In vitro propagation of Hoya wightii ssp. palniensis K.T. Mathew, a highly vulnerable and endemic species of Western Ghats of Tamil Nadu, India

In vitro propagation of Hoya wightii ssp. palniensis (Asclepiadaceae), a highly vulnerable and endemic plant species of Western Ghats, Tamil Nadu, India was carried out. Shoot tip explants were cultured on MS medium fortified with cytokinins (KN, BA, 2-iP and TDZ) in various concentrations and in combination with auxins (IBA, IAA and NAA). High frequency of shoot bud proliferation and multiplication was observed on KN (4.65 iM) + IBA (1.47 iM). Multiple shoot induction efficiency was increased on ascorbic acid (100 mg/l) supplemented medium along with KN (4.65 iM) +IBA (1.47 iM). Rhizogenesis was observed on MS medium supplemented with IBA (0.98 iM), plantlets produced through micropropagation were hardened with the survival success of 56%. The efficient plantlet regeneration protocol developed would aid ex situ conservation of this vulnerable species.