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Herbicide tolerance comes to sorghum

Alta Seeds launches igrowth weed control system.

Over-the-top herbicide control of grassy and broadleaf weeds in grain sorghum is finally here. 

The igrowth sorghum – sorghum hybrids tolerant to imidazolinone (IMI) herbicide – is a new herbicide-tolerant grain sorghum technology that Alta Seeds will have ready to go for the 2021 growing season.

Alta is partnering with UPL, a global crop protection company, which expects its IMIFLEX herbicide to gain EPA approval by the end of the year, according to Lynn Justesen, UPL’s senior technical services lead for row crops.

The igrowth sorghum system represents the “most significant innovation in grain sorghum since hybridization,” says Tanner Antonick, Alta Seeds regional sales manager for the central region. Sorghum farmers have pleaded with the industry for better grass control in the crop. Igrowth promises it is vastly superior to the over-the-top grass products currently on the market. And, for grassy weeds like shattercane and johnsongrass, the igrowth system using IMIFLEX is the only means of control. 

A non-GMO technology, igrowth was discovered through advanced genetic screening of Advanta’s elite germplasm. This naturally occurring tolerance means no DNA from other species or plants was introduced into the igrowth sorghum genome, and igrowth has global market acceptance. When paired with the companion herbicide, the igrowth technology reduces the number of weeds competing for water and nutrients in the soil, allowing the sorghum crop greater access to crop inputs.

Still, farmers need to use a systems approach when using igrowth, says Sarah Lancaster, weed specialist at Kansas State University. Using IMIFLEX with other products in a tankmix will assure the best weed control. 

“Proper management and stewardship of the igrowth system is very important,” Antonick agrees. “We’re going to require a stewardship agreement that details best practices.” 

The igrowth lineup

Alta Seeds already has five igrowth grain sorghum hybrids ready to launch in 2021, says Zach Eder, U.S. technology development manager for Alta Seeds. These include a mix of medium-early and medium maturity hybrids suited for farmers from Texas north to Nebraska, and east into the Corn Belt, the company says. 

Plus, Alta Seeds has about 20 grain and forage hybrids in the research and development pipeline as the next generation of igrowth sorghum seeds. 

Growers can learn more about igrowth hybrids by visiting

While igrowth represents a way for farmers to add grain sorghum to rotations in which grassy weeds have made sorghum production difficult, it is not a panacea. Antonick says it is imperative that growers adhere to stewardship principles like using different modes of action. Also, KSU’s Lancaster points out that in many areas throughout the High Plains, growers face challenges of ALS-resistant pigweed. Thus, IMIFLEX may not be effective against palmer amaranth in Kansas and Oklahoma. 

Still, it’s a new tool that widens the window for grain sorghum production, she says. 

In addition to controlling weeds like shattercane, johnsongrass, Texas panicum, and purslane, IMIFLEX promises other benefits:

  • Excellent crop safety.
  • A wide application window, from preemerge to bloom, although EPA will determine the label.
  • Multiple tank mix options.
  • Low use rate of 6 to 9 ounces per acre.
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