Abstract
Southern corn rust is a serious disease in the warm, southwest regions of Japan. To develop closely linked molecular markers for marker-assisted selection of maize lines resistant to this disease, we studied a resistance gene of an inbred line, IM-150. In the F_2 and F_3 generations derived from a cross between IM-150 and a susceptible inbred, Mi44, the ratio of resistant to susceptible individuals based on natural infection in the field fitted the expected 3:1 segregation ratio for a dominant locus. Results of linkage analysis between the resistance gene and simple sequence repeat (SSR) markers suggest that the resistance gene of IM-150 is located on the short arm of maize chromosome 10. The results of QTL analysis based on disease ratings indicated that the resistance gene was located in a region extending more than 38cM. We combined amplified-fragment-length polymorphism and bulked segregant analysis to develop new markers closely linked to the resistance gene. Three such SSR markers will be useful in marker-assisted selection for breeding of maize resistant to southern corn rust.
