VIRUS-FREE WINE GRAPE CULTIVARS

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: SPECIAL GRANT
• Reporting Frequency: Annual
• Accession No.: 0220241
• Grant No.: 2009-34559-20300
• Proposal No.: 2009-05845
• Project Start Date: Sep 1, 2009
• Project End Date: Aug 31, 2011
• Grant Year: 2009
• Program Code: [DD-L]- Virus-free Wine Grape Cultivars, WA

Recipient Organization
WASHINGTON STATE UNIVERSITY
240 FRENCH ADMINISTRATION BLDG
PULLMAN,WA 99164-0001

Performing Department
Prosser Irrigated Ag Res & Ext Center

Non Technical Summary
Grapes are the most valuable horticultural crop in the world and in the U.S., yet grape cultivar development resources are only modestly supported. The Pacific Northwest (PNW) represents a growing segment of premium wines in the US and is also the leading producer of juice grapes in the US. Washington state ranks second in the nation for production of premium wine and first in Concord grape juice. The Washington wine industry alone has grown from a few hundred acres in 1970 to now over 32,000 acres, while juice grape production remains stable at 26,000 acres. The wine and juice grape industries combined add over $3 billion to the Washington state economy each year. Growth in Oregon and Idaho has paralleled that in Washington, albeit on a smaller scale. As the industry matures, ageing vineyards and periodic winter freezes create the need for certified plants, grown and tested regionally, to renew vineyards. In addition to being the foundation of a healthy grape industry, disease-free plants are also needed to comply with international trade agreements (WTO and NAFTA). With the establishment of WTO, the U.S. and other member countries agreed to comply with the standards set by the International Plant Protection Convention (IPPC) when adopting plant quarantine measures. Under IPPC rules, growers are required to plant certified vines or drop existing quarantines which protect grape growers from introduced diseases. Without quarantines, accidental introduction of devastating diseases poses significant danger to PNW vineyards. Access to disease-free plants and a science-based program for importation and evaluation of new plant material are vital to the continued growth of the industry. As a source for disease-free material, the Foundation Block also is a valuable resource for ongoing research by the regional land-grant universities and USDA-ARS. The ability of the PNW wine and juice industry to remain competitive is dependent upon the consistent production of high-quality fruit to make premium products to supply both domestic and export markets. This in turn will enhance the economic sustainability of the industry and associated tourism and other rural industries and communities. Diversification would be very desirable as the narrow genetic basis of these cultivars puts the regional industry at risk from invading or latent pathogens and from changing consumer demand and outside competitors. In addition, most new plantings, especially in Washington and Idaho, are currently not grafted to phylloxera-resistant rootstocks, which puts them at risk from the devastating phylloxera (Daktulosphaira vitifoliae) root aphid in the future.

Animal Health Component

75%

Research Effort Categories

Basic

25%

Applied

75%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
212	1131	1101	50%
212	1131	1160	30%
203	1131	1060	20%

Knowledge Area
212 - Pathogens and Nematodes Affecting Plants; 203 - Plant Biological Efficiency and Abiotic Stresses Affecting Plants;

Subject Of Investigation
1131 - Wine grapes;

Field Of Science
1060 - Biology (whole systems); 1101 - Virology; 1160 - Pathology;

Keywords

vitis

grapevine

cultivar

clone

rootstock

clean plants

virus disease

crown gall

indexing

propagation

Goals / Objectives
(1) Increase the number of grape selections from worldwide sources at Washington State University's Irrigated Agriculture Research and Extension Center at Prosser, WA, and distribute virus-free planting material to serve the needs of Pacific Northwest (PNW: Washington, Oregon, Idaho) wine, juice, and table grape growers and researchers. This planting, termed Foundation Block, will support objectives 2 and 3. (2) Evaluate the performance (growth, yield formation, cold hardiness, fruit, and wine quality) of wine and juice grape cultivars and rootstocks in the unique PNW growing region. (3) Evaluate interactive effects on grapevine performance of climate variation and plant diseases, such as those caused by viruses or crown gall. (4) Develop educational and extension programs and materials for growers regarding the value of virus-free plant material and of cultivar and rootstock diversification and use.

