The genetic basis of disease resistance in Maize

This chapter presents an overview of diseases important to global maize production, outlines the current understanding of the genetic underpinnings for resistance to these diseases, and explores how these findings can be used to improve maize. With a primary focus on fungal diseases, we review the current understanding of qualitative and quantitative resistance. In order to dissect the genetics of quantitative resistance to three important diseases, new datasets and resources have been utilized. A number of populations have been evaluated for various maize diseases, including biparental populations, association mapping panels, and the nested association mapping population. By generating lists of genes suspected to be involved in the interaction between plant and pathogen, both genome-wide association mapping and nested association mapping have provided hints about the biology of disease resistance. As part of the study of the architecture of disease resistance, both singledisease resistance and multiple-disease resistance have been explored. Multiple-disease resistance is rare, but some genes apparently confer resistance to multiple pathogens. As high-resolution mapping becomes available, the challenge remains to translate this knowledge into breeding outcomes. Markerassisted selection can be used to utilize these results, but there is a disconnect between the wealth of mapping information and the application of this data. Genomic selection is emerging as a powerful tool for maize improvement. The challenge, however, remains to apply mapping studies and basic biology to plant breeding to decrease the amount of maize lost to pathogens.