Effect of Varying NAA Hormone Concentrations on In Vitro Subculture of Raja Bulu Banana (Musa sp.)

Tissue culture, a method involving the sterilized in vitro propagation of plant parts, offers potential for producing disease-free seedlings. This study aimed to (1) evaluate the effect of NAA (1-naphthaleneacetic acid) concentrations on root induction in Raja Bulu banana (Musa sp.) plantlets; (2) assess rooting percentage, root count, leaf number, root length, root mass, leaf color, plant height, and stem diameter; and (3) identify the optimal NAA concentration. Conducted from January to March 2025 at Salaman, Magelang (270 m a.s.l.), the experiment employed a Completely Randomized Design (CRD) with four NAA treatments (0, 2, 4, and 6 ppm) and six replications. Each bottle culture contained two plantlets. After 35 days, plantlets treated with 2 ppm NAA exhibited the highest root count (5.83 roots), with superior performance across other parameters. Elevated NAA concentrations (4–6 ppm) resulted in decreased rooting and chlorophyll content, indicating potential hormonal imbalance and phytotoxicity. The study concludes that 2 ppm NAA is the most effective concentration for rooting Raja Bulu banana in vitro. Future research should investigate the combined effects of auxins and cytokinins, natural biostimulants, and varying culture conditions to further enhance propagation efficiency.