Genetics of Biotypes B and C of the Hessian Fly1

Abstract

The results of a study of the genetic interrelationship between varieties of wheat, Biotypes B and C of the Hessian fly, Mayctiola destructor (Say), and progenies of the hybrids of the 2 biotypes suggested that: (1) the gene for virulence (ability to attack ‘Monon’ wheat) in Biotype B flies and the gene for virulence to ‘Knox 62’ in Biotype C flies are on separate chromosomes. (2) The allele M in Biotype C that causes it to be avirulent to Monon wheat is located near the centromere; the allele K in Biotype B that causes it to be avirulent to Knox 62 is located at a considerable distance from the centromere. (3) During spermatogenesis in the Hessian fