Best Paper (Again!), New V&E Newsletter, Clean Plants

WSU/USDA-ARS Collaboration Yields Another “Best Paper Award”

Anthocyanin is responsible for the color in grapes, apples and many other fruits. Bottom: Julie Tarara
Anthocyanin is responsible for the color in grapes, apples and many other fruits. Bottom: Julie Tarara

For the second year in a row, WSU researchers and their USDA colleagues based at the Irrigated Agriculture Research and Extension Center in Prosser have won a Best Viticulture Paper Award from the American Society for Enology and Viticulture.

USDA-ARS researcher Julie M. Tarara, based at WSU’s Prosser R&E Center, and her co-authors won Best Viticulture Paper in the American Journal of Enology and Viticulture for a paper entitled “Berry Temperature and Solar Radiation Alter Acylation, Proportion, and Concentration of Anthocyanin in Merlot Grapes.”

Anthocyanin is a natural phenolic compound that can be found in grapes and wine. Of all the compounds involved in creating a great bottle of wine, phenolics comprise only a small portion. Phenolics have potential human health benefits, but are essential to wine for their contributions to appearance, taste and mouthfeel. In addition, phenolics are valuable to plants: they give fruit a white to purple color, help provide protection against UV radiation, attract pollinating insects and can aid seed dispersal by herbivores.

Understanding how phenolics are formed under varying environmental conditions is critical to ensuring that wine grape producers are able to deliver the best possible fruit to winemakers. What Tarara and her colleagues found was that concentrations and profiles of the anthocyanin class of phenolics in grape berries appear to be determined by a combination of exposure to solar radiation and the temperature of berries as they mature.

Tarara and her colleagues write, “Our data indicate that temperature is a strong environmental determinant of anthocyanin profile in the berry skins, above a potentially low threshold of exposure to solar radiation.”

The scientists conclude that ultimately, “Manipulating vineyard conditions to alter the anthocyanin profile of the berry may become a useful approach to strategic management as we better understand the contribution of individual anthocyanins to final fruit and wine quality.”

In 2008, WSU horticultural scientist Markus Keller and research technology supervisor Lynn J. Mills won Best Viticulture Paper for research on pruning cold-injured Merlot vines. In 2007, Thomas Henick-Kling, the new director of WSU’s program in viticulture and enology, was a co-author of the year’s Best Enology Paper. And in 2003, WSU food scientist Sara Spayd, along with Tarara and others, authored the Best Viticulture Paper.

For more information on the 2008 Best Viticulture Paper, please visit: Voice of the Vine, Feb. 21, 2008,

New Issue of WSU Wine and Grape Research and Extension Newsletter

The Spring 2009 issue of the WSU Wine and Grape Research and Extension Newsletter is now available as a free PDF download. To get your copy, please visit:

The WSU Wine and Grape Research and Extension Newsletter offers more technical information than does Voice of the Vine; it is intended for professionals working in research and the wine industry. Follow the link above to activate your free subscription.

Certified Planting Stock: What Is It?… And Why You Should Care

This article is adapted from one by Gary Ballard, manager of the NorthWest Grape Foundation Service.
This article is adapted from one by Gary Ballard, manager of the NorthWest Grape Foundation Service.

The WSU-operated NorthWest Grape Foundation Service is part of the National Clean Plant Network, a nationwide effort to supply agricultural producers with “clean,” virus-free plant material. Considerable scientific expertise and rigor is needed to thoroughly screen plant material for viruses and to propagate the clean material. The clean material is then released to certified commercial nurseries throughout the Pacific Northwest where it is grown for sale to producers.

When a grapevine is purchased as a certified nursery plant, it comes with a state-issued certification tag that represents a process outlined in the state’s administrative codes and administered by the WSDA. Inspectors from the WSDA routinely monitor the mother blocks for pathogens during the season, while the NorthWest Grape Foundation Service ensures that the material provided has tested free of known viruses and diseases.

Planting certified grape stock is a vineyard manager’s best insurance against the introduction or spread of grape pathogens. Certification is assurance that the vine passed a rigorous testing process confirming it is free of the pathogens identified by Washington state’s administrative codes.

The certification process starts when plant material is vigorously tested for specifically identified pathogens with laboratory indexing methods. If the selection is found to be compromised with one or more listed pathogens, propagation methods are undertaken to remove the pathogens. Once laboratory and biological indexing show the selection to be tested free of the listed pathogens, the selection is promoted to “registered release” status.

If unwanted pathogens are introduced via infected non-certified vines, elimination becomes very difficult, if not impossible. Pathogens can move throughout the planting and into adjacent blocks, causing negative effects on fruit quantity and quality, and subsequent economic grief. Considering the prevalence of viruses and the expense of keeping them at bay, the National Clean Plant Network is not only a great investment, it is a necessary one.

For more information on the NorthWest Grape Foundation Service, please visit:

For more information on what WSU researchers are doing to combat grape viruses, please visit: