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Genetics

Variation in Pathogenicity, Virulence, and Aggressiveness of Colletotrichum graminicola on Corn. D. G. White, Associate professor, Department of Plant Pathology, University of Illinois, Urbana 61801; Janet Yanney(2), and B. Anderson(3). (2)Former graduate research assistant, Department of Plant Pathology, University of Illinois, Urbana 61801, Present address: Florida Research Station, Funks Seeds International, 9107 South Jog Road, Lake Worth, FL 33463; (3)Graduate research assistant, Department of Plant Pathology, University of Illinois, Urbana 61801. Phytopathology 77:999-1001. Accepted for publication 2 December 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/Phyto-77-999.

Twelve isolates of Colletotrichum graminicola from corn and two from sorghum differed in pathogenicity, virulence, and aggressiveness following inoculation of stalks of three corn inbreds and two sorghum cultivars. Isolates were pathogenic only on the host species from which they were isolated. Of the 12 isolates from corn, one was not pathogenic. Variation in virulence ranged from virulence on all three corn inbreds to virulence on only the very susceptible inbred, C123. Aggressiveness, measured by the ability to cause premature death of the inbred C123, also varied among isolates. In general, isolates that caused the most discoloration of stalk pith were the most aggressive. Since inbred × isolate interactions were significant, results of studies on breeding for resistance and yield loss potential of anthracnose stalk rot could be greatly affected by the isolate used in the study.