Shriveling grape berries on severely water-stressed vines mysteriously begin expanding again at veraison, even while the leaves are wilting. For years, wine grape growers have been discouraged from applying irrigation near harvest for fear of diminishing fruit quality. Recent discoveries by Washington State University scientists have debunked that theory as well as another long-held belief about grape physiology. Since the mid-1980s, grape physiologists believed that the xylem inside grape berries broke down at veraison, said Dr. Markus Keller, Washington State University viticulturist. This was based on a “not very focused” photograph showing what was thought to be damage to the […]