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Resistance

Quantification of Disease Resistance that Reduces the Rate of Tobacco Etch Virus Epidemics in Bell Pepper. Guy Boyd Padgett, Former graduate research assistant, Department of Plant Pathology, University of Georgia, Athens 30602, Current address: Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, 70803; Forrest W. Nutter, Jr.(2), Cedric W. Kuhn(3), and John N. All(4). (2)(3)Assistant professor, and professor, respectively, Department of Plant Pathology, University of Georgia, Athens 30602, (2)Current address: associate professor, Department of Plant Pathology, 351 Bessey Hall, Iowa State University, Ames 50011; (4)Professor, Department of Entomology, University of Georgia, Athens 30602. Phytopathology 80:451-455. Accepted for publication 26 September 1989. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/Phyto-80-451.

Tobacco etch epidemics, caused by tobacco etch virus (TEV), were monitored in three pepper genotypes over a 3-yr period at two locations in northeast Georgia. The three genotypes were Yolo Wonder B (susceptible), Tambel 2 (moderately resistant), and Asgrow-XPH-5021 (moderately resistant). The effect of host resistance on the development of TEV epidemics was indicated by the following results: 1) final TEV disease incidence was 45% less in resistant genotypes, 2) relative area-under-the-disease-progress curve was 42?68% less in resistant genotypes, 3) apparent infection rate was about 50% less in resistant genotypes, and 4) time for TEV disease incidence to reach 50% was delayed 23?37 days in resistant genotypes. All four methods of quantifying the effect of host resistance on TEV disease progression were highly correlated. The consequence of the rate-reducing resistance in Tambel 2 and Asgrow-XPH-5021 was to increase fruit yield (average of 24%), fruit weight (14%), and number of fruit when compared to susceptible Yolo Wonder B.