Echinochloa crus-galli is a problematic weed that affects rice yield. Understanding the mechanisms underlying herbicide resistance in E. crus-galli is essential for sustainable rice cultivation. This study demonstrated that the R-HY population of E. crus-galli developed a moderate (3.4-fold) resistance to cyhalofop-butyl following prolonged selection pressure. This population also displayed cross-resistance to pinoxaden and multiple resistance to penoxsulam and tripyrasulfone. No mutations were