Selection and realized heritability analysis of resistance to imidacloprid in cotton aphid( Aphis gossypii)

【Aim】In order to evaluate the resistance risk of the cotton aphid,Aphis gossypii Glover,to imidacloprid,the selection and realized heritability analysis of resistance to imidacloprid in A. gossypii were performed in the laboratory. 【Methods】The imidacloprid-susceptible and resistant strains were developed by individual reverse and group selection,with the LC50values of 0. 176 and 14. 657 mg /L,respectively. The realized heritability( h2) of A. gossypii resistance to imidacloprid was estimated by Tabashnik's method. 【Results】Compared with the LC50value of the original field strain of A. gossypii( 0. 346 mg/L),the LC50value of the imidacloprid-susceptible strain had a 2-fold decrease. The resistance index of the imidacloprid-resistant strain was 83. 27-fold as high as that of the imidaclopridsusceptible strain after 40 generations of selection. The realized heritability( h2) of A. gossypii resistance to imidacloprid was 0. 1478. It was predicted that A. gossypii would require 30. 2 to 38. 1 generations to obtain 100-fold resistance to imidacloprid under breeding pressure of imidacloprid with 80%- 90%mortality for each generation of selection. 【Conclusion 】 The results suggest that A. gossypii has resistance risk to imidacloprid.