What do you say to a person who has just told you that they study diseases of winegrapes? You want to sound interested, so maybe something like, “Oh, good. Make sure nothing happens to my wine.” What you may not realize is what a tall order that is.
Grapevines have a key trait that distinguishes them from annual crops and many tree crops – they will easily root and produce a full-sized plant from a cutting. This fact alone has important implications, but to compound the issue, their fruit possesses an extensive palette of flavors. Together, these properties have created a cycle of artificial selection, in contrast to Darwinian natural selection, that extends back by an astounding stretch. Cabernet Sauvignon, the most widely planted grapevine in the world, is a relatively recent development, having been grown from cuttings only since the 17th century. By contrast, the grapevine known in France as Mourvèdre, which is in actuality the Spanish Monastrell, had long been in cultivation before the first written mention of it by a Franciscan Friar in 1371, and apocryphal reports suggest its introduction to Spain by the Phoenicians in the pre-Christian era. These “varieties” of grapevine are not equivalent to varieties of an annual vegetable. They are not an ever-expanding family of individual plants produced from seeds that have certain marketable characteristics. Rather, a grapevine “variety” is a humongous single vine cut into myriad pieces and spread across landscapes and continents.
The reason for the durability of named vines is simple: you find something you really like, and you keep it going. Amplify that algorithm with the affirmation of millions of wine drinkers, and the result is the domination of vineyardscapes by a very few familiar “varieties” – Cabernet, Chardonnay, Merlot, Syrah, a few others – names that have come to be associated more with the characteristics found in a glass of wine than with an individual vine that germinated centuries ago, only to be kept alive using ever more advanced techniques.
There is problem with immortality, though – the rest of the world never stops. Evolutionary biologists call this the Red Queen Hypothesis. In nature, organisms find themselves among parasites and pathogens that are constantly evolving, producing individuals that are better at overcoming the defenses of their host organism. A more virulent individual, let’s say an insect, uses its new-found success to produce extra offspring, and a population of killers sets out to destroy the host and its kind. Individual host organisms, let’s say buttercups, fall one after another, but at the population level the hosts have a secret weapon, and it is the same one that the attacker had used to gain its advantage – evolution. Somewhere in the natural population there is a host individual that can keep the attacker at bay, either tolerating it or eliminating it when it attacks. This host individual and its offspring go on to repopulate the habitat where their kind had lost the battle. In short, there is a co-evolutionary arms race between a parasite and its host, and complete victory by either side is rarely seen.
Evolution is handicapped, though, without sexual reproduction. The reshuffling of genes that happens when two different individuals mate creates offspring that not only embody new combinations of genes, but in addition, harmful mutations can get shuffled out. In the case of a virus, which creates copies of itself without the sex, mistakes occurring during the cycle of replication will lead to mutations that mostly interfere with the functioning of the offspring, causing the production of perhaps millions of duds for every stronger mutant that arises. For organisms that don’t produce quite that many offspring, the best bet for evolving stronger offspring is sex.
And the connection to the Red Queen? In Through the Looking Glass, the Red Queen explains that in Looking-Glass Land everyone has to run as fast as they can just to stay in place. Species in the environment have to constantly evolve in order to merely continue living as they do in the face of changing conditions. Organisms that are prevented from evolving, such as those that have been dormant for a very long time or those that have been reproducing without sex, can find themselves hopelessly behind in the co-evolutionary arms race.
That is not to say that a grapevine propagated through cuttings does not evolve. A mutation can happen in a growing tip, leading to a whole branch with that mutation. Thoughtful grape growers have always observed that a vineyard grown up from cuttings will have vines of different quality. They find something they really like and they keep it going. The set of cuttings taken from a single vine is referred to as a clone. Institutions have had to step in and systematize the selection of clones, assigning each clone a number to keep track of its juice quality and disease susceptibility. However, the amount of genetic resources, the foundation for evolution, found within a single grapevine “variety” is very limited. Evolution can only tinker one step at a time based on what has come before. A whole new gene for resistance to the latest crippling outbreak will not arise where no precursor existed before. The viticulturists of Europe had their first hard lesson in this limitation in the latter nineteenth century.
