Loop‐Mediated Isothermal Amplification for Detecting the <i>ACCase</i> Gene <scp>Ile‐1781‐Thr</scp> Mutation in Fenoxaprop‐ <i>P</i> ‐Ethyl‐Resistant <i>Alopecurus myosuroides</i>

ABSTRACT Alopecurus myosuroides is among the most problematic weed species affecting crop production globally. In Chinese wheat fields, its management has predominantly relied on acetyl‐CoA carboxylase (ACCase)‐inhibiting herbicides, such as fenoxaprop‐ P ‐ethyl, over the past two decades. However, the prolonged use of this herbicide class has led to the rapid evolution of resistance in A. myosuroides . In this study, a suspected fenoxaprop‐ P ‐ethyl‐resistant population, AHHY‐1 (R), was collected from a wheat field in Anhui Province, China. Whole‐plant dose–response experiments revealed that, compared with the susceptible population AHFX‐1 (S), the R population exhibited high‐level resistance to fenoxaprop‐ P ‐ethyl, with a resistance index of 33.25. Sequencing of the target gene indicated that the isoleucine residue at position 1781 (ATA codon) in the ACCase carboxyltransferase domain of R plants was substituted with threonine (ACA codon), with a mutation frequency of 100%. To enable rapid and efficient detection of the common Ile‐1781‐Thr mutation in A. myosuroides , a loop‐mediated isothermal amplification (LAMP) assay was developed. Following systematic optimization of primer sequences, reaction components, and amplification conditions, the LAMP assay reliably distinguished between wild‐type and mutant genotypes. The incorporation of SYBR Green I dye facilitated visual detection of amplification via a distinct color change, observable without instrumentation. Notably, the LAMP assay demonstrated approximately 10 5 ‐fold greater sensitivity than conventional PCR. Collectively, the developed LAMP method provides an efficient tool for detecting the Ile‐1781‐Thr mutation in the ACCase gene of A. myosuroides , offering a valuable tool for resistance monitoring and management strategies.