Abstract: The methods of cross and back-cross between resistant and susceptible populations were used for exploring the inheritance mode of resistance to deltamethrin in the cotton bollworm Helicoverpa armigera (Htubner). The results showed that the degree of dominance of F_Rs and F_sR were 0.34 and 035, respectively. The difference between expectations and actual values of both backcross ratios of RS∶SS and SR ∶SS was significant at 1∶1, and the backcross plateaus were at 35%-45%, suggesting that the resistance of cotton bollworm to deltamethrin was controlled by the incompletely dominant genes. The anaphthylacetate esterase may be an improtant factor resulting the resistance of cotton bollworm to deltamethrin.

Key words: cotton bollworm, pyrethroids, resistance inheritance, detoxffication