Capacidade combinatória em meloeiro (Cucumis melo L.) e potencial agronômico de híbridos monoicos de melão

Abstract

A diallel cross was used to evaluate combining ability of powdery mildew and PRSV- W resistant lines (`O', 'R', '015' and `017') and four OP cultivars (Amarelo Chile, Amarelo Ouro, Eldorado and Orange Flesh) for yield and fruit quality characteristics in melon. Two monoecious yellow skinned lines, `O' and 'R', were used as female parents. Six andromonoecious acessions (lines 015 and 017, and four open pollinated cultivars — Amarelo Chile, Amarelo Ouro, Eldorado and Orange Flesh) were used as male parents. The 12 hybrids between the two parental groups were gown, along with the parental genotypes and five commercial F1 hybrids and an open pollination cultivar in a randomized block design with three replications, in Mossoró, State of Rio Grande do Norte, Brazil. Analysis of variance showed significant differences among parents and experimental and commercial hybrids, as well as heterosis for most of the traits studied. Specific combining ability (sca) effects were more important than the general combining ability (gca) effects, indicating non-additive gene action for most of the traits. The effects of male parents on the hybrid means were larger than those of the female parents. The experimental hybrids tended to produce bigger fruits, but all of them were suitable for the usual commercialization practices. The combinations OxAC, OxAO, Ox017, RxAO and Rx015, the hybrid Gold Mine, `O' , Eldorado and 'OFMAISA' were good genotypes for yield, especially for local markets. The male parental '015' and the commercial F1 hybrids Gold Pride and AF-522 produced smaller fruits, more suitable for external markets. No major differences were found for pulp resistance, but total soluble solids (TSS) were found to be high on Rx017, OxOF, OxE, RxOF, OxAC, `017', 'AO', 'R' and Gold Mine. When compared the reference genotypes (Amarelo Ouro, AF-646 and Gold Mine) the experimental hybrids were generally superior in yield to 'AO', but inferior to AF-646 and Gold Mine; for the average fruit weight and TSS, the hybrids had superior performance relative to reference genotypes. These findings showed the viability of producing F1 hybrids of melon from monoecious parental not using the emasculation practice that enhances the costs of the hybrid seeds.