VIEW ARTICLE

Resistance

Bacterial Vascular Necrosis and Rot of Sugarbeet: Genetic Vulnerability and Selecting for Resistance. E. D. Whitney, Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, U.S. Agricultural Research Station, Salinas, California 93915; R. T. Lewellen, Research Geneticist, Agricultural Research Service, U.S. Department of Agriculture, U.S. Agricultural Research Station, Salinas, California 93915. Phytopathology 68:657-661. Accepted for publication 13 October 1977. Copyright © 1978 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-68-657.

Field and greenhouse selections of sugarbeet for resistance to an Erwinia species that incites vascular necrosis and rot have shown high degrees of resistance following two cycles of selection. In all selections tested, resistance for the desired trait was increased. Resistance of hybrids with a selected pollinator as one parent also showed an increase in resistance when compared with hybrids from the same seed parent and the susceptible unselected pollinator. The greater vulnerability to Erwinia of the pollen parent of currently grown hybrid sugarbeet cultivars in California appeared to be the result of genetic drift. This drift probably was due to the use of too few plants to reconstitute the gene pool after each cycle of selection for virus yellows resistance.