CHARACTERIZATION OF RESISTANCE TO PIERCES DISEASE IN MUSCADINIA ROTUNDIFOLIA AND THE POTENTIAL FOR CONFERRING RESISTANCE TO GRAFTED VITIS VINIFERA SCIONS

• Author(s): Ruel, Johnathan; Walker, Andrew;
• Abstract: Muscadinia rotundifolia is a wild grape native to the Southeast U.S. In field trials, as well as in the wild, this species exhibits strong resistance to Pierces disease (PD). Incorporating this resistance into Vitis vinifera production systems in California will require identifying prime breeding material and increasing our understanding of the mechanism of resistance. The first objective of this study was to determine if resistance to Xylella fastidiosa (Xf) and PD varies among wild M. rotundifolia populations across a natural gradient of disease pressure. Greenhouse trials are underway using material collected in Florida, Georgia and Tennessee. The second objective was to test the common belief that some M. rotundifolia cultivars are more Xf resistant than others are. Again, trials are currently underway. Thirdly, we want to test if Xf resistance in M. rotundifolia is consistent when challenged with different Xf strains from Florida and California. Lastly, we want to examine the potential for conferring Xf and PD resistance to V. vinifera scions by grafting them to resistant M. rotundifolia rootstocks. This project is ongoing and only very preliminary results are available now. One such result is that even the least resistant M. rotundifolia selections are much more resistant than the Vitis vinifera cultivars. We have also confirmed that supposed graft incompatibility between the two species can be overcome using green grafting techniques. These grafted plants are entering disease trials now.
• Publication Date: Aug 2003
• Journal: 2003 Pierce's Disease Research Symposium