VIEW ARTICLE

Genetics

Hypovirulence, Vegetative Incompatibility, and the Growth of Cankers of Chestnut Blight. Sandra L. Anagnostakis, Department of Plant Pathology and Botany, Assistant Scientist and Director, The Connecticut Agricultural Experiment Station, P.O. Box 1106, New Haven 06504; Paul E. Waggoner, Department of Plant Pathology and Botany, Assistant Scientist and Director, The Connecticut Agricultural Experiment Station, P.O. Box 1106, New Haven 06504. Phytopathology 71:1198-1202. Accepted for publication 11 March 1981. Copyright 1981 The American Phytopathological Society. DOI: 10.1094/Phyto-71-1198.

American chestnut trees were inoculated with pairs of strains of Endothia parasitica, and the rate (b) of the expansion of the area of cankers was measured. Hypovirulence (H) agents in one strain of the pair decreased b markedly if both strains were in the same vegetative compatibility (v-c) group. With increasing numbers of v-c alleles different between the pair, the decrease in b became less and less until the decrease became insignificant when different alleles at five v-c genes separated the pair of strains. Although various strains in different v-c groups were used, the results were consistent. French and Italian H agents had similar effects on b.