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Analysis of Quantitative Trait Loci for Resistance to Southern Leaf Blight in Juvenile Maize

March 2006 , Volume 96 , Number  3
Pages  221 - 225

P. J. Balint-Kurti and M. L. Carson

First author: U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS) Plant Science Research Unit, North Carolina State University, Raleigh 27695; and second author: USDA-ARS, Cereal Disease Laboratory, St. Paul, MN 55108

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Accepted for publication 15 October 2005.

A set of 192 maize recombinant inbred lines (RILs), derived from a cross between the inbred lines Mo17 and B73, were evaluated as 3-week-old seedlings in the greenhouse for resistance to southern leaf blight, caused by Cochliobolus heterostrophus race O. Six significant (LOD >3.1) quantitative trait loci (QTL) were identified for disease resistance, located on chromosomes 1, 2, 3, 6, 7, and 8. Results were compared with a previous study that had used the same RIL population and pathogen isolate, but had examined resistance in mature rather than juvenile plants. There was a very weak but significant correlation between the overall resistance phenotypes of the RILs scored as mature and juvenile plants. Two QTL were found in similar positions on chromosomes 1 and 3 at both growth stages. Other QTL were specific to one growth stage or the other. Twenty-three of these RILs, together with the parental lines, were inoculated in the greenhouse with four C. heterostrophus isolates. Results indicated that the quantitative resistance observed was largely isolate non-specific.

Additional keyword: corn.

The American Phytopathological Society, 2006