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European grape. Purple bunch wine grapes.

AUBURN UNIVERSITY, Ala.— Alabama wine grape growers will soon have access to disease resistant bunch grape varieties as new grape varieties send ripples through the entire wine-making community.

For many years, Alabama’s commercial grape producers have been limited to native muscadine, American and French-American hybrid bunch grape cultivars. The limited access is due to heavy bacterial disease pressure that suffocates most European grapes cultivated in the southeast. However, game-changing new cultivars are set to release for commercial production in early 2020.

Pierce’s Disease

Elina Coneva and Andy Walker inspecting European bunch grapes.

Dr. Elina Coneva and Dr. Andy Walker inspect the V. Vinifera vines growing in Clanton, Alabama.

Pierce’s Disease (PD) is a crippling disease affecting grape production in the United States, especially in warm, southern regions. At present, there is no known cure for PD.

Pierce’s Disease:

  • clogs the xylem vessels of the vine
  • prevents water and mineral transportation to plant organs
  • leads to vine decline, yield loss and eventual vine death

A new development from Andy Walker, a grape breeder at UC Davis, will make PD-resistant grape varieties available for commercial cultivation in Alabama. The new European (Vitis vinifera) grape selections are expected to produce high quality yield in regions with PD pressure where Vitis vinifera production was previously not a viable option.

Elina Coneva, an Alabama Extension fruit crops specialist, has been at the forefront of research on the PD-resistant varieties in Alabama. Coneva and her team have been cultivating and evaluating three PD-resistant predominantly European grape selections at the Chilton Research and Experiment Station since 2010.

“Our results are very promising,” Coneva said. “The newly developed PD-resistant European grape progeny have the potential to greatly impact the fruit industry in Alabama and the southeast by providing new specialty fruit crops to the market.”

Coneva said the new varieties will also broaden the window of economic opportunities for small- and medium-sized family farms in the state and the southeastern region, while boosting existing industries such as agritourism.

Alabama Growing Conditions

Aside from determining viability in Alabama growing conditions, Coneva said the study has allowed her team to develop proper management techniques in a given set of environmental conditions.

Alabama’s weather patterns have allowed for research in a warm, humid environment. The normally abundant rainfall—combined with hot growing seasons—promote a vigorous vine growth, sometimes at the expense of an optimal fruit crop. Alabama growing conditions create the perfect storm for disease development and spread.

“Intense management and records by the team at the Chilton Research and Experiment Station have allowed us to develop guidelines that farmers will use when the PD resistant V. vinifera cultivars become available—hopefully during spring or summer 2020,” she said.

As part of the development of best management practices for V. vinifera grapes, Coneva has been able to study and implement the proper European grapevine training techniques. European grapevines are trained differently than traditional muscadine vines.

“The vertical shoot positioning training system facilitates the upright growing habit of V. vinifera cultivars and contributes to efficient pest management practices, while concentrating the crop load within a compact fruiting zone,” Coneva said.

European grape. Bunch grape variety.Other Research

Researchers established an experimental vineyard at the Sand Mountain Research and Extension Center (SMREC) near Crossville, Alabama in 2007. There, researchers study ten PD tolerant American and French-American hybrid bunch grape cultivars. Results have indicated several cultivars that may be suitable for commercial production in Alabama and the Southeast.

More Information

For more information on the PD resistant V. vinifera cultivars release and cultivation in Alabama, contact Coneva. For further information, visit www.aces.edu or contact your county Extension office.

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