
Making Harvests More
NutritiousBy Hank Becker May 20, 1999While most crop breeding focuses on
better yield or pest resistance, Ross Welch is exploring ways to breed crops to
help alleviate shortages of trace elements and vitamins in the diets of many
people around the world. For billions of people, plant foods dont provide enough of these
micronutrients, which are critical to health. The most prevalent micronutrient
problem, iron deficiency, affects more than 2 billion people. Zinc, iodine,
essential trace elements and vitamins are other critical micronutrients that
can be deficient in some diets, according to Welch, a plant physiologist with
the Agricultural Research Service in
Ithaca, N.Y. He and colleagues have launched an international effort to pinpoint rice,
wheat, corn, bean and cassava varieties that are high in micronutrients. Their goal: plants that more efficiently take up micronutrients from soil
and transport them to edible plant parts in forms the human digestive system
can take up and use. Already, Welchs team has found enhanced ability to accumulate iron and
zinc in 24 genetic types of common bean from the seed bank of the
International Center for
Tropical Agriculture in Cali, Colombia. In the 24 genotypes, they found
iron levels of 51 to 157 micrograms per gram of dry weight and zinc levels of
30 to 65 mg/g. In rat feeding studies, the iron bioavailability ranged from 53
to 76 percent. This diversity is strong evidence that breeders could produce
new varieties with higher content and bioavailability of iron and zinc. Recent tests of bioavailable iron and zinc levels in fifteen
IRRI rice lines also found
some exploitable diversity. The scientists plan future rat studies to determine
iron and zinc bioavailability in selected micronutrient-enriched lines of rice,
wheat, corn and cassava. A story about the research appears in the May issue of Agricultural Research magazine
and on the World Wide Web at: http://www.ars.usda.gov/is/AR/archive/may99/harv0599.htm ARS is U.S. Department of Agriculture's chief research agency. Scientific contact: Ross W. Welch, ARS
U.S. Plant, Soil and
Nutrition Research Laboratory, Ithaca, N.Y., phone (607) 255-5434, fax
(607) 255-1132, [email protected]. U.S. Department of Agriculture | |