What is a grape variety? excerpt from The evolution of wine grape varieties Arunda 83 Rebsaft Dr José Vouillamoz, Switzerland

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1 What is a grape variety? excerpt from The evolution of wine grape varieties Arunda 83 Rebsaft Dr José Vouillamoz, Switzerland Throughout the evolutionary history of the grapevine, every single grape variety is the result of a single vine grown from a single seed, and this seed is the result of a sexual event that took place between two parent varieties (Figure 5). Several parameters have to be fulfilled for the spontaneous birth of a new grape variety: a flower in a grape bunch has to be fertilized for a berry to be formed the bunch must not be harvested the berry must fall on the ground or be eaten and carried away by an animal the pip must germinate and grow into a seedling the seedlingmust not be dug up the plantlet has to survive for at least three year to bear fruits and to be identified by a human eye as an interesting grapevine the plantlet has to be propagated vegetatively for all its lifespan Until the end of the 19 th century, all the vineyards in the Ancient World were intermixed with several grape varieties planted without real structure, so that crossings between distinct varieties could happen all the time and new vines were free to grow. This spontaneous birth of new varieties has become almost impossible in modern, regimented, monovarietal vineyards, where self-pollination is far more common and where every new plantlet would be torn out. As a consequence, the natural evolution of grape varieties has almost come to a dead end, and since the 19 th century it was replaced by artificial crossings made in breeding research centres. Figure 5. How does a new grape variety appear? Every grape variety is the result of sexual reproduction.a grape variety is defined as the group of morphologically distinct clones developed during vegetative propagation via cuttings and derived from a single seed born from two parent varieties.

2 When one of the billiards of grape pips produced by selfing every year on the planet is planted, the seedling represents a new and distinct variety that is highly consanguineous with the mother plant (inbreeding), which is why selfing has never been favoured by human hands, simply because the resulting plants are usually degenerative and more susceptible to diseases. The enormous genetic diversity observed among grape varieties (Aradhya et al. 2003; Cipriani et al. 2010; Myles et al. 2011)sounds like evidence that cross-fertilization has prevailed for the origins of the ca in existence today, with the combination of distinct genomes leading to more distinctive and interesting new varieties thanks to the apparition of new traits. Additional new traits may then appear as a result of mutations. Mutations Once a new variety has been selected, it is vegetatively propagated by cuttings or layering in order to maintain the desired morphological and organoleptical traits. At each cell division during plant growth, errors are likely to occur when DNA is replicated: these errors are spontaneous mutations. The vast majority of these mutations affect non-coding portions of DNA (over 90% of the DNA of higher organisms has no known biological function; also referred to as "junk DNA") and have no effect on the plant. The mutation rate in coding DNA (genes) of higher organisms is roughly one mutation per 300 cell divisions (Drake et al. 1998). After decades or centuries of vegetative propagation, each grapevine plant harbors hundreds of thousands of new mutations. Most of them will go unnoticed, and only those affecting berry size or colour, cluster size, leaf shape, ripening period or any other effetthat is spectacular to the human eye will be noticed and propagated separately. However, as spectacular as the morphological change can be, the accumulation of mutations over time do not result in new grape varieties, these are only clones of the variety. Therefore, a grape variety can be defined as a group of morphologically distinct clones originating from a single initial seed, which was sexually produced by a father variety fertilizing a mother variety (Boursiquot and This 1999) (Figure 5). The older a variety is, the higher will be the number of its clones. For example, Pinot has hundreds of clones simply because it is very old, and not because it would be more prone to mutations than other varieties, as it has been mistakenly suggested (Bernard 1995). Pinot Noir (black-berried), Pinot Gris (grey- or pink-berried) and Pinot Blanc (whiteberried) are often considered as distinct varieties, but they are nothing else than skin colour variations of the same variety, as a result of a particular type of mutation: the insertion of a transposon (or jumping gene ) in the DNA region that regulates a gene responsible for anthocyans synthesis (called VvmybA1) causes the loss of black berry skin colour (This et al. 2007). Pinot Noir, Pinot Gris and Pinot Blanc are undistinguishable by DNA profiling, and are therefore considered one and the same variety. Founder varieties Since every individual (grape, human, etc.) receives half of its DNA from his father and half from his mother, DNA profiling is also useful for the reconstruction of parentages (paternity test) and pedigrees, which requires between 20 to 60 microsatellites to be analysed for statistical confidence. The first successful paternity test was realised in 1997 when Professor Carole Meredith and her doctoral student John Bowers at the University of California in Davis have shown that Sauvignon, the noble Bordeaux grape variety, was most likely derived from a natural cross between Franc and Sauvignon Blanc (Bowers and Meredith 1997) (Table 1).This came as a big surprise to the wine world. Since then, the study of the relationships between grape varieties has entered the new era of historical genetics, with the discovery of several subsequent and unexpected parentages (see Sefc et al for an overview). Uniparental parentages were then successfully studied: when one of the parents is missing (ie not yet analysed or extinct), it is still possible to detect parentoffspring relationships between two varieties when they share at least one value at each microsatellite, which has been shown to require a minimum of 50 to 60 microsatellites to be statistically proven (Vouillamoz and Grando 2006). However, it is not possible to determine which one is the parent and which one is the progeny, simply because the age of a variety is unknown. When both parents are missing, the use of a recently developed probabilistic approach has

