Submitted to: American Society of Sugarbeet Technologists
Publication Type: Proceedings
Publication Acceptance Date: March 9, 1995
Publication Date: N/A
Interpretive Summary: Host plant resistance is an efficient method of controlling many crop diseases. Incorporating disease resistance while maintaining or increasing yield and quality is a constant challenge for commercial plant breeders. The task is especially difficult if the desired resistance is not simply inherited, as is the case with most sugarbeet (Beta vulgaris L.) Diseases, including Cercospora (Cercospora beticola Sacc.) leaf spot. Cercospora resistant parental lines are available and many commercial sugarbeet hybrids have at least some resistance to Cercospora. Commercial yield trials often are planted at sites that avoid Cercospora infestation or it is controlled with chemicals. Under these conditions, neither the value of resistance nor the inherent yield reduction, if any, associated with breeding for resistance is apparent. This study examines the trade-off between Cercospora resistance and performance and provides insight for choosing hybrids for specific environmental and management situations.
Technical Abstract: Forty commercial hybrids, all recommended for growing in Cercospora-threat areas, were grown at Fargo, North Dakota (no Cercospora) and at Fort Collins, Colorado in 1991 and 1992. The field at Fort Collins was inoculated with Cercospora to produce an epidemic. Disease severity was recorded (0=no symptoms to 9=complete defoliation). Root yield was measured at both locations. In both years, root yields at Fargo were directly related to disease severity at Fort Collins. Regression of root yields on damage ratings indicated a 1.0 ton/acre increase for each increment (increased susceptibility) on the damage scale in 1991 and 1.1 ton/acre increase in 1992.