North America is home to various native species of grape, which have evolved independently from the Old World’s winegrape. They host a particular set of insects and microbes with which they have engaged in their own co-evolutionary arms races. After millions of years of separation, samples of these North American natives were brought to Europe by collectors, along with an inconspicuous hitchhiker, phylloxera. Phylloxera is something like an aphid that feeds on grapevine roots. The North American vines had evolved defenses to keep phylloxera from overrunning their root systems, but the European winegrapes not only lacked experience with phylloxera, they had a stunted range of genetic resources upon which evolution could work.
One of the tenets of Darwinian evolution is that unfit individuals must have their reproduction reduced, an outcome often accomplished by the individual’s untimely demise. All the ancient heirloom grapevines began to quickly succumb to the invader. Wine production dropped precipitously. The only hope for the besieged vines came from a mutualistic species that had co-evolved with them – humans. From the human practice of horticulture came the ability to switch the roots on the winegrapes with roots from North American natives through grafting. The stitched-together plant would then have roots that resisted infestation and fruits that tickled European palates in just the right spot. Vast areas were re-planted with grafted grapes, and the ancient vines were saved.
And then the cycle repeated itself. With all those American vines embarking for Europe to be turned into rootstocks, another hitchhiker was able to make its way across the Atlantic. This time the vines’ leaves and other green tissues were the target, and the organism’s appearance on the surface of the tissues was the source of its name, downy mildew. Again the European vines had no resistance, again wine production dropped, and again human ingenuity came up with a solution. Now, besides being grafted onto resistant rootstocks, the European vines would have to be sprayed annually with a mixture of copper sulfate and lime, the so-called Bordeaux mixture.
As the immortal vines with elegant names are kept alive by human intervention, they rack up additional attackers, from powdery mildew to mealybugs to viruses to other fungi to bacteria to leafhoppers and more. According to the late W. Douglas Gubler, an international authority on grapevine diseases, grapes are the hardest crop to grow organically. The asset of easy vegetative propagation became a liability in the long run. Can the vines now be saved with lots of good sex? Unfortunately it is not so simple.
The phylloxera crisis in France, which was eventually resolved with rootstocks, also had prompted a second line of investigation into overcoming the plague: French vines were mated with American vines to produce offspring with a higher level of resistance to phylloxera than the French parent vines. Vines with genetic resistance would require less human intervention, and they might even have a shot at continuing to evolve stronger resistance. The problem was that French wine drinkers noticed what they considered off-flavors in the resulting fermented product. This observation became a stigma attached to any cross-bred grapes, and when a wine glut hit years later and production had to be cut back, the low-hanging fruit was vines with American parentage, which were demonized with a propaganda campaign and eventually banned. In 1979 France convinced the entire European Union to take up the ban. Thus the tool of breeding for resistance was removed by law from the toolbox of plant protective practices.
The story was not much better in America. The pioneering vintner Robert Mondavi found that he could distinguish his products from his competitors by listing the name of the grapevine on the wine bottle, creating a market for varietal wines. A bottle labeled “Cabernet Sauvignon” would fetch a premium over a bottle labeled “red”. If Cabernet Sauvignon were bred with a grapevine resistant to powdery mildew, though, the offspring would not be Cabernet Sauvignon, and no amount of mating the successive offspring with the original Cabernet Sauvignon would allow a descendant to take the name of its prestigious French ancestor. A vine with 98% genes of Cabernet Sauvignon is a nobody. The market would doom the creation of resistant grapevines.
Fortunately, the wine industry became enlightened on the need to use breeding to create new vines resistant not only to diseases and pests, but also climate change. The ban on breeding in Europe was lifted in 2021. Germany benefited from a breeding program that was running during the French prohibition, but now even French researchers are have joined the effort.
Unfortunately, grapevine breeding is an arduous process. A vine grown from seed will normally take three years to produce berries. The first generation of offspring from a cross will necessarily have to be bred with the winegrape parent in order to produce another generation with more desirable grape qualities, and the process likely will take multiple rounds. Each round must be accompanied by testing for disease resistance and other horticultural qualities. The juice of the berries from a resistant vine might seem good, but fermentation can create unpredictable compounds with possible undesirable flavors, thus necessitating additional years for flavor testing. Once a single vine with all the necessary qualities is produced, it must be propagated out for nursery stock. In California, Dr. Andrew Walker was able to shorten grapevine generation time through clever breeding and care, and to test for resistance quickly using DNA technology. This way it took him only 20 years to develop five new “varieties” with resistance to the southern California scourge of Pierce’s Disease, as well as to phylloxera and nematodes, that produce wines that evoke the qualities of the most popular varietals.
