Callus induction, high frequency shoot organogenesis and assessment of clonal fidelity in Torenia bicolor Dalzell.

• T. bicolor is an endemic annual trailing herb growing in Western Ghats.
• An efficient protocol for the mass propagation of T. bicolor has been described.
• The highest shoot regeneration from callus was observed on MS + BA + NAA.
• The rooted shoots were transplanted to soil and acclimatized successfully.
• ISSR analysis revealed genetic stability of regenerated plants.

An efficient protocol for the mass propagation of Torenia bicolor using internode derived callus organogenesis has been described. The optimum callusing was observed when internode explants were cultured on MS medium augmented with 4.0 μM 2,4-dichlorophenoxy acetic acid (2, 4-D) and 0.5 μM kinetin (Kn). The calli were subcultured on MS medium supplemented with various concentrations of N6-benzylaminopurine (BA; 1.0-5.0 μM) or Kn (1.0-5.0 μM) alone or in combination with naphthalene acetic acid (NAA; 0.5-1.5 μM) for shoot regeneration. The highest shoot regeneration in terms of percent response (100%) and number of shoots (89.3) was observed on MS medium supplemented with 4.0 μM BA and 1.0 μM NAA. The best rooting was observed on half strength MS medium augmented with 0.6 μM indole-3-butyric acid (IBA). On this medium, 100% shoots rooted with an average number of 6.8 roots per shoot. The rooted shoots were transplanted to soil and acclimatized successfully. Of the 80 plants transplanted to soil 72 survived. Inter simple sequence repeat (ISSR) analysis clearly indicated that callus derived plants of T. bicolor resembled the parent plant at the genetic level. The protocol described here could be used for the mass multiplication and conservation of this endemic plant.

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