GENERATION AND EVALUATION OF JUGLANS MICROCARPA HYBRIDS AND PARADOX ROOT STOCK SELECTIONS FOR CROWN GALL RESISTANCE (2012-2013)
Project Number: 5306-22000-015-09
Start Date: May 01, 2012
End Date: Apr 30, 2013
1. Identify and characterize a novel source of crown gall (CG) resistance in Juglans microcarpa genotypes and associated hybrids maintained in the USDA/ARS National Clonal Germplasm Repository in Davis, CA.
2. Clonally propagate CG resistant genotypes using micro propagation and standard propagation techniques.
3. Characterize crown gall resistant phenotypes of clonally propagated cuttings from genotypes exhibiting crown gall resistance.
Open pollinated seeds collected this fall from selected black walnut and butternut accessions maintained at the Wolfskill Experimental Orchards in Winters, CA will be stratified, germinated and grown under glasshouse conditions. Once seedlings reach a trunk diameter of at least 0.5cm, the crown of the tree will be inoculated with A. tumefaciens. Selections that consistently show CG resistance for three years will be clonally propagated and tested for resistance to Phytophthora root rot, lesion nematodes and Armillaria root disease.