Phenotypic characterization, reproductive biology and vegetative propagation of Adansonia digitata L. wild populations in Malawi

Baobab (Adansonia digitata L.) is a multipurpose indigenous fruit tree with high nutritional and economic value and contributes significantly to livelihoods of local people, particularly in areas where it occurs. For this study, phenotypic characterization of five selected wild baobab populations in Malawi was compared using fruit and seed traits among fruit shapes and tree characteristics. Furthermore, age and existence of fruits in baobab trees over years were determined. Amenability of the baobab tree to vegetative propagation was investigated using grafting, cuttings and air layering. Lastly, the study identified mating systems in A. digitata. Results revealed the presence in Malawi of 13 unique fruit shapes of which only three (ellipsoid, oblong, ovate), could be found in all the studied populations. There were significant differences (P ≤ 0.001) for fruit and seed traits among the fruit shapes. Seed coat colours found were; light brown, brown spotted, dark brown and grayish brown while seed shapes were; very-reniform, reniform and oblong. Tree characteristics varied from one to another. Age estimates ranged from 48 years to 180 years with a diameter at breast height (dbh) of 104.09 cm and 422 cm respectively. Fruit shapes were distributed across all ages with ellipsoid shape found across all ages. Significant differences were observed for grafting success between grafting methods (P ≤ 0.003) and ortets (P ≤ 0.001) in October and November. No callusing and rooting were observed for treatments propagated using cuttings and air layering. Mating system results showed bud becoming fully opened at around 19:21 pm. Buds in all the treatments flowered (100 %). Fruit abortion was high in cotton cloth (95.7%), followed by mosquito net (87.5%) and chicken wire (78.3%). Fruit production was highest in control treatment (33%). Vigorous fruit growth was only attained in the control treatment. High tree diversity revealed in this study can be used in vi selection and cultivation of the species by promoting grafting of trees possessing desirable attributes for farmers to benefit. It is envisaged that the information generated could help formulate conservation, management, improvement and domestication strategies, which are important for projects promoting the sustainable use and domestication of the African baobab in the agroforestry systems.