Genetic Study of the Grape Reveals Weakness in Our Wine Supply
Shrink a grape, and you get a raisin. Shrink the grape genetic tree, and you get a looming disaster for oenophiles. That’s according to scientists who discovered that our cultivated wine grapes are more closely related than previously thought.
Sean Myles, a researcher at Stanford University, created a gene chip for common grape cultivars using genomes from the Department of Agriculture. In his study, published in the Proceedings of the National Academy of Sciences, he reveals that 75 percent of our 583 kinds of cultivated grapes are either parents, children, or siblings of each other.
â€œPreviously people thought there were several different families of grape,â€ Dr. Myles said. â€œNow weâ€™ve found that all those families are interconnected and in essence thereâ€™s just one large family.â€ [New York Times]
In this grape-world equivalent of the Jerry Spring Show, wines like merlot, pinot noir, and chardonnay are all interrelated in one big incestuous mash-up. And it’s the cultivators who are partly to blame.
The reason is obvious in retrospect. Vines can be propagated by breaking off a shoot and sticking it in the ground, or onto existing rootstock. The method gives uniform crops, and most growers have evidently used it for thousands of years…. The result is that cultivated grapes remain closely related to wild grapes, apart from a few improvements in berry size and sugar content, and a bunch of new colors favored by plant breeders. [New York Times]
Another reason is that wine connoisseurs cherish their distinctive varieties, and wine flavors and carefully guarded varietal names change once you start crossbreeding grapes–something that’s traditionally been avoided. But the consequences of holding onto our pure-bred merlots and cabernet sauvignons is that it makes these varieties more susceptible to insect pests, resulting in a wino arms race, with vintners having to use evermore potent pesticides.
This situation cannot be sustained indefinitely, in Dr. Mylesâ€™s view. â€œSomeday, regulatory agencies are going to say â€˜No more,â€™Â â€ he said. â€œEuropeans are gearing up for the day, which will come earlier there than in the U.S., for laws that reduce the amount of spray you can put on grapes.â€ [New York Times]
Before you start stockpiling wines for the future, you should note that there are a few paths wine growers can take, ranging from traditional interbreeding between pest-susceptible varieties and more robust ones to genetic modification.
M. Andrew Walker, an expert grape breeder at the University of California, Davis, said that there are â€œample pest- and disease-resistance genesâ€ in the grapevine genus, which has about 60 species, but few in Vitis vinifera, the particular species to which wine and table grapes belong. He agreed that it will be necessary to introduce many of these genes from other Vitis species into vinifera. â€œConsumers and wine promoters will have to move beyond dependence on traditional vinifera varieties,â€ Dr. Walker said. [New York Times]
And if you’re an entrepreneur, the future of wine looks even brighter.
This is good news for breeders seeking to develop cultivars that are resistant to disease, says Myles, as so few of the potential crosses have actually been made. [New Scientist]
Image: flickr /wickenden