An optimized method for in vitro propagation of African baobab (Adansonia digitata L.) using two-node segments

Adansonia digitata L. (African baobab), is an important multi-purpose tree, whose distribution is at present limited to wild or semi-domesticated individuals widespread in Africa. Its distribution is threatened by seedling clearance for other land use and potentially by overharvesting induced by growing commercial use of baobab fruit. Recently, efforts have been made to establish baobab domestication and conservation strategies, with mixed results due to the low germinability of baobab seeds, a factor that hinders the possibility of developing commercial A. digitata plantations. Here, micropropagation was tested as a method for clonal propagation of explants from in vivo-grown seedlings. In vitro shoot multiplication was achieved by enhanced axillary bud proliferation of sterilized two-node segments. Bud break was dependent on cytokinin supply, but the combination of 1.0 or 10.0 µM zeatin riboside and 10.0 µM indole-3-butyric acid (IBA) increased the formation of microshoots after 8 weeks of culture. Regenerated microshoots rooted successfully in in vitro nutrient medium containing 10.0 µM IBA and normally grew in a greenhouse after acclimatization.