Attack of the clones

Many centuries ago, probably somewhere in eastern France, a farmer was walking through his vineyard of pinot noir, inspecting the progress of the ripening fruit. Then, he saw it: a cluster of grayish-purple grapes dangling among the black ones—a mutant. These are always exciting for farmers, who often refer to such genetically unique offshoots as “sports,” or “clones.” The man almost certainly tasted one of the grayish freak fruits—and he almost certainly liked it.

He clipped the branch from the vine. Planted in the ground, the shoot made roots and grew into its own vine. Several years later, perhaps, cuttings were taken from the new plant and propagated. Within decades, there were vineyards full of that dull purple grape. Its name would become pinot gris.

This process of selecting mutant branches from grapevines and propagating them into cultivated varieties of their own still occurs today, and as a result we have thousands of wine “clones,” as winemakers refer to these varieties. Clones are extremely closely related to their parent vines and usually so resemble them that they are named as subvarieties to the original, like merlot 181, chardonnay 446 and cabernet sauvignon 8.

But occasionally a mutated branch of bud wood produces a grape so different from the original that it gains an entirely new varietal name—as pinot gris did, and as pinot blanc also did after mutating off of a pinot gris vine, and as a white grape named shalistin did after appearing on a cabernet sauvignon vine in South Australia in the 1980s.

At Arrowood Vineyards & Winery in Sonoma County, winemaker Heidi von der Mehden works with numerous clones—including seven of syrah, six of cabernet sauvignon and three of grenache. Von der Mehden says understanding clones and how each differs from its cousin is critical in the vineyard. Certain clones, she explains, produce better fruit in certain locations, and each clone offers its own unique characteristics. Von der Mehden’s chardonnay vineyards, for example, include the Rued clone, Dijon 96, Dijon 95, the Robert Young clone and clone 4.

The latter is a popular, high-yielding grape. Arrowood’s vineyard manager, Brian Malone, likens clone 4 to the meat of a meal.

“All the other clones are the spices you put on top,” he said.

The chardonnay Z clone is a zesty grape whose aromatics resemble the legendary perfume-like scent of Muscat and which, used conservatively, can add elegance to a blended wine.

Clonal numbers rarely reach the front of a wine bottle, where available space is traditionally occupied by long and laborious vineyard designations, regional appellations and family names.

But Noble Vines, a winery near Monterey, is putting numbers of featured grape clones on the label. Clone number 337 is its flagship cab, 667 its pinot noir, 446 its chardonnay and 242 its sauvignon blanc—each bottle stamped boldly with the large numerals. Winemaker James Ewart says he believes customers who care increasingly about the origins of their food have particular interest in understanding clonal variations of wine grapes.

Growing certain varieties of grapes in particular regions lays the groundwork for good winemaking, Ewart adds.

“But we are further dialing in our focus and narrowing in even more specifically on the best clones of each variety for the area,” he explained.

But the term “clone” may be something of a misnomer in this context, because these mutated grape varieties are different from the vines they originated from, not identical to them, as “clone” implies. The reason it has become standard to call them clones is that none of these varieties originated from fertilized seeds (as most popular fruit varieties originally did). Rather, they all first appeared as genetically distinct shoots on existing vines and were then selected, cut and propagated asexually—that is, cloned after the offshoot has already grown.

John Preece, a geneticist and wine grape specialist with the USDA’s National Clonal Germplasm Repository near Davis, says so-called wine grape clones would best be referred to as “subclones.” Pinot gris, he explained, is a subclone of pinot noir. Ditto for cab 337, cab 4 and cab 191—all subclones within the cabernet sauvignon family. Only in and of itself is each subclone actually a clone.

The topic gets technical and confusing and, to the layman, seemingly arbitrary, and for many people there may be something appealing in the thought not so much of understanding wine but simply of drinking it.