Assessment of stability for expression of monoecism in newly developed inbred lines of muskmelon (Cucumis melo L.) and their evaluation for horticultural traits

Abstract

In muskmelon, development of F₁ hybrids involving andromonoecious inbred lines as female parents is laborious, costly and time-consuming. Therefore, monoecious lines can potentially exploited to replace maternal andromonoecious lines in hybrid production. However, in muskmelon the linkage of the monoecious trait with oval fruit shape and sourness limited its extensive utilization in hybrid breeding. Thus, the present investigation was carried out to investigate a set of newly generated melon inbred lines for stability monoecious trait and their evaluation for morphological and biochemical characteristics, such as average fruit weight (g), flesh thickness (cm), rind thickness (mm), fruit shape index, total soluble solids (TSS), ascorbic acid, acidity, β-carotene and firmness (kg/cm²). Through assessment of andromonoecy index (AI), eighteen stable monoecious lines have been identified. The monoecious line, Mono-1621/CTS, exhibited the highest β-carotene (2.73mg/100g), while Mono1426/S-1 recorded the highest TSS (14.9 °Brix). Unlike earlier reports, AI showed no correlation with fruit shape index or sourness, suggesting these traits are independent of sex expression in muskmelon. This indicates that stable monoecious lines with low sourness, ideal TSS/TA ratio, and round fruits can be developed using improved genetics and modern breeding tools. Furthermore, identified lines with horticulturally desirable traits can further be utilized in heterosis breeding by selecting suitable parent combinations.