ASSESSMENT OF HYBRID VIGOUR IN TROPICAL PAPAYA (CARICA PAPAYA L.)

Abstract

The papaya (Carica papaya L.), native to tropical America is a member of the family Caricaceae. One of the normal methods of crop improvement in papaya is through exploitation of hybrid vigour. This investigation was carried out at Department of Fruit Crops, Horticultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore-3, India during the year 2001 to 2003. A total of five hybrids developed by crossing five dioecious parents and five hybrids developed by crossing 5 gynodioecious parents were evaluated along with their parents for yield and quality parameters. The hybrids CO 2 × Pusa Giant and CO 5 × 9-1(D) registered significantly favorable negative heterosis for days to flowering. The hybrids CO 2 × Pusa Giant, 9-1(D) × CO 5, Pusa Dwarf x 9-1(D) registered high positive significant heterosis for number of fruits. Except the cross CO 3 × CO 7, all other gynodioecious hybrids recorded high positive heterosis over both the mid parents and better parents for number of fruits. The cross, CO 7 x Exotica was highly heterotic for fruit number. The dioecious cross CO 2 × CO 5 showed high positive relative heterosis for fruit weight. Except IIHR 37 × Coorg Honey Dew, all other four gynodioecious hybrids showed high positive significant heterosis and heterobeltiosis for fruit weight. The dioecious hybrid CO 2 × CO 5 registered a high fruit length and a high circumference. Only the cross CO 7 × Exotica registered a high negative heterosis for cavity index. The cross Pusa Dwarf x 97 (D) registered positive heterosis for papain recovery. The crosses Pusa Dwarf × 9-1(D) and HHR 37 × Coorg Honey Dew, the gynodioecious crosses, CO 3 x CO 7 recorded moderate mean and significant heterosis for carotene content. The hybrids 9-1(D) x CO 5 and CO 3 × CO 7 registered not only high heterosis for ascorbic acid but also recorded significant negative heterosis for total acids. Higher flesh thickness with maximum heterosis was observed in the cross CO 3 × CO 7.