ELECTRON-BEAM IRRADIATION EFFECTS ON WHEAT QUALITY, SEED VIGOR, AND VIABILITY AND PATHOGENICITY OF TELIOSPORES OF TILLETIA-CONTROVERSA AND T-TRITICI

Wheat seed infested with sori or free teliospores of Tilletia controve rsa and T. tritici, respectively, were irradiated with high energy ele ctrons at doses ranging from 0-10.2 kGy to determine the suitability o f electron irradiation to disinfest wheat. The germination of spores w as then assayed to determine the sensitivity of each smut species to i rradiation. Data indicated that T. controversa teliospores were somewh at more resistant to electron beam radiation than were teliospores of T. tritici. For T. tritici, doses of 4.5 and 6.7 kGy completely elimin ated germination of free teliospores and teliospores in intact sori. F or T. controversa, 10.2 kGy was required to completely eliminate germi nation of both free teliospores and teliospores in sori. Substerilizin g doses of radiation delayed germination of the teliospores of both sp ecies. There was no significant deleterious effect of irradiation on w heat quality measurements, except for reduced surface texture and wate r absorption. As expected, irradiation significantly reduced seed germ ination and seedling vigor. Irradiation dosages above 2.6 kGy on telio spores significantly eliminated T. tritici infection of wheat, while i rradiation 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.