Genetical Studies on Resistance to Chlorinated Hydrocarbons in Euxesta notata (Wied.)

Abstract

AbstractThe inheritance of dieldrin-resistance and DDT-resistance was studied in a laboratory colony of the spotted root maggot Euxesta notata collected in 1960 at Delhi, Ontario. By appropriate selection methods the colony was divided into 4 strains, namely dieldrin-resistant, dieldrin-susceptible, DDT-resistant and DDT-susceptible. Crosses made between the R and S strains showed that dieldrin-resistance segregated sharply, and was inherited as if due to a single gene allele. An excess of heterozygotes over that expected suggested a certain amount of over-dominance with respect to survival. DDT-resistance did not segregate sharply, but the results of the various crosses were in agreement with the idea that this factor, which was very slightly dominant, was due to a single gene allele. Cross-resistance data for R and S strains indicated that dieldrin-resistance and DDT-resistance were completely separate entities in this species.