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Genetics

Genetics of Phytophthora infestans: Determination of Recombination, Segregation, and Selfing by Isozyme Analysis. R. C. Shattock, Visiting fellow, Department of Plant Pathology, Cornell University, Ithaca, NY 14853, Permanent address of senior author: School of Plant Biology, University College of North Wales, Bangor, Gwynedd, LL57 2UW, U.K.; P. W. Tooley(2), and W. E. Fry(3). (2)(3)Research associate, and professor, respectively, Department of Plant Pathology, Cornell University, Ithaca, NY 14853. Phytopathology 76:410-413. Accepted for publication 25 September 1985. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/Phyto-76-410.

High levels of oospore germination (greater than 50%) were observed in some matings between A1 and A2 compatibility types of Phytophthora infestans. The parental isolates were predominantly of recent Mexican origin. The electrophoretic patterns at two enzyme loci, glucosephosphate isomerase and peptidase were identified in 685 single-oospore progeny from seven crosses. Progeny from parents homozygous for different alleles were heterozygous. Progeny from parents heterozygous for these alleles segregated 1:2:1 (homozygous fast:heterozygous:homozygous slow), as expected for a diploid organism. The ratio of A1:A2 compatibility type in the progeny was generally 1:1. A large number of self-fertile progeny were recorded from several crosses.