Issue link: https://read.dmtmag.com/i/603228
www.goodfruit.com Good Fruit Grower DECEMBER 2015 35 While it still uses classical breeding techniques by carefully selecting parent plants and cross-pollinating, the Cornell program now incorporates DNA test- ing of seedlings. The testing grew from a major U.S. Department of Agriculture-funded effort (www.vitisgen. org) Reisch co-led with USDA plant pathologist Lance Cadle-Davidson to employ state-of-the-art genetic tools to determine whether a particular plant has certain desirable genes long before it is actually planted out in the field. Through this effort, Cornell and other researchers are developing gene-identifying markers to scan young seed- lings' DNA for certain traits, such as resistance to fungal diseases. "The DNA test can be performed in about a four- to eight-week period, and can determine which of those seedlings, for instance, have the genes for powdery and downy mildew resistance," he said. Reisch's research shows that the DNA tests are more than 99 percent accu- rate for these disease resistance-associated genes. This prescreening for disease resistance reduces both time and expense, Reisch asserts, because instead of planting thousands of seedlings and later winnowing down that number to those that are disease-resistant, breeders already know the vines are resistant before putting them in the field. "That makes it much more efficient. We can focus on an elite group of seedlings to begin with, rather than having to wait for multiple years of field-based ratings," he said. The technology makes the development of new grapes more precise, but it's still a lengthy process. In fact, Reisch said, 15-30 years typically pass from the time of the initial cross until the new variety's release to the market. Most of that time is devoted to examining and reexamining every aspect of the new grape in the field, such as the presence of perfect flowers; good cluster size to yield sufficient quantities of fruit; high grape quality; and cold tolerance. "In later stages of testing, we send the most promising selections out to other universities or cooperating grow- ers for feedback as to how our potential new varieties are doing in different locations," he explained. "This multi- year testing is really important, because we're asking a Goose Watch Winery was the first in the nation to offer the new wine varietal Aromella, made from a grape developed in Cornell's breeding program. COURTESY OF LINDSAY BOLTON