Effects of indole-3-butyric acid and 1-naphthaleneacetic acid on in vitro rooting and the substrate mixing ratio on growth during the nursery stage of Mai vang (Ochna integerrima) HD01 line

Identifying suitable plant growth regulators for the rooting stage and substrate mixing ratio for seedlings in the nursery remains a significant challenge, particularly in relation to Mai vang. This plant existed in culture and tradition for a long time and was considered a symbol of the traditional Tet. The experiments were conducted on Mai vang HD01 line, which was selected from Huu Duc Mai garden in Binh Loi apricot village, known for its exceptional characteristics. The objective of this study was to determine the optimal Indole-3-butyric acid (IBA) and 1-naphthaleneacetic acid (NAA) concentrations appropriate for root formation from shoot samples in in vitro condition and the optimal substrate mixing ratio appropriate for the growth of Mai vang HD01 line during the nursery stage. The study including two experiments were arranged in completely randomized design with one-factor and two-factor. For rooting induction, the culture medium supplemented with concentrations of IBA combined with concentrations of NAA was used, while to grow, Mai vang HD01 plants were planted in a substrate of coconut fiber, sand, rice husk ash, and vermicompost with different mixing ratios. The results showed that Mai vang HD01 shoots were cultured on Murashige and Skoog medium supplemented with 0.5 mg/L IBA combined with 2 mg/L NAA suitable for rooting and creating complete plants. The number of roots, root length, plant height and number of leaves were 6.9 roots; 3.5 cm; 2.3 cm and 5.9 leaves, respectively on day 60. Mai vang HD01 plants in the nursery stage were suitable for planting on a substrate with a mixing ratio of 1 coconut fiber:1 sand:1 rice husk ash:1 vermicompost with a 100% survival rate. They grew quickly to a height of 5.1 cm which was higher than that of plants planted on other substrate mix ratios on day 40.