Association Mapping for Enhancing Maize (Zea mays L.) Genetic Improvement

Association mapping through linkage disequilibrium (LD) analysis is a powerful tool for the dissection of complex agronomic traits and for the identification of alleles that can contribute to the enhancement of a target trait. With the developments of high throughput genotyping techniques and advanced statistical approaches as well as the assembling and characterization of multiple association mapping panels, maize has become the model crop for association analysis. In this paper, we summarize progress in maize association mapping and the impacts of genetic diversity, rate of LD decay, population size, and population structure. We also review the use of candidate genes and gene-based markers in maize association mapping studies that has generated particularly promising results. In addition, we examine recent developments in genome-wide genotyping techniques that promise to improve the power of association mapping and significantly refine our understanding of the genetic architecture of complex quantitative traits. The new challenges and opportunities associated with genome-wide analysis studies are discussed. In conclusion, we review the current and future impacts of association mapping on maize improvement along with the potential benefits for poor people in developing countries who are dependent on this crop for their food security and livelihoods.