Abstract

In the present investigation, 40 Fusarium oxysporum f. sp. vasinfectum isolates obtained from cottongrowing provinces in Egypt and five reference strains representing physiological races 1, 2, 3, 4 and 5 were characterized by random amplification of polymorphic DNA (RAPD) and by amplified fragment length polymorphism (AFLP). Cluster analysis using data generated by both RAPD and AFLP markers, clearly separated F. oxysporum f. sp. vasinfectum races. The reference strains belonging to race 3 and to race 5 generated similar amplification patterns (level of genetic similarity: 92 %), while a lower level of similarity (76 %) was observed between race 3 and race 1. No correlation was found between the two PCR-based techniques data and the geographic origin of the isolates tested. These results may suggest that the Egyptian isolates of F. oxysporum f. sp. vasinfectum belong to one race and this race could be race 3, but could not be discriminated from race 5. Both techniques generated specific genomic patterns, which differentiated closely related races. Unique fingerprint profiles generated by the RAPD and AFLP techniques can be exploited for race identification purposes but additional pathogenicity testing on differential cultivars is needed to ascertain their precise determination.

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