Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/12/1998
Publication Date: N/A
Technical Abstract: This is the first genetic and spatial analysis of Aphanomyces cochlioides populations. Isolations were made along transects at single sites in Texas (TX), Minnesota (MN) and North Dakota (ND). Randomly amplified DNA analysis (RAPD) was performed on 39, 41, and 47 isolates respectively with two A. eutiches isolates used as an outgroup. Isolates were scored for 57 bands. Only three banding patterns were identified (A, B and C). Pattern A isolates were found in all three locations. Pattern B isolates were only found in ND and MN and pattern C isolates were only found in TX. Pattern A and C isolates represented one genetic group (I) with 2% genetic distance between them. Pattern B isolates represented a second genetic group (II) 25% genetically distant from group I. No genetic intermediates were found between groups I and II. Distribution of the pathogen was found to be aggregated at the MN and TX sites (P <0.5) but uniform at the ND site. Distribution amongst the pattern A and C isolates and A and B isolates was random. This suggests that groups I and II are genetically isolated by a mechanism other than spatial distance.