Name for all wild vines originating in North America. According to the geographical distribution of the Vitis wild species, the subgenus Vitis subg. Vitis is divided into a European, Asian and American group. In America about 30 wild species are recognized. All have 19 pairs of chromosomes (2n = 38). The second subgenus Vitis subg. Muscadinia, which only occurs in America, has a different DNA structure with 20 chromosome pairs (2n = 40). There is only one Muscadinia species (with three varieties), whose correct name should be Muscadinia rotundifolia. However, it is usually called Vitis rotundifolia is called.
Although Muscadinia does not play a particular role in wine production, its resistance to phylloxera and nematodes makes it interesting and sought-after for breeding new varieties and rootstocks. The different chromosomes cause great problems in crossings. Strawberry aroma and foxton are a special negative characteristic of some American vines for the European palate. This is especially true for Vitis labrusca and Vitis rotundifolia. The most important American species are:
American wild species are important in viticulture because they are resistant (resistant) to diseases and pests introduced into Europe from America. Thus, many American wild species (Vitis riparia and especially Vitis cinerea) are resistant at their roots to phylloxera, which is native to America and was introduced to Europe from the middle of the 19th century. In addition, the wild species are naturally resistant to the harmful fungi powdery and downy mildew, which also originate from America. This phylloxera resistance of the roots was used against phylloxera, which spread rapidly in Europe in the last third of the 19th century. During grafting, European scions are grafted onto American rootstocks. All ungrafted, root-resistant vines are called direct carriers (self-carriers).
The solution to the mildew problem is attempted by cross-breeding. Here, fungus-resistant wild species are crossed with fungus-prone European grape varieties. The result of these interspecific crossings are so-called hybrids. These primary hybrids often show a high fungus resistance, but in many cases the unwanted fox tone of the wild species is also inherited. Many hybrids and rootstocks were bred around the turn of the century by famous French breeders like Georges Couderc (1850-1928) and Christian Oberlin (1831-1915), which is why this group of varieties is called "French hybrids":
The varieties originally crossed in America and introduced to Europe are called "American hybrids". Various American wild species are crossed with each other to produce rootstocks that are not only highly resistant to phylloxera and powdery mildew but also suitable for as many different locations and soil types as possible. America's most important historical varieties include Alden, Alexander, Blanc du Bois, Carlos, Catawba, Clinton, Concord, Delaware, Isabella, Niagara, Noah, Norton, Scuppernong, Steuben and Taylor, as well as the European Vinifera Vine Mission(Listán Prieto), the first to be introduced in America:
American vines are still cultivated in many US states today and, because of their fungus resistance, are cultivated throughout South America, Japan, Canada and in the former Eastern Bloc countries. Within the EU, the use of pure American vines for quality wines is prohibited. Further planting is also prohibited. In Europe, however, American species are used today for the new breeding of PIWI varieties (fungus-resistant). For the vine family tree, see vine systematics, as well as Asian vines and European vines.
Graphics: Norbert F. J. Tischelmayer
Grape varieties: Ursula Brühl, Doris Schneider, Julius Kühn Institute (JKI)