In vitro shoot multiplication and rooting from seedling explants of Pterocarpus angolensis in Zambia

Pterocarpus angolensis is a savanna tree species growing mostly in the southern part of Africa. Exploitation for its medicinal and commercial uses has led to diminishing of wild populations. Developing reliable in vitro protocols for propagation would enable mass production of desired genotypes for domestication and conservation of P. angolensis. In this study, the effect of 6-benzylaminopurine (BAP), isopentenyl-adenine (2-iP) and thidiazuron (TDZ) were tested for shoot induction on cuttings from four weeks old P. angolensis seedlings. BAP at 5 mg/l gave higher shoot multiplication compared with 0–2 mg/l BAP. Although axillary buds opened on cuttings treated with 0.1 to 2 mg/l TDZ, no elongation occurred. Shoots placed on 0.5–5 mg/l 2-iP produced roots but no axillary shoots. Indole-3-butyric acid (IBA) and indole-3-acetic acid (IAA) were tested for ability to induce rooting of micropropagated shoots. IAA at 1 mg/l and IBA at 1-4 mg/l induced higher percent rooting than other auxin concentrations. Shoots on media lacking auxins also rooted well (48%), suggesting that no growth regulator was required for rooting of 4 weeks old P. angolensis shoots.