Inheritancemode and realized heritability of resistance to imidacloprid in the brown planthopper, Nilaparvata lugens (Stål) (Homoptera: Delphacidae)

BACKGROUND: The brown planthopper, Nilaparvata lugens (Stål), is a serious pest that causes enormous losses to the rice crop in Asia. The genetic basis of imidacloprid resistance was investigated in N. lugens. RESULTS: The resistant strain, selected for imidacloprid resistance from a field population of N. lugens collected from Nanjing, Jiangsu Province, China, showed a 964-fold resistance compared with the laboratory strain. Progenies of reciprocal crosses (F1 and F1') showed similar dose-mortality responses (LC50) to imidacloprid, and also exhibited a similar degree of dominance (D), 0.58 for F1 and 0.63 for F1'. Chi-square analyses of self-bred and backcross progenies (F2, F2' and BC respectively) rejected the hypothesis for a single gene control of the resistance. The estimated realized heritability (h2) of imidacloprid resistance was 0.1141 in the resistant strain of N. lugens. CONCLUSION: The results showedthat imidacloprid resistance in N. lugens was autosomal andwas expressed as an incompletely dominant trait, probably controlled bymultiple genes.