In Vitro Propagation of Variegated Cymbidium lancifolium Hooker

Variegated Cymbidium lancifolium is a highly valued ornamental plant sought after in local and international markets. The commercial production of variegated C. lancifolium through traditional propagation methods faces significant challenges, such as low propagation rates and prolonged growth periods. This study aims to develop effective in vitro propagation techniques for variegated C. lancifolium through asymbiotic seed germination to enhance production efficiency and meet market demand. We examined the effects of various plant growth regulators and coconut water (CW) on in vitro seed germination. The highest germination percentage (46.8%) was recorded in Murashige and Skoog (MS) medium supplemented with 50 mL/L CW, 4.0 µM α-naphthalene acetic acid (NAA), 2.3 µM kinetin (KN), and 2.9 µM gibberellic acid (GA₃). Seed-derived rhizomes were placed on MS medium containing indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), and NAA for proliferation. Among the auxins, NAA was the most effective, significantly increasing rhizome proliferation, with the highest number (17.4) and length (2.1 cm) observed at 5.0 µM. The rhizome explants were cultured in MS medium enriched with kinetin (KN), N⁶-(2-isopentenyl)adenine (2-IP), and N⁶-benzyladenine (BA) to promote plantlet regeneration. Of the cytokinins tested, BA at 10.0 µM resulted in the highest rate of plantlet regeneration (79.4%), the greatest number of plantlets (4.4 per culture), and notable plantlet height (8.5 cm). We obtained plantlets with dark green leaves, light green leaves, and distinct variegation patterns. They were transferred to three different substrate mixtures for acclimatization. The substrate made of orchid stone (30%), wood bark (30%), coconut husk chips (20%), and perlite (20%) supported the highest survival rate (95.9%). This study successfully established optimized in vitro propagation techniques for variegated C. lancifolium, enabling enhanced germination, rhizome proliferation, and plantlet regeneration to meet the growing market demand.