Grape Clones: Nature Versus Nurture

By Sandon Purcell

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Sandy Purcell, Molecular Biologist, Financial Advisor and Chevalier

 

 

 

Years ago, when I was an undergraduate at U.C. San Diego (and aspiring Basketball player), I remember reading about the legendary Chicago Bulls player,Michael Jordan. Mr. Jordan, it turns out, was 6’- 6”, and 195 pounds, which also happened to be exactly my size and weight. If we were anatomically almost identical, and both worked very hard at our sport, why were our outcomes so completely different? While Mr. Jordan effortlessly plied his trade above the rim, gracefully swooping in for highlight-reel dunks, earning scores of millions, and six NBA championships, I scrapped beneath the rim, with nothing but bumps and bruises to show for my efforts. What was the difference? Quite simply;   Genetics.”

 

 

From the inception of life on planet Earth, Nature has been utilizing genetics to create the vast biodiversity of life we see today. Plants and animals are constantly being “tweaked” through various minute mutations in their genetic codes. Each of these mutations creates a very subtle difference in a species (most are invisible to the naked eye). However, these subtle differences are extremely important, as they render a species more (or less) fit for survival and propagation within a constantly changing environment. As agrarian societies began to understand this ability to propagate desirable characteristics within a species, they sought to “engineer” more of what they were looking for. Plants were crossed to produce seeds that would yield larger, heartier (and perhaps tastier) produce. Animals were selectively bred that would yield stronger horses and cattle to pull the plow, sheep with superior wool etc

In the 20th Century, advances in the field of Genetics, and Molecular Biology ushered in a new era of possibilities for “engineering” change within plants and animals. Recombinant DNA Technology pioneered at Stanford University in the 1970’s enabled scientists to “splice” desired genes into DNA. Cloning technology was developed originally to amplify small quantities of altered DNA into large amounts. Eventually, techniques were developed for cellular cloning, and after that, organism cloning which is basically creating a new, multicellular organism (or more often, organisms) genetically identical to the original.

 The term “clone” is used in horticulture to refer to descendants of a single plant which were produced by vegetative (asexual) reproduction. Many horticultural plant cultivars (A cultivar is a plant or grouping of plants selected for desirable characteristics that can be maintained by propagation) are clones, having been derived from a single individual, multiplied by some process other than sexual reproduction. As an example, some European cultivars of grapes represent clones that have been propagated for over two millennia.

romanee contiOn a small plot of land (4.4 acres), in the village of Vosne-Romanee, in the heart of Burgundy, France, lie the vineyards of Domaine de la Romanee-Conti (abbreviated DRC). From this modest parcel of land, some of the most sought after wine in the world is produced. Cases of prime vintages have sold at auction for more than $200,000. While it is true that the iron-rich limestone soils of this vineyard are ideal, it is also true that within a very short distance, on soil of similar makeup, is produced some rather ordinary Village wine. Again, if we are to assume that the soil, iron-rich limestone on a base of rock and marl is quite similar, and the grape (Pinot Noir) and weather are the about the same, how is it that wines of such dramatically different character and quality are produced?  Genetics played a central role!

California’s wine industry is based on a single species of grape, Vitis vinifera L. !

The genetic diversity within this species accounts for the wide variation in the size, shape, color, flavor, and yield of fruit that different grape cultivars may have. Over time, people selected grapes with

Grafting

Grafting

favorable traits and propagated them in vineyards. Grapes propagated from cuttings or by grafting are literally clones of the mother vine and thus display identical traits. This is how many thousands of grapevine varieties have been selected, named, and cultivated around the world .

Winemakers now have an incredible landscape of choices available to them when selecting grape clones for their Winery. Clone choice is only one of many important decisions when establishing a vineyard. Variety choice, site climate, soil type, vineyard design (spacing, trellising, and rootstock), and annual cultural practices(irrigation, canopy management, and crop load) will impact final wine quality far more profoundly than clonal choice.

 

There is no such thing as a “perfect” clone that will overcome a grower’s inappropriate site selection or poor management decisions. There is no one “best” clone. A clone’s suitability for a particular vineyard depends on the target wine market and desired wine style, as well as the site and vineyard conditions noted above. High-yielding clones are just as appropriate for low-cost wines as low-yielding clones are for high-value wines. When the retail bottle price for a variety can vary by more than 20-fold, there is clearly room for more than one clone.

Thus, the term “best” is value-laden and must be carefully defined by the producer’s goals .

 

Just as Michael Jordan, blessed as he was with great genetic talent, needed to work tirelessly in the gym, guided by skilled coaches and trainers to maximize those talents and achieve greatness, winemakers must take clones of similar genetic “talent”, and through great soil, weather, and skilled winemaking produce wines of great character and distinction.

 

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