Food security

What are corn tillers?

If you want to start a heated discussion, ask your social group for their thoughts on pineapple pizza the next time you order take-out.

While the opposition is strong, more pie-lovers approve of pineapple on pizza than many people realize. In fact, nearly half of Americans think pineapple is an acceptable pizza topping, according to a 2017 survey by Slice.

In my world, the topic of “corn tillers” is controversial as well. Corn tillers have a negative reputation with farmers and agronomists around the world. Like pineapple pizza toppers, most people form opinions about corn tillers, even though we do not understand them very well.

tall corn crops with labeled tiller stems on each side of main stalk
Part of a study in Kansas about the effect of corn tillers on yield, this mid-season corn plant has 10 fully developed leaves at 40 days after planting. It also has two healthy tillers developing, one on each side of the main stalk (labeled in white). Research at Kansas State University shows that despite current assumptions, corn tillers do not reduce yield. Credit: Rachel Veenstra

First, corn is a type of grass! Tillers are a type of branching structure found in grasses and other species like alfalfa. For example, grass tillers are the reason your lawn fills in after seeding.

Tillers grow from the stem base of individual grass plants. They take advantage of the space that each plant has available. This is the reason you commonly see grass growing in clumps in your lawn.

While this growth habit is common in grass species, this behavior is not typical for our favorite modern grass crop, corn!

Uniformity of plant structure and grain production was one of a plant breeder’s goals when creating crop species for more intense management. Tiller growth went against this goal in corn. So, corn breeders suppressed the tillering trait over time.

woman wearing hat kneeling and examining tiller stalks on corn plants in field
Rachel Veenstra, a doctoral student at Kansas State University, checks tiller development on corn plants. Corn is part of the grass family, which commonly creates “tillers” as part of their development. Tillers were thought to reduce grain yield. Each of her hands is holding a tiller stalk away from the central, main corn stalk. Some of the tillers are removed as part of a study on the effects of corn tillers on grain yield. Credit: Jessica Veenstra

As crop fields have been progressively managed more intensively, additional corn plants are planted per area. When plant breeders are developing new corn genetics, they cannot test every possible field situation the plants could experience. Certain conditions are identified as “typical” and used for this testing process. Typical conditions usually include more plants per area, which is commonplace in locations that receive adequate rain and have good soil.

However, some production systems cannot support the management practices evaluated by corn breeders. In less productive areas, farmers commonly reduce plants per acre as a way to save precious resources, like water. When fewer plants are grown, each plant has access to more light and other key resources and is more likely to develop tillers – even modern corn plants.

Corn tillers have been given the nickname “suckers.” This moniker assumes that these tillers steal water, nutrients, and energy resources from grain developing on the primary ear of corn. The primary ear is the dominant grain development site on a corn plant, and typically the only one.

This single ear of corn is the main “product” of corn plants. Grain from these ears is the product sold by the farmer. (Silage – chopped up ears, stalks, and leaves – is another product, but usually not the primary one.)

single corn plant in harvest state showing four ears of corn, two of which grew on tiller stalks
This single corn plant has four ears of corn at harvest time. Two grew on tillers – a few more than the typical single primary ear! This plant is part of a study investigating the effect of tillers on corn grain yields at Kansas State University. Credit: Rachel Veenstra

If tillers are growing, the corn plant is dividing energy. That energy could otherwise be fully dedicated to adding more, larger grains to the primary ear. This observation led to the assumption that grain production from the corn plant as a whole is reduced when tillers are present.

Our research at Kansas State University suggests otherwise!

Our work is focused on corn tiller development and grain yield impacts. Research on corn tillers is scarce, and modern conclusions are unavailable. To fill this gap, our team tested the impacts of tiller growth on final corn yields for three different years in fields across the state of Kansas.

Regardless of management practices or climate, the presence of tillers in corn never reduced yields in any of our trials. That is, we have concluded that the “sucker” assumption is not valid.

It is time to rethink our opinions on both pineapple pizza and corn tillers, I suppose.

Answered by Rachel Veenstra, Kansas State University For more information on the work we are doing with corn tillers in Kansas, I invite you to visit my Ph.D. project website (https://rveenstra.wixsite.com/tillers), read our paper in Crop Science (https://acsess.onlinelibrary.wiley.com/doi/full/10.1002/csc2.20576), and check out the new K-State Research and Extension bulletin (https://bookstore.ksre.ksu.edu/pubs/MF3571.pdf).

About us: This blog is sponsored and written by members of the American Society of Agronomy and Crop Science Society of America. Our members are researchers and trained, certified, professionals in the areas of growing our world’s food supply while protecting our environment. We work at universities, government research facilities, and private businesses across the United States and the world.

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