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Blanc du Bois was bred to be tolerant to Pierce's disease.


The first commercial planting of certified Blanc du Bois, 'Whitely Vineyards' in Montgomery, TX.

Clean Plant Success Story: Blanc du Bois  

Blanc du Bois is a hybrid bunch grape developed by crossing Vitis vinifera and native Florida grapes. It was bred in 1968 by University of Florida breeder John Mortensen specifically to be tolerant of Pierce’s disease. Pierce’s disease, caused by the bacterium Xylella fastidiosa, is a devastating disease which is especially challenging in the southeast. There is no treatment for it and the primary means of control is planting resistant or tolerant cultivars.

In Texas, Blanc du Bois showed great winemaking potential and researchers understood the value of starting with clean planting stock. Dr. Mark Black at the Texas AgriLife Extension Service submitted an 'Austin County, Texas' clone of Blanc du Bois obtained from Cat Spring, Texas to Foundation Plant Services in 2010. The original material tested positive for grapevine leafroll associated virus-3; was successfully treated to eliminate virus in 2010 and planted in Russell Ranch Foundation Vineyard in 2013.

Clean Blanc du Bois planting stock has been distributed  nationwide since 2014. Acreage of Blanc du Bois is on the rise and Texas leads in production. In 2017, Blanc du Bois ranked fifth in acreage of grape cultivars in Texas with 210 bearing acres.  Now, new plantings of Blanc du Bois can all be sourced from certified material, leading to more productive and healthy vineyards.


To learn more about the Blanc du Bois, read Fritz Westover’s article in Wines and Vines.

The Story of Zinfandel

The source of a selection is often a fascinating story.  An example of such story is the discovery of the origin of the grape cultivar Zinfandel in Croatia, which is told in the book Winegrapes of UC Davis by Nancy Sweet available on the FPS website. 

Following several plant exploration trips around Croatia by scientists from the University of Zagreb, a potential candidate for a “Zinfandel” clone in Croatia was identified in 2002; only a few vines of that candidate clone remained in Croatia at that time. Samples from the candidate selection, known in Croatia as Crljenak kaštelanski, were evaluated using DNA technology in Dr. Carole Meredith’s lab at UC Davis. The DNA profile of the Crljenak vines matched that of California’s Zinfandel and Italy’s Primitivo.  Dr. Meredith arranged for dormant material to be shipped to FPS in 2002 for inclusion in the public foundation grapevine collection at UCD.

The original material was tested from 2003-2005 and found to have virus. A microshoot tip tissue culture selection was created in 2008 and qualified for the Russell Ranch Foundation in 2012 under the name Zinfandel 42.1. It is believed that the Croatian “Zinfandel clones” offer genetic diversity for the variety in California, having developed for such an extended time in another location.  Zinfandel 42.1 was also returned to Croatia as a part of an exchange program to return the virus-tested material to its source country.


The Croatian wine industry was revitalized by the attention received in the story of the discovery of the origin of Zinfandel and many new Croatian cultivars have been identified and developed into wines as a result.





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