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Analysis of Allozymes of Three Distinct Variants of Verticicladiella wageneri Isolated from Conifers in Western North America. William J. Otrosina, Research plant pathologist, USDA Forest Service, Pacific Southwest Forest and Range Experiment Station, 1960 Addison St., Berkeley, CA 94701; Fields W. Cobb, Jr., Professor, Department of Plant Pathology, University of California, Berkeley, 94720. Phytopathology 77:1360-1363. Accepted for publication 10 April 1987. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1987. DOI: 10.1094/Phyto-77-1360.

Isolates representing the three variants of Verticicladiella wageneri from hard pine. Douglas-fir, and pinyons were subjected to isozyme analysis by starch gel electrophoresis of mycelial extracts. Nine allozymes distributed among 10 putative loci produced scoreable banding patterns. From the resultant genotypic information, allele frequencies and genetic distance measures were calculated. Seven of the 10 loci were monomorphic across all variants, indicating a degree of genetic uniformity in the fungus. The magnitude of the differences between the pinyon variant and the others is reflected in apparent fixation for alternate alleles between these variants in the isocitrate dehydrogenase locus and between the pinyon and the hard pine variant for the glutamate-oxaloacetate transaminase locus. The genetic divergence of the pinyon isolates indicated by the isozyme data correspond to geographic and ecological isolation of the host. The designation of a third variety of V. wageneri delimiting the Douglas-fir variant is suggested.

Additional keywords: Ceratocystis wageneri, electrophoresis, isozymes, population genetics, root disease fungi.