Project summary:

The purpose of the project is to support the breeding programs for the development of perennial ryegrass varieties with durable, broad-spectrum resistance to stem rust, crown rust, and leaf rust, adapted to future climate conditions. The project has four goals linked to three work packages: establishment of a diverse collection of rust pathogen isolates for resistance screening, identification and validation of quantitative trait loci (QTL) conferring durable multi-rust resistance under varying temperature conditions and development of new ryegrass genotypes with durable multi-rust resistance through the stacking of favorable resistance alleles.

The project includes the following activities: 1) Collection and characterization of the diversity of stem rust, crown rust, and leaf rust pathogens in perennial ryegrass. Expansion of a genetically diverse collection of rust isolates from Denmark and other countries, development and application of molecular markers for pathogen characterization, and establishment of a representative isolate panel for evaluating the resistance in ryegrass germplasm. 2) Evaluation of resistance under field and controlled environmental conditions to assess stability across rust species and different climate conditions, together with the development of AI-based high-throughput phenotyping methods for accurate identification and quantification of rust infections. Identification and validation of genetic loci conferring durable, broad-spectrum resistance to multiple rust species through QTL mapping and genome-wide association studies.  3) Development of new ryegrass varieties with durable resistance to stem rust, crown rust, and leaf rust using genomic selection, speed breeding, and stacking of validated resistance QTL.