Discrimination of cassava‐associatedBemisia tabaciin Africa from polyphagous populations, by PCR–RFLP of the internal transcribed spacer regions of ribosomal DNA

Abstract: Restriction fragment length polymorphism (RFLP) analysis of the ribosomal DNA internal transcribed spacer regions ofBemisia tabaciwas used to distinguish cassava‐associated populations from other host‐associated populations. Endonuclease restriction profile analysis indicated that cassava‐associated populations from Africa represent a distinct group, with a significant level of separation into subgroups that were not linked to geographical origin. Analysis of molecular variance (amova) revealed that a high proportion of the total genetic variation (47%) was attributable to among‐population differences within the host‐associated groups. Principal coordinate analysis supported the differentiation between the cassava and the non‐cassava group, a result which was in agreement with the cluster analysis of the restriction fragment profile. Internal transcribed spacer RFLP markers, especiallySmaI, identified in this study can be used to monitor the spread ofB. tabacibiotypes, especially of the more virulent biotype B that has so far not been reported in the cassava‐growing belt of Africa.