Date of Graduation


Document Type


Degree Name

Master of Science in Crop, Soil & Environmental Sciences (MS)

Degree Level



Crop, Soil & Environmental Sciences


Jason K. Norsworthy

Committee Member

Trent Roberts

Second Committee Member

L T. Barber

Third Committee Member

Andy Maromoustakas


ACCase, Fluazifop, Grain Sorghum, TamArk, Weed Science


Herbicide-resistant crops have been commonly used in corn, cotton, and soybean since the 1990s to control numerous different grass and broadleaf weeds. However, this technology has not been available for grain sorghum producers whom have faced challenges controlling grass weeds. Recently a collaboration between the University of Arkansas and Texas A&M University has resulted in a new bred line of grain sorghum, TamArkTM, which is resistant to ACCase inhibitor herbicides which have been previously used to control grass weeds in broadleaf crops. Multiple studies were conducted to determine the sensitivity of TamArkTM and problematic grass weeds to ACCase inhibitor herbicides, and to determine if johnsongrass in major sorghum producing states is resist to new herbicides that could be used in herbicide resistant grain sorghum. It was determined that TamArkTM grain sorghum was not sensitive to ACCase inhibitors from the aryloxyphenoxypropionate and phenylpyrozolin families. These herbicides also resulted in greater than 90% control of problematic grass weeds in grain sorghum. Johnsongrass resistance was found with fluazifop, nicosulfuron, imazamox, and glyphosate but was not deemed widespread.