Molecular methods have been used to characterize diversity among pathogenic and non pathogenic isolates of Fusarium spp. and to determine genetic relationships among formae speciales. Pathogenicity tests performed on dry beans (Phaseolus vulgaris) and soybeans (Glycine max)with 17 isolates of Fusarium solani did not demonstrate host specificity. Amplified Ribosomal DNA Restriction Analysis (ARDRA) was used to analyze the ITS1 - 5,8S rDNA - ITS2 region, amplified with primers ITS4 and ITS5. The amplified products were digested with the restriction enzymes Hae III and Msp I. Banding patterns generated by the enzyme Hae III enabled the differentiation of three groups within F. solani, one specific for isolates of F. solani f. sp. phaseoli and the other two for F. solani f. sp. glycines. The ARDRA technique, using the enzyme Hae III, is a promising marker to differentiate the formae specialesphaseoli from glycines within the F. solani complex.
