22 / SEEDWORLD.COM DECEMBER 2018 “We’re looking for the one mutation in millions that would cause resistance,” Gaines says. Researchers plant the treated seed in test plots, spray the resulting plants with ACCase inhibitors, such as qui- zalofop and clethodim, which control grasses and not broad- leaf plants, and see which ones survive. From there, the research team can tell which gene or mutation enabled the plant’s survival. “If and when we discover the resistance trait, we’ll start working with plant breeders to do inbred lines, so they can work with varieties,” Gaines shares. “We’ll also work with an herbicide company to develop a new herbicide label.” The new variety that is developed will need a herbi- cide label and EPA’s approval. Gaines anticipates that the process from beginning to end (from seed treatment and planting for experiments to an herbicide being used in the field) will take 10 to 12 years. The wait could be worth it for producers. “This would be an addi- tional management tool for a difficult problem,” Gaines says. “It doesn’t solve everything, but anything we can do to diversify weed management is good. It could make grow- ing sorghum an option in fields where it isn’t right now.” Research partners include Colorado Sorghum; Michael Bartolo at Colorado State Arkansas Valley Research Center in Rocky Ford; Phil Westra, Colorado State Extension weed specialist; and Olivia Todd, doctoral student. Testing Germplasm To the east, two K-State scien- tists were awarded grants for PROJECT 2 Researcher: Mithila Jugulam, Kansas State University associate professor of weed science Grant: $30,000 annually Duration: 3 years, starting in 2015 Status: Ongoing Scope: To evaluate sorghum germplasm from around the world and identify herbicide- tolerant traits with the goal of breeding that trait into elite lines. AT A GLANCE PROJECT 1 Researcher: Todd Gaines, Colorado State University assistant professor of weed science Grant: $150,000 Duration: 5 years, starting in 2016 Status: Ongoing Scope: To develop new herbicide resistant traits in sorghum using mutagenisis PROJECT 3 Researcher: Anita Dille, Kansas State University professor of weed ecology Grant: $160,000 Duration: 18 months, spanning two crop years Status: Complete Scope: To evaluate the ecol- ogy of grass weeds found in grain sorghum and determine critical control stages, as well as species of concern. separate research projects: one for identifying germplasm with herbicide tolerance and the other for understanding ecology and competition. When Jugulam first began her career at K-State as a weed physiologist, sorghum grow- ers were expressing their concerns about the lack of herbicide options available. She began to brainstorm solutions with Curtis Thompson, a retired K-State Extension weed specialist. The checkoff granted Jugulam’s research team $30,000 annually for three years to evalu- ate sorghum germplasm and identify herbicide- tolerant traits. The project began in 2015 when researchers collected 1,000 different sorghum genotypes from around the world. Jugulam explains: “We thought if we screen a large collection of sorghum genotypes, we could identify lines that are naturally tolerant.” Seed samples were grown in Petri dishes con- taining various herbicide concentrations and tested in the laboratory. The researchers then observed whether or not plants grew from these media and examined any resulting physical appearance and, if any, damage from the herbicide. From those experiments, they found 30-40 genotypes that exhibited tolerance to the herbicide. These plants then were tested in the greenhouse, where the genotypes were narrowed down to three or four that showed elevated herbicide tolerance. For comparison purposes, a sensitive genotype and a commer- cial check also were used in the experiment. The genotypes with high herbicide toler- ance were tested for two years in the field. The results were consistent with what was found in the lab and greenhouse. The primary data showed that in the tolerant lines, herbicide degrades rapidly, similar to how the same herbi- cides work in corn. The research team also looked at yield to see if there would be any loss. “Compared to nontreated, the treated herbicide-tolerant genotypes did not have any yield penalty,” Jugulam says.