Individuals all over Minnesota have enjoyed the fruits of this project - figuratively and literally - if they have enjoyed eating a Minnesota-grown fruit such as the Haralson or Honeycrisp apple." - James Luby

The University of Minnesota has one of the oldest fruit breeding programs in North America, dating back to the early twentieth century. It serves a region that experiences all the vagaries of a continental climate, with temperatures undergoing extreme fluctuation from summer to winter. Precipitation levels - as rain during the growing season and snow during the dormant season - can also vary dramatically from year to year. These represent difficult conditions for growing fruit in the state. The goal of this breeding program is to develop cultivars that will survive and bear fruit regularly at a commercially profitable level under such climatic conditions.

Method

We assess the cold hardiness of genotypes using laboratory freezing tests and multiple-location field tests. "Test winter" conditions have always been critical to progress in selecting for cold tolerance, given the variability of temperatures and snow cover from one Minnesota winter to the next. Since this variability can provide slightly different challenges to the acclimation and deacclimation capabilities of a given plant, we expose the fruits to as many different test winter conditions as possible for a more complete assessment of potential adaptation. We also interact with growers at association meetings to get input for developing breeding goals. Later, we undertake extensive field-testing at experiment stations throughout the state, as well as at sites of cooperating producers. Advanced testing (using cloned genotypes) is conducted at two to six locations in Minnesota, depending on the crop. By testing at multiple locations, advanced selections usually experience one or more test winter situations each year. While growers participate in the advanced stages of testing, they are also the ones to make immediate and direct use of the newly developed technologies once research is complete.

Beyond direct application, we publish various papers in scientific journals describing the technical aspect of our developmental research. For example, a more recent document is in the process of being published that deals with anti-oxidant activity in the fruit of different blueberry varieties. Another involves genetic diversity in North American wild strawberries.

Results

- Over the past century, this program has produced dozens of new fruit cultivars.

- In 1996, we introduced Frontenac grapes for red wine production. This helped a recent expansion of Minnesota's wine industry.

- Our most recent achievements include developing Zestar and popular Honeycrisp apples, Polaris and Chippewa blueberries, and Mesabi and Winona strawberries.

- We are releasing a new grape variety in 2003 for white wine production. We are also in the early stages of development for other new fruit varieties.

The entire Minnesota fruit-growing industry represents tens of millions of dollars in income for growers. Our research has successfully aided in boosting production of various fruits, both in recent years and throughout the past century. For example, a 1999 apple tree survey from the USDA Statistic Service said that over 80,000 Honeycrisp apple trees have been planted in Minnesota alone since 1990, with 945,000 being planted across the U.S. In their lifetime of over twenty years, each of these trees will produce at least 40 bushels of apples (average 2 bushels per year). With a conservative average price estimate of $25 per bushel, this represents a gross income of approximately $1,000 per tree. Thus, the potential gross income from trees that have already been planted could alone reach tens of millions of dollars for Minnesota producers.

Net income estimates for such products are inevitably lower given the input costs that must be figured in. While costs for chemical, plant, equipment, and labor inputs vary from fruit to fruit, reduced chemical applications will eventually reduce overall input costs. Also, as certain varieties achieve greater popularity, they can command higher prices, especially when they are new and perceived as superior to existing products. Consumption of our newly developed varieties has also consistently increased. For example, over the past two decades, Minnesota-grown apples have expanded their share of the state's total apple market, growing from approximately eight percent in the early 1980s to fifteen percent at present. As a reflection of this trend, the Minnesota landscape now hosts approximately 200 apple orchards that grow over 400,000 trees. Commercial apple production for the state reached 24.9 million pounds in 1999, with a production value of nearly $8 million for that year alone. The added appeal that products like the Honeycrisp offer to consumers exemplifies the opportunity for expanding fruit production in the state.