Project Methods
Continue selecting and testing the most appropriate and promising grapevines for the PNW. The advisory group meets at least twice yearly to identify grape selections for inclusion in the program and determine priorities for funding, virus indexing, plant certification, and educational activities. Cultivar selection will be followed by acquisition of hardwood cuttings that will be rooted and potted for growth in the greenhouse. Laboratory indexing on these plants for graft-transmissible agents will be done several times beginning 4-5 months following initial growth. A plantlet is made from each growing tip of the potted greenhouse plant by aseptic micro-tip tissue culture procedures. Shoot tips, 0.3 to 0.5 mm in length, will be surface-sterilized prior to establishment on nutrient medium in agar. This procedure results in a plant that is free of crown-gall bacteria and potentially free of any virus or virus-like organism that may be present in the original cutting. Several plantlets from each selection will be propagated in this manner and transferred to pots. 4-5 months after potting of the tip-cultured plantlets, laboratory indexing by means of enzyme-linked immunosorbent assay (ELISA) and/or reverse transcription polymerase chain reaction (RT-PCR) will be done for currently known viruses. Once a selection has been cleared for growth in the field, five plants from a single original tip will be planted in the Foundation Block. All other plants derived from tissue culture will be destroyed, so that all plants and resulting propagation material can be traced to a single shoot tip from a single-vine source. Selections will be registered following ampelographic observations and/or DNA typing. Care of the planting will follow stringent sanitation practices to minimize the chance of virus introduction by controlling virus vectors such as dagger nematodes and mealybugs. All plants in the Foundation Block will be re-tested on a regular schedule by employing a combination of biological and field indexing, and ELISA and RT-PCR assays. Cold hardiness of bud and cane tissues will be evaluated each winter by differential thermal analysis. Critical temperatures for bud, bark, and wood tissues will be determined. The cold hardiness information will be made publicly available on the WSU VineWeb site (http://winegrapes.wsu.edu/frigid.html). Results from these studies will be communicated to fieldmen, growers, and nurseries through grower meetings, web-based communication, and viticulture extension programs that have been established throughout Washington, Oregon, and Idaho. Hands-on workshops will be organized in partnership with academic professionals and Washington State Department of Agriculture employees. In addition, seminars and lectures will be organized for invited speakers from different disciplines of the Viticulture and Enology Program at WSU as well as representatives from WSDA and USDA-APHIS. The topics will cover aspects of virus diseases and certification programs, as well as cultivar characteristics and performance.

