Two experiments with melon plants (Cucumis melo L.) Cantalupensis Group were carried out in the summer, in the field and in an unheated greenhouse, aiming to evaluate the effect of nitrogen rates on fruit physical (weight, diameter, flesh pulp thickness, and cavity diameter) and chemical (total soluble solids, titratable acidity, and pH) characteristics. Each experiment consisted of four randomized blocks containing five nitrogen rates (0, 75, 150, 300, and 450 kg.ha-1). The nitrogen, applied as urea, had 30% placed in furrows before seedlings transplantation, and the remaining 70% of each N rate were trickle-applied throughout the plant cycle. In both greenhouse and field, the increase in N applied increased fruit physical characteristic values. In the greenhouse, with the N rate of 312 kg.ha-1, that gave the maximum commercial yield (MCY), fruit fresh weight, diameter, flesh thickness and cavity diameter were, respectively, 1.280 g, 12.6 cm, 3.1 cm and 6.1 cm. In the field, with 344 kg ha-1 of N, which led to MCY, the corresponding same values were 1.390 g, 13.1 cm, 3.4 cm and 5.9 cm, respectively. Total soluble solids were not influenced by N rates, averaging 9 and 9.5% for greenhouse and field, respectively. At both environmental conditions, titratable acidity increased with the N rates, reaching 0.13% in field and 0.14% in the greenhouse at N rates for MCY. Greenhouse fruit pH was not affected by N rates, averaging 6.83, while field fruit pH increased with the increase in N level, reaching 6.99 at the N rate for MCY.
Cucumis melo; Cantalupensis Group; fruit characteristics; unheated greenhouse; field