Other fruit industries have benefited, as well. For example, our efforts in grape development have done much to encourage Minnesota's wine industry over the past decade. While processing is generally viewed as a low value added activity for most fruits, it derives great commercial value when turning grapes into wine. In the mid 1980s, Minnesota only had a few wineries. However, with the introduction of new cold-hardy grape varieties, we now have ten wineries statewide. Local grape production has also allowed a number of high-end jelly/jam producers to benefit in the state.

Also noteworthy is our work with blueberries. Minnesota had essentially no blueberry production before we introduced the first cold-hardy varieties in the early 1980s. Now blueberries are grown on approximately 100 acres throughout the state. While the total acreage may not seem economically significant up front, the fact that blueberries achieve a high gross income of $10,000-15,000 per acre makes this a considerable contribution to local economies.

One of our research objectives is to develop cold hardy fruit varieties that carry built-in pest and disease resistance so that they can be produced in sustainable, perennial orchards and plantations. This, in turn, reduces the need for chemical pesticide and fungicide applications. Our efforts in this regard have been quite successful thus far. For example, apple scab is the major fungal disease of apples in Minnesota, generally requiring 6-8 sprays per growing season to control. Our recently developed Honeycrisp apple, however, carries a high genetic resistance to apple scab. This high level of resistance should permit greatly reduced applications of fungicides when this variety is produced.

In 5-10 years, we hope to realize a net reduction in chemical use as more popular fruits, such as the Honeycrisp apple or Frontenac grape (genetically resistant to downy mildew) replace existing susceptible varieties. However, it is too early to tell how much the overall use of fungicides can be reduced in Minnesota.

Individuals all over Minnesota have enjoyed the fruits of this project - figuratively and literally - if they have enjoyed eating a Minnesota-grown fruit such as the Haralson or Honeycrisp apple. A primary goal of this research is to develop new fruits that offer more variety in terms of flavor and texture balances that will appeal to different tastes. For example, the Honeycrisp apple was a breakthrough in texture in that it provides a novel "mouth feel" (how crunchy it is perceived to be in the mouth). The Zestar, on the other hand, offered consumers an improved flavor in terms of sugar-tart balance. For blueberries and strawberries, we gain the freshness of locally produced fruits without loss of flavor during transport.

The following are some of the characteristics we have successfully attained in various fruit types:

- For apples, our major emphases have been on combining a firm, crisp, juicy texture with pleasing flavors, disease resistance (e.g., apple scab), and longer storage life.

- For grapes, we look for varieties with good quality for production of red or white wines, cold hardiness, resistance to diseases (e.g., powdery mildew) and pests (e.g., phylloxera), and tolerance of phenoxy herbicides, such as 2,4-D.

- For strawberries, we have combined eating quality with soil-borne disease resistance (e.g., black root rot and red stele root rot) and foliar disease resistance (e.g., leaf spot and leaf scorch).

- For blueberries, we look for cold hardiness, productivity, large berry size for more efficient hand harvest, aromatic flavor, firmness, attractiveness in the landscape, and optimal use in commercial plantations.

The combined effects of these efforts have contributed to the widespread enjoyment of delicious, healthy fruits being grown on plantations that beautify the landscape. This has encouraged the further development of a culture for fruit growing in an otherwise obstinate Minnesota climate.

Minnesota County
All Counties, International, National, Upper Midwest

Publication for Further Information
150 Years of Hardy Plants. Minnesota Experiment Station. BU-7564. 2000.

Primary Researcher
James Luby
lubyx001@umn.edu

Participating Individuals
Zata Vickers - Food Science and Nutrition Anna Katharine Mansfield - Horticultural Science Emily Hoover - Horticultural Science Cindy Tong - Horticultural Science David Wildung - North Central Experiment Station (Grand Rapids) Carl Rosen - Soil, Water & Climate Steve Poppe - West Central Experiment Station (Morris)
2 Undergraduate Students
3 Volunteers

Department
Horticultural Science

Government Funding Type
State

Additional Funding Information
Average annual funding is $40,000.00