Abstract:

Vitellaria paradoxa C.Gaertn.(sheabutter tree) is an indigenous African tree species that is widely distributed in the dry areas of northern and eastern Uganda. The species is widely known for its oil which is used in cooking, cosmetics and traditional medicine. Local folk classification recognises the presence of different ethno-varieties on the basis of fruit and nut characters. In the present study, 176 trees representing 44 ethno-varieties from three farming systems of Uganda were assessed to determine the patterns of morphological variation and establish the congruence between morphological variation and folk classification. The results show high variation in pulp weight (CV = 35.9 %), stem diameter (CV = 28.48 %), fruit weight (CV = 27.81 %) and canopy diameter (CV =26.69 %). There was a strong positive correlation between pulp and fruit weight (r = 0.963, p\0.001), leaf length and leaf width (r = 0.652, p\0.001) and between petiole length and leaf length (r = 0.788, p\0.001). There was no underlying quantitative morphological structuring among the 44 ethno-varieties. Hierarchical cluster analysis using quantitative morphometric data produced three groups without
clear aggregation based on ethnographic or geographic separation. However, a combination with qualitative
traits as perceived by farmers provided good congruence with folk classification. Quantitative morphological data alone does not solve any discrete forms of V. paradoxa that are related to folk classification. There is need to utilize biochemical and molecular markers to unravel the underlying variation for use in selection and improvement of shea butter tree ethno-varieties.