Will wine consumers accept the new varietals? Time will tell, but there is another obstacle. A few years ago it became apparent that the area planted to vineyards in California was too much to match the demand for wine. All the grower costs, from land tenure to machinery to irrigation to agrochemicals to labor to marketing, not to mention the years of growth before the first harvest, require a certain minimum price of the resulting wine to repay. Without the demand to match the supply, prices can drop below that minimum, and if growers can’t cut back on expenses, they will fail.
Gluts and price crashes are well known with agricultural products. When the price of a product is good, growers plant more of it in order to make a bigger profit, and more growers join in. Given the lag between planting and marketing, the glut and the price crash are not apparent until the growers have already invested their money. Winegrapes in particular seemed like a profitable investment. New millionaires created by Seattle’s high tech sector, confident in their management abilities, have filled Washington’s Yakima Valley with new vineyards, apparently before consulting with experts like Dr. Gubler. To their surprise, their investment has soured due to the extensive diseases that have become apparent.
A more insidious threat to sustainability in the grape industry comes from an unexpected player: the Harvard endowment. With more money at its disposal than any university in history, Harvard is hard-pressed to find ways to invest that will keep the money growing. Vineyards have become one more item in their portfolio. In one instance, they have filled southern California’s remote Cuyama Valley with vineyards of Pinot Noir. Cuyama Valley is a hot dry inland terrain with a limited groundwater supply. Pinot Noir is a cool-loving vine known for finickiness in yielding a quality wine. Harvard’s plan is to get the vineyards producing and then sell them for a profit. In the meantime they are pumping the aquifer dry, threatening the livelihoods of the valley’s small farmers and ranchers, not to mention the future growth of the grapevines themselves. As for finding a buyer, it will have to be someone with more money and even less grape-growing smarts.
Hand in hand with the expansion of winegrape production has been the consolidation of the industry. E. & J. Gallo, the company that invented cheap wine, has been on a years-long buying spree and now owns over a hundred brands, including some from the high-end Napa Valley. Robert Mondavi’s winery is now in the hands of spirits conglomerate Constellation. The top three US wine corporations account for over half of sales of domestic wine. Although consolidation in the wine industry is partly a function of consolidation of distributors and retailers, current market conditions are making many smaller wineries anxious to sell their business. Once a label belongs to a marketing behemoth, the management can cut costs in response to falling retail prices by lowering quality of established labels without lowering price. Job security of employees becomes rickety. The exigencies to make up for a declining profit rate by boosting volume can also lead to a homogenization of products. An observation that a visiting Brazilian once shared with me about US retail is that there is a large variety on the shelf, but it’s the same variety in all the stores. Meanwhile, the stronger competitive position of the large companies makes business an even greater struggle for the small producers.
What is a concerned wine-drinker to do? A legacy of unfortunate decisions has to a large extent tied the individual consumer’s hands. You can question established concepts such as “variety” or “vineyard” or “consumer demand”, but you’re not in a position to use your dollars to bring back lost genetic diversity, break up monocultural landscapes of genetically identical vines, or reverse corporate conglomeration. Perhaps you could start by seeking out small producers with direct-to-consumer marketing, the ones who are most at risk from market fluctuations and whose small volume makes them invisible to large distributors and retailers. You could educate yourself on the new breeds of winegrape that incorporate resistance to problem diseases and pests and give the resulting wines a try. You could branch out into other types of beverages. You could be philosophical about the whole situation and embrace the impermanence of your favorite Cabernet label. The bigger issues are systemic, though, and require actions beyond the individual level. It would take a movement to change the acceptability of cross-bred grapes, to fight conglomeration, or to tamp down unsustainable expectations of return on investment.
So don’t leave the fate of your wine to the professionals. You have a role to play. Wine drinkers unite!