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

The genetics of phosphine resistance was studied in a resistant strain of t he red flour beetle, Tribolium castaneum (Herbst), developed from field col lections 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 i nsects. 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 autos omal and semidominant with a degree of dominance -0.47 ( -0.51, -0.44). Mod ified chi-square analysis and contingency analysis of data from the respons e of test crosses of F-1 progeny to both the susceptible and resistant stra ins and on F-2 progeny were highly significant. Low-level resistance typica l of Australian populations of T. castaneum is conferred by 1 gene.