Through collaboration between the Kenya Agricultural Research Institute (KARI) and Cornell University, we have been working to identify, characterize and use chromosomal segments conditioning superior levels of quantitative disease resistance in maize. This effort is focused on northern corn leaf blight (NCLB) and gray leaf spot (GLS), diseases of global importance that cause severe losses in the Kenyan highlands and mid-altitudes. To identify potentially useful sources of resistance, KARI researchers assembled a panel of 83 maize lines, screened them in the field, and analysed the diversity and relatedness of the panel, using molecular markers. A set of lines showing resistance to multiple diseases was identified. Ongoing work is aimed at identifying trait-marker associations that can be used for selecting superior combinations of resistance loci in elite breeding lines. At Cornell, studies have focused on genetic dissection of disease quantitative trait loci (dQTL). As a basis for identifying genomic regions of interest for analysis in these materials, we analysed the published studies in which dQTL were mapped on maize and rice chromosomes. Clusters of dQTL were detected across studies, implying that certain areas of the cereal genome are associated with broad-spectrum disease resistance. A more precise localization of dQTL is, however, needed to allow existing genetic diversity for resistance to be more effectively characterized and exploited. To improve the genetic localization and characterization of dQTL, we initiated development of a set of near-isogenic lines (NILs) for dQTL . Availability of NILs will allow us to critically evaluate the apparent colocalization of multiple disease resistance and other phenotypic effects; characterize the host–pathogen interaction with regard to field performance, specificity, components of resistance, and gene expression; and use complementary chromosomal segments for breeding. NILs are currently under development from a range of sources, including available mapping populations, populations developed through recurrent selection for disease resistance, and other reputable sources of resistance. Useful chromosomal segments identified through these analyses will be combined in the KARI breeding program using strategic combinations of phenotypic and marker-assisted selection. Better localization of dQTL will facilitate marker-assisted selection, which is not feasible when the estimated QTL region spans tens of centimorgans.