Oncidium orchid has high demand and economic value especially in floriculture industry. This study aimed to optimize a suitable medium for rapid proliferation of protocorm-like bodies (PLBs) of Oncidium Golden Anniversary orchid. Results from this study confirmed that ½ MS semi-solid medium displayed the highest growth index and total numbers of PLBs. Inclusion of 20g/L sucrose and 1mg/L BAP produced the highest PLB proliferation rate, while adding charcoal gave no significant effect. Half-moon PLB size contributes to the highest growth rate on using a thin cell layer (TCL) system. Hence, the best medium for Oncidium Golden Anniversary PLB proliferation was ½ MS semi-solid media supplemented with 20 g/L sucrose and 1 mg/L BAP.
