Next generation genotyping to enable use of maize genetic resources

Germplasm banks of the world house many tens of thousands of accessions of maize landraces and wild relatives. These collections are priceless; together they represent the broadest reserve of genetic variability of maize and potentially hold many genes and alleles of interest novel to modern cultivars. At present it is difficult for genebank clients to choose which accessions would be the most useful for their situation and as a result these resources are largely underutilized. The Mexican funded Seeds of Discovery project (SeeD) uses cutting edge approaches to address this lack of information and to help scientists access high value novel genes and alleles to develop “climate and challenge ready” maize cultivars. One objective within the initiative is to create a molecular atlas of maize, via genotyping by sequencing (GBS) technologies, containing profiles of more than 40,000 maize landraces, advanced lines and wild relatives. Adaptation of GBS approaches has enabled us to cost effectively genotype genetically heterogeneous and diverse landraces and report population level distance and diversity parameters. This move from SNP based genotypes of individuals to more comprehensive population level SNP fingerprints enables enquiry and use not only by those interested in germplasm development but by germplasm conservationists and evolutionary biologists alike. Here we outline the modified GBS approach that we are using and discuss the value and relevance of next generation approaches to facilitate access to, and assisting in the management of, germplasm bank collections.