NORWICH, U.K. — Field testing of wheat biofortified to create high-iron white flour revealed the plants contained double the amount of iron in the white flour fraction of the grain.

Scientists at the John Innes Centre, Norwich, rearranged the D.N.A. by inserting two extra sequences, also from wheat, that result in an accumulation of iron. The additions were deemed successful after initial tests in a greenhouse environment revealed significantly increased grain iron content.

The new variety was bred to address iron deficiency anemia, a global health issue. The variety released after further field trials will be made available for breeding into elite wheat varieties for countries that allow genetic modification of crops.

“The research aims to address the persistent problem of iron deficiency, a nutritional deficiency that particularly affects girls and women in the U.K. and other parts of the world,” said project leader Cristobal Uauy of the John Innes Centre. “This problem is currently addressed by adding iron powder to flour and breakfast cereals, which could be replaced by using our high-iron wheat for these food products.”

Analysis of grain grown in the first field test revealed a similar result to the greenhouse-grown initial tests: a two-fold iron increase in hand-milled white flour compared to control wheat. The high-iron grains from the field trial were found to be slightly smaller than the control, and its weight was off by about 10%. But those differences were more than offset by the appearance of more grains per spike, creating a comparable total weight of grain per spike.

The first field trial of the high-iron variety grew comparably to the control wheat despite spring drought conditions at the Innes Center in the East of England region of the United Kingdom. The trial was harvested in early August.

“We are pleased with progress so far, which demonstrates that the method is working in the field,” said Janneke Balk, Ph.D., an Innes Centre researcher on the project. “In field trials, plants are exposed to different weather conditions, which is very different from climate-controlled growth rooms.”

The next steps are two additional field trials in 2020 and 2021, as is customary to study its development over the course of differing weather patterns. Further research will assess how the iron is processed and consumed in the body using cell cultures of intestinal cells, in the laboratory of Professor Paul A. Sharp, King’s College London.

Researchers are planning tests to determine if iron in the field-grown high-iron wheat is absorbed more thoroughly by cells in the body than control wheat, as it was with greenhouse-grown tests.

“Wholemeal flour that uses the bran and wheat germ portions of the wheat seed produces more iron, but it is not all absorbed into the body,” Mr. Uauy said. “By producing high-iron white flour we can have the biggest impact on health.”

Dr. Balk and Mr. Uauy work in a publicly funded laboratory where they also are investigating non-G.M. approaches to develop high-iron wheat varieties. Initial results of those explorations are expected in three to five years.