using a randomized block design. Analysis of variance (ANOVA) indicated no genotype × water replacement interaction (p > 0.05) for most variables, demonstrating parallel responses to drought. Water replacement at 50% reduced mean fruit weight by 45.7%, leaf dry mass by 40.5%, and total dry mass by 34.0%. The 50% water deficit increased intrinsic water use efficiency by 31.7% and electrolyte leakage by 52.7%, while increasing leaf phosphorus and potassium concentrations by 29.8% and 35.4%, respectively, due to a tissue concentration effect. Soluble solids and titratable acidity remained stable. Genotypes A-09 and A-52 exhibited the highest total dry mass of both shoots and roots. It is concluded that water deficit proportionally reduces growth and yield without altering fruit quality. Therefore, genetic improvement programs should prioritize the selection of genotypes with high baseline performance, as demonstrated by A-09 and A-52.