DIFFERENTIATION OF FUSARIUM-OXYSPORUM F SP VASINFECTUM RACES ON COTTON BY RANDOM AMPLIFIED POLYMORPHIC DNA (RAPD) ANALYSIS

We used pathogenicity and random amplified polymorphic DNA (RAPD) mark ers to assess genetic diversity among 46 isolates of Fusarium oxysporu m f. sp. vasinfectum of worldwide origin. Based on pathogenicity tests on five differential cotton cultivars and species, isolates were diff erentiated into three races (A, 3, and 4), restricted to defined geogr aphic areas. The amount of genetic variation was evaluated by polymera se chain reaction amplification with a set of 11 random 10-mer primers . All amplifications revealed scorable polymorphisms among the isolate s, and a total of 83 band positions was scored (1/0) for the 11 primer s tested. Genetic distances between each of the isolates were calculat ed, and cluster analysis was used to generate a dendrogram showing rel ationships between them. Isolates clustered into three groups correspo nding to their pathological reactions. We suggest that RAPD markers ca n be a quick and reliable alternative for differentiating isolates of F. o. vasinfectum into their respective pathogenicity group.