Impact of Vein Banding on Vine Performance: Interaction Between
Viroid analyses of vein banding symptomatic vines from the control plots at U.C. Kearney as well as the Delano area indicated the presence of grapevine yellow speckle viroid (GYSVd-1). Vein banding symptoms continued to be associated with the dual infection by viroids and fanleaf. GYSVd-1 was also common to collections of the “mystery disease” tissues made in the Napa Valley. Characterization of the viroids associated with both symptom patterns will continue. Preliminary evaluation of the effect of vein banding on vine performance have been made. Performance trials of vines, + and – viroids in combination with + and – fanleaf are being established at U.C. Davis. Materials were collected for the Viroid-free Trials at Oakville. Cabernet Sauvignon and Sauvignon blanc on Teleki 5C have been nurseried at U.C. Davis and are ready for field planting. All viroid-free vines maintained at U.C. Riverside have been made available for establishment of a Foundation Vineyard at U.C. Davis. A collection of selected rootstock germplasm materials has been initiated to begin evaluation of the effects of viroids on rootstock/scion reactions.