Utility of Isubgol, Gum Arabic and Sago as Alternative Gelling Agents to Agar For in vitro Regeneration and Multiplication of Protocorms of Vanda testacea (Lindl.) Reichb.F. -A Rare Medicinal orchid

Presently, the efficacy of isubgol, gum Arabic, and sago as an ecofriendly and cheap substitute to expensive gelling agent agar was tested to assess the proliferation potential of Vanda testacea protocorm segments. M medium supplemented with 2% sucrose and gelled with 0.9% agar (control), 3.5% isubgol (derived from Plantago ovata seed husk), 5% gum Arabic (exudates from stem and branches of Acacia Senegal) and 7% sago (stem and pith exudate of Metroxylon sagu) was used as source of nutrition. All the alternative gelling agents initiated regeneration in the explants; isubgol and sago-gelled medium favoured maximum number of PLBs and shoots/explant. Profuse rooting was observed in isubgol-gelled medium whereas in sago-gelled medium rooting was delayed. Poor response of the cultures (in terms of average number of PLBs and shoots/explant) was observed in medium gelled with gum Arabic. This communication primarily focuses to develop a low cost protocol for multiplication of a rare medicinal orchid Vanda testacea.