Penn State Study Reveals How Corn Roots Evolved Over Time

By Blake Jackson

Corn, first domesticated from its ancestor teosinte in central Mexico nearly 9,000 years ago, has undergone remarkable transformations through human selection. Early farmers bred the wild plant’s hard, tiny kernels into the large, edible ears familiar today.

Alongside these changes, the roots of corn now the most widely grown crop in the United States and second worldwide by acreage also evolved in response to shifting environments and agricultural practices.

Because the role of roots in crop domestication remains less understood, a research team led by Penn State scientists conducted a study to examine how root traits developed over time. Their findings, published in New Phytologist, shed light on how environmental pressures, including climate change, carbon dioxide levels, and farming practices, shaped corn’s underground growth.

The team analysed ancient corn DNA, paleobotanical records such as plant fossils, pollen, and chemical traces, and used the OpenSimRoot Model a Penn State-developed computer program that simulates crop response to soil conditions.

The research identified three major root changes during corn’s domestication: fewer nodal roots, the appearance of multiseriate cortical sclerenchyma (thick-walled root cells aiding deeper penetration), and an increase in seminal roots that help seedlings absorb nutrients early on.

“We reconstructed the root phenotypes of corn and teosinte, as well as the environments of the Tehuacán Valley one of the oldest regions of corn domestication over the last 18,000 years using a combination of ancient DNA, paleobotany and functional-structural modeling to reconstruct how root traits evolved over time,” explained Jonathan Lynch, distinguished professor of plant nutrition and senior author.

“The research suggests that root phenotypes that enhance plant performance under nitrogen stress were important for corn adaptation to changing agricultural practices.”

The study’s timeline highlighted key stages: between 12,000-8,000 years ago, rising carbon dioxide encouraged deeper root systems; by 6,000 years ago, irrigation shifted nitrogen deeper into soil, further shaping roots; and around 3,500 years ago, more seminal roots emerged as agriculture intensified and soils degraded.

Reflecting on the findings, Lynch noted their modern relevance: “That’s not only interesting historically because that’s how we got modern corn but it also gives some guidance as to what we can do with corn roots in the future to make them better adapted to developing conditions.”

Photo Credit: gettyimages-oticki