Efficient Induction of Papaya Embryogenic Callus and Plant Regeneration

Papaya ( Carica papaya L.) has high medicinal and production value, and it is of great significance to carry out efficient induction and plant regeneration of embryogenic callus of papaya for its industrial development. In this study, Zhongbai, the main papaya cultivar from Hainan was used as explants to explore the effects of different hormones and their additive combinations on embryogenic callus induction and plant regeneration. The results showed that the most suitable medium for papaya callus induction was K5: 1/2 MS+5 mg/L 2, 4-D+0.5 mg/L KT+3% sucrose+3.6 g/L phypagel. The most suitable medium for papaya embryogenic callus induction was M13: 1/2 MS+5 mg/L 2,4-D+0.6 mg/ L-proline+3% sucrose+3.6 g/L phypagel. And the most suitable medium for papaya bud differentiation was Ci: 1/2 MS+0.2 mg/L 6-BA, 0.2 mg/L NAA+3% sucrose+3.6 g/L phypagel. The best method for rooting of papaya was treatment with 100 mg/L rooting powder and soil plantation. This ‘two-steps’ embryogenic callus induction system we created can significantly shorten the growth cycle of embryogenic callus. Furthermore, the system has a certain broad spectrum in different varieties of papaya, this study provides a solid foundation for further improving the efficiency of genetic transformation of papaya.