Dr. Andrew Walker, UC Davis Photo:Liz Hafalia-The Chronicle

Wine starts and can end in the vineyard; mites/insects (visible and microscopic), diseases, mildew, and Mother Nature make it a miracle wine ever makes it onto the shelf.

Even as vineyard managers adopt Biodynamic®, organic or sustainable vineyard practices, there will always be challenges to maintaining healthy vines. The most recognized disaster of the 19th century for the wine industry was phylloxera; a disease in which a small bug feeds on the roots of vines. With no known totally effective preventative measures, research discovered there were ways to minimize the phylloxera impact; the solution was and is through grafting vinifera wine grapes onto American species rootstocks that are phylloxera resistant. This is just one example of the constant need for research to sustain the wine industry.

Most research today involving vines; farming practices; diseases and pest control methods, are conducted by universities throughout the U.S. However, there are some private research efforts too.  In the winery there are many techniques that impact/imbue the characteristics of wine. But, research is ongoing to develop new varieties that will meet certain grower and winery specification for improved disease control, aromas, taste, yields and climate change adaptations. Additionally, there are ongoing efforts to develop vines that can withstand extreme temperatures, poor soil conditions (such as salinity), and altitude effects. University of California-Davis’ Dr. Andrew Walker is very involved with the issue of grapes grown in saline soils.

As an aside. I recently tasted my first “Cotton Candy” table grape and it does taste like cotton candy. This grape was patented and became commercially developed in Bakersfield, California through a very complicated commercial vine breeding program, writes Michaellen Doucleff in “The Salt” August 6, 2013. This example of great research is not rare, it wasn’t that long ago when all watermelons had seeds.  Today you can hardly buy a watermelon with seeds. New apple varieties having come to market over the past few decades also point to successful research and breeding results.

There are many wine grape research projects underway at major universities in the U.S. After talking to many university researchers in the field of wine grapes and vines, one impactful effort on wines are the research efforts at the University of California-Davis (UCDavis). There are professors at UCDavis, and other universities, doing research on many wine related projects.  Some projects are about finding farming methods, rootstock, etc. what will preserve the health of vineyards. There is continuing work on Pierce’s Disease and ongoing research on a wide range of rootstock issues (nematodes, fanleaf, drought and salt resistance) and to a lesser extent on Powdery Mildew. This work will never become obsolete because plant DNA and pathogens will always evolve.

There are many universities doing wine grape research in addition to UCDavis. Some of the other great schools doing wine grape research are: California State University-Fresno, Cornell University, University of Arkansas, Washington State University, Oregon State University and Cal Poly State University-San Louis Obispo.  With 125 years as a research university in enology and viticulture, UCDavis has the history behind them.

Remember, all 50 states have vineyards and a wine making presence.  However, based upon the size of the vineyard/wine footprint, California is the elephant in the room. That said, each indigenous growing region in the U.S. has its own challenges in addressing vineyard/vine health, diseases and changes in consumer preferences.  Regional nurseries and growers go to regional universities for research in solving regional wine grape issues and characteristics.

To put the subject of grape/vine research impact into an economic perspective, we need to look at what dictates the importance of California relative to wine. Using TTB data (Tax and Trade Bureau) they report there were 12,335 wine making operators in the U.S in 2017.  (This number can be misleading based upon the way the TTB counts bonded wineries.) A more realistic number of active producing wineries is approximately 10,000, of which California is home to approximately 50% of all U.S. wineries. According to Beverage Daily.com, California wine alone accounts for $71.2 billion in revenue.

Rachel Arthur reports the total economic impact of wine on the U.S. economy is approximately $219.9 billion and contributes $196 billion in tax revenue to the federal government. (Ms. Arthur says there are 10,236 winery facilities in the U.S.  My estimates of wineries just in Sonoma and Napa Counties are: 1,300.)  The Wine Institute reports, California accounts for nearly 85% of all U.S. wine production out of a total U.S. production of 807,000,000 gallons.

