The invention discloses a molecular detection method for 
rapid identification of genotypes of anti-fenoxaprop-P-ethyl 
Beckmannia syzigachne containing Ile-1781-Leu 
mutation based on LAMP technology. The detection method can be used for early warning and 
epidemiological monitoring of 
Beckmannia syzigachne containing the Ile-1781-Leu 
mutation. The detection method comprises altogether three main steps: (1) respectively extracting 
genomic DNA of a sample to be detected; (2) designing 
specific primers and carrying out LAMP isothermal amplification; and (3) adding the fluorescent dye 
SYBR Green I into an LAMP amplification product and observing 
color changes, or carrying out separation through 
agarose gel electrophoresis with 3.0% 
agarose and observing amplification results, wherein whether there is a 
population of 
Beckmannia syzigachne containing the Ile-1781-Leu 
mutation is determined based on the results, a 
population of Beckmannia syzigachne is determined to be a 
population containing the Ile-1781-Leu mutation if the LAMP amplification product is yellow or 
electrophoretogram is in the form of a scalariform strip, and a population of Beckmannia syzigachne is determined to be a population not containing the Ile-1781-Leu mutation if the LAMP amplification product is orange or 
electrophoretogram has no strip amplification. According to the invention, isothermal amplification is realized, expensive instruments and equipment and tedious 
electrophoresis process are not needed, and detection time and cost are substantially reduced. Compared with common PCR, the detection method provided by the invention has the characteristics of high sensitivity, strong specificity, high detection accuracy, etc.