GENETIC STUDIES OF CHLOROPYRIFOS, AN ORGANOPHOSPHATE INSECTICIDE RESISTANCE IN ANOPHELES STEPHENSI LISTON - A MALARIA MOSQUITO

摘要

A diagnostic dose of 0.2 ppm of chloropyrifos was used against the late third instar larvae of A. stephensito establish homozygous resistant and susceptible strain, by selective inbreeding for 23 and 5 generations respectively. Genetic crosses were carried out between homozygous resistant, susceptible, F hybrid (RxS), backcrosses and F_2 generations. The dosage - mortality (d-m) lines were constructed for each of the crosses and degree of dominance was calculated. The data of the crosses between resistant and susceptible strain and dosage mortality relationship of the crosses clearly showed that the gene for Chloropyrifos resistance (cpr) is incompletely dominant and autosomal. For the first time, the genetic basis of Chloropyrifos resistance has been studied among mosquitoes, especially in A. stephensi. The gene cpr is an excellent marker, which could be used in the synthesis of genetic sexing strain/s (as a conditional lethal) for the preferential elimination of females in the genetic control program of A. stephensi in India.