More than 20 years ago, a plant breeder predicted that corn of the future would look like Christmas trees. Smaller leaves on top would allow more light in, postulated Dave Nanda, Indianapolis, now retired. He reasoned that plant design might change, and yields could go much higher.

Today, researchers at the University of Illinois are attempting to turn a similar idea into reality. Steve Moose, director of the Stephen Moose Corn Functional Genomics Lab at Illinois, along with graduate and postdoctoral students, is testing various concepts in the field. Many of their ideas come to life in the CornBox plots at the U of I Agronomy Farm in Champaign, Ill.

Matthew Runyon, a graduate student working with Tony Studer, associate professor of crop sciences at U of I, is comparing corn with narrower leaves, achieved through a mutant gene, to corn with traditional, droopy larger leaves.

“The idea is to do a better job of capturing sunlight and turning it into energy,” Moose says. “With today’s hybrids, by the time corn plants are tasseling and silking, it is difficult for sunlight to penetrate and reach lower leaves on the plant. With narrower leaves, more light should penetrate deeper into the canopy.”

Narrower leaves: Testing the concept

The idea might sound counterproductive to some. Wouldn’t reducing leaf area also lower the amount of photosynthesis occurring in the plant?

Runyon counters that the impact of allowing more light to penetrate deeper into the canopy offsets that possible effect. Once light penetrates the canopy, lower leaves become much more productive and can contribute more to plant growth and development.

Runyon notes that one advantage to narrower leaves could be higher planting densities in the future. The average plant stand in Illinois cornfields today is around 32,000 plants per acre, he says, and perhaps slightly higher on the most productive soils. With hybrids with narrower leaves, it should be possible to push plant densities higher, hopefully resulting in higher yields.

Results in the first year of the trial in 2023 were encouraging, Runyon says. Yields of hybrids with narrower leaves at higher densities were promising in both 30-inch and 20-inch rows. In 20-inch rows, they saw the highest yield potential at final plant populations of 42,000 and 48,000 plants per acre.

Corn plant what-ifs?

Part of the reason for the tests that Moose and his crew are conducting is to explore future possibilities. He believes there may be even more potential if it were possible to fine-tune the concept of changing the leaf size of plants even further.

“What if we could develop corn plants where earlier leaves that emerged were larger?” Moose asks. “They could intercept more light and help close the row canopy quickly.

“Then leaves emerging later would be narrower, like on these plants we’re testing. They could capture the maximum amount of sunlight during the most important part of the season for corn.”