Researchers at the University of California Davis have developed five new grape varieties that have proven to be resistant to Pierce’s disease and are being made available for growers. Geneticist and professor of viticulture and enology at UC Davis, Dr. Andrew Walker led the research which resulted in the new winegrape varieties of Camminare Noir, Paseante Noir, Errante Noir, Ambulo Blanc, and Caminante Blanc.
“We went through thousands of seedlings over the last 15 years or so and the plants that we have released were crossed in 2009 primarily,” said Walker. “It took another ten years after we got to that final stage to go through enough wine tasting evaluation and grow-outs in different sites to really be convinced that they were useful.”
The breeding research was guided from the beginning with the understanding that taste will be a critical factor in determining the viability of new varieties. “Wineries and winemakers are telling us that these grapes stand alone; that they’re very high quality and they are very excited about growing them,” Walker noted.
Support for the grape breeding research was made possible by funding from the Pierce’s Disease and Glassy-Winged Sharpshooter Board, which invested more than $30 million since 2001. The development of the resistant varieties was a lengthy process to ensure the most optimal results. “We don’t really want to develop plants that tolerate the disease or tolerate it in some way that you still have fairly high bacterial levels in the plants. We want the lowest possible levels we can achieve,” Walker explained.
The new grape varieties will be available in limited quantities from nurseries which went through the licensing process with UC Davis InnovationAccess. More propagation material is expected to be made available for growers in 2020. “The growers can now start putting in their requests for materials,” Walker noted, “by 2021 there should be fairly large amounts available from nurseries.”
Listen to Walker’s interview below.