Dissecting the genetic basis of fruit quality traits in muskmelon using crosses with Cucumis melo var. callosus and C. melo var. momordica

Fruit quality is an important component in muskmelon (Cucumis melo L.) breeding due to its direct influence on consumer preference and market value. The majority of commercial varieties of muskmelon are highly susceptible to various diseases and pests. Consequently, researchers increasingly rely on wild relatives as critical genetic resources for introgressing resistance in breeding programmes. In this context, the present study aimed to elucidate the genetic control of eight fruit quality traits: fruit length, fruit diameter, flesh thickness, cavity width, fruit shape index, average fruit weight, total soluble solids (TSS) and titratable acidity using generation mean analysis. Two inter-varietal crosses were developed involving wild relatives, DSM 132 (C. melo var. callosus) and DSM 19 (C. melo var. momordica), with a commercial variety, Hara Madhu, as the common recurrent parent. Six segregating populations (P₁, P₂, F₁, F₂, BC₁P₁, BC₁P₂) were evaluated across multiple seasons (2022-2024). Scaling and joint scaling tests revealed that the additive-dominance model alone was insufficient, suggesting the involvement of non-allelic interactions. Six-parametric model analysis showed that dominance (h) and dominance × dominance (l) interactions were most significant for most of the fruit quality traits. Duplicate epistasis was observed for most of the quality traits, including TSS, average fruit weight, flesh thicknessand titratable acidity, suggesting the potential for heterosis breeding or recurrent selection to improve these traits. Overall, the present findings provided insights into the genetic architecture of fruit quality traits in muskmelon and paved the way for the strategic use of wild relatives in breeding programmes.