Evolution and Domestication of Wine Grape
The Eurasian grapevine (Vitis vinifera) belongs to the plant family Vitaceae, is the most economically important horticultural crop and cultivated in larger areas in the different parts of the world for fruit, juice and mainly for wine. The family Vitaceae comprises of about 60 inter-fertile wild Vitis species, of which Vitis vinifera is the only species indigenous to Eurasia, which is cultivated extensively for wine production and remaining species are exclusively spread in temperate to warm climatic zones of the Northern hemisphere (Soejima and Wen 2006). Based on morphological differences Vitis vinifera subdivided into most cultivated V. vinifera ssp vinifera and wild form V. vinifera ssp sylvestris. Presently cultivated grape derived from wild form (V. vinifera ssp sylvestris), which woody climber grows in riverside basins, and distributed widely from western Europe to the Trans-Caucasian Zone except for the most southern Mediterranean region (Arnold et al 1998). Grapevine cultivation and domestication appear to taken place in a geographical area between the Black Sea and Iran between the seventh and fourth millennia BC (Zohary and Hopf, 2000). The cultivated forms from this geographical area might have evolved and distributed to Near East, Middle East, and Central Europe by humans. So these regions are started considering as secondary domestication centers (Garcia et al., 2006).Myles et al. (2011) studied over 1000 samples of cultivated and wild grapes from the USDA grape collections in New York, Geneva, Davis, and California to explore the history of grape domestication using thousands of molecular markers. The archeological records revealed that domestication of cultivated grapes(V. vinifera ssp vinifera) are found more closely related to the wild progenitor (V. vinifera ssp sylvestris) from North East region 6000-8000 years ago by confirming the earlier evidence of the origin of vinifera in the North East.
Several dramatic changes might have happened during domestication process of the biology of grapes to ensure the greater yield, customary production and desired sugar content for better fermentation (Pouget, 1988). The major changes occurred during this domestication process which includes changes in bunch and berry size and dioecious wild plants to most cultivated hermaphrodite plants. Seed morphology studies of different Vitis species revealed that domestication of grape probably began with Eurasian wild grape (V. sylvestris) in Southeast Asia and southern Armenia and Georgia (Gyulai et al. 2009). This et al (2006) discussed archaeological and historical evidence of primo-domestication of grape in Near-East region and also the presence of wild grape forms in different places of Europe during the Neolithic period in his detailed review on historical origin and genetic diversity of wine grapes. They also reported the first convincing evidence of seeds of domesticated grapes dated from nearly 8000 BP was excavated in Georgia and turkey. The same kind of study on archeological and historical data, Terral et al., (2010) analyzed seed shape characterization of cultivated varieties such as ‘Claritte and Mondeuseblanche’ and well preserved archeological seeds to provide accurate information about wild and cultivated grapes and their relation to domestication process. They suggest that the Languedoc region might have constituted a domestication center. Based on recent archaeological written sources demonstrated the cultivation of Grape in Southern France is dated back 600 BCE and also excavations made over larger areas of South-Eastern France clearly depicted the spread of viticulture during that period (Brun, 2011). Also different archaeobotany and genetics studies treated grapevine domestication as a most complex, slow, and progressive procedure. Interestingly Bouby et al (2013) revealed grape primary domestication facts in Southwest Asia and hypothesized slow domestication process probably related to the role of sexual reproduction, which is more important than other facts.
Dissemination of the domesticated wine grape lines
Grape cultivation started spreading from its initial domesticated regions such as Jordan valley during 3000-3500 BC to other parts of the world includes northern, eastern and western parts of Eurasia to Northern Africa (De Candolle, 1886). Later these grapes were introduced into new world countries (America) starting from the 16th century by European colonists, as a seed followed by cuttings from their primary originated places (East Europe, Italy, France, Germany, Spain). During the 19th-century theses, cultivars were spread to South America, Australia, and New Zealand further to North Africa (Royer, 1988). Likewise, wine grape species spread from traditional temperate growing regions to non-traditional tropical regions such India, Thailand, Brazil, and Venezuela etc for the wine production. Drastic reduction in genetic diversity for both wild and cultivated grapes recorded in Europe during the 19th century because of the widespread of diseases (Phylloxera, mildews) from North America and as well as human impact on their natural habitats. Especially the cultivated grapevine cultivars faced drastic reduction in genetic diversity over the last 50 years, on account of globalization of wine markets and companies, which led to development of new cultivars for wine production as well as table purpose such as Chardonnay, Cabernet Sauvignon, Syrah, and Merlot and disappearance of old local cultivars and landraces (This et al., 2006). Zecca et al. (2012) published first study on molecular phylogeny of the genus Vitis mainly based nuclear and chloroplast sequences to reconstruct the evolutionary history of grapes, the results showed the fascinating facts about speciation process of grapes which probably result from both paleogeographical and paleoclimatic forces and also found primary disjunction between old world and new world species.