Here is another economic factor to think about. What happens if disease impacts a vineyard and plants are pulled out of the vineyard and the vineyard is replanted? Depending on vines planted per acre, (1,000 up to 3,000) and the new vines cost the grower $7.00 per vine, the losses due to diseases can be enormous.  This does not include costs for labor, trellis’s, new irrigation system and the vineyard laying fallow land for 3 years. To add perspective, a few years ago, a vineyard planted in vines could command approximately $400,000 per acre in Sonoma.

Ultimately healthy vines and vineyards have a significant and direct impact on the California and U.S. economy, not to mention the livelihood of approximately a million workers. A repeat of phylloxera would have a major impact economically, not to mention desperate wine drinkers. Research is ongoing; no condition attacking the vine is ever solved in perpetuity.

“Phylloxera is again rearing its ugly head. Most recently, it has been found in the American states of California and Oregon, where years of grafting vines had somehow weakened them, allowing the pest to thrive. There is still no pesticide that can effectively eradicate the pest without harming bees or the environ­ment. Using resistant rootstock for vines is still the most effective treatment,” says Nellie Ming Lee, “Post Magazine”, Nov. 3, 2016. Dr. Walker however comments that, “No evidence of North American Vitis species-based rootstocks declining to phylloxeras.  Need rootstocks for lots of reasons other than phylloxera resistance, but they must be phylloxera resistant in addition to new added traits.

As noted above, wine production in the U.S. is of significant value economically. Obviously, California is a powerful engine for the wine industry and it takes many universities and researchers to keep the wine industry healthy, growing and producing quality fruit and thus, wines. This also recognizes the diverse growing regions where wine is produced, all having unique issues. Simultaneously researchers also lead the way in developing new varieties that might interest the ever-changing consumer tastes.

There are new varieties being developed at research universities that may become the next great grape for blending or as a branded variety that offer growers natural resistance to diseases and mites. But, the underpinning of all solutions is that the new vine must deliver on great aromas, flavors, and production yields. That is what wineries demand.

Historically the U.S. has found varieties of the European grape species (Vitis vinifera) to be more acceptable and those varieties have been improved upon through research in DNA profiling, rootstock adaptation, and breeding. There are approximately 5,000 grape varieties and 50 species that have been used at various times and for various purposes around the world.  Today in the U.S., there are only about 20-30 varieties used extensively.

In a recent USDA study, it was found that 75% of cultivars are closely related (sibling or parent-offspring) to at least one cultivar, says Tim Martinson of Cornell University. “Cultivar” is defined as-a variety of plant that originated and persisted under cultivation.

“The native American species of wine grapes are known by its botanical name-Vitis labrusca, however, in the early 1700’s that species proved not to be a great quality for wines-relative to aromas and flavors. Today the most prevalent grape species for wine is-Vitis vinifera,” says Dr. Andrew Walker of UCDavis.  Vitis vinifera is the primary wine grape across the world. It might be a surprise to realize that the U.S. is the sixth largest in area/acreage of planted vines.  It is amazing that the U.S. has so much acreage in planted vines in such a short period of time.

The first commercial wine produced in the U.S. was in early 1800’s and today the U.S. is the sixth largest in planted grape acreage in the world; behind France, Italy, Spain, China and Turkey.  As a relatively young country and industry, it is amazing how fast it has grown. This is due in part to benefits of research.  Note: Cabernet Sauvignon came from the marriage of Cabernet Franc and Sauvignon Blanc.  (The first traces of attempts at making wine in the New World however date back to 1556.)

During Prohibition, “actually wine acreage increased in California due to the stipulation in the law that stated that wineries could produce 200 gallons per year for personal consumption,” noted Walker. A study performed in 1925, during the heart of Prohibition, found that demand for sacramental wine increased by 800,000 gallons in a two-year period, reports Jennifer Jordan.

