BREEDING ROOTSTOCKS RESISTANT TO AGGRESSIVE ROOT-KNOT NEMATODES
Grape Genetics Research
2010 Annual Report
1a.Objectives (from AD-416)
To develop improved grapevine rootstocks resistant to aggressive virulent root-knot nematodes.
1b.Approach (from AD-416)
Grapevine rootstock germplasm will be screened for resistance to aggressive virulent root-knot nematodes, crosses made, and resistant seedling selections identified through screening.
We screened more than 2000 candidate grape rootstock seedlings for resistance to aggressive root-knot nematodes. We select only those seedlings which completely suppress nematode reproduction and show zero nematode egg masses. Selected seedlings are propagated and then planted into the vineyard. We tested the propagation ability of 190 selections (already tested once for nematode resistance) and of these retested 80 selections to confirm nematode resistance in replicated trials. Cuttings produced callus, roots, or shoots in combination (or none of these). 176 selections showed at least both callus and shoots on 75% or more of their cuttings. We identified eleven more easily propagated nematode resistant selections to be grafted to Syrah for a rootstock trial to be planted in 2010 at the University of California Kearney Ag Center, Parlier, California. Project monitoring was accomplished by providing a detailed written report of research activities and progress to the California Table Grape Commission.