Progress 08/15/06 to 08/14/08
Outputs
OUTPUTS: Grape cuttings were obtained from Foundation Plant Services (FPS) at UC Davis and Oregon State University based on recommendations from an advisory group (industry representatives, state regulatory agency representatives, university researchers and extension specialists). Cuttings were grown in a greenhouse and propagated by meristem culture to eliminate crown-gall. Plants were then virus-indexed by ELISA and/or RT-PCR optimized for detection of grapevine leafroll-associated viruses, grapevine viruses A and B, grapevine fanleaf virus, tomato ringspot virus, grapevine fleck virus, and rupestris stem pitting-associated virus. Of 170 selections acquired to date, 90 tested selections have been planted in the Foundation Vineyard on a quarantine site at WSU's Irrigated Agriculture Research and Extension Center in Prosser, WA. Virus-retesting so far has not revealed any viruses, but regular testing will continue to ensure the planting remains clean. Remaining selections are currently at various stages of development (meristem culture, virus indexing, or propagation). A graduate research assistant is studying interactions of viruses with environmental effects on grapevine performance. We also developed a website (http://nwgfs.wsu.edu) with educational information about grapevine certification, virus indexing, plant selection and introduction, and current listings of available selections and certified nurseries. Throughout each winter, we evaluated grapevine cold hardiness by differential thermal analysis and posted critical temps on the internet (http://winegrapes.wsu.edu/frigid.html) to assist growers with decisions on matching cvs. to sites and on frost protection measures. We established a field trial that includes Chardonnay (CH), Merlot (ME), and Syrah (SY) grafted to 6 rootstocks in addition to own-rooted plants. Another field trial was planted with Concord juice grapes on 3 rootstocks and on their own roots. We also established a link with the national NE-1020 project to plant ~20 wine grape selections at a testing site in ID for performance evaluation. In 2006, own-rooted CH in the wine-grape rootstock trial had higher yields than grafted vines, while no differences were found for ME. Own-rooted SY had the lowest yields and SY grafted to 3309 the highest. Rootstocks did not affect sugar and color accumulation and acid degradation in CH and ME, but sugar accumulation was fastest on own-rooted SY, and less color accumulated in SY on 140-2. CH and ME, but not SY juice had the highest pH on their own roots (ME also on 101-14) and the lowest on 140-2. Although rootstocks did not affect juice potassium (K), variations in K rather than titratable acidity explained most of the difference in pH between and within cvs.: ME contained the most and CH the least K. ME juice was high in proline but low in arginine, SY was low in proline but high in arginine, while CH was low in both amino acids. Grafting did not affect juice proline, while juice from own-rooted CH and SY, but not ME, contained more arginine than that from grafted vines. In practical terms, high juice pH can lead to poor wine stability, and low arginine may result in stuck fermentations. PARTICIPANTS: Markus Keller, Ken Eastwell, Naidu Rayapati, Washington Association of Wine Grape Growers, Washington State Wine Commission TARGET AUDIENCES: Target audiences include wine and juice grape growers in the Pacific Northwest and the nurseries which sell plants to them. Efforts to deliver science-based knowledge include a website (http://nwgfs.wsu.edu) with educational information about grapevine certification, virus indexing, plant selection and introduction, and current listings of available selections and certified nurseries. Throughout each winter, we evaluated grapevine cold hardiness by differential thermal analysis and posted critical temps on the internet (http://winegrapes.wsu.edu/frigid.html) to assist growers with decisions on matching cvs. to sites and on frost protection measures. More detailed progress reports were included in a compiled booklet of wine-grape-funded progress reports that was available at the Wine Research Review held in Prosser, Washington on February 22, 2008. Copies of the progress-report booklet were also mailed to members of the Washington Wine Commission and the Wine Advisory Committee, and copies are available in the WSU Agricultural Research Center. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The WSU Grape Foundation Block and associated research programs have had an immediate impact on nurseries and vineyards throughout Washington, as documented by the strong increase in sales of propagation material over the last three years. The block has expanded rapidly to become a regional service center serving the grape and wine industries of Washington, Oregon and Idaho. As a result, approximately half of all grower requests for inclusion of grape selections in the block now come from the wine and table grape industries outside of Washington. Nurseries throughout the region are buying virus-tested plant material, so that future plantings will be free of debilitating virus and bacterial diseases. The information on the performance and cold hardiness of varieties and rootstocks under the arid summer and cold winter conditions of the inland Pacific Northwest is highly valued by growers, because it enables them to make informed decisions on the selection of planting material and sites, and on frost protection measures during the winter season.
Publications
- Keller M. and L.J. Mills. 2005. Recovery of Merlot vines from winter injury: a matter of bud number Proc. XIV Internat. Symp. `Groupe d'Etude des Systemes de Conduite de la Vigne'. Geisenheim, Germany, pp. 74-79.
- Mills L.J., J.C. Ferguson and M. Keller. 2006. Cold hardiness evaluation of grapevine buds and cane tissues. Am. J. Enol. Vitic. 57:194-200.
- Keller M. and L.J. Mills. 2007. Effect of pruning on recovery and productivity of cold-injured Merlot grapevines. Am. J. Enol. Vitic. 58: 351-357.
- Keller M., L.J. Mills and D.S. Hackett. 2007. Field grafting and cold injury: grafting height but not rootstock affects scion survival. Proc. XV International Symposium `Groupe d'Etude des Systemes de Conduite de la Vigne'. Porec, Croatia, pp. 294-300.
- Olmstead M.A. and M. Keller. 2007. Chip bud grafting in Washington state vineyards. Washington State University Extension Bulletin EB2023E: 4 pp.
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