Tissue Culture for Rapid Propagation of A Cymbidium goeringii Hybrid

  Objective  Optimum conditions for an efficient, rapid propagation from rhizomes of a Cymbidium goeringii hybrid were investigated.

  Method  Rhizomes of the aseptically seeded F₁ hybrid between two C. goeringii cultivars, Huang-mei and Huang-he, were cultivated on various media (i.e., 1/2MS、modified 1/2MS, and HyponexⅡ) with added plant growth regulators (i.e., 6-BA, NAA, TDZ, and/or IBA) to monitor the plant growth throughout propagation, differentiation, and rooting of the regeneration process. The seedlings were subsequently transplanted outdoor to determine their survival rate.

  Result  In the propagation stage, the optimal medium was 3.0 g HyponexⅡ·L⁻¹ + 0.5 mg 6-BA·L⁻¹ + 3.0 mg NAA·L⁻¹ + 1.0 g activated carbon (AC)·L⁻¹ + 30.0 g sugar (Su)·L⁻¹ + 7.0 g agar (Ag)·L⁻¹ to achieve a growing rate of 7.31 and a multiplication coefficient of 6.02. The optimal medium for differentiation was 2.0 mg 6-BA·L⁻¹ + 0.3 mg NAA·L⁻¹ + 30.0 g Su·L⁻¹ + 7.0 g Ag·L⁻¹ to deliver an averaged 90.00% differentiation, 5.44 buds per rhizome segment, and 2.53 cm height of seedling. For optimum rooting, the medium was 1.5 mg IBA·L⁻¹ + 2.0 g peptone·L⁻¹ + 1.0 g AC·L⁻¹ + 25.0 g Su·L⁻¹ + 7.0 g Ag·L⁻¹ to result in 100.00% root-generation with an averaged 8.03 roots at 3.00 cm long per plant. The survival rate of plantlets 60 d after transplantation was up to 96.53%.

  Conclusion  HyponexⅡ applied at 3.0 g·L⁻¹ was found highly efficient for the C. goeringii rhizome regeneration; and, the addition of 1.5 mg·L⁻¹ of IBA in the medium significantly enhanced the rooting for the seedlings.