The goal of this continuing research project is to further our understanding of Fusarium oxysporum, which is the most common Fusarium species infecting soybean roots in Iowa. While some strains of F. oxysporum are aggressive pathogens of seedlings and roots of adult plants, others are weakly pathogenic. Through this proposal and a complementary proposal to USB, we hope to more thoroughly describe the populations of Fusarium oxysporum found on soybean roots, in terms of genetic variability, virulence, fungicide sensitivity, and adaptation to environmental conditions. This information will help to distinguish among pathogenic and non-pathogenic strains so that disease caused by F. oxysporum...