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23-08-2019 13:02

Over hybriden en kruisingen

 

Druiventaal verduidelijkt

 

Ook in kringen van wijnexperts is er verwarring over druiven-terminologie. Wat is nu precies een hybride? Wat verstaan we onder een kruising? Wat zijn klonen of mutaties? Of een nieuwe variëteit? Tom Jarvis legt het uit in een duidelijk artikel op Wine-Searcher. Behalve de Vitis Vinifera kennen we nog andere ‘stam’- soorten. Die zijn te vinden in de Verenigde Staten, China en Siberië.

 

 

“There are around thought to be as many as 10,000 varieties of wine-producing grapevines, of which around 1500 are used on a commercial scale. Vitis vinifera is the vine species from which the vast majority of quality wine grapes belong.
However, there are actually 60 or so species of vine. Apart from Vitis vinifera, half a dozen or so are usually identified as being of interest to viticulturalists. Those native to North America are V. aestivalis, V. rupestris, V. riparia (aka V. vulpine, the riverbank grape) and V. labrusca. Vitis rotundifolia – responsible for the muscadines – is native to the southern half of the US;. Vitis amurensis, the Asiatic grape species, originates from Siberia and China.

 

Grape variety

A new grape variety is created whenever a vine is pollinated by another, and a grape seed grows into a plant – most modern wine grape varieties are hermaphrodites. A cutting from a Chardonnay vine produces another Chardonnay plant. But if you grow a Chardonnay seed, the plant is something else. If the grapegrowing industry intentionally grew vines from seed, rather than propagated cuttings, the number of grape varieties would be unquantifiable. The circumstances in which many grape varieties were created – spontaneous, intentional or otherwise – are not known. In a regimented modern vineyard, accidental births are less likely.

 

Clones and mutations

A viticultural clone, strictly speaking, is a vine that has been selected from an identical mother vine. This can be done deliberately to reproduce positive characteristics seen in the mother vine. All clones are considered part of the same variety, though a mother vine may have mutated to some degree in order to be noticed.

Mutation is a constant throughout the natural history of grapevines. A vineyard might be planted with thousands of vines propagated from the same variety, but they are not subject to identical conditions. Over time mutations will take place, genetic differences will be detectable and the vines will show different characteristics.

Over time and repeated propagations of different vines from this vineyard, grapes with the same general DNA profile can end up being regarded as distinct varieties. Sometimes mutation will change the color of the grape, or make other substantial changes. However they are correctly described as the same variety.

The noble grape variety most often associated with clonal variation is Pinot Noir. The variety is genetically unstable and shows a distinct propensity to mutate. As a consequence there are hundreds of different clones worldwide. In France alone more than 40 are officially recognized.

It is scientifically more accurate to refer to the Pinot group, rather than identify Pinot Gris, Pinot Blanc and Pinot Noir as distinct varieties – even though shops and wineries will always make the distinction. This is because they have identical general DNA profiles. Pinot Meunier is a chimera – a mutation with two tissue layers of different genetic material. Pinot Moure and Pinot Teinturier are also close genetic relations.

Sangiovese also has a variety of established clones, including Brunello in Montalcino. Often winemakers will use one or more clones to add complexity to wines.

 

Crossings

A crossing is a new grape variety created by the cross-pollination of two varieties from the same species. Without an adjective such as "spontaneous", the term usually infers creation at a nursery or research institute, usually with the intention of combining positive characteristics of both parents.

The majority of those we see made into wines are, of course, examples of vitis vinifera x vitis vinifera. Pinotage is a well-known South African example, created from Pinot Noir and Cinsaut in 1925 by Abraham Perold. However, the results were planted in his garden and forgotten, and only planted commercially in 1943.

 

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