How did research become so important to the wine business? “In the late 1800’s, phylloxera was devastating the American wine industry,” says Dr. Andy Walker.  There are always newer challenges that come up. As a more recent example, nearly two decades ago Dr. Walker took on the task of finding a way to address Pierce’s Disease and step up the effort to control mildew diseases. Mildew diseases are such that current vines are not able to adequately defend against; if not addressed they can destroy vineyards and grape production. A major national effort with Pierce’s Disease (PD) has the disease mostly in control now, by supporting research on insect control, development of new resistant varieties and efforts to produce a rootstock-based resistance.

As Dr. Walker points out, his work in viticulture research touches all aspects of the wine business; from the field to the consumer. Dr. Walker is credited with his work in development of a resistant vine for Pierce’s Disease.  “Pierce’s is one of a few diseases in the vineyard that kills the vine. It is no wonder the industry had committed $46 million to research control methods for Pierce’s Disease by developing news ways to control the insect vector, developing new resistant varieties, new ways to predict environmental conditions that favor disease development, and economic impacts of the disease.  But, we are never far from economic issues of PD.

“The wine industry is complex, and the consumers rarely think about our work in crafting new varieties of wine grapes, working to control diseases and pests in an environmentally friendly way, and creating new varieties to adapt to climate change,” says Dr. Walker.  “But, I believe consumers also have a part to play in controlling vine diseases; they need to be more willing to accept new varieties and find room for the word “blend” in the context of fine wines.”

What Dr. Walker started talking about is how consumers have succumbed to buying wine based upon the name of a variety-such as Cabernet Sauvignon or Syrah. Most consumers in the U.S. buy wine by a varietal name; they shun the label saying “blend”.  In reality, virtually all wines are blends and do not come from a 100% varietal grape; even the finest French wines are blends. Due to marketing, to combat European wines (that do not use primarily variety names in marketing), the U.S. industry is locked into keeping the “varietal” nomenclature front and center. This practice does not maximize the benefits of new vine development. Are wine consumers stuck in a rut?  Personally, I have long gone with the blend labeled wines; percent regulations are all that makes a wine a varietal and a change of 1% in a dominate varietal juice will change it to a blend label.

Dr. Tim Martinson, a Senior Extension Associate in the Cornell University School of Integrative Plant Science, explains this wine marketing moniker (“varietal”) this way. Writing in April 2018, “Wines and Vines”-The Frozen Genetics of International Wine Cultivars: “The key obstacle that seems insurmountable is the marketing dominance of varietal wines like Chardonnay and Cabernet Sauvignon.  Even if breeders and researchers can provide growers disease resistance new varieties, with the aromas and taste attributes of say Cabernet Sauvignon, wineries may not be able to market it as a ‘blend’ label.” By TTB regulations for a wine to be labeled using a specific varietal, it must be made with at least 75% of the fruit of that variety.  Therefore, most all variety labeled wines are technically a blend of at least 25%.

“Some people believe, “Once you find a solution to Mildew or Pierce’s Disease (as examples), you can just move on and eventually run out of problems,” says Dr. Walker. “Diseases evolve and there is always a new problem or even the recurrence of a problem once assumed to have been solved.” “Vines and diseases are always adapting and evolving.”

What are some of the major drivers in the constant battle against vineyard diseases and stresses?

  • Climate change patterns such as heat, cold, moisture, etc. “Note: diseases are challenging enough even without climate change.  Growers have to cope with variable weather,” says Dr. Martinson.
  • The evolution of diseases and pests in vines and soil.
  • Combining various attributes of grape varieties through breeding efforts and getting a new more resistant vine with desired profiles that winemakers accept and want, that will help increase demand for hybrid vines at the nursery level.
  • Improved DNA research. The key point is: ”DNA markers help optimize cross-breeding efforts of grape breeders.”
  • Keeping in mind environmental issues, consumers are now becoming more aware of what methods are being used in the vineyard to ameliorate diseases and pests.

Solutions to issues with grape vines are not easy, inexpensive or quickly solved. But luckily with enough time and money most problems can be addressed.

