FERTILIZING ABILITY OF CRYOPRESERVED POLLEN IN INTER-INTRA SPECIFIC CROSSES IN CARICA PAPAYA L.

Abstract

Fertilizing ability of cryopreserved pollen for intra and inter specific crossing in Carica species was investigated. Pollen of Carica papaya cultivar 'Washington' and Carica cauliflora were cryostored for six and eight years and viability tested using hanging drop method. Cryopreserved pollen was placed onto compatible stigmas of C. papaya cultivar 'Solo'. Fruit and seed formation from these crosses were assessed as a function of fertilizing ability of cryopreserved pollen. Seeds recovered from both intra and inter specific crosses were also assessed for germination. In Carica papaya 'Washington' and Carica cauliflora, pollen cryostored after six and eight years showed germination of pollen tubes comparable to controls. No changes in vigour parameters were observed after cryostorage for six and eight years. 'Washington' pollen stored at -196°C for eight years can still be effective in pollination and brought about fruit set and seed development to the extent of 80 and 86 respectively. In the case of Carica cauliflora, the results are 85 and 76 respectively. Seed set with six-and eight-year cryostored pollen germinated to the extent of about 82 and 83 respectively over the control. The study indicates the possibility of establishing a pollen bank for Carica species to improve breeding efficiency, heterosis breeding and hybrid seed production as well as conserving nuclear genetic diversity (NGD).