ARS scientists and colleagues are suiting up a wholesome cranberry variety with a newly isolated genetic trait. Using traditional breeding methods, they have created an experimental cranberry line with a high level of absorbable antioxidants.
Plant pathologist James J. Polashock, with the ARS Fruit Laboratory, and Nicholi Vorsa, with the Philip E. Marucci Center for Blueberry and Cranberry Research and Extension at Rutgers University, collaborated on the project. Both scientists are located at the center in Chatsworth, New Jersey.
The cultivated, typical American cranberry, Vaccinium macrocarpon, has long been prized for its brilliant red fruit. The deep-colored pigments are made up of anthocyanins, which are a subclass of flavonoids. The many plant chemicals in this large group are widely studied for their purported health benefits, including their role as antioxidants.
The researchers found that a cranberry species from Alaska, Vaccinium oxycoccus, is genetically similar enough to the American cranberry to enable interspecies hybridization, producing fertile progeny. The Alaskan species is attractive to the breeders because its fruit anthocyanins are mostly linked to glucose.
Here’s why that’s good.
In nature, anthocyanins are mostly bound to sugars. Anthocyanins that are bound to the sugar glucose are very high in antioxidant capacity. And flavonoids bound to glucose have been found to be more readily absorbed in the human gut.
But the anthocyanins found in the American cranberry are bound mainly to other, less-absorbable sugars, namely galactose and arabinose. Generally, less than 5 percent of the anthocyanins in the typical cranberry are glucose linked, according to Polashock.
By crossing the American and Alaskan species, researchers have created a cranberry with high levels of more bioavailable antioxidants.
“The progeny of these crosses also deliver the proanthocyanidins known for inhibiting E. coli from adhering to the lining of the bladder and causing urinary tract infections,” says Polashock.
The first-generation hybrids contained up to 50 percent anthocyanin linked to glucose. Through backcrossing, the researchers have now produced progeny that also offer good productivity, vigor, and adaptation. The next step is to produce a horticulturally acceptable cultivar for growers to use.—By Rosalie Marion Bliss, Agricultural Research Service Information Staff.
"New Cranberry Hybrid High in Antioxidants" was published in the January 2008 issue of Agricultural Research magazine.