Efficient plant regeneration through callus culture in Hedychium spicatum Buch.Ham. Ex. D. Don using response surface methodology

Hedychium spicatum (Family-Zingiberaceae), commonly known as spiked ginger lily, is widely known for its medicinal properties and high market demand. The species is harvested mainly from the wild to meet the raw material requirements for the pharmaceutical and cosmaceutical industries; therefore, it needs urgent attention for its conservation and mass production. The present study developed an efficient in vitro propagation protocol for large-scale species production. The central composite design-response surface methodology (CCD-RSM) was designed to optimize the plant growth regulators (PGRs) concentration for maximum callus production, shoot regeneration, and rooting. The seed was used as explants in Murashige and Skoog (MS) medium with different concentrations of naphthalene acetic acid (NAA; 2.5-5.0 µM) in combination with thidiazuron (TDZ; 2.5-5.0 µM) for callus induction. TDZ (4.76 µM) with NAA (2.84 µM) showed maximum callus induction (100%) after 6 weeks of incubation. Callus pieces were transferred to MS medium with different concentrations of TDZ, NAA, and Indole-3-butyric acid (IBA) for shoot regeneration. The highest regeneration frequency (100%) was observed on MS medium enriched with TDZ (2.72 µM) and NAA (3.5 µM) that showed a maximum number of shoots/explants (16.34 no.). Regenerated shoots were rooted better (average number of roots/shoot − 11.75) on MS medium with NAA (2.11 µM) and IBA (1.17 µM) in combination. After the subsequent acclimatization and hardening process in the greenhouse, the plants were planted in the experimental field, and their survival rate was 89% after 2 years of establishment. The protocol established in the present study has prospects to meet the challenges of quality planting material for large-scale cultivation and raw material sources for industrial utilization.