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Research Highlights

Research Highlights
Researchers Finding Promise of Natural Tolerance to Off-Target Dicamba Damage in Soybeans

Aerial image shows plots of soybeans in Missouri resistant and susceptible to dicamba drift. Photo: Pengyin Chen, University of Missouri

By Carol Brown

If soybeans don’t possess the trait that protects them from the dicamba herbicide they can suffer from the chemical’s detrimental effects. Researchers in Missouri are studying non-Xtend® soybeans to find natural tolerance to dicamba, which could give farmers more options when growing the crop.

“After seeing a lot of off-target dicamba damage to our non-Xtend soybeans over the last few years, we noticed some plants responded differently,” said Caio Canella Vieira, a graduate student at the University of Missouri (MU). “We’ve found that some lines were tolerant, and others have been susceptible.”

“We’ve used this visual data to look at yield performance. We found there is a strong yield penalty with off-target dicamba damage,” Canella said. “The severity was variable across the genotypes and maturity groups.”

Canella is working with Pengyin Chen, the project investigator for this research funded by the Mid-South Soybean Board. A soybean breeder and head of the Delta Center soybean breeding team at MU, Chen said that after seeing a strong correlation between soybean yield and damage levels, he and his team will work to confirm whether a natural tolerance to dicamba exists.

The documenting of tolerant and susceptible plants was conducted for three years in Louisiana, Mississippi, Arkansas and Missouri in more than 3,000 soybean research plots. Chen and his team will begin the controlled study this year.

“We’ll confirm through a greenhouse study by controlling the environment, the dosage, duration and frequency of the dicamba exposure,” Chen said. “We’ll use this material to make genetic populations to study the genes that control the tolerance trait. The end goal is to introduce farmers to a non-Xtend soybean variety with a natural tolerance to the herbicide.”

“If a neighboring farmer is planting Xtend and you are not, you’re going to get hit,” Canella cautioned.  “We need to find varieties that fit where everyone’s going to be happy and no one loses.”

Canella said there is a niche market where farmers can make extra money with conventional soybeans. This is a growing market and has enormous potential for human feed and this needs to be protected, he said.

Furthering public breeding programs

Another reason for this research — which may not be as evident to farmers but just as important — are public breeding programs, such as the one at MU, have developed traits that private breeders haven’t emphasized, Canella said.

“Soybeans with high protein, high oleic oil, resistance to nematodes, and other seed quality traits were developed under conventional background,” he said.

Most public breeding programs don’t have a license to use Xtend and must rely on conventional Roundup Ready or LibertyLink varieties to use in research, so they need to keep the herbicide resistance going, Canella said.

“In addition to reduced seed costs, farmers could benefit by gaining a trait without paying for it,” Chen said. “Maybe farmers could even save the seeds because the trait would not be protected. It would be free to everybody who could use it. We’re excited. Hopefully, we’ll get there.”

To find research related to this Research Highlight, please visit the National Soybean Checkoff Research Database.