Virulence variation and RAPD polymorphism in African isolates of Phaeoisariospis griseola (Sacc.) Ferr., the causal agent of angular leaf spot of common bean

Fifty four isolates of Phaeoisariopsis griseola, the agent of common bean a ngular leaf spot disease from the Great Lakes Region of Africa, were charac terised according to their virulence behaviour and their molecular patterns . Virulence properties were revealed through the inoculation of 29 genotype s of Phaseolus vulgaris, Phaseolus coccineus and Phaseolus polyanthus. Diff erences in reaction types revealed high variability among these isolates. M ost of them, even when collected within the same location, showed differenc es in their respective reactions on many plant genotypes. For molecular typ ing, RAPD amplifications were performed for each isolate using five random primers. Isolates with different patterns were collected within one region. Simultaneously, similar molecular patterns were found in isolates collecte d at different sites. However, the average of molecular similarity, based o n the percentages of shared bands for each isolates pair, was higher among isolates collected within one site. No direct correlation between molecular pattern and pathotype was observed.