Mode of inheritance of chlorpyrifos resistance in diamondback moth

Abstract

Diamondback moth is one of the destructive insect pests of brassicaceous vegetable crops worldwide with increased insecticide resistance. Chlorpyrifos is one of the most widely-used organophosphate insecticides to control various pests including P. xylostella. The insecticide resistance in Plutella xylostella can be best managed by perceiving CPF resistance inheritance. We designed this experiment to evaluate CPF resistance's genetics of two genetically pure lines of P. xylostella, namely insensitive AChE1-carrying Kar-R resistant strain and Gu-S wild-type strain. A considerable difference was observed among LC50 values of F1 (Kar-R♀ × Gu-S♂) and F1′ (Kar-R♂ × Gu-S♀) strains due to reciprocal crosses between each resistant strain and susceptible strains. The degree of dominance values were 0.58 and 0.75, respectively suggesting an autosomal and partially dominant resistance. The χ2 goodness-of-fit test results and measuring the number of genes which segregate in CPF-resistant strain suggested that several genetic factors control the resistance.