Calcium in Potatoes
March 20, 2003
Germplasm stored in the
Agricultural Research Service's U.S.
Potato Genebank at Sturgeon Bay, Wis., may help scientists increase calcium
levels in this popular vegetable.
Every year, the typical American consumes more than 140 pounds of potatoes,
more than any other vegetable. So increasing calcium in the tubers could
significantly boost consumers' intake of this important nutrient.
Boosting calcium would help the potatoes, too, because increased levels of
calcium have been shown to reduce the severity of tuber defects such as
internal brown spot and hollow heart. These internal blemishes either render
potatoes unfit for sale or reduce their market value.
Geneticist John B. Bamberg, who manages the
Genebank, has been working with Jiwan Palta, a physiologist with the
Department of Horticulture at the University of
Wisconsin-Madison. The two are trying to identify which of the nearly 200
wild, tuber-producing potato species are best at accumulating calcium in their
tubers. While screening many potato species, the scientists found two South
American species that stand out--Solanum gourlayi and S.
When grown in low-calcium soil, S. gourlayi tubers ranked first for
calcium accumulation, taking up more than double that of cultivated potato.
When grown in high-calcium soil, this species ranked second, taking up three
times more than cultivated potato tubers. While S. microdontum exhibited
only average calcium accumulation in the control environment, it had the
highest increase of any species when grown in the high-calcium soil.
Bamberg and Palta have made hybrids that will now serve as models for
genetic and physiological investigations of the high-calcium trait. They will
also begin to transfer genes for super-high-calcium accumulation from the wild
species to the cultivar breeding pool with the help of other researchers at the
ARS Vegetable Crops Research
Unit in Madison.
Read more about this in the March issue of Agricultural Research
ARS is the U.S. Department of
Agriculture's chief scientific research agency.