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Genetics

Genetics of Phytophthora infestans: Characterization of Single-Oospore Cultures from A1 Isolates Induced to Self by Intraspecific Stimulation. R. C. Shattock, Visiting fellow, Department of Plant Pathology, Cornell University, Ithaca, NY 14853; 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 76:407-410. Accepted for publication 25 September 1985. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/Phyto-76-407.

Selfed oospores were produced by A1 compatibility type isolates of Phytophthora infestans by pairing with A2 compatibility types of either P. infestans or P. drechsleri positioned on the opposite sides of a polycarbonate membrane. Nine single-oospore cultures were derived from one A1 isolate, and one single-oospore culture was derived from another A1 isolate. Segregation for some (but not all) observed characteristics was detected in the progeny. Two of nine progeny from one isolate were segregants for electrophoretic variants of the enzyme peptidase. Hyphae of all nine progeny grew more compactly than those of the parents. There was no segregation for compatibility type. Virulence of two progeny cultures was identical with that of the parent. The other progeny were either nonpathogenic or failed to sporulate in vitro.