Genetic expression of reproductive and fruit quality traits in snap melon ( Cucumis melo var. momordica L.)

Improvement of snap melon ( Cucumis melo L. var. momordica (Roxb.) has been constrained by the lack of adequate information on genetic control of different fruit and quality characters. The study was conducted to determine gene action, heterosis and narrow sense heritability for 13 quantitative characters using 5 × 5 half diallel analysis. No interaction between genes was evident in controlling most characters suggesting the adequacy of additive-dominance model. Both additive and dominance components of genetic variance were significant in most characters however, dominance component was much higher in magnitude. Overwhelming response of over-dominance was evident for most traits. Symmetrical distribution of positive and negative alleles in parents was recorded for days to first male and female flower, and number of fruits per plant while, asymmetrical distribution was evident for 10 characters. Dominant alleles were more frequent for 11 characters while, recessive alleles were more frequent for fruit length and diameter. One gene group showing dominance was responsible for the inheritance of 11 characters; two gene groups controlled days to first male flower while, three gene groups conditioned number of fruits per plant. Narrow sense heritability for different characters was very low to medium (2.75–34.58%). Hybrid breeding can be used to improve fruit yield and quality in snap melon however, manifestation of heterosis was highly dependent on the parents and traits considered.