Influence of Basal Medium and Organic Additives on In Vitro Germination and Plant Growth of Endangered Orchid Gastrochilus fuscopunctatus

<i>Gastrochilus fuscopunctatus</i> is a rare epiphytic orchid in Korea threatened by habitat loss and illegal collection. This study aimed to establish an efficient in vitro propagation system by evaluating asymbiotic germination and seedling growth. Mature seeds germinated on both Hyponex (Hy) and Orchid Seed Sowing Medium (OSM), but protocorm development was more active on Hy, regardless of 1 µM NAA supplementation. For seedling culture, Murashige and Skoog (MS), Hy, and Orchid Maintenance Medium (OM) were tested with apple homogenate (AH), banana homogenate (BH), and coconut water (CW). At 7 months, Hy supported the greatest biomass and root formation, while Hy + BH produced the highest values (0.066 g fresh weight, 1.3 cm root length). Although BH improved growth on MS and OM, the effects were less pronounced. At 14 months, Hy + BH again yielded superior results (1.93 g fresh weight, 5.3 cm root length, 17.2 leaves), clearly outperforming all other combinations. AH and CW showed inconsistent or limited effects across media, indicating strong medium-additive interactions. These findings demonstrate that Hy + BH is the most effective combination for both early and prolonged growth of <i>G. fuscopunctatus</i>, providing a practical framework for ex situ conservation and reintroduction.