Evolution of ACCase-inhibitor resistance in Chloris virgata is conferred by a Trp2027Cys mutation in the herbicide target site.

Background: Chloris virgata is a troublesome weed in tropical regions. With the evolution of glyphosate resistance in key grass species, acetyl CoA carboxylase (ACCase) inhibitors have become a commonly used tool in soybean production areas in Brazil. We assessed if suspected resistant populations exhibited cross resistance to the different classes of ACCase inhibitors and investigated the resistance mechanisms in C.