An efficient callus-based in vitro regeneration protocol for Warburgia Ugandensis Sprague,an important medicinal plant in Africa

Warburgia ugandensis Sprague is a woody species in the family Canellaceae and an important source of medicines in Africa. Natural propagation of W. ugandensis is problematic due to its recalcitrant seeds and lack of an efficient in vitro regeneration system for this species. This study describes an efficient regeneration protocol. Petiole bases and shoot tips were used as explants. Callus tissue developed when the explants were cultured on Murashige and Skoog medium containing 30 g L^?1 sucrose and 7 g L^?1 agar (MS30 medium), supplemented with 1.0 mg L^?1 indole-3-butyric acid (IBA), 1.6 mg L^?1 6-benzylaminopurine (BA), and 0.1 mg L^?1 thidiazuron (TDZ). Adventitious buds were efficiently induced from the callus when the MS30 medium was supplemented with 0.8 mg L^?1 BA and 0.2 mg L^?1 IBA. Root induction occurred within 7–10 d on half-strength MS30 medium supplemented with 0.8–1.0 mg L^?1 1-napthalene acetic acid (NAA), 0.2 mg L^?1 IBA, and 0.03% (w/v) activated charcoal (AC). Roots were followed by root elongation on the same medium but lacking NAA and IBA. Approximately 50% of the plantlets cultured produced roots, while more than 80% of the plantlets survived and successfully grew to maturity.