Effect of plant growth regulators (PGRs) on micropropagation of a vulnerable and high value medicinal plant <i>Hedychium spicatum</i>

Abstract

A complete micropropagation protocol was developed by applying different plant growth regulators (PGRs) of a vulnerable and high value aromatic medicinal plant, Hedychium spicatum. Three cytokinins, 6-benzyladenine (BA), kinetin (KN) and thidiazuron (TDZ) were used and among these, the lower concentration of TDZ (1.0 μM) was found to be the most effective treatment in relation to induction of high frequency shoot multiplication (83.33%), number of shoots per explant (3.86 shoots) and average number of shoots per flask (19.33 shoots). Indole-3-acetic acid (IAA), indole-3-butyric acid (IBA) and α- naphthalene acetic acid (NAA) were the used auxins in this study for in-vitro rooting. Among these used auxins, the lower concentration of IBA (2.5 μM) was the prominent plant growth regulator regarding in vitro rooting. Well rooted and healthy plantlets were obtained after 2 months of hardening and transferred to the field (1990 m) with 90.0% survival. On the basis of available literature, this is the first and significant study regarding the comparative effect of different PGRs on in-vitro propagation study of H. spicatum. This significant study could be useful for large scale propagation and ex-situ conservation of this vulnerable Himalayan species.

Key words: Cytokinins, thidiazuron, shoot multiplication, in-vitro propagation, ex-situ conservation.