Definition: DNA and grape varieties

Press release from the Swiss National Science Foundation (20 June 2006).

The rich diversity of Swiss vines

Genetic profiles of grape varieties on the Internet

Biologists at the University of Neuchâtel have just made the genetic profiles of all grape varieties grown in Switzerland available on the Internet. This database, the "Swiss Vitis Microsatellite Database", was created as part of the National Centre of Competence in Research "Plant Survival" programme, with financial support from the State Secretariat for Education and Research.

The result of work carried out by researchers from the National Centre of Competence in Research "Plant Survival", the Swiss Vitis Microsatellite Database (SVMD) is now available on the Internet. It shows the rich diversity of Swiss vines.

"With more than a hundred varieties recorded, Switzerland certainly holds the world record for the number of grape varieties grown in such a small wine-growing area, approximately 15,000 hectares," says José Vouillamoz (photo) at the end of this work carried out in collaboration with Claire Arnold (photo), a specialist in wild vines. The researchers identified 125 grape varieties currently cultivated in Switzerland, including 103 Vitis vinifera (wine grape) varieties. They also counted 32 individual European wild vines in Valais.

Genetic fingerprints

There are still considerable inequalities when it comes to the distribution of these different varieties. Eighty per cent of these 15,000 hectares are covered by just four grape varieties: Chasselas, Pinot, Gamay and Merlot. Only Chasselas is a regional variety from the Lake Geneva area, the other three having been imported from France. "The abundance of grape varieties cultivated in Switzerland would allow for greater diversification of wine products, provided that we are willing to reduce the omnipresence of these four varieties," comments José Vouillamoz. He also has a personal database of nearly 2,000 genetic profiles of vines from around the world.

Since launching their project last autumn, Claire Arnold and her colleague have processed 582 DNA samples, 175 of which were analysed by Andrea Frei at the Agroscope research station in Wädenswil. The analysis involves taking DNA samples from very young leaves approximately one to two centimetres long, then extracting genetic fingerprints that allow for detailed comparisons, such as the ability to detect synonyms. For example, a specimen named Seidentraube in Wädenswil was found to be identical to Lignan Blanc from the University of California, Davis.

The majority of the vines were provided by Agroscope research stations, with an additional 58 donations from private collectors and 88 specimens donated by individuals, professional winegrowers and amateurs. As the researchers expected, a significant proportion of the DNA analysed from private winegrowers belongs to interspecific grape varieties, i.e. crosses between American vines (several species of Vitis) and European vines (a single species: Vitis vinifera). In the SVMD, this category concerns 22 genetic profiles, found mainly in Ticino. José Vouillamoz and Claire Arnold ultimately encountered only two cases, from Valais, whose variety they were unable to determine. However, it cannot be ruled out that these are simply spontaneous crosses between two grape varieties that developed in the vineyard.

Preservation of traditional grape varieties

This work raises the question of whether it is worthwhile to cultivate all these different grape varieties in Switzerland. Of course, local specialities such as Amigne de Vétroz and Completer des Grisons must be preserved and protected at all costs, according to the two researchers. On the other hand, grape varieties recently introduced from abroad, such as Spanish Mourvèdre or Sicilian Nero d'Avola, or interspecific varieties such as Noah and Clinton, are of little interest to Swiss vineyards. The focus should be on traditional or indigenous grape varieties before testing foreign varieties whose behaviour in Switzerland is unknown. In addition, new (intraspecific) crosses, such as Gamaret and Garanoir, developed at Agroscope research stations, offer interesting prospects, particularly due to their increased resistance to disease.

The implementation of the SVMD was motivated by Switzerland's participation in the European COST 858 vine project, whose main objective is to improve knowledge of the biological phenomena involved in grape ripening and defence against disease and drought. The Swiss database will also provide a useful reference tool for all foreign laboratories, as it contains a large number of grape varieties grown throughout the world.

Address of the Swiss Vitis Microsatellite Database:

http://www.unine.ch/nccr/svmd

For further information:

University of Neuchâtel

NCCR Plant Survival

Rue Emile-Argand 11

CH-2009 Neuchâtel

Dr Claire Arnold (photo)

e-mail: claire.arnold@unine.ch

tel.: +41 32 71825 03

Dr José Vouillamoz (photo)

e-mail: jose.vouillamoz@unine.ch

Tel: +41 27 322 71 65 or +41 79 299 49 40