Abstract
Farmers and traders have developed a system of names to refer to different qat (Catha edulis) cultivars, using stem color as the primary trait to differentiate them. In this study, we tested if the named cultivars from Ethiopia, Kenya, and Yemen represent genetic clusters. We also quantified clonal reproduction and tracked the geographic dispersal of cultivated-qat genotypes using microsatellite genotypes of specimens collected from across the major qat growing regions (Ethiopia, Kenya, and Yemen). Specimens were mapped to determine whether names, morphology, genetic clusters, or genotypes (in particular clones) were geographically restricted. Stem color was found to be a plastic trait because specimens of the same genotype have different colored stems. A single cultivar name was often applied to numerous clonal groups and genetic clusters, creating widespread homonymy in the ethnotaxonomy of qat cultivars. The East African Rift (EAR) in central Ethiopia was found to be a barrier to the exchange of both clonal groups and certain cultivar names. In Kenya, both cultivar names and clonal groups were broadly dispersed geographically. Nearly all of these clonal groups originated from the Mt. Kenya/Meru area in central Kenya.