Combining genomic tools such as DNA sequencing with field research studies makes it possible to develop blueberry and strawberry varieties that meet grower and consumer demands.

Growing profits with new berry varieties

Summer is a “berry” good season for Michigan fruit. The state leads the nation in growing blueberries, producing 109 million pounds in 2010. Michigan’s strawberry production will never outpace California’s production, where more than 80 percent of the U.S. crop is grown, but Michigan farmers produced 2.9 million pounds of strawberries in 2010, according to U.S. Department of Agriculture data.

Jim Hancock, Michigan State University AgBioResearch small plant breeder specializing in strawberries and blueberries, is working to bring these fruits to consumers in greater quantities and for a longer period of time.

“We are trying to extend the season for Michigan’s blueberry growers,” said Hancock, a professor in the MSU Department of Horticulture.

There is almost a year-round supply of fresh blueberries. Product comes from Chile in the winter, and then the U.S. harvest starts in Florida and Georgia in April. Michigan’s harvest is at the end of the season, starting in late June. “We own most of the production at the end of the growing season,” Hancock said. “The later Michigan goes and the longer the berries can be stored, the better the prices because our only competition is from growers in the Pacific Northwest.”

The focus of his blueberry breeding project is to develop mid- to late-season varieties with extremely high fruit quality. He has developed two late-season varieties and one midseason variety with a long storage life.

“These have been a big hit,” Hancock said. “In fact, the varieties — Aurora, Draper and Liberty, which were released in 2005 — are the most widely planted blueberry varieties in the world.”

However, there’s a streak of perfectionism in Hancock.

“One of the late-season varieties has good flavor but not great flavor,” he said. “I’d like to have a late one with exceptional flavor.” Hancock often is evaluating as many as 10,000 blueberry plants at any given time.

Breeding for flavor involves crossing varieties with good flavor and then tasting the berries and measuring sugars and acidity in the fruit. In addition, Hancock runs a volunteer taste panel for opinions on flavor.

“The panel gives me a better handle on what people really like,” he said. “I found that my palate wasn’t sweet enough for a lot of people. Consumers want a little tart, but they want more of a perception of sweetness.”

The focus of the strawberry breeding project is on developing repeat flowering or ever-bearing varieties. “Ever-bearing” means that during the season the variety would have three crops of berries or a continuous harvest lasting a couple of months. In the Midwest and East, there is not an ever-bearing strawberry that is commercially viable.

As with blueberries, the goal is great flavor. And the plants have to be resistant to diseases caused by soil pathogens, such as black root rot.

“We have determined that temperature rather than the amount of daylight is most important to flowering,” Hancock said. “This was a fundamental shift in how we viewed new varieties.”

A multi-state trial of his new strawberry selections will take place next year, and Hancock hopes that at least one of them will look good enough to be released as a variety.

Advances in genomic technology are assisting fruit breeders, and Hancock is excited about the possibilities.

“The idea is to develop molecular tools that plant breeders can use to enhance breeding efficiency,” Hancock said. “This is a dream come true for me. We can use some of this genome information right away. It’s now possible to do things with less money, and I certainly have a greater appreciation of molecular tools.”

Hancock also credits the success of the blueberry and strawberry breeding programs to a widespread collaborative group.

“There are dozens of people from many states contributing in various ways,” he said. “Ultimately our own imaginations must put everything together, but a lot of people have worked unselfishly on these projects.”