|SHEPHERD, LISA - Iowa State University|
Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2013
Publication Date: 6/15/2013
Citation: Block, C.C., Shepherd, L.M. 2013. Relationship between resistance to Stewart's wilt and Goss's wilt in dent corn inbreds. American Phytopathological Society Abstracts. 103:S2.17.
Technical Abstract: Stewart's wilt, caused by Pantoea stewartii subsp. stewartii and Goss's wilt, caused by Clavibacter michiganensis ssp. nebraskensis (Cmn), are the two prominent bacterial leaf blight pathogens in maize in the US. Goss's wilt has become much more widespread in geographic range since 2008 and many popular hybrids are susceptible. In 2010 and 2011, we screened 35 dent corn inbreds for resistance to Goss's wilt infection. The pool of inbreds represented a broad range of known Stewart's wilt disease reactions. Plants were grown in inoculated field trials and individual plant disease reactions were scored during the seed filling period, using a 1 to 9 scale (1= highly resistant, 9= highly susceptible). As a group, inbreds showing good resistance to Stewart's wilt, with mean scores ranging from 1.3 to 3.0, also showed good resistance to Goss's wilt, with mean scores ranging from 1.0 to 2.6. Inbreds that were systemically infected by P. stewartii, with mean scores ranging from 5.2 to 8.3, were also systemically infected by Cmn, with mean scores ranging from 5.5 to 8.0. The Pearson correlation coefficient, calculated from mean disease severity ratings, was 0.92 and the Spearman rank correlation of inbred rankings was 0.88. The strong correlation between Stewart's wilt and Goss's wilt resistance may allow maize breeders to select potential Goss’s wilt-resistant parent lines based on available Stewart's wilt resistance data.