Crossed (wine)

The propagation of grapevines is an important consideration in commercial viticulture and winemaking. Grapevines, most of which belong to the Vitis vinifera family, produce one crop of fruit each growing season with a limited life span for individual vines. While some centenarian old vine examples of grape varieties exist, most grapevines are between the ages of 10 and 30 years. As vineyard owners seek to replant their vines, a number of techniques are available which may include planting a new cutting that has been selected by either clonal or mass (massal) selection. Vines can also be propagated by grafting a new plant vine upon existing or by layering one of the canes of an existing vine into the ground next to the vine and severing the connection when the new vine develops its own root system.

In commercial viticulture, grapevines are rarely propagated from seedlings as each seed contains unique genetic information from its two parent varieties (the flowering parent and the parent that provided the pollen that fertilized the flower) and would, theoretically, be a different variety than either parent. This would be true even if two hermaphroditic vine varieties, such as Chardonnay, cross pollinated each other. While the grape clusters that would arise from the pollination would be considered Chardonnay any vines that sprang from one of the seeds of the grape berries would be considered a distinct variety other than Chardonnay. It is for this reason that grapevines are usually propagated from cuttings while grape breeders will utilize seedlings to come up with new grape varieties including crossings that include parents of two varieties within the same species (such as Cabernet Sauvignon which is a crossing of the Vitis vinifera varieties Cabernet Franc and Sauvignon blanc) or hybrid grape varieties which include parents from two different Vitis species such as the Armagnac grape Baco blanc, which was propagated from the vinifera grape Folle blanche and the Vitis labrusca variety Noah.

...
Wikipedia