Anthracnose stalk rot, caused by the fungus Colletotrichum graminicola is the most common stalk rot disease in maize worldwide.  U.S. yield losses averaging 6.6% on over 37.5 million acres annually are associated with reduced grain weight caused by premature plant death, lodging, and grain quality losses.  The utilization of NIL’s for high resolution mapping resolved a QTL to an approximate 3 cM region on chromosome 4, but no putative resistant gene could be identified using the B73 and Mo17 physical map. A candidate resistance gene, Rcg1, was identified using a BAC library from the resistant isoline, DE811ASR(BC5) and further validated by a knockout approach with Mutator and through RNA expression studies. Isohybrids developed by crossing DE811 and DE811ASR(BC5) to diverse public inbreds indicated over a  three fold reduction in top dieback and significant yield advantage under inoculated conditions with no significant yield differences under uninoculated conditions.  The complete absence of this gene and of the surrounding sequences in elite corn belt inbreds B73 and Mo17 indicates non-colinearity at the genic level. The occurrence of genic non-colinearity indicates that a genomic library from the gene donor genotype may be necessary in map-based cloning projects and also provides strong support for the conservation and utilization of exotic germplasm for discovering genes of economic importance.  Parts of this research were conducted in collaboration with DuPont/Pioneer Hi-Bred International, Inc.