Effects of Different Concentrations of 6-Benzylaminopurine (BAP) on the In Vitro Growth of Dendrobium spectabile (Blume) Miq. Plantlets

Dendrobium spectabile (Blume) Miq. is an ornamental orchid with high economic value and considerable potential for commercial cultivation. However, conventional propagation is relatively slow, making in vitro culture an effective alternative for producing large numbers of uniform plantlets. This study aimed to evaluate the effects of different concentrations of 6-benzylaminopurine (BAP) on the growth of D. spectabile plantlets and to determine the optimal BAP concentration for in vitro plantlet development. The experiment was arranged in Completely Randomized Design (CRD) consisting of five BAP concentrations (0, 0.5, 1.0, 1.5, and 2.0 mg/L) using Vacin and Went (VW) medium. The observed parameters included plantlet survival percentage, visual appearance, plantlet height, number of leaves, number of shoots, root length, number of roots, and fresh weight. Data were analyzed using analysis of variance (ANOVA), followed by Tukey’s test at the 5% significance level. The results showed that BAP concentrations significantly affected the growth of D. spectabile plantlets. A concentration of 1.5 mg/L BAP was the most effective for promoting plantlet height, number of leaves, number of shoots, and fresh weight, whereas 0.5 mg/L BAP produced the greatest root length and number of roots. These findings indicate that 1.5 mg/L BAP is the optimal concentration for enhancing shoot growth, while 0.5 mg/L BAP is more suitable for root development of D. spectabile plantlets cultured on VW medium.