Inheritance of physiological and biochemical attributes using numerical and graphical approaches of line × tester in Praecitrullus fistulosus.

Praecitrullus fistulosus (Stocks) Pangalo is one of the nutrient-rich vegetables crops with proven therapeutic value. This study was designed to investigate the inheritance of important physiological and biochemical traits of Praecitrullus fistulosus. A set of 15 cross combinations were developed from five lines and three testers and evaluated for two years. The results depicted significant (p < 0.05) variation among the genotypes (parents and crosses) with respect to flavonoids, phenolic compounds, total carbohydrates, vitamin C, and carotenoids during both studied years. Data were analysed with traditional line × tester analysis for inheritance pattern, and the genotypes (parents and hybrids) were further analysed using polar plots for heterosis and gene action, and principal component biplot analysis for graphical explanation of combining abilities. The physiological traits, i.e., flavonoids, antioxidants, and total soluble proteins, showed significant means square values and general combining ability for genotypes, i.e., 20 and 47. The F1 hybrids 20 × 42, 8 × 63, and 20 × 40 showed high and significant specific combining ability for flavonoids, antioxidants, vitamin C, and carotenoids. GCA, SCA, and the PCA biplot also showed comparable results. The studies of heterosis using polar plots showed the preponderance of overdominance for the majority of traits. Conclusively, both conventional and graphical attribution of data using line × tester analysis could lead Praecitrullus fistulosus breeders to the selection of suitable breeding methods.