From the Plant Sciences newsletter:

Assistant Professor Jeffrey Ross-Ibarra has been awarded a three-year $448,000 grant by the USDA/CSREES for his project “Scanning for Yield: High-Throughput Discovery of Candidate Agronomic Loci for Marker-Assisted Selection in Maize” which takes a novel, population genetics approach to identifying candidate genes. Marker-assisted selection (MAS) has become one of the most important tools of modern plant breeding, but its success relies on the availability of markers that associate with agronomic traits. While traditional approaches such as QTL and association mapping have been successful at identifying markers for MAS, they suffer from several important disadvantages, such as the context-dependence of the markers identified. By identifying markers that have changed in frequency as the result of historical selection, selection mapping approaches can circumvent some of these problems. Ross-Ibarra and his team will genotype 60,000 single nucleotide polymorphisms in a stratified chronological sample of nearly 500 maize lines, including wild teosintes, landraces, early inbreds, and modern inbreds. They will use novel statistical methods to identify candidate agronomic loci (CAL) that have increased in frequency due to selection during maize improvement. Because of the central role yield has played in maize improvement, they predict many of these CAL will be associated with yield. They will directly test this prediction in yield trials comparing the efficiency of selection using their list of CAL to selection using random markers or phenotype alone.