Resistance of Leptochloa chinensis(L) Nees. to cyhalofop-butyl in rice field of direct seeding and resistance biochemical mechanism research

ObjectiveIn the present study,resistance of Leptochloa chinensis(L) Nees. to cyhalofop-butyl in rice field of direct seeding and influence of cyhalofop-butyl on L. chinensis(L) Nees. metabolic enzyme and antioxidase were studied, in order to provide reference for control and resistance management of L. chinensis(L) Nees. MethodUsing whole-plant assay method, resistance levels of different L. chinensis(L) Nees. populations from ten rice fileds of direct seeding to cyhalofop-butyl were detected. The differences between resistant and susceptible L. chinensis(L) Nees. popula-tions in activities of Glutathione s-transferase(GSTs), superoxide dismutase(SOD), peroxidase(POD) and catalase(CAT) were analyzed. ResultResults showed that Meijiang population was identified as susceptible population, the resistance in-dex of other populations to cyhalofop-butyl was 1.2-11.0, and the highest resistance index was 11.0, which was found in Chashan'ao town, Hengyang. The activity of GSTs in resistant population increased sharply after 2 days of 75.000 g/ha cyhalofop-butyl treatment, reached the highest value after day 3, then decreased rapidly and became steady after day 5. One day after the treatment, the activity of GSTs in susceptible population increased sharply and reached the maximum on day 2, and then declined. The activity of GSTs in the susceptible population was lower than that of the resistant population during day 3-7. The variation trend of SOD, POD and CAT activities in resistant and susceptible populations was similar, but the values of resistant population was significantly higher than those of susceptible population. ConclusionAmong ten L. chinensis(L) Nees. populations, the resistance level of Chashan'ao population to cyhalofop-butyl was the highest, which is at a moderate level. The resistance of the resistant L. chinensis(L) Nees. population to cyhalofop-butyl may be related to the enhancement of GSTs, SOD, POD and CAT activities.