(Wines&Vines) - A small group of commercial winemakers and viticulturists recently sampled grapes and wines made from the 2014 harvest of Pierce’s disease (PD)-resistant wine grape cultivars at the University of California, Davis. With Vitis vinifera parentage and quality, these advanced selections of PD-resistant cultivars represent some of the most promising wine grapes produced from the breeding program of Dr. Andy Walker, whose research at the UC Davis Department of Viticulture and Enology is funded by the California Department of Food and Agriculture Pierce’s Disease/Glassy-Winged Sharpshooter (GWSS) Board.

Small quantities of wine (less than 5 gallons of each cultivar) were produced from UC Davis field trial vines harvested in August. The wines were made by Walker’s assistant grape breeder Alan Tenscher, a former Napa Valley winemaker, and UC Davis teaching and research winemaker Chik Brenneman. These very young wines—four reds and three whites—and grape clusters harvested from 17 PD-resistant cultivars, were tasted by Douglas Fletcher, vice president of winemaking for Terlato Wine Group; Paul Skinner, who produces Sequum Wines and owns the viticulture consulting company TerraSpase; Jan Krupp of Stagecoach Vineyards in Napa Valley; and viticulturist Daniel Bosch of Constellation Wine Brands. The group also visited the UC Davis field trial vineyard and sampled grapes off the vines. 

A goal of the tasting was to obtain input on preferred wine and grape lots. These preferences will play a role in deciding which cultivars to advance toward commercial introduction. For comparison, the UC Davis researchers also have field vines planted from two PD-resistant hybrids considered high quality where they are grown in southern and eastern states: the white wine grape Blanc du Bois and the red wine grape Lenoir, or Black Spanish.