Wines from PD-resistant vinifera closer to market.
Davis, Calif.--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 were produced using 17 PD-resistant cultivars harvested in August from UC Davis field trial vines. The group sampled the wines as well as grapes off the vines. A goal of the tasting was to obtain input to help decide which cultivars to advance toward commercial introduction.
Walker and his lab have been traditionally breeding wine grape varieties of Vitis vinifera with the native American species 'Vitis arizo-nica, which carries PD-resistance genes, over five generations of crosses to progressively increase the percentage of vinifera parentage and characteristics to 97% with the fifth and final cross. Each generation carries resistance genes. The first 97% vines were produced in 2009, and the first wines from field trials of these were produced in 2011.
Terlato Winemaker Doug Fletcher has tasted grapes from the UC Davis vineyard for the past three vintages and sampled wines from two recent vintages. He has been impressed with the quality of the selections at both the 94% and 97% vinifera levels compared to French-American hybrids that are more commonly grown outside California.
In 2013, Walker advanced 10 PD-resistant cultivars to UC Davis Foundation Plant Services (FPS); these included both 94% and 97% vinifera parentage of Chardonnay, Cabernet Sauvignon, Zinfandel and Petite Sirah, along with three PD-resistant rootstocks.
In a previous tasting, Terlato winemaker Doug Fletcher said he and others preferred a wine made from a white PD-resistant cultivar with Chardonnay parentage to a pure Char-donnay selection produced for comparison.
As part of another research project, Walker is involved with similarly breeding cultivars with genes for powdery mildew resistance. His future goal is to breed cultivars that have resistance to both PD and powdery mildew.
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|Comment:||Wines from PD-resistant vinifera closer to market.|
|Publication:||Wines & Vines|
|Date:||Dec 1, 2014|
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