Hypersensitivity in Capsicum chacoense to Race 1 of the Bacterial Spot Pathogen of Pepper. A. A. Cook, Professor, Department of Plant Pathology, University of Florida, Gainesville 32611. Y. G. Guevara, Bacteriologist, Centro Nacional de Investigaciones Agropecuarias, Maracay, Venezuela. Plant Dis. 68:329-330. Accepted for publication 26 October 1983. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-329.

Plants of Capsicum chacoense PI 260435 were found to respond in a hypersensitive manner to pathotype 1 of the pepper strain of Xanthomonas campestris pv. vesicatoria. Infiltration inoculation with 10⁸ bacterial cells per milliliter followed by incubation at 30 C caused visible collapse of inoculated leaf tissues within 24 hr. Leaf lesions did not enlarge beyond the areas originally infiltrated. The concentration of bacteria in inoculated leaf tissue was greatly reduced during the first 24 hr of incubation, while electrolyte loss from such tissue was increased during the same period. Evidence was obtained that hypersensitivity (resistance) from C. chacoense to pathotype 1 resulted from a dominant, genetic factor.