The present invention is in the field of plant breeding and disease resistance. More specifically, the invention includes a method for breeding corn plants containing quantitative trait loci that are associated with resistance to gray leaf spot, a fungal disease associated with Cercospora spp. The invention further includes germplasm and the use of germplasm containing quantitative trait loci (QTL) conferring disease resistance for introgression into elite germplasm in a breeding program for resistance to gray leaf spot.