Desenvolvimento da abóbora manteiga (Cucurbita moschata Duchesne) em resposta a doses crescentes de Ethrel®720.

Abstract

Butternut squash stands out among cucurbits cultivated in Brazil due to its wide edaphoclimatic adaptation, high nutritional value, and socioeconomic importance. However, the crop presents physiological limitations related to sexual expression, characterized by the predominance of male flowers, especially under hot climate conditions, which compromises fruit set and productivity. Therefore, floral differentiation and the induction of female flowers in cucurbits remain a major challenge. In this context, the present study aimed to evaluate the effects of different doses of Ethrel 720® on vegetative growth, floral expression, and productive characteristics of butternut squash. The experiment was conducted using increasing doses of the growth regulator (0, 150, 300, 450, 600, and 750 mL ha⁻¹), applied in two sequential applications at 30 and 45 days after transplanting the seedlings to the field. Irrigation was performed by drip irrigation every two days, supplying sufficient water to ensure the formation of a wetted soil bulb. Plants were monitored for vegetative development, branching, and productive units. The results showed non-linear responses to ethephon doses, with intermediate doses promoting a better balance between vegetative and reproductive growth, whereas higher doses resulted in limiting physiological effects. It is concluded that the rational use of ethephon can be an efficient strategy for managing sexual expression in butternut squash, contributing both to vegetative growth at lower doses and to an increase in potentially productive flowers (450 mL ha⁻¹ treatment), consequently increasing the number of fruits per plant (450 mL ha⁻¹ treatment) and improving fruit quality, as indicated by higher soluble solids content (15% Brix) in treatments between 450 mL ha⁻¹.