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