Research can be ongoing at multiple locations around the U.S. Research expenses are/can be covered by state and local governments, the wine industry, and the USDA.  In the case of Pierce’s Disease (spread by the Glassy Winged Sharpshooter) this was a 14-year project that involved spraying regimens, research and experimentation with insects, such as wasp’s, that could help control the Glassy Winged Sharpshooter. In total, the campaign to attack the PD problem cost $65 million of which approximately $4.6 million was granted to UCDavis for research. One resultant solution was the development of a new PD resistant rootstock. Cornell University and others were also involved.

(Note: Rootstock does not influence aromas or flavors, it’s primary function is to protect the plant from pest from within the soil.)  The rootstock commented on above is not very close to commercialization and it works by producing antibiotic compounds that move from the rootstock to the fruiting variety where the antibiotics kill the PD bacterium, it has ways to go in terms of acceptance and field proofing.

With the development of new vines, the recovery of these costs can be a consideration. One option to handled research cost recovery at the nursery level.  The proven benefits of the research with new vines and rootstock are handed off to nurseries. Nurseries will do the necessary volume production of the new vine by propagating vines via dormant cuttings.  The nursery will also do the necessary marketing/selling to the growers.  In most cases, the university owns the patent on the new variety or rootstock and licenses the new vines to nurseries for mass production. Such licenses can call for a fee per plant. For example, it might be $0.50 per plant.

As DNA sequencing is becoming a ubiquitous tool in the wine grape research labs, in 1998 UCDavis used this tool to define the mother and father of the Syrah grape which dates from approximately 600 BC. The real mother and father varietal was Dureza and Mondeuse blanche.

DNA mapping of various grape species can shorten the process of developing new varieties which can: impart new aromas and flavors, reduce the need for pesticides, provide drought resistance vines, improve cold resistance in vines, improve grape yields, and offer disease resistance benefits.

Previously, without the help of vine DNA research, developing new vines and rootstock was tedious and is often a trial and error exercise in hopes of getting desired results and getting those resultant plants to market.

As Tim Martinson, Senior Extension Associate, Cornell University points out in his March 2018 “Wines and Vines” article- “Grape Breeders No Longer Flying Blind”, the old methods were daunting. For example, grape breeders had to:

  • Emasculating grape flowers, using tweezers to remove stamens, bagging them to keep them pure.
  • Taking that male pollen and spread them over emasculated flowers of the female parent; all of this to get maybe 50-150 seeds for testing.
  • Then plant those seeds next year and then wait, ultimately hoping to get enough good plants.
  • Select 5-15% of the seedlings and replant them in a vineyard.
  • 3 to 4 years later you get a chance to evaluate results and keeping maybe only 10% of those results.
  • Replant the 10% and wait some more.
  • Then test for disease resistance, fruit chemistry and evaluate the results against the desired results.

DNA markers and tests let breeders know ‘right away’ whether the seedlings have the ‘right genes’, so they can keep the good seedlings and discard the ones that don’t have the genes they want. They don’t have to waste time or space growing out vines without the right genes. They still must go through the 10 to 15-year evaluation process before releasing a variety.  This process has nothing to do with GMO!  Before DNA testing, grape geneticists faced a complex task in determining how desirable traits were inherited and mapping those traits to specific location on each chromosome.

Today DNA sequencing has reduced research costs and allowed breeders to locate genetic markers in various varieties of vines that allow them to produce the desired results.  A USDA funded program (VitisGen) has now identified 70 marker-traits that have positive results in developing vines that are resistant to: powdery mildew, downy mildew, Phomopsis and black rot. That is a big deal!

Research in the wine industry is economically valuable, time consuming and impacts wine consumers directly.  As consumers we do not read a lot about wine grape research, but it does impact us economical wines and with wines that taste and smell great. Here I only addressed research affecting the vine but there is research on fermentation processes, aroma profiles, wine chemistry.

Cheers!