Submitted to: Sugarbeet Research and Extension Reports
Publication Type: Other
Publication Acceptance Date: 1/30/1998
Publication Date: N/A
Technical Abstract: Isolates of Aphanomyces were collected from 80 soil samples from a sugarbeet field in south central Minnesota and from 80 samples from a northeast North Dakota field in its first year of sugar beet production. Root rot was severe in both fields. Genetic analysis by RAPDs were performed on the 41 isolates of Aphanomyces from the Minnesota field and on 45 of the 61 isolates from the North Dakota field. Only two RAPD phenotypes, designated A and B, were found. Group A and group B isolates differed by 14 banding differences, but there was no variation in banding patterns within groups. Group A isolates predominated at both sites: 26 of 41 isolates from the Minnesota field and 37 of 45 isolates from the North Dakota field. Aphanomyces was aggregated in the Minnesota field but randomly distributed in the North Dakota field. Results indicate that groups A and B represent genetically isolated forms of Aphanomyces coclioides or, perhaps, two distinct species.