The widely held belief amongst winemakers that high yielding grape crops result in poor quality wine was challenged at the West Australian Wine Outlook Conference, yesterday.

Jim Campbell-Cause, technical manager for Albert Haak and Associates showed delegates a graph relating berry colour to yield, based on measurements made at 22 vineyards in the south-west of Western Australia.

The vineyards carried crops of both Shiraz and Cabernet Sauvignon grapes.

"There is no relationship between berry colour and yield," he said. "Producers can increase yields and still keep quality up."

Berry colour is a strong indicator of anthocycanin content, which in turn is a measure of grape quality.

Campbell-Cause said it was too early to draw general conclusions.

"Since the data set is limited, we cannot show the general conclusion that higher yielding vines are better suited to making higher quality wine.

"We certainly can conclude that wine of the very highest quality can be produced from Margaret River Cabernet cropping in excess of 10 tonnes/ha," he said.