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

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 F-1 progeny from the reciprocal crosses (R female x S male and S female x R male) 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 F-1 progeny to both the susceptible and resistant strains and on F-2 progeny were highly significant. Low-level resistance typical of Australian populations of T. castaneum is conferred by 1 gene.