COMBINING ABILITY AND HETEROTIC STUDIES ON HYBRID MELON (Cucumis melo L.) POPULATIONS FOR FRUIT YIELD AND QUALITY TRAITS

Abstract

In different crop plants, combining ability and heterosis are used as important diagnostic tools for assessing the performance of parental genotypes and their hybrids. This research aimed to evaluate heterotic and combining ability effects in the diallel crosses of melon (Cucumis melo L.) for yield- and quality-related traits. Seven melon (C. melo L.) genotypes were grown and crossed in a complete diallel fashion to produce F1 hybrids. During the 2019 crop season, 49 melon genotypes (7 parents + 42 F1 hybrids) were grown in a randomized complete block design with three replications. Observations were made for seven characters. Analysis of variance revealed significant (P ≤ 0.01) differences among the melon genotypes for harvest age, fruit flesh thickness, fruit total soluble solids, fruit length, and fruit diameter and merely significant differences (P ≤ 0.05) for fruit weight. Combining ability analysis revealed that mean squares due to general combining ability (GCA) were significant for fruit diameter but were nonsignificant for all other traits. However, mean squares due to specific combining ability (SCA) were significant for all traits. The parental genotypes PK-165, PK-464, and PK-669 exhibited the highest and desirable GCA effects for yield and quality traits. Hence, these genotypes could be used to generate high-yielding hybrid/open-pollinated cultivars. GCA:SCA ratios further revealed that the traits of harvest age, fruit flesh thickness, fruit total soluble solids, fruit length, and fruit weight were controlled by dominant gene action, whereas fruit diameter was managed by additive and dominant genes. The majority of the traits were controlled by nonadditive gene action, verifying that the said breeding material could be efficiently used for the production of hybrid cultivars on the basis of heterotic effects.