Phytopathology (1996) 86, S63-S64

D.K. Malvick and J.A. Percich (1996)
Variability in pea-infecting strains of Aphanomyces euteiches from different geographical locations
Phytopathology 86 (11 suppl.), S63-S64
Abstract: Variability among populations of A. euteiches was investigated using pathogenicity and randomly amplified polymorphic DNA (RAPD) analyses. Strains of A. euteiches were isolated from soil samples collected in pea fields using pea (Pisum sativum) as a baiting host. Fifty strains were isolated from each of two fields near Waseca, MN; 11 from near Arlington, WI; and 6 from near Athena, OR. Five pea cultivars (cv.) having different levels of resistance to Aphanomyces root rot and one cv. of alfalfa and snap bean were inoculated with zoospores, and root rot severity (RS) was rated using a 0-5 scale. All strains were pathogenic to one or more pea cv. and about 45 and 15% were pathogenic to alfalfa and bean, respectively. RS levels varied among strains on individual pea cv. and on the three host spp. RAPD analysis using three primers that differentiate among pathotypes of A. euteiches revealed genetic differences among the strains. These differences were not associated with host range. RAPD analysis will be done with additional primers to further characterize genotypic variability. The genetic differences and host range variation detected among strains were not related to geographical origin.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Aphanomyces euteiches	Pea (Pisum sativum)	U.S.A. (NW)
	Aphanomyces euteiches	Pea (Pisum sativum)	U.S.A. (mid N)