Crop Tech Corner

Ancient Cob Provides New Answers to Corn's Genetic History

Emily Unglesbee
By  Emily Unglesbee , DTN Staff Reporter
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An ancient ear of corn from Mexico has proved to be a halfway point in the long breeding journey from corn's ancestor, teosinte, to modern corn hybrids. (DTN photo illustration by Nick Scalise)

ROCKVILLE, Md. (DTN) -- This bi-monthly column condenses the latest news in the field of crop technology, research and products.


What does a 5,310-year-old cob of ancient maize have in common with a modern corn hybrid? Genetic tinkering by humans, for one thing. By sequencing the genome of an ancient ear of corn found in the Tehuacan Valley of Mexico, scientists from Denmark's Natural History Museum have spotlighted the agronomic priorities of corn's early breeders. The researchers believe the cob represents almost exactly the halfway point between modern corn and teosinte -- corn's ancient ancestor that was singled out for domestication by humans. After sorting through the genes of this particular cob, scientists found that a number of genes had already been the focus of selective breeding efforts. Specifically, genes that control the hardness of the seed coating and flowering time had been modified to suit human consumption. It also became clear to the scientists that the ancient cob still lacked many key modern traits, particularly the modification of genes that allow cereal crops to hold onto their grain and not disperse them before humans can collect them. Higher sugar content was also not yet a focus of genetic selection in the ancient cob, the researchers found.

You can read more about the study and its conclusions here:….


It took a damaging late-spring freeze in 2012 to prove just how tough prairie cordgrass is to University of Illinois agronomist D.K. Lee. After an early and warm spring, temperatures plummeted overnight in mid-April, covering his biomass grass crops with frost, Lee recalled in a press release. The miscanthus and switchgrass promptly died. But the prairie cordgrass -- already known for its flood and salt tolerance -- shook off the frost and continued growing. Intrigued, Lee and his colleagues conducted an experiment, shocking a lab-grown cordgrass sample with a brutal cold snap, from 77 degrees to 23 degrees Fahrenheit. By examining the plant's gene expression during this temperature change, they discovered certain genes switched on immediately after the chill and then 30 minutes later. The first genetic reaction allowed the plants to keep cell-damaging ice crystals from forming; a later reaction likely tended to damaged cells. These genes allow cordgrass to avoid the tissue damage that dooms other crops after freezing events. The goal is to someday make more crops as tough as cordgrass, Lee said. "If we understand more about freezing tolerance, we could eventually apply it to annual crops and potentially expand the production area for crops such as corn."

You can read the University of Illinois press release here:…, and find Lee's study here:….


Phytophthora root rot is in for a surprise. There's a new fungicide aimed at knocking back this disease. This week DuPont Pioneer announced the Environmental Protection Agency (EPA) has registered a new fungicide called Lumisena containing a new active ingredient called oxathiapiprolin. It's the first time since the 1970s there's been a new product to take on this pesky disease.

Oxathiapiprolin is the first member of a new class of piperidinyl thiazole isoxazoline fungicides with exceptional activity against plant diseases caused by oomycete pathogens. The fungicide will be sold as a seed treatment by Pioneer. It is designed for use on soybeans and sunflowers. According to a Pioneer press release, company trials of Lumisena-treated soybeans showed a 32% drop in the incidence of the Phytophthora fungus, compared to untreated seed. The release also stated that university research trials showed that the seed treatment provided better protection than conventional fungicides. For many decades, growers have used the same two fungicides, mefenoxam and metalaxyl, to control the disease, and their effectiveness has waned.

DuPont Pioneer will have wide-scale demonstration plots of Lumisena fungicide seed treatment during the 2017 growing season, and it will be commercially available in 2018 on Pioneer brand seed.

You can read more about Lumisena in Pioneer's press release here:…

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Emily Unglesbee