THE GENETICS OF RESISTANCE TO PIERCES DISEASE

• Author(s): Walker, Andrew; Riaz, Alan;
• Abstract: This project was part of the American Vineyard Foundation Long Term Project on Pierces Disease. Our component of this project focuses on understanding the genetics of resistance to Xylella fastidiosa (Xf), the causal agent of Pierces disease (PD). The studies include understanding the inheritance of resistance to Xf in Vitis rupestris x Muscadinia rotundifolia and developing genetic markers for Xf resistance. It integrates into two other projects a fine-scale mapping project for Xf resistance, and the breeding of PD resistant table and raisin grapes. These Xf resistance studies are being carried out on potted and replicated plants under greenhouse conditions using needle inoculation with the 'Stag's Leap' strain of Xf. The plants are grown for 12 to 16 weeks and then evaluated for the presence of Xf and irregular shoot lignification symptoms. ELISA is used to test stem samples from 10 cm above and 10 below and at the point of inoculation. This system has proved to be highly reliable, efficient and quantifiable.
• Publication Date: Dec 2002
• Journal: 2002 Pierce's Disease Research Symposium