Marker-Assisted Breeding for Rust Resistance in Oats

Oat (Avena sativa L.) is an important cereal crop grown world-wide for human and livestock consumption. Oat production can be adversely challenged by major diseases such as crown rust and stem rust. Race-specific seedling resistance genes are the primary means of controlling crown and stem rust of oat in Canada. Many race-specific resistance genes have been mapped and markers that are closely linked to them have been identified. However, the use of these markers in oat breeding has been limited by the economics of marker-assisted selection (MAS). The primary objective of this study was to develop markers linked to Pc91 and Pc94 for deployment in high throughput marker-assisted selection in oat breeding programs. A KASPar assay was developed from a previously reported DArT marker that co-segregated with Pc91. The KASPar assay accurately postulated the Pc91 status of 16 North American oat breeding lines. The assay was validated on four populations segregating for Pc91 which was subsequently implemented in an oat marker-assisted breeding program. This is the first report of localization of the crown rust resistance gene Pc91 to the oat chromosome 3C. Following this successful work, economical marker assays are being developed for crown rust resistance gene Pc94, stem rust resistance gene Pg13, and for resistance to stem rust race NA67.