In vitro clonal propagation of an aromatic medicinal herb Ocimum basilicum L. (sweet basil) by axillary shoot proliferation

Summary

An efficient protocol for in vitro propagation of an aromatic and medicinal herb Ocimum basilicum L. (sweet basil) through axillary shoot proliferation from nodal explants, collected from field-grown plants, is described. High frequency bud break and maximum number of axillary shoot formation was induced in the nodal explants on Murashige and Skoog (1962) medium (MS) containing N⁶-benzyladenine (BA). The nodal explants required the presence of BA at a higher concentration (1.0 mg·l⁻¹, 4.4 µM) at the initial stage of bud break; however, further growth and proliferation required transfer to a medium containing BA at a relatively low concentration (0.25 mg·gl⁻¹, 1.1 µM). Gibberellic (GA₃) at 0.4 mg·l⁻¹ (1.2 µM) added to the medium along with BA (1.0 mg·l⁻¹, 4.4 µM) markedly enhanced the frequency of bud break. The shoot clumps that were maintained on the proliferating medium for longer durations, developed inflorescences and flowered in vitro. The shoots formed in vitro were rooted on half-strength MS supplemented with 1.0 mg·l⁻¹ (5.0 µM) indole-3-butyric acid (IBA). Rooted plantlets were successfully acclimated in vermi-compost inside a growth chamber and eventually established in soil. All regenerated plants were identical to the donor plants with respect to vegetative and floral morphology.