Electron Beam Irradiation Effects on Wheat Quality, Seed Vigor, and Viability and Pathogenicity of Teliospores of Tilletia controversa and T. tritici . J. W. SITTON, Seed Technology Laboratory, Department of Crop and Soil Sciences, Washington State University, Pullman 99164-6422. J. BORSA, AECL Research, Whiteshell Laboratories, Pinawa, Manitoba, Canada ROE ILO, T. R. SCHULTZ, Cooperative Extension, 2525 Merryfield St., Friday Harbor, WA 99250, and J. D. MAGUIRE, Seed Technology Laboratory, Department of Crop and Soil Sciences, Washington State University, Pullman 99164-6422. Plant Dis. 79:586-589. Accepted for publication 12 January 1995. Copyright 1995 The American Phytopathological Society. DOI: 10.1094/PD-79-0586.

Wheat seed infested wilh sori or free teliospores of Tilletia controversa and T. tritici, respectively, were irradiated with high energy electrons at doses ranging from 0 10.2 kGy to determine the suitability of electron irradiation to disinfest wheat. The germination of spores was then assayed to determine the sensitivity of each smut species to irradiation. Data indicated that T. controversa teliospores were somewhat more resistant to electron beam radiation than were teliospores of T. tritici- For T. tritici. doses of 4.6 and 6.7 kGy completely eliminated germination of free teliospores and teliospores in intact sori. For T. controversa, 10.2 kGy was required to completely eliminate germination of both free teliospores and teliospores in sori. Substerilizing doses of radiation delayed germination of the teliospores of both species. There was no significant deleterious effect of irradiation on wheat quality measurements, except for reduced surface texture and water absorption. As expected, irradiation significantly reduced seed germination and seedling vigor. Irradiation dosages above 2.6 kGy on teliospores significantly eliminated T. tritici infection of wheat, while irradiation doses of 10.2 kGy on sori reduced infection from 75.5 to 0.08%. No T. controversa infection was observed in wheat seed inoculated with irradiated or nonirradiated teliospores

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