New Genotypes of Fusarium oxysporum f. sp vasinfectum from the Southeastern United States

Sixty-one isolates of Fusarium oxysporum f sp vasinfectum were collected from cotton plants (Gossypium spp.) with symptoms of Fusarium wilt to determine The composition of races present in the southeastern United States Analysis of partial sequences of the translation elongation factor gene revealed four mean genotypes, as well its the presence of races 3 and 8 for the first time in the United States outside of California The majority of isolates ( 16 of 27) sampled From Arkansas were novel genotypes A upset of isolate,; representing the novel genotypes was compared with previously described races using sequences from translation elongation factor. phosphate permase, and beta-tubulin genes and their pathogenicity oil a total of six Upland (Gossypium hurstum) and Pima (G barbadense) cotton cultivars. Two of the novel genotypes belonged to a clade containing races 1. 2. 4, 6. and 4 and two shared ancesti-v with race 3 All new genotypes were pathogenic to at least some of the cotton cultivars tested. The Pima cv Phytogen 800 wits relatively resistant to all genotypes of the pathogen These results indicate that the population of F. oxysporum f sp vasinfectum in the southeastern United States is more diverse than previously recognized