Walnut Scion & Rootstock Improvement
Walnut Scion & Rootstock Improvement
Walnut Scion & Rootstock Improvement
University of California
Walnut Scion & Rootstock Improvement

Obj. 2: Mapping of Resistance Genes & Deployment of Molecular Markers

Genetic, physical, and functional mapping of disease resistance genes and deployment of molecular markers for rapid screening of resistance.

Employing state-of-the art genomic approaches and tools to discover genes conferring resistance to key diseases and develop genetic markers for their manipulation in rootstock breeding. These markers will be the first of their kind for Juglans spp.

Reference Genome Sequencing:

  • Complete development of a high resolution English walnut reference genome sequence to facilitate mapping of resistance genes and marker development.


  • Discover and map genes conferring resistance to soil-borne pathogens in wild Juglans mother trees.

Marker Development:

  • Develop molecular markers to select for resistance genes in segregating populations and for efficient development of resistant rootstocks.

Expected Outcomes:

  • Walnut reference genome sequence for J. regia and J. microcarpa.
  • Comparative genetic maps densely populated with molecular markers for the discovery and mapping of disease resistance genes.
  • Knowledge based and genomic tools for gene discovery and the deployment of marker assisted selection in walnut rootstock breeding.
  • Genomic resources for wild relatives of English walnut, which will accelerate biological, agronomic and forestry research.
  • Generation of a physical map for J. microcarpa.
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