Abstract:

Vitellaria paradoxa C. Gaertn. (shea butter
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 %), stemdiameter (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 resolve any discrete forms of V.
paradoxa that are related to folk classification. There is
need to utilise biochemical and molecular markers to
unravel the underlying variation for use in selection
and improvement of shea butter tree ethno-varieties.