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Title:   Author  item
                                            Grunwald, Niklaus

                                                         - *Nik*
  Submitted to: International Aphanomyces Symposium 
                                    Publication Type: Proceedings
                                    Publication Acceptance Date: 8/1/2003
                                    Publication  Date: 10/1/2003
                                    Citation: GRUNWALD, N.J. WITHIN FIELD PHENOTYPIC AND GENOTYPIC DIVERSITY IN APHANOMYCES EUTEICHES. INTERNATIONAL APHANOMYCES SYMPOSIUM. P. 60-66. 2003.Interpretive Summary: Aphanomyces root rot of pea is caused by the Oomycete plant pathogen Aphanomyces euteiches. Our objectives were to assess the degree of genetic and phenotypic variation in populations of this pathogen within two grower's fields with a history of Aphanomyces root rot.  We evaluated two hypotheses: (1) populations of A.  euteiches are diverse genotypically and phenotypically within single fields, and (2) that  populations of A.  euteiches from different fields are well differentiated.  Genotypic diversity was determined using amplified fragment length polymorphism fingerprinting while phenotypic diversity was based on greenhouse studies to determine disease severity readings on 5 pea clones differing in resistance to A. euteiches. Populations of A. euteiches recovered from two fields in northeast OR and western WA are genetically diverse within a field, yet well distinctly different when contrasting these two fields. At the same time, both populations are well adapted to their pea hosts and all isolates were very aggressive to the five pea lines included in this study.
                                Technical Abstract: Our objectives were to assess the degree of variation for genotype and pathogenicity in a population of Aphanomyces euteiches within two grower's fields with a history of Aphanomyces root rot.  We evaluated two hypotheses: (1) populations of A.  euteiches are diverse genotypically and phenotypically within single fields, and (2) that  populations of A.  euteiches from different fields are well differentiated.  Genotypic diversity was determined using amplified fragment length polymorphism fingerprinting while phenotypic diversity was based on greenhouse studies to determine disease severity readings on 5 pea clones differing in resistance to A. euteiches. Populations of A. euteiches recovered from two fields in northeast OR and western WA are genetically diverse within a field, yet well differentiated when comparing both fields. At the same time, both populations are well adapted to their pea hosts and are very aggressive to the five pea lines included in this study.


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