DEVELOPMENT OF HIGH-EFFICIENCY IN VITRO REGENERATION SYSTEM FOR RAPID CLONAL PROPAGATION OF GLYCYRRHIZA GLABRA L.

Abstract

Glycyrrhiza glabra L. (licorice) is a high-value medicinal plant prized for its major bioactive triterpenoid saponin, glycyrrhizin. However, commercial exploitation is severely bottlenecked by low seed viability, prolonged root maturation, and destructive wild harvesting. This study established an efficient, highly reproducible in vitro regeneration protocol for rapid clonal propagation using nodal explants and shoot tips. Surface-sterilised explants were cultured on Murashige and Skoog (MS) medium supplemented with different concentrations and combinations of cytokinins and auxins. Maximum shoot induction frequency (66%) and superior shoot length (7.50±0.12 cm) were achieved on MS medium supplemented with 2.0 mg L-1 6-benzylaminopurine (BAP) and 1.5 mg L-1 indole-3-butyric acid (IBA). Multiple shoot proliferation reached its peak (75% multiplication frequency) on MS medium containing 2.0 mg L-1 BAP and 1.5 mg L-1 (KN). Optimal adventitious rooting (100% response) was induced on half-strength MS medium fortified with 1.5 mg L-1 α naphthaleneacetic acid (NAA) and 1.0 mg L-1 BAP. Fully rooted plantlets were successfully acclimatized ex vitro in a hardened substrate mix of cocopeat, garden soil, and sand (2:2:1 v/v), exhibiting high survival rates without phenotypic somaclonal variation. This high-frequency direct organogenesis protocol offers a robust technological platform for mass clonal multiplication, germplasm conservation, and sustainable phytopharmaceutical raw material supply.