Inheritance of phosphine resistance in Tribolium castaneum (Coleoptera: Tenebrionidae)

Abstract

The genetics of phosphine resistance was studied in a resistant strain of the red flour beetle, Tribolium castaneum (Herbst), developed from field collections in Queensland, Australia. A program of inbreeding and selection was maintained for 5 generations to promote homozygosity in this strain and a laboratory-susceptible strain. The strain was then 12.7 times resistant in the Food and Agriculture Organization of the United Nations test on adult insects. Data from the testing of F1 progeny from the reciprocal crosses (R♀ × S♂ and S♀ × R♂) indicated that resistance was autosomal and semidominant with a degree of dominance −0.47 (−0.51, −0.44). Modified chi-square analysis and contingency analysis of data from the response of test crosses of F1 progeny to both the susceptible and resistant strains and on F2 progeny were highly significant. Low-level resistance typical of Australian populations of T. castaneum is conferred by 1 gene.