Combining ability analysis and heterosis for antioxidants, carotenoids and shelf life in papaya (Carica papaya L.)

Papaya, a prominent tropical fruit crop in India, is witnessing expanding cultivation across the country’s diverse agro-climatic zones. This growing popularity is due to its nutritional value, year-round production and economic significance. However, the availability of varieties with improved nutritional and fruit quality remains limited. The trial to investigate combining ability and heterosis for nutritional and eating-quality traits in papaya was conducted at the ICAR-Indian Agricultural Research Institute, New Delhi. The quality traits under study were total soluble solids (TSS), total phenolic content, total flavonoid content, antioxidant activity, β-carotene, lycopene, total carotenoids, fruit firmness, and shelf life. 6 inbred lines of papaya were crossed in a full diallel mating design to develop 30 F1 hybrids, including the reciprocal crosses. The per se mean performance and general combining ability led to the identification of the best parental lines, like P-9–12 for TSS, total carotenoids, β-carotene, lycopene, antioxidants, fruit firmness, and shelf-life, and P-9–5 for total phenolic and flavonoid content. The range of heterosis was low to moderate in papaya hybrids for the traits studied, except for total carotenoids and lycopene, where a high range of heterosis was recorded. The best performing hybrids and specific combiners like PN x P-7–2 for TSS, PS3 x P-7–9 and P-9–5 x PS3 for total phenolic content, P-9–12 x P-9–5 and P-7–2 x P-7–9 for total flavonoid content, PS3 x P-7–2 for antioxidant, P-7–2 x P-9–5 for lycopene, P-7–2 x PN for β-carotene, PS3 x P-7–9 for total carotenoids and P-7–2 x PS3 for fruit firmness and shelf life were identified. Hybrids exhibiting high SCA effects along with desirable mean performance may serve as promising candidates for future hybrid development programs. The study indicated the importance of both additive and non-additive gene action in governing quality and nutritional traits. It demonstrated substantial scope for developing nutritionally superior papaya hybrids with improved shelf life and consumer acceptability.