Impact of Vein-Banding on Vine Performance: Interaction Between

Molecular characterization of the grapevine viroids associated with fanleaf in the induction of vein banding symptoms as well as “mystery disease” samples from Napa has identified a common variant of grapevine yellow speckle viroid (GYSV-1) found in both sources. The complete viroid content may be variable, however, the titer of GYSV-1 tends to be greater in symptomatic tissues. A series of specific and generic primers for RT-PCR amplification and nucleotide sequencing have been developed and tested for detection of all viroid variants closely-related to GYSVd and included within the ASSVd family. These probes are being employed for the identification of the causal agents of yellow speckle, vein banding, and the “mystery” diseases which may comprise a related collection of subtle variants of GYSVd. Land has been prepared for the viroid-free Oakville Performance Trial and Cabernet Sauvignon / Teleki 5C are ready for planting. All available viroid-free materials have been propagated for establishment of a Viroid-Free Foundation Vineyard. An isolated planting site has been identified at UC-Davis. Materials are being collected for the rootstock germplasm sensitivity study.