Progress 09/01/09 to 08/31/11

Outputs
OUTPUTS: (1) The number of grape selections from worldwide sources held in the Foundation Block at Washington State University's Irrigated Agriculture Research and Extension Center at Prosser, WA, was increased to 196 in 2011. An additional 112 selections have been acquired and are currently being tested. Selections include multiple clones of wine, juice, table, and ornamental grape cultivars and rootstocks of importance to the grape-related industries of the Pacific Northwest (Washington, Oregon, Idaho) and throughout the U.S. All available selections are listed on the website of the Northwest Grape Foundation Service (http://wine.wsu.edu/research-extension/plant-health/nwgfs/current). All selections were tested for and found free of virus and bacterial diseases as per our Standard Operating Procedures. More than 10,000 dormant hardwood cuttings and 650 mist-propagated potted plants of 218 virus-free selections were distributed to nurseries, growers, and researchers. (2) The performance (growth, yield formation, cold hardiness, fruit, and wine quality) of wine and juice grape cultivars and rootstocks, and their suitability for the unique Pacific Northwest growing region were evaluated. A rootstock field trial was completed at WSU Prosser (WA), with Merlot, Syrah, and Chardonnay on their own roots and on the rootstocks 5C, 99R, 140Ru, 1103P, 3309C, and 101CU. Results on vine performance and fruit and wine composition have been submitted for publication. In a collaborative effort with the USDA (K. Shellie, Parma, ID), a field planting of wine grape cultivars was established to evaluate cultivar performance as part of the NE-1020 multi-state project. Cold hardiness of buds, phloem, and xylem of 20 wine and juice grape cultivars was evaluated throughout the winter, and results were continually posted on our website (http://wine.wsu.edu/research-extension/weather/cold-hardiness). (3) A field experiment was conducted with Merlot grapevines to evaluate interactive effects on grapevine performance in relation to infection with grapevine leafroll disease (GLRD). Plants were identified in a commercial vineyard in such a way that individual vines exhibiting typical symptoms of GLRD and testing positive for GLRaV-3 were adjacent to healthy vines. Tested variables included gas exchange, plant water status, flavonoid biosynthetic pathway gene expression, leaf nutrient status, yield, fruit composition, cold hardiness, and wine composition. (4) Educational and extension programs and materials for growers were developed and distributed regarding the value of virus-free plant material and of cultivar and rootstock diversification and use. Activities included development of print and teaching materials, online information (http://wine.wsu.edu/research-extension/plant-health/virology), as well as oral presentations at industry meetings, workshops, and field days with grower groups. PARTICIPANTS: PI: Markus Keller: General project oversight and leadership, and evaluation of cultivar and rootstock performance and of grapevine cold hardiness. Co-PI: Naidu Rayapati: Research on grapevine-GLRD interactions, field evaluation of impacts of virus diseases on grapevines, epidemiology of GLRD, and extension/outreach program development. Co-PI: Ken Eastwell: Virus and bacteria indexing and evaluation of bacterial diseases in grapevines. Scientific Assistant: Gary Ballard: Management of Grape Foundation Block, performance of day-to-day activities including tissue culture, plant propagation, and vineyard maintenance. Research Associates: Linga Gutha and Olufemi Alabi: Evaluation of grapevine-GLRD interactions and studies on field performance of wine grapes with GLRD. TARGET AUDIENCES: - Nurseries through print, telephone, and web-based outreach and, workshops, industry meetings, and field days - Grape growers and winemakers through print, telephone, TV, and web-based outreach and, workshops, industry meetings, field days, tailgate meetings, and on-site visits - Undergraduate and graduate students, and continued-education certificate students (primarily in Horticulture and in Viticulture and Enology) through classroom and online education PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
(1) The Northwest Grape Foundation Service and associated research programs continue to have a very significant impact on nurseries and vineyards throughout the Pacific Northwest and beyond, as documented by the strong increase in requests for and distribution of propagation material over the last five years. The Foundation Block has expanded rapidly to become a regional service center serving the grape, juice, and wine industries, primarily in Washington, Oregon, and Idaho, but increasingly in many other states and in Canada as well. As a result, this program was integrated in 2011 into the National Clean Plant Network. Approximately half of all grower requests for inclusion of grape selections in the Foundation Block now come from wine and table grape industries outside of Washington. Nurseries and growers throughout the region and elsewhere are buying virus-tested plant material so that future plantings will be free of debilitating virus and bacterial diseases. (2) The information on the performance and cold hardiness of cultivars 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 vineyard sites, as well as on frost protection measures during the winter season and on adequate management responses following cold damage. Our website (http://wine.wsu.edu/research-extension/weather/cold-hardiness) has developed into a one-stop shop for information on these issues, and is very highly accessed throughout each winter season. (3) Symptomatic leaves of GLRD-affected Merlot grapevines were associated with up-regulation of flavonoid biosynthetic pathway genes and anthocyanin accumulation. Leaf photosynthesis and chlorophyll fluorescence differed between GLRD-affected and unaffected leaves only after veraison. Macro- and micro-nutrients in leaf samples were generally within the normal range and indicated no significant differences. Fruit ripening in GLRD-affected vines lagged behind unaffected vines. Yield per vine was lower in GLRD-affected vines. Small-lot wines from infected vines had lower pigments (anthocyanins, small and large polymeric pigments), phenolics, tannins and alcohol than wines made from fruit harvested from unaffected vines. These results demonstrated that GLRD affects vine performance and impacts fruit and wine quality from own-rooted Merlot grapevines grown in eastern Washington. Studies on field spread of GLRD indicated that clean plantings, when planted in close proximity to disease-infested older blocks, are at the risk of infection by the disease. Thus, management tactics should be adapted to avoid risk of infection from external sources. (4) Our websites (http://wine.wsu.edu/research-extension/plant-health/nwgfs/current and http://wine.wsu.edu/research-extension/plant-health/virology) have developed into one-stop shops for information on clean plants and questions regarding their use.

Publications

• Ferguson J.C., J.M. Tarara, L.J. Mills, G.G. Grove and M. Keller. 2011. Dynamic thermal time model of cold hardiness for dormant grapevine buds. Ann. Bot. 107: 389-396. Keller M. 2011. Rootstock effects on wine are minor. Good To Know Column, Good Fruit Grower 62: 25-26. Keller M. 2011. WSU grape cold hardiness program. WSU Viticulture and Enology Extension News, Spring: 2. Moyer M., L. Mills, G. Hoheisel and M. Keller. 2011. Assessing and managing cold damage in vineyards. Washington State University Extension Manual. EM042E, 12 pp.

