In vitro Regeneration of Red Dragon Fruit (Hylocereus polyrhizus) Stem Segments

Abstract

Traditionally, the propagation of dragon fruit (Hylocereus spp.) is carried out through seed or vegetative cuttings. However, propagation by cuttings is too slow to meet the demand for large-scale plantations and is not genetically true-to-type. With the fruits’ increasing demand, an effective in vitro propagation of dragon fruit was developed to produce high – quality planting materials for large-scale production of dragon fruit. This study was conducted to establish the appropriate concentration of bleach for surface sterilization and determine the effective level of 6-benzylaminopurine (BAP) for the shoot initiation of dragon fruit explants in vitro. Surface sterilization of the explants using commercial bleach (a.i. sodium hypochlorite) at a concentration of 50% for 2 min significantly reduced contamination (33.33%) and yielded higher percent survival (54.99%) compared to 20% and 10% concentrations. The addition of different levels of BAP to Murashige and Skoog (MS) medium resulted in shoot regeneration, with early shoot initiation (20 days) and the highest shoot length (9.89mm) observed at 3 mg L-1 BAP after 4 weeks of incubation. The number of shoots was numerically higher at 5 mg L^-1, but this difference was not statistically significant. These results can be recommended for establishing dragon fruit explants in vitro at the surface sterilization and shoot initiation stages. Subsequent rooting and acclimatization stages, which were beyond the scope of this study, are still required before clean, off-season planting materials can be produced for large-scale production.