Abstract: Pterocarpus marsupium Roxb., a medicinal and multipurpose leguminous tree commonly known as Indian kino, Vijaysar or Bijasal, is valued for its pharmacologically important bark, heartwood and other tissues. Conventional propagation is relatively slow and natural regeneration may be inadequate for meeting conservation and planting requirements. In vitro culture provides an efficient alternative for multiplication of selected genotypes and for production of uniform plant material for pharmacological studies. The present study framework evaluates the effect of different cytokinins and auxins on in vitro regeneration, shoot multiplication, rooting and acclimatisation of P. marsupium. Nodal segments and cotyledonary nodes are considered suitable explants, with Murashige and Skoog (MS) medium used as the basal formulation. Cytokinins including 6-benzyladenine (BA), kinetin (Kn), 2-isopentenyladenine (2iP) and meta-topolin (mT) are compared alone and in combination with low concentrations of indole-3-acetic acid (IAA) or α-naphthalene acetic acid (NAA). Rooting is evaluated using indole-3-butyric acid (IBA), including a two-step induction procedure. Practical observations indicate that cytokinin concentration has a marked effect on regeneration frequency, shoot number and shoot elongation. BA at 4.0 µM with 0.5 µM IAA and 20 µM adenine sulphate has been reported to produce 85% regeneration, 8.6 shoots per explant and 4.8 cm shoot length from nodal segments. In cotyledonary-node cultures, 7.5 µM meta-topolin produced 9.58 shoots per explant with 4.12 cm shoot length, while 7.5 µM meta-topolin plus 1.0 µM NAA produced 17.44 shoots per explant and 5.72 cm shoots in 85% cultures. IBA-based two-step rooting has also produced high-quality roots, including approximately 7.35 roots per shootlet and 4.54 cm root length in meta-topolin-derived cultures. Acclimatisation is a critical final phase and study shows survival around 75–80%. These findings indicate that cytokinin identity, concentration and interaction with auxin are decisive for regeneration efficiency and plantlet quality. The most useful protocol is therefore one that balances multiplication with shoot quality, rooting and ex vitro establishment.

Keywords: Pterocarpus marsupium; micropropagation; cytokinins; auxins; BA; kinetin; meta-topolin; NAA; IAA; IBA; shoot regeneration; rooting; acclimatisation; medicinal tree.