New approach to genetically modifying corn boosts yields 10 percent

By Joan Conrow

November 5, 2019

Corn (maize) yields can be increased by as much as 10 percent by modifying one gene to turn on earlier than it usually does in the growth cycle of the plant, new research concludes.

The findings are important because maize is the most widely grown cereal crop in the world, serving as a staple food for millions of humans, as well as livestock. It also has many industrial uses. But current yields are not anticipated to keep pace with demand.

“In the approaching decades, food security will likely be more of an issue as there will be an increased demand for grain which will need to be met in an environmentally sustainable manner,” the researchers wrote in their abstract. “To date, commercial transgenic maize has primarily targeted resistance to insects and herbicides. Here we describe a transgenic approach to improve the yield and yield stability of maize.”

The study, published in PNAS, focused on zmm28, a gene that turns on when the corn plant begins to flower. By using a promoter, researchers got zmm28 to turn on earlier, essentially making it work harder and longer.

Researchers tested the enhanced gene in 48 different corn hybrids over a period of three years in different growing conditions across the United States. The plants typically produced yields that were 3 to 5 percent higher than the control groups, with some of the genetically modified hybrids yielding 8 to 10 percent more grain.

The increased yields are due to several factors. The engineered plants grew slightly larger leaves, which are better at performing photosynthesis, and they were also 16 to 18 percent more efficient in nitrogen use.

“[The] transgenic plants demonstrated that their enhanced agronomic traits are associated with elevated plant carbon assimilation, nitrogen utilization, and plant growth,” the abstract stated. “Overall, these positive attributes are associated with a significant increase in grain yield relative to wild-type controls that is consistent across years, environments, and elite germplasm backgrounds.”

Researchers are optimistic that their work can be applied to other cereal crops. Corteva is already seeking approval of the new corn varieties from the US Department of Agriculture and estimates it could take six to 10 years to navigate regulatory processes around the world.