In vitro regeneration and transformation studies on Pelargonium graveolens (geranium) - an important medicinal and aromatic plant

Development of improved protocols for the regeneration of Pelargonium graveolens is important for their commercial utilization. Callus was induced from leaf explants on Murashige and Skoog (MS) medium supplemented with auxins and combinations of auxins and cytokinins. Micropropagation of nodal bud explants was achieved using medium supplemented with cytokinins. The regenerated explants were acclimatized and the transformation potential of geranium was demonstrated using Agrobacterium tumefaciens. Maximum proliferation was obtained in medium supplemented with combinations of 20 µM indole butyric acid (IBA) + 10 µM kinetin (KIN), 20 µM IBA + 10 µM benzyl amino purine (BAP) and 20 µM indole-3-acetic acid (IAA) + 10 µM KIN. Plantlets were regenerated when callus was given a photoperiod of 16 h light and 8 h dark conditions at 25°C. After being transferred to greenhouse conditions, the plantlets were successfully acclimatized and transferred to the field condition. The study has established an efficient protocol for in vitro regeneration and transformation of P. graveolens as an alternative method for vegetative propagation.