3 detected unsuspected brothers, half-siblings, grandparents or grandchildren in the complex pedigree of Syrah (Vouillamoz and Grando 2006). Table 1. In 1997, Sauvignon was unexpectedly found to be the natural progeny of Franc and Sauvignon Blanc.At each of the 32 microsatellite that were analysed, Sauvignon obtained one value from its father ( Franc) and one value from its mother (Sauvignon Blanc). Franc Sauvignon Sauvignon Blanc Microsatellite Microsatellite Microsatellite Microsatellite Microsatellite Microsatellite etc. Table 2. Most grape varieties cultivated today in western Europe seem to descend from a small group of founder varieties through spontenous crossings. France Italy Croatia Spain Alps Founder varieties Pinot, Gouais Blanc, Garganega, Nebbiolo, Tribidrag Cayetana Blanca Rèze Savagnin, Teroldego, Luglienga Franc, Bianca, Mondeuse MuscatBlanc Noire à PetitsGrains

4 After 15 years of pedigrees reconstruction, it appears that a limited number of founder grape varieties gave birth by spontaneous crossings to a large number of progenies that represent the grape germplasmof Western Europe today (Table 2). Franc is one of them: besides having given birth to Sauvignon, it is also the parent of two other Bordeaux varieties, Merlot and Carmenère (today more widespread in Chile and China than in its homeland). But the most important founder variety seems to be Gouais Blanc, an almost forgotten grape that used to be widespread all over western Europe in the Middle Ages : it is the parent of no less than 80 grape varieties, like Riesling from Germany, Chardonnay and Gamay from Burgundy, Furmint from Hungary, Blaufränkisch from Austria, etc. Savagnin, known under different names and forms (Traminer, Gewürztraminer, GelberTraminer, Savagnin Rose, etc.), has also significantly influenced the western European viticulture by giving birth to varieties as diverse as Sauvignon Blanc and Chenin Blanc from the Loire, Verdelho from Madeira, GrünerVeltliner from Austria, etc. Pinot, without colour distinction, comes not far behind, having engendered Chardonnay and Gamay in Burgundy, and possibly Savagnin itself. There are several other founder varieties in western Europe (Table 2), and future studies on the pedigrees of grape varieties from all over the Ancient World will undoubtedly identify many other founder varieties for each region, providing a much better understanding of grape varieties evolution. Photo: The author José Vouillamoz (right) together with Patrick McGovern (left) infront of a wild grapewine on the shore of the headwaters of the Tigris River in south eastern Turkey (photo: Ali Ergül) References whole article Aradhya MK, Dangl GS, Prins BH, Boursiquot JM, Walker MA, Meredith CP, Simon CJ (2003) Genetic structure and differentiation in cultivated grape, Vitis vinifera L. Genetical Research 81: Arnold C, Gillet F, Gobat J-M (1998) Situation de la vigne sauvage Vitis vinifera ssp. sylvestris en Europe. Vitis 37: Barnard H, Dooley AN, Areshian G, Gasparyan B, Faull K (2011) Chemical evidence for wine production around 4000 BCE in the Late Chalcolithic