Elimination of a Recessive Allele Conferring Resistance to Bacillus thuringiensis from a Heterogeneous Strain of Diamondback Moth (Lepidoptera: Plutellidae)
Authors: LIU, YONG-BIAO; TABASHNIK, BRUCE E.
Source: Journal of Economic Entomology, Volume 91, Number 5, October 1998 , pp. 1032-1037(6)
Publisher: Entomological Society of America
Abstract:We devised and tested a procedure for eliminating a recessive allele conferring resistance to Bacillus thuringiensis subsp. kurstaki from a laboratory strain of diamondback moth, Plutella xylostella (L.), composed of resistant and susceptible individuals. We established a homozygous susceptible strain (LAB-PS) from a heterogeneous strain (LAB-P) as follows: We obtained F1 progeny from 7 single-pair families from the heterogeneous strain. Hybrid F2 progeny were produced in 7 mass crosses, each of which involved 10 female F1 progeny from a single-pair family and 10 males from a resistant strain (NO-QA). The hybrid F2 progeny were tested in bioassays with a liquid formulation of B. thuringiensis toxin Cry1Ab at a diagnostic concentration that kills susceptible homozygotes and heterozygotes, but not resistant homozygotes. If the resistance allele occurred in either of the 2 parents that produced a particular F1 family, the hybrid F2 progeny derived from that family were expected to contain at least 25% homozygous resistant individuals that would survive exposure to the diagnostic concentration of CrylAb. Conversely, 0% survival of a set of hybrid F2 progeny in the diagnostic bioassay would indicate that the single-pair family from which it was derived was homozygous susceptible. We found 0% survival in 1 set of hybrid F2progeny and used the F1 single-pair family from which this set was derived to establish a homozygous susceptible strain. Subsequent bioassays showed that diagnostic concentrations of CrylAb or CrylAa killed 100% of larvae tested from this strain. The LC50 of CrylAb at 5 d for the susceptible strain was 7-fold lower than that for the heterogeneous strain. The procedure can be adapted for other insects and other traits, such as resistance to other insecticides.
Document Type: Research Article
Publication date: October 1, 1998
- Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.
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