20 / SEEDWORLD.COM DECEMBER 2018 UNLIKE CORN AND soybeans, sorghum has not yet been privy to the development of herbicide-resistant technology and the use of glyphosate. That’s not to say that weeds aren’t a problem for sorghum growers, they are. Weeds in sorghum fields can result in up to a 60 percent to 70 percent yield loss if not controlled, according to research from Kansas State (K-State) University. “There’s economic value in controlling them if you know there’s enough competing with the crop,” says Anita Dille, a K-State University professor of weed ecology. However, controlling grass weeds in sorghum is a unique challenge because sorghum is a grass, explains Mithila Jugulam, a K-State University associate professor in weed science. Any herbicide used on grass weeds, such as johnsongrass, barnyard- grass and shattercane, could also affect sorghum. While sorghum does have pre-emergence herbicides avail- able, these herbicides need moisture for activation and are only active for a short period. Weeds can still grow throughout the cropping season. Controlling grass weeds is a challenge that sorghum grow- ers struggle with year in and year out. That’s why the Sorghum Checkoff awarded three scientists funding to pursue research that could help in finding a solution. The Quest One of the scientists who received funding is Todd Gaines, a Colorado State University assistant professor of weed science. The checkoff awarded his research program $150,000 over the course of five years to develop new herbicide resistant traits through mutagenesis. “Mutations are the basis of genetic variation,” Gaines says. “In a sense, we speed up the process and make new variations.” The project began in 2016 with the first round of mutagen- esis. The following year, the researchers sprayed plants in the field at research centers in Fort Collins and Rocky Ford but were unable to find a resistant plant. In 2018, they used a different mutagenesis method and are in the process of growing the treated seed containing that trait. Next summer, herbicide will again be applied, and by the end of the project, the researchers will know if they’ve found a mutation that provides resistance to herbicides used on grasses. Gaines says that they already know a great deal about the way resistance to herbicides works. Based on that knowledge, he says there are seven different places in one sorghum gene where they could find a mutation that would let sorghum resist grass herbicides. As U.S. sorghum growers voice concerns about the lack of weed control options, the Sorghum Checkoff has funded three projects to help provide answers. Elise Brown elise.e.brown@outlook.com Research Weeds UPROOTS As part of the research effort to identify germplasm with natural herbicide tolerance, Kansas State University doctoral student Balaji Aravindhan Pandian is part of a team evaluating 1,000 different sorghum genotypes from around the world.