Adding Value to the National Small Grains Collection with Molecular Data.

The National Small Grains Collection (NSGC) has more than 140,000 accessions of barley, oat, rice, rye, Triticale, wheat and wild relatives of the small grains. These materials are maintained, evaluated, and distributed to researchers worldwide and data generated via evaluation studies are available online via the Germplasm Resources Information Network (GRIN). Recent technological advances have made it feasible to genotype parts of the barley and wheat collections, including the core subsets which were designated to maximize geographic representation. The resulting DArT and SNP marker data have been used to elucidate the population structure of these crops within the NSGC and to conduct association mapping studies using GRIN data and data generated from specific studies. Population structure information is valuable for collection management, by providing a measure of genetic diversity by geography that could be used to target future acquisitions and by identifying likely duplicate accessions.  Association mapping has identified possibly novel alleles for resistance to diseases and abiotic stresses within NSGC accessions. Marker data will also be valuable in establishing mini-core collections of a few hundred accessions that maximize genetic diversity per accession. Mini-cores should be useful for assessment of traits that are difficult or expensive to measure. The application of molecular technology to the NSGC and the ongoing analysis of this data should increase the value of the collection to plant breeders and other scientists.