Effect of Culture Medium Composition on In Vitro Regeneration, Acclimatization, and Production Cost of Dendrobium phalaenopsis Sa-Nook ‘Thailand Black’ Plants

The <i>Dendrobium</i> genus originates from tropical and subtropical regions of Asia, extending to northern Australia. Species and hybrids of this genus, including <i>Dendrobium phalaenopsis</i> Sa-Nook 'Thailand Black', are the second most popular cultivars worldwide. To meet this demand, it is necessary to implement techniques such as micropropagation, which allows the mass production of plants. The objective of this study was to evaluate the effect of plant growth regulators (NAA, BA, and TDZ) on the in vitro regeneration of <i>D. phalaenopsis</i> Sa-Nook 'Thailand Black' plants, their acclimatization, and production costs. Rootless shoots of 1-1.5 cm in height were grown on 50% MS medium supplemented with BA (0, 2.22, 4.44, or 8.88 µM), TDZ (0, 2.27, 4.54, or 9.08 µM), and NAA (0 or 2.69 µM), individually or in combination. After the second phase of in vitro shoot growth, the highest number of shoots per explant (8.5) was observed with 9.08 µM of TDZ. Plants regenerated with this concentration of TDZ showed the highest survival rate (96%) at 90 days of greenhouse cultivation, as well as the formation of new shoots (0.9), and the lowest production cost per plant (0.49 USD).