Grapes domesticated 8,000 years ago
Dan Vergano
Source - http://content.usatoday.com/communities/sciencefair/post/2011/01/domestics-grape-genome-sequenced/1
In wine there is truth, in vino veritas, as the ancient Romans put it. And the truth is that people first cultivated grapes for vino about 8,000 years ago, finds a genetics study.
In the current Proceedings of the National Academy of Sciences, a team led by Sean Myles of Cornell, looked at "1,000 samples of the domesticated grape, Vitis vinifera subsp. vinifera, and its wild relative, V. vinifera subsp. sylvestris." Comparing the gene maps across the grapes, the team concludes that humanity has only begun to explore the genetic diversity of the humble grape.
"Archaeological evidence suggests that grape domestication took place in the South Caucasus between the Caspian and Black Seas and that cultivated vinifera then spread south to the western side of the Fertile Crescent, the Jordan Valley, and Egypt by 5,000 y ago. Our analyses of relatedness between vinifera and sylvestris populations are consistent with archaeological data and support a geographical origin of grape domestication in the Near East. Grape growing and winemaking then expanded westward toward Europe, but the degree to which local wild sylvestris from Western Europe contributed genetically to Western European vinifera cultivars remains a contentious issue. Our results ... all support a model in which modern Western European cultivars experienced introgression from local wild sylvestris."
"Grapes are one of the world's most economically important fruit crops, and this study shows not only the potential for developing new approaches for improving existing varieties, but also the genetic relationships between many common varieties," said Edward Knipling, of the Agriculture Department, which sponsored the research, in a statement.
Earlier this week, a UCLA team reported archaeological evidence from an Armenian cave of the earliest known wine press, dating to 6,000 years ago.
The new analysis suggests that people have been conservative in crossing varieties, after the earliest domestication of wild grapes. The researchers call for genetically-guided cross-fertilization of grape varieties for increased hardiness. The lack of diversity in domestic grapes left wine-makers ripe for the attack of phylloxera root louse pests over a century ago that wiped out vineyards across France and Italy, impoverishing many families.
"We propose that the adoption and widespread use of vegetative propagation has been a double-edged sword during grape breeding. Although the production of fine wine would be impossible without the control over genetic variability that vegetative propagation offers, vegetative propagation has also discouraged the breeding of new cultivars and is at least partially responsible for a worldwide grape industry dominated by cultivars sharing extensive coancestry. Other factors that have contributed to the small number of cultivars in use today include the devastation of European vineyards in the second half of the 19th century by mildews and phylloxera and the development of the global wine industry. Currently, grapes face intense pathogen pressures, and are thus intensely chemically treated. There are numerous examples of sources of resistance to these pathogens, both from wild Vitis species and from vinifera cultivars that are often found in marginal areas of cultivation and remain largely unexploited. The grape is clearly exceptional in terms of its domestication and breeding history compared with most crops studied to date. The vinifera grape has retained high levels of genetic diversity since its domestication ∼7,000 y ago, yet its genetic variation remains relatively unshuffled within an extended pedigree. Developing an environmentally sustainable wine and grape industry will rely on tapping into this tremendous diversity by genetically characterizing the world's germplasm collections and using marker-assisted breeding approaches to generate improved cultivars."