Effect of nutritional environment, sucrose and thidiazuron on the ability of somatic embryo regeneration through culture of vietnamese green dwarf coconut (cocos nucifera l.f.) plumules

Coconut palm (Cocos nucifera L.) is a globally significant perennial crop, providing substantial economic benefits and sustainable livelihoods for millions, particularly in tropical regions. However, global decline in coconut palm cultivation, led to the urgent development of efficient and rapid propagation strategies for high-quality plant. Somatic embryogenesis using plumule as explant was one of the most prominent methods for Dwarf coconut cultivar. In this study, several factors of coconut somatic embryogenesis were researched including effects of plumule maturity and sucrose concentration on the induction of primary embryogenic callus, as well as the impact of sucrose concentration during the subsequent callus multiplication stage. Furthermore, the effect of thidizuron (TDZ) on regeneration of coconut somatic embryo was studied. The results indicated that plumule maturity and sucrose concentration significantly influence primary callus induction, with the highest formation rates observed from 14-day preculture plumules, cultured in 45 gL-1 sucrose-supplemented medium. Sucrose concentration also affected significantly on embryogenic callus formation during callus multiplication stage. Crucially, this research demonstrated that TDZ, at concentrations ranging from 25 µM to 50 µM, effectively promoted development, germination, and plantlet regeneration of coconut somatic embryos. The result from the experiment provided valuable insights into optimizing the in vitro propagation protocols for coconut, paving the way for enhanced production and conservation efforts.