Wine grape variety evaluation

Virginia’s wine grape variety palette is diverse and is driven by consumer recognition/demand as well as suitability of the variety for our challenging growing conditions. The top varieties grown by acreage are depicted in Figure 1. All varieties have strengths and weaknesses. Chardonnay, for example, has been the most widely grown variety since the 1980s, due in part to consumer recognition, adaptability of the variety to many growing sites, and generally high quality of resultant wines. But Chardonnay is also highly susceptible to many diseases and it demonstrates a very early bud break in spring which can predispose the variety to subsequent frost injury. This weakness was apparent again in the spring of 2020, owing to a warmer than average March, followed by a cool April and early May punctuated by sub-freezing events that resulted in frost damage across the Commonwealth.

We’ve conducted two wine grape variety evaluations since the late-eighties, and are currently starting a third. The first trial was conducted at the AHS Jr. AREC starting in 1988 and was completed in the mid-nineties. It introduced a number of new varieties to Virginia, including Petit Manseng (Figure 2), Tannat, Fer Servadau, Petit Verdot and Muscat Ottonel. The second trial was conducted at the Southern Piedmont AREC in Dinwiddie County. Top performers from that warmer site included Norton (Vitis aestivalis hybrid), Mourvedre, Roussanne, and Traminette (interspecific hybrid).  The third trial commenced with plantings in 2020 again at the AHS Jr. AREC and will comprise 15 varieties in a randomized, replicated planting. Vines are spaced 4 feet apart in the row and will be head-trained and cane-pruned, with vertically shoot-positioned canopies.  The focus of the 2020 planting, which will be installed over a 2-year period, is disease resistance combined with high wine quality potential.

Included in the 2020 planting are varieties that have recently become available in the US from breeding programs both here in the US and in Europe. While disease resistance is a primary consideration, the variety must also have an ability to withstand repeated wetting from late-season rains, withstand winter low temperatures, have good composition at harvest (pH, flavors, etc.), and have excellent wine quality potential. Furthermore, the variety should not suffer from unusual physiologic disorders that reduce crop potential. Viognier, for example, suffers from primary bud necrosis, a physiologic disorder which severely limits crop yield in some vineyards. To adequately evaluate these traits, the varieties should be grown and cropped for 6 or more seasons to account for seasonal variability. The original Winchester planting included 8 years of data including wine evaluations by the department of Food Science and Technology at Virginia Tech.