Fatty acid and tocopherol patterns of variation within the natural range of the shea tree (Vitellaria paradoxa)

The shea tree, Vitellaria paradoxa, is one of the most economically and culturally important indigenous tree species in the Sudano-Sahelian region. Its seeds contain a vegetable fat, internationally known as shea butter, which is widely used in edible, cosmetic and pharmaceutical sectors. Based on samples from 456 trees distributed in 17 locations across the species natural range from Senegal to Uganda, the fatty acid and tocopherol variation, and its relationship with geographic and climatic variables, was assessed in order to address the pattern and the origin of this variation across the natural range. Significant differ- ences between Western and Eastern regions for oleic, stearic acid, saturated-unsaturated acid ratio and c-tocopherol were identified that it is postulated maybe a result of genetic drift due to the evolutionary history of shea tree populations. Within regions the difference among stands was significant for most constituents; however the major part of the variation was observed among trees within stand (53-90 %). Relationships with climatic variables were not veri- fied, weakening evidence for clinal variation hypoth- eses suggested by previous studies.