Since man domesticated grapevines, he has manipulated plants for improved quantity and quality. Site selection, spacing, fertilization, tilling, pruning, irrigation, grafting rootstocks, selection for traits like pest and disease resistance and the isolation and propagation of plants with the best performance (mass selection or Selection Massale) all have been effectively used.
Cloning is the most efficient way of propagating grapevines of the same genetic material and specific performance characteristics. By taking vine cuttings from a host plant over time, rooting them and planting a site, genetic material of that vineyard will all be the same.
Most simply, a clone is a cutting from a vine that contains the same DNA as the mother plant. For example, Chardonnay is a variety. Within the Chardonnay variety there are prime cool climate clones (Dijon clones from Burgundy) and those from other sources (California’s Wente and Mount Eden clones, for example).
In cool climates, clones are chosen to achieve sufficient flavor and ripeness levels within a shortened growing season. For hot climes, complexity and retained acidity are the focus. The advantage to planting a specific clone is that the fruit all ripens at the same time with consistent flavor and component levels (sugar, acidity, tannin, extract….).
Due to their specific genetic makeup, clones are propagated and certified by vine nurseries. Through certification and records a vine’s genetic traits can be tested to determine its clone, and then can be purchased by growers looking for particular growing and fruit traits.
There are some winegrowers who believe that such a vineyard makes less complex wines. There are also concerns that vines of one DNA type might be similarly susceptible to pests and diseases. This is why many vineyards contain several clonal selections, for longevity of the vines and complexity of flavor in the final wine.