Jun 13, 2012

Breeding strawberries

I heard three strawberry breeders speak in East Lansing, Mich., this spring during a meeting of the RosBREED Project. RosBREED seeks to improve marker-assisted breeding efforts in the Rosaceae plant family (which includes strawberries).

One of the tremendous benefits of RosBREED is the gathering of minds in one place, breeders and geneticists working in common and sharing information – “cross fertilization,” as Jim Hancock, a professor with Michigan State University, put it.

Tom Davis, a professor of plant biology and genetics at the University of New Hampshire, said he considers himself more of a geneticist than a breeder. His role with RosBREED is to harvest information from the strawberry genome – which his lab helped to sequence – to develop tools for breeders. An exciting development has been the work on transferring wild strawberry genes to domesticated berries. Turns out, the strawberry has a huge wealth of wild germplasm and traits right here in North America.

“We can find wonderful things we can use right here instead of going halfway around the world,” Davis said.

In particular, Davis has been studying pigmentation traits. One of the pigments, cyanidin, that makes up the red color in strawberries has a much higher antioxidant potential than others.

“We’ve identified the source of genes for high cyanidin content from a strawberry that grows wild in the coast of Oregon,” he said.

Thanks to genetic markers, breeders can now integrate such wild traits into cultivated strawberry species, and do it quickly, Davis said.

Chad Finn, a geneticist with USDA’s Agricultural Research Service, said the strawberry industry has diverse needs. Different types of berries are required for each market. Strawberries in the Midwest and East Coast, for example, are grown on perennial production systems geared mostly toward local sales. In the Pacific Northwest, where Finn is based, strawberries are almost all grown for processing.

“We’re more interested in how they freeze and thaw in the product and how they taste in your ice cream,” Finn said.
When breeding for processing markets, you go out in the field and try to identify berries with great color, that still taste good after freezing or thawing and have a certain level of pH and Brix. That’s kind of a tall order when you’re selecting on a hot day in the middle of summer, Finn said.

Hopefully, new genetic tools will allow breeders to select parents or seedlings that have desirable traits without going through the typical time-consuming, expensive process, he said.

Driscoll’s, probably the largest strawberry producer in the world, has been very involved in the RosBREED Project. The company has provided a lot of matching dollars and expertise. Driscoll’s supplied a lot of the berry populations Finn is studying from overseas. It would have cost ARS an awful lot of money and time to find those berries on its own.

“We’re appreciative of the private partners we have,” Finn said.

By Matt Milkovich, Managing Editor