Wednesday, February 02, 2011

Do wine grapes need more sex?

In a recent study, Sean Myles, a researcher at Cornell University working on the genetics of grapes, reveals that 75 percent of our 583 kinds of cultivated grapes are either parents, children, or siblings of each other. A graph of grape family relationships shows that for instance, Sauvignon Blanc is a parent of Cabernet Sauvignon and is also related to Traminer, Pinot Noir, Chardonnay, and Muscat. The reason for this interrelatedness? Very little sex for the last 8,000 years.

The reality is that wine consumers are deeply attached to these traditional grape varieties and so most vineyards are planted with clones to make sure that the qualities of these varieties are preserved. However, the lack of grape diversity is worrisome. Vines have low resistance to many diseases and pests and farmers have to spray their vineyards with large amounts of fungicidal chemicals to protect them.

“We can't just go on using the same cultivars for the next thousand years”, says Dr Myles. To tackle this issue, his team has produced genomic maps of more than 1,000 samples, which link the presence of genetic markers to traits such as acidity, sugar content, or disease resistance.

“If you know the genetic markers associated with these traits, you can plant them out as seedlings, look at its DNA as soon as you get the first leaf tissue, and say for example 'we'll keep these five because we know their genetic profiles are associated with the traits we're interested in',” explains Dr Myles.

If we could identify and maintain the genes responsible for the taste of varieties like Chardonnay or Merlot, we could produce a wider variety of grapes that are resistant to disease and with the desired combination of traits. The new variety may not be Chardonnay but may taste like Chardonnay.

Genomically selected grape varieties may be ready sooner than you think.

See also New grapes needed to keep wine flowing.

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