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United States Department of Agriculture

Agricultural Research Service

Title: Performance of rhizomania resistant sugarbeet under normal and resistance-breaking strains of Beet necrotic yellow vein virus.

Authors
item Lewellen, Robert
item Liu, Hsing Yeh
item Gillen, Anne
item Strausbaugh, Carl

Submitted to: American Society of Sugarbeet Technologists
Publication Type: Proceedings
Publication Acceptance Date: March 1, 2007
Publication Date: December 1, 2007
Citation: Lewellen, R.T., Liu, H., Gillen, A.M., Strausbaugh, C.A. 2007. Performance of rhizomania resistant sugarbeet under normal and resistance-breaking strains of Beet necrotic yellow vein virus.. American Society of Sugarbeet Technologists.

Interpretive Summary: Rhizomania in sugarbeet (Beta vulgaris) is caused by Beet necrotic yellow vein virus (BNYVV). Resistance to BNYVV is conditioned primarily by the allele Rz1. Since 2003, it has been observed that Rz1 has been compromised by resistance-breaking strains of BNYVV. A second resistance gene Rz2 originally identified in B. vulgaris spp. maritima (WB42) appears to continue to provide partial resistance to the resistance–breaking strains. Sugarbeet cultivars with single and combinations of resistance genes were evaluated in baited plant greenhouse tests based on ELISA values. These cultivars and other experimental hybrids and breeding lines were evaluated in field trials at Salinas and Brawley, CA and Kimberly, ID under BNYVV noninfested and infested conditions. Infested conditions included both normal and resistance-breaking strains. The performance in the field substantiated the baited plant results. Significant interactions occurred for components of yield between cultivars (source of resistance) and strains of BNYVV. The Rz1 allele appeared to continue to provide some protection to losses caused by the resistance-breaking strains. Quantitatively inherited resistance selected against normal strains also provided partial protection against losses to the resistance-breaking strain. Because of the demonstrated vulnerability of single, major genes, the search is being continued for additional sources of resistance. A promising source is from WB151 and other B. vulgaris spp. maritima accessions and populations.

Technical Abstract: Rhizomania in sugarbeet (Beta vulgaris) is caused by Beet necrotic yellow vein virus (BNYVV). In current commercial cultivars, resistance to BNYVV is conditioned primarily by the allele Rz1. Since 2003, observations indicate that Rz1 has been compromised by resistance-breaking strains of BNYVV (RB-BNYVV). A second resistance gene Rz2 originally identified in B. vulgaris spp. maritima (WB42) appears to provide partial resistance to the resistance–breaking strains. Sugarbeet cultivars with single and combinations of resistance genes were evaluated in baited plant greenhouse tests based on ELISA values. These cultivars and other experimental hybrids and breeding lines were evaluated in field trials at Salinas and Brawley, CA and Kimberly, ID under BNYVV noninfested and infested conditions. Infested conditions included both normal and RB-BNYVV strains. The performance in the field substantiated the baited plant results. Significant interactions occurred for components of yield between cultivars (source of resistance) and strains of BNYVV. The Rz1 allele gave a high level of protection against normal BNYVV but was defeated by the RB-BNYVV strains originating from the Imperial Valley of California. The Rz2 allele either alone or in combination with Rz1 provided partial resistance to the RB-BNYVV strains. The Rz1 allele appeared to continue to provide some protection to losses caused by the resistance-breaking strains. However, this apparent partial protection may have been due to mixed normal and RB-BNYVV strains occurring in the field trials. The performance of the Rz1 entry showed a continuous gradation from fully resistant to fully susceptible, depending upon the history and severity of the RB-BNYVV infestation. Resistance in C28 (C79-4) introgressed into sugarbeet from PI 206407 (resembling Swiss chard) did not condition resistance to RB-BNYVV. Resistance in WB41 introgressed into sugarbeet (C79-2) and reported to be Rz3 conditioned partial resistance to all BNYVV strains tested. Quantitatively inherited resistance selected against normal strains also provided partial protection against losses to the resistance-breaking strain. Because of the demonstrated vulnerability of single, major genes, the search is being continued for additional sources of resistance. A promising source is from WB151 and other B. vulgaris spp. maritima accessions and populations. At this time it is not known if the resistance conditioned by these sources from wild beet is the same or different from the known Rz2 and Rz3 factors.

Last Modified: 11/23/2014
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