Phenotyping soybean lines for resistance to multiple Fusarium species. Gabriela Morel-Gadea, D.A. Mayfield, S.R. Cianzio and G.P. Munkvold.

Fusarium root rot is among the top ten most destructive diseases of soybean in the United States. It is caused by a complex of Fusarium species which interact and increase symptoms of other soil-borne diseases. Management relies primarily on seed treatments which are limited to early growth stages and lack efficacy against all species of Fusaria. Breeding for genetic resistance in soybean cultivars is a viable alternative for managing diseases caused by these pathogens. In this study, virulent isolates of F. graminearum, F. oxysporum, and F. solani were used to identify resistant parental lines of soybean populations previously characterized for F. virguliforme resistance. Of the ten parental lines, only one showed resistant reactions to all three species of Fusarium, while four lines showed resistance to F. oxysporum and F. solani. This information can be used to guide investigations to identify markers for resistance to the Fusarium root rot complex in soybean breeding populations. The identification of soybean germplasm conferring resistance to this disease complex provides information to improve available cultivars and better manage seedling diseases.

Keywords: Fusarium spp., soybean, resistance, breeding.