Innovations in grain sorghum: lower fertilizer use, better weed control

Grain sorghum, a key crop in arid regions, faces significant challenges: high nitrogen fertilizer dependency and limited options for controlling weedy grasses like johnsongrass. Addressing these issues, scientists are advancing genetic engineering and breeding techniques to enhance the crop’s resilience, productivity, and sustainability.

Reducing fertilizer dependency

A collaborative research initiative, funded by the U.S. Department of Energy’s Advanced Research Projects Agency-Energy (ARPA-E), aims to improve grain sorghum’s nitrogen-use efficiency. Part of a $38 million investment in nine projects, this effort seeks to reduce nitrogen pollution from U.S. bioenergy feedstocks.

Sakiko Okumoto, PhD, a plant physiologist at Texas A&M AgriLife Research, leads the project integrating biological nitrification inhibition (BNI)—a trait found in wild sorghum relatives. BNI can lower fertilizer application needs while maintaining yields. Collaborating on this effort, Veena Veena, PhD, MBA, from the Donald Danforth Plant Science Center, applies genome modification technologies to develop sorghum lines with traits like improved nutrient cycling, drought resistance, and resilience.

These innovations are expected to reduce costs for grain ethanol producers, enhance environmental benefits, and promote sustainable agricultural practices.

Innovations in weed management

Meanwhile, researchers from the Arkansas Agricultural Experiment Station and Texas A&M AgriLife Research have developed a herbicide-resistant trait for grain sorghum, providing a novel solution for controlling grass weeds such as johnsongrass.

The breeding program began with the discovery of herbicide-resistant johnsongrass in Arkansas. The resistance trait, targeting acetyl-CoA carboxylase (ACC-ase), was transferred to grain sorghum using advanced hybridization techniques. The resulting product, ArkTam sorghum, offers robust resistance to most ACC-ase herbicides, enabling effective post-emergence weed control.

“Sorghum producers have long sought post-emergence grass control options,” said Bill Rooney, PhD, a sorghum breeder at Texas A&M. “This trait delivers a critical solution and has garnered significant interest.”

Field trials show ArkTam sorghum’s high tolerance to ACC-ase herbicides and strong control over problematic grass species. This advancement addresses farmers’ challenges with herbicide-resistant weeds and restrictive herbicide regulations.

Advancing sustainable sorghum production

By tackling fertilizer dependency and weed management, these innovations underscore the collaborative efforts of institutions like Texas A&M AgriLife Research and the Donald Danforth Plant Science Center. Together, they offer grain sorghum producers sustainable, cost-effective solutions to critical agricultural challenges.