Hybrid or crossing?

In these pages in your April issue you stated that Johanniter is a hybrid. My understanding is that hybrids, whose parents are two vitis species of which one may be vinifera, are used mainly as rootstocks, not for winemaking. Is Johanniter not a crossing? Stefano Mazzola, by email Ian D’Agata, DWWA Regional co-Chair for Italy, replies: Johanniter (originally Fr 179-68) is a hybrid developed in 1968 by multiplying Riesling with Fr 589-54 (itself the result of Seyve-Villard 12-481 and Freiburg 153-39 mating). Hybrids are also called ‘inter-specific varieties’ to avoid the stigma associated with the term ‘grape hybrid’, almost unanimously (but unfairly) associated with low-quality wine. In fact, hybrids are not only associated with rootstock material but can give very fine wine on their own, such as the underrated but lovely wines made with Seyval Blanc and the good ones made with Ravat and Vignoles.

A hybrid occurs when individuals of two different species hit it off (like Vitis vinifera and Vitis berlandieri). A crossing refers to the mating of two individuals of the same species (ie. vinifera), such as in the case of Kerner, a Riesling x Trollinger cross. Vitis vinifera members are characterised by high potential wine quality, but lower disease resistance than most of the hardier non-vinifera American or Asian grape species. The resulting hybrid is a new variety one hopes will have the quality of one parent and the hardiness of the other.

But what exactly constitutes a hybrid and a crossing can become murkier over time: if you backcross a hybrid repeatedly with a vinifera variety, the offsprings gradually become more vinifera-like. For this reason, many dislike newly created grape varieties being called hybrids, because the hybrid parent is (in the case of some new varieties at least) many generations removed from the end result.