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Genetics

Stability of Endothia parasitica Hypovirulence in Culture. Neal K. Van Alfen, Assistant Professor, Department of Biology, Utah State University, Logan, UT 84322; Richard A. Jaynes(2), and James T. Bowman(3). (2)Geneticist at the Connecticut Agricultural Experiment Station, New Haven, CT 06504; (3)Professor, Department of Biology, Utah State University, Logan, UT 84322. Phytopathology 68:1075-1079. Accepted for publication 21 December 1977. Copyright © 1978 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-68-1075 .

Rate of pigment development in culture was directly correlated with virulence in strains of Endothia parasitica derived from French-hypovirulent strains (hypovirulent strains originally isolated in France). This correlation between the rate of pigment formation and virulence allowed the stability of the hypovirulent state to be demonstrated in culture. Cultures changed both from hypovirulent to virulent and from virulent to hypovirulent. The frequency of these changes in culture was influenced by the age of the colony, the origin of the individual strain, and ultraviolet but not X-ray irradiation.