Progress 09/01/09 to 08/31/10

Outputs
OUTPUTS: (1) The number of grape selections from worldwide sources held in the Foundation Block at Washington State University's Irrigated Agriculture Research and Extension Center at Prosser, WA, was increased to 173 in 2010. Selections include multiple clones of wine, juice, table, and ornamental grape cultivars and rootstocks of importance to the grape-related industries of the Pacific Northwest (Washington, Oregon, Idaho) and throughout the U.S. All available selections are listed on the website of the Northwest Grape Foundation Service (http://wine.wsu.edu/research-extension/plant-health/nwgfs/current). All selections were tested for and found free of virus and bacterial diseases as per our Standard Operating Procedures. More than 5000 dormant hardwood cuttings and mist-propagated potted plants of 150 virus-free selections were distributed to nurseries, growers, and researchers in the Pacific Northwest and nationwide. (2) The performance (growth, yield formation, cold hardiness, fruit, and wine quality) of wine and juice grape cultivars and rootstocks, and their suitability for the unique Pacific Northwest growing region were evaluated. A rootstock field trial was completed at WSU Prosser (WA), with Merlot, Syrah, and Chardonnay on their own roots and on the rootstocks 5C, 99R, 140Ru, 1103P, 3309C, and 101-14MG. Results on fruit and wine composition were recently reported at the 19th Annual Conference of the Northwest Center for Small Fruits Research in Boise, ID, and are currently being prepared for publication. In a collaborative effort with the USDA (K. Shellie,Parma, ID), a field planting of wine grape cultivars was established to evaluate cultivar performance as part of the NE-1020 multi-state project. Cold hardiness of buds, phloem, and xylem of 20 wine and juice grape cultivars was evaluated throughout the winter, and results continually posted on our website (http://wine.wsu.edu/research-extension/weather/cold-hardiness). (3) A collaborative (with N. Rayapati) field experiment was conducted with Merlot to evaluate interactive effects on grapevine performance of variation in climate and soil moisture and of leafroll virus infection. Tested variables included gas exchange, plant water status, yield, fruit composition, and cold hardiness. (4) Educational and extension programs and materials for growers were developed and distributed regarding the value of virus-free plant material and of cultivar and rootstock diversification and use. Activities included development of print and teaching materials, online information (http://wine.wsu.edu/research-extension/plant-health/virology), as well as oral presentations at industry meetings, workshops, field days, and tailgate meetings with grower groups. PARTICIPANTS: PI: Markus Keller: General project oversight and leadership, and evaluation of cultivar and rootstock performance and of grapevine cold hardiness. Co-PI: Naidu Rayapati: Method development and evaluation of virus diseases in grapevines. Co-PI: Ken Eastwell: Virus and bacteria indexing and evaluation of bacterial diseases in grapevines. Scientific Assistant: Gary Ballard: Management of Grape Foundation Block, performance of day-to-day activities including tissue culture, plant propagation, and vineyard maintenance. Research Associate: Linga Gutha: Evaluation of grapevine performance under leafroll virus infection and varying soil moisture. TARGET AUDIENCES: - Nurseries through print, telephone, and web-based outreach and, workshops, industry meetings, and field days - Grape growers and winemakers through print, telephone, TV, and web-based outreach and, workshops, industry meetings, field days, tailgate meetings, and on-site visits - Undergraduate and graduate students (primarily in Horticulture and in Viticulture and Enology) through classroom and online education PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
(1) The Northwest Grape Foundation Service and associated research programs continue to have a very significant impact on nurseries and vineyards throughout the Pacific Northwest and beyond, as documented by the strong increase in requests for and distribution of propagation material over the last five years. The Foundation Block has expanded rapidly to become a regional service center serving the grape, juice, and wine industries, primarily in Washington, Oregon, and Idaho, but increasingly in many other states and in Canada as well. As a result, approximately half of all grower requests for inclusion of grape selections in the Foundation Block now come from wine and table grape industries outside of Washington. Nurseries and growers throughout the region and elsewhere are now buying virus-tested plant material, so that future plantings will be free of debilitating virus and bacterial diseases. Our websites (http://wine.wsu.edu/research-extension/plant-health/nwgfs/current and http://wine.wsu.edu/research-extension/plant-health/virology) have developed into one-stop shops for information on clean plants and questions regarding their use. (2) The information on the performance and cold hardiness of cultivars 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 vineyard sites, as well as on frost protection measures during the winter season and on adequate management responses following cold damage. Our website (http://wine.wsu.edu/research-extension/weather/cold-hardiness) has developed into a one-stop shop for information on these issues, and is very highly accessed throughout each winter season.

Publications

• Alabi, O.J., Martin, R.R. and Naidu, R.A. 2010. Sequence diversity, population genetics and potential recombination events in Grapevine rupestris stem pitting-associated virus in Pacific Northwest Vineyards. J. Gen. Virol. 91: 265-276.
• Gutha, L.R., Casassa, L.F., Harbertson, J.F., and Naidu, R.A. (2010). Modulation of flavonoid biosynthetic pathway genes and anthocyanins due to virus infection in grapevine (Vitis vinifera L.) leaves. BMC Plant Biology 10: 187 (doi:10.1186/1471-2229-10-187).
• Keller, M. 2010. Managing grapevines to optimise fruit development in a challenging environment: a climate change primer for viticulturists. Aus. J. Grape Wine Res. 16: 56-69.
• Keller, M. 2010. The Science of Grapevines: Anatomy and Physiology. Elsevier: Academic Press, Burlington, MA.