Regeneration of Embryogenic Cells and Haustorium-like Structures of Dua Xiem Xanh (Dwarf Green Xiem Coconut) Sourced from Go Cong, Vietnam

Aim: Coconut is one of the most valuable crops, producing remarkable products. The Vietnamese Xiem Green Dwarf variety sourced from Go Cong province is particularly renowned for its use in fresh coconut water production. With the growing demand of seedling for coconut production and decline in crop yields, it is essential to focus on coconut cultivation. Methods: Somatic embryogenesis offers a promising solution for this issue. This study evaluates factors: including plumule maturity, sucrose supplementation in culture media, and the effects of TDZ. Coconut embryos were pre-cultured for germination at four durations: 0, 7, 14, and 21 days, before the plumules were excised and used as explants for callus induction. To assess the impact of sucrose on callus formation, three different sucrose concentrations were tested: 30, 45 and 60 g. The embryogenic callus that developed was then cultured in a plant growth regulator-free medium before the regeneration stage. To promote somatic embryo development and germination, TDZ was tested at various concentrations. Results: The results indicate that 14-day plumule maturity and 45 g of sucrose were optimal for callus induction. Additionally, TDZ showed a significant effect on generating coconut somatic embryos, with the best results observed at concentrations ranging from 25 µM to 50 µM. Conclusion: This research established a somatic embryogenesis protocol for the Vietnamese Xiem Green Dwarf variety, considering new factors for coconut improvement.