Seleção recorrente de genótipos de abóbora (Cucurbita moschata) para incremento da qualidade dos frutos

Abstract

Pumpkins (Cucurbita spp.) possess significant social, economic, and food importance due to income generation related to their production, the high demand for consumption, a relatively accessible commercial value, and the functional compounds they contain, especially carotenoids, the main of which is [beta]-carotene. In this scenario, one of the ways to genetically improve this crop is developing high yield cultivars, with fruits showing nutritional and functional appeal and meeting market demands. From this perspective, this study aimed to select pumpkin genotypes with higher fruit quality, especially with high [beta]-carotene contents. A first experiment was conducted with 12 lines (population x0). The best fruit of each plant was evaluated for mass, length, largest and smallest diameter, peel and pulp thickness, cavity diameter, peel and pulp color (evaluated by the lightness - L, chroma – C, and Hue angle - H), titratable acidity (AT), soluble solids content (SS), carotenoids, -carotene, cryptoxanthin, [beta]-carotene, lycopene, and xanthophyll. Based on the data referring to these variables, a ranking was performed by applying a 10% selection intensity. The 19 best fruits ranked constituted the second experiment (population x1). The fruits generated were subjected to a new selection using a 10% selection index, based on the data referring to mass, length, largest and smallest fruit diameter, mean thickness of peel and pulp, cavity diameter, peel and pulp color (L, C, and H), pulp firmness, SS and AT content, and ascorbic acid content. The titratable acidity (0.000019) and the content of cryptoxanthin (0.001) were the variables with the lowest genetic variance, whereas the carotenoid content had the highest (10472.57). The variables of fruit length, largest diameter, peel thickness, pulp thickness, peel lightness, peel Hue angle, and the contents of lycopene and xanthophyll showed the highest genetic variance values compared to the phenotypic variance. The coefficient of genotypic variation was higher than the coefficient of environmental variation for fruit length, largest fruit diameter, mean peel thickness, mean pulp thickness, peel L, C, and H, and the contents of [beta]-carotene, lycopene and xanthophyll. Population x1 had genetic gains for all variables. The genotypes selected have quality traits with the potential to generate advances in pumpkin breeding programs, particularly for fruits with thicker and orange pulps and with ascorbic acid contents above 75 mg 100 g-1.