Solving mysteries of the grape

In days gone by vignerons would sometimes come across a rogue grape variety in a local vineyard and wonder what it was. Time to call in an ampelographer – an expert in identifying and classifying grapevines. This person would have looked at the colour and shape of the berries, assessed whether the leaves were crinkly or smooth and whether their edges were rounded or variegated. If still in doubt the ampelographer may have consulted one of the beautifully illustrated books on grapevine varieties.

These days it’s a lot simpler: vines are just sent off for DNA testing. Bang! There’s your answer.

The advent of DNA testing has enabled researchers to develop family trees for grape varieties, identifying a variety’s mother and father, siblings and children. In doing so they have thrown light on some mysteries that have engaged the wine world for decades.

The origin of shiraz

For ages, there was an argument about where shiraz originated. The vines in Australia had been brought here from France where syrah, the French name for shiraz, was grown in the valley of the Rhone River. However, there is a city in Iran called shiraz and some had suggested that the grape variety had originated there and been brought to France by the Romans.

DNA testing revealed that the parents of shiraz were a little known red variety called dureza and a white variety, mondeuse blanche. As the home of both these varieties is in the south- east of France, close to where shiraz has long been grown, it’s a pretty safe bet that this part of France is where shiraz originated. So maybe we should start calling it syrah.

The mother of merlot

There is more merlot planted in France than any other grape variety, about 115,000 hectares of it. Once DNA testing got into full swing it became apparent that merlot’s father was cabernet franc and that merlot had a half-sister, malbec. But the mother of both merlot and malbec was nowhere to be found. It was no longer propagated anywhere and was thought to be extinct.

Then someone spotted an old, scrappy looking vine in Brittany, of all places, and sent it off for a DNA test. Lo and behold it was the missing link – the mother of merlot. After a serious vine hunt another four vines were discovered in the Charente region of France, north of Bordeaux. The newly discovered variety was named Magdeleine Noire de Charentes and, after hanging on by a thread, the mother of both merlot was saved!