Near Eastern highlands Journal of Archaeological Science 38: Bernard R (1995) Aspects of clonal selection in Burgundy. American Journal of Enology and Viticulture Proceedings of the international symposium on clonal selection, June 1995, Portland, Oregon:52-59 Boursiquot J-M, This P (1999) Essai de définition du cépage. Le Progrès Agricole et Viticole 116: Bowers JE, Meredith CP (1997) The parentage of a classic wine grape, Sauvignon. Nature Genetics 16:84-87 Cipriani G, Spadotto A, Jurman I, Di Gaspero G, Crespan M, Meneghetti S, Frare E, VIgnani R, Cresti M, Morgante M, Pezzotti M, Pe E, Policriti A, Testolin R (2010) The SSR-based molecular profile of 1005 grapevine (Vitis vinifera L.) accessions uncovers new synonymy and parentages, and reveals a large admixture amongst varieties of different geographic origin Theoretical & Applied Genetics 121: Drake JW, Charlesworth B, Charlesworth D, Crow JF (1998) Rates of spontaneous mutation. Genetics 148: Gamkrelidze TV, Ivanonv VV (1990) The early history of Indo-European languages. Scientific American 262: Gray RD, Atkinson QD (2003) Language-tree divergence times support the Anatolian theory of Indo-European origin. Nature 426: Jacquat C, Martinoli D (1999) Vitis vinifera L.: wild or cultivated? Study of the grape pips found at Petra, Jordan; 150 BC - AD 40. Vegetation History & Archaeobotany 8:25-30

5 McGovern PE (2003) Ancient Wine: The Search for the Origins of Viniculture. Princeton University Press Myles S, Boyko AR, Owens CL, Brown PJ, Grassi F, Aradhya MK, Prins B, Reynolds A, Chiah J-M, Ware D, Bustamante CD, Buckler ES (2011) Genetic structure and domestication history of the grape. Proceedings of the National Academy of Sciences 108: Negrul AM (1938) Evolution of cultivated forms of grapes. Comptes Rendus (Doklady) Académie Sciences USSR 18: Sefc KM, Pejić I, Maletić E, Thomas MR, Lefort F (2009) Microsatellite markers for grapevine: tools for cultivar identification & pedigree reconstruction. In: Roubelakis-Angelakis KA (ed) Grapevine Molecular Physiology & Biotechnology, 2nd edn. Springer Science+Business Media B.V., New York, pp This P, Lacombe T, Cadle-Davidson M, Owens CL (2007) Wine grape (Vitis vinifera L.) color associates with allelic variation in the domestication gene VvmybA1. Theoretical & Applied Genetics 114: This P, Lacombe T, Thomas MR (2006) Historical origins and genetic diversity of wine grapes. Trends in Genetics 22: Vavilov NI (1926) Studies on the origin of cultivated plants, Leningrad Vouillamoz JF, Grando MS (2006) Genealogy of wine grape cultivars: Pinot is related to Syrah. Heredity 97: Vouillamoz JF, Grando MS, Ergül A, Agaoglu S, Tevzadze G, Meredith CP, McGovern PE (2004) Is Transcaucasia the cradle of viticulture? DNA might provide an answer. In: Vieira A (ed) III Symposium of the International Association of History and Civilization of the Vine and the Wine. Centro de Estudos de História do Atlântico, Funchal (Madeira), October 5-8, 2003, pp Zohary D, Hopf M (2000) Domestication of plants in the Old World, Third edition edn. Oxford University Press Inc., New York