Hybrid grapes are grape varieties that are the product of a crossing of two or more Vitis species. This is in contrast to crossings between grape varieties of the same species, typically Vitis vinifera, the European grapevine. Hybrid grapes are also referred to as inter-species crossings or "Modern Varieties." Due to their often excellent tolerance to powdery mildew, other fungal diseases, nematodes, and phylloxera, hybrid varieties have, to some extent, become a renewed focus for European breeding programs. The recently developed varieties (Rondo and Regent) are examples of newer hybrid grape varieties for European viticulturalists. Several North American breeding programs, such as those at Cornell and the University of Minnesota, focus exclusively on hybrid grapes, with active and successful programs, having created hundreds if not thousands of new varieties.
Hybrid varieties exhibit a mix of traits from their European, Asiatic, and North American parentage. Those varieties which derive from Vitis labrusca parentage (such as those still used in the production of Austrian Uhudler) have a strong "candied" or "wild strawberry" aroma, while those that derive from Vitis riparia often have a herbaceous nose with flavours reminiscent of black currants. Most hybrid grape varieties struggle to produce adequate tannin for red wine production, and usually display a level of acidity that exceeds what consumers of wines produced from Vitis vinifera are accustomed to. These attributes proved unpopular in Europe, and were among the factors that led to the prohibition of the commercial growth of hybrid vines in many countries in Europe.
During the first half of the 20th century, various breeding programs were developed in an attempt to deal with the consequences of the Phylloxera louse, which was responsible for the destruction of European vineyards from 1863 onwards. After extensive attempts, grafting European varieties onto North American rootstock proved to be the most successful method of dealing with the problem.
However, hybrid grape varieties were introduced as a solution to many of the viticultural problems of shorter-season, cooler and more humid wine regions, such as those in the northeast and Pacific Northwest of North America. From the 1950s onwards, grape varieties such as De Chaunac, Baco noir, Marechal Foch, Vidal, etc. have been a staple of the wine industries in Ontario, New York, Pennsylvania, etc. Only since the 1970s and 1980s have vinifera varieties begun to displace hybrid grapes in this area. Even in those areas where Vitis vinifera now predominates, hybrid varieties still have "cult following" with some wine consumers. Furthermore, in some cases hybrid grapes are used to produce unique and exceptional products; for example, ice wine produced from Vidal blanc or Vignoles in Ontario and New York. Hybrid grapes are expanding in traditional vinifera wine regions, because they can be easier to grow and can ripen earlier than vinifera (which reduces bird predation and reduces the risk of fruit hanging into the Fall rains), and because they typically have much more disease resistance (thereby requiring less spraying, which lessens tractor fuel usage and the volume of spray applications). Therefore, hybrid grapes are considered a "Green" alternative to vinifera grapes.
The best-known grape species in reference to viticulture include:
While rare, interspecific hybrid vines can result in the wild from cross-pollination. Due to the abundance of American Vitis species one finds such natural hybrid vines on the American continent. The majority of the well-known hybrid vines however, have been artificially created. The earliest named hybrid in America was the Alexander grape, discovered around 1740 near a vineyard planted for William Penn along the Schuylkill.