In a previous post, we touched on the varieties grown at the vineyard – most of which are cold hardy hybrid varieties bred and developed at the University of Minnesota (six out of our nine to be exact!). But how are these varieties developed?
The Criteria
There are three main criteria looked for in grape breeding: cold tolerance, disease resistance, & grape chemistry (ex. ripening potential & acidity).
The Methods
A new variety can be developed in two different ways: mutation & intentional cross pollination. An individual grape vine that develops mutations might be isolated, propagated, & developed as its own variety. Such was the case of Frontenac Gris (a mutation of Frontenac) or Pinot Blanc (a mutation of Pinot Noir).
Given that grapes are self-pollinating, accidental cross pollination is unlikely to occur and so most hybrid grapes are the result of manual cross pollination. The pistil of one variety is carefully fertilized by the pollen of another variety. The resulting grapes and seeds are those of the new variety.
The Steps
- Selection of parent plants & cross pollination
Both parent plants must have the desired characteristics of the new variety. Cold hardy or disease resistant varieties are often crossed with varieties that have good fruit characteristics. Once selected, the pollen from the mother plant is carefully removed and pollinated with pollen from the father plant. The resulting grapes contain seeds with the genetic makeup of the new variety.
2. Raising & testing the seedlings
The seeds from the parent vine are harvested, dried, & subjected to cold stratification (exposing seeds to cold, moist conditions) to trigger germination. Once planted, the resulting seedlings are raised in a controlled environment and subsequently weeded out according to the desired characteristics. The best seedlings are selected and grown to maturity, while continuing to undergo testing across a variety of environments.
3. Propagation & commercialization
Once evaluated & approved, the new variety must be propagated to be made available for commercial sale.
DNA Informed Breeding
It’s important to note that while this process may seem simple, it can take several years to upwards of a decade to complete. Luckily, recent technology in the of DNA testing can somewhat accelerate the breeding process. Launched in 2011, VitisGen uses genetic sequencing to identify seedlings disease resistant & cold tolerance traits, thus enabling easier & earlier selection of seedlings.
Fun Facts
- In North America, most hybrid varieties are developed at either Cornell or the University of Minnesota
- Since 1944, UMN has released 13 new varieties (although not all varieties remain commercially available)
- As of 2023, less than 5% of vineyards worldwide are planted with hybrid varieties. With climate change and the increased focus on sustainability, however, this number is expected to rise.
Up next: The History of Hybrid Grapes
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