One sweetpotato breeding line resistant to sweetpotato feathery mottle virus (SPFMV) was
infected by graft-inoculation with SPFMV and developed severe symptoms of sweetpotato virus
disease, following co-inoculation with sweetpotato chlorotic stunt virus. Coat protein (CP) gene
sequences from eight East African isolates of SPFMV and two West Africa isolates from Nigeria
and Niger were determined. Phylogenetic analysis of sequences of these isolates and those of
non-East African origin previously reported, showed that the East African SPFMV isolates form
a separate cluster. The monoclonal antibody MAb 7H8 divided Uganda SPFMV isolates into
serogroups, which differed in prevalence in different districts of Uganda and in two common sweetpotato cultivars.