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

Abstract

Hedychium spicatum(Family-Zingiberaceae), commonly known as Kapoor Kachri 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) experiment was designed to optimize the plant growth regulators (PGRs) concentration for maximum callus production, shoot regeneration and rooting. Seed radicle was used as explants in Murashige and Skoog (MS) medium supplemented 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 (5µM) with NAA (2.5µM) showed maximum callus induction (98%) after 6 weeks of incubation. Callus pieces were transferred to MS medium supplemented 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 2.5 µM TDZ and 3.5 µM NAA that showed a maximum number of shoots/explants (16.19 no.). Regenerated shoots were rooted better (average number of roots/shoot - 11.71) on MS medium supplemented with 2 µM NAA and 1.5 µM IBA in combination. After subsequent acclimatization and hardening process in the greenhouse, the plantlets were planted in the experimental field with a survival rate of 83% after 4 months. 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.