The University of Minnesota Horticulture Research Center (HRC) in Excelsior is dedicated to breeding wine and table grape varieties that can withstand the harsh Minnesota winters. Although the University is well known for its apple breeding program—most notably for creating the Honeycrisp apple—its efforts in grape breeding remain less recognized, according to HRC researcher Erin Treiber.
The last table grape was released by the University in 1977, while its most recent wine grape variety was introduced in 2022, as reported by the University's Enology Department. Developing cold-hardy grapes is essential to ensure survival through Minnesota's frigid winters. Disease resistance and flavor are also key factors in breeding efforts.
Grapes, being a perennial crop, regrow each year without the need for replanting. To produce fruit in the warmer months, the buds at the base of the grapevine must survive the winter, Treiber explained.
John Thull, another researcher at the HRC, noted that grape breeding relies on cross-pollination to combine desired traits in new varieties. This occurs through the plant's perfect flowers, which contain both stamen and pistil. To prevent self-pollination, the stamen is removed before flowering and stored until needed for controlled pollination.
Thull clarified that the process involves only traditional plant breeding methods. "There's no genetic splicing, there's no GMO stuff that we're doing," he said. "We're just doing classical breeding and seeing what comes out."
Most grapes are crossbred with Vitis riparia, a cold-hardy species native to Minnesota. However, Vitis riparia lacks desirable flavor, often tasting more like a vegetable, Treiber noted. To improve flavor, it is cross-pollinated with European grape varieties, which are less cold-tolerant but offer better taste. "If you cross those European varieties with the native grapes, some percentage of those should be cold hardy," Thull said.
The development of new grape varieties is a slow process. It takes at least five years before a new variety is ready for tasting and around a decade to determine whether it's suitable for eating or winemaking. "By the time you can make a batch of wine from it, that's like year 10," John Thull said. While the HRC does produce wine from its grapes, limited yields from individual vines typically result in only a few bottles per batch.
Source: The Minnesota Daily