Project Number: 5306-22000-015-19
Project Type: General Cooperative Agreement

Start Date: Sep 01, 2012
End Date: Aug 31, 2014

Objective:
Evaluate resistance of the walnut rootstock germplasm, interspecific hybrids, and transgenic selections to root-lesion nematode.

Approach:
Fifty open-pollinated (OP) seedlings will be maintained in the greenhouse where they will be challenged with P. vulnus (root-lesion nematode) using screens routinely conducted in the lab. NEM populations will be identified and quantified. MTs with a high percentage of OP seedlings that are highly and moderately NEM resistant will be clonally propagated for further replicated evaluations. Approximately 200 interspecific hybrid seedlings from the selected MPs will be evaluated for resistance to NEM. The resistance ratings will be used to map the genetic loci mediating NEM resistance. Interspecific hybrids showing NEM resistance will be micro-propagated, and validated under greenhouse conditions. Validated NEM-resistant clones will be clonally propagated and tested in fumigated and non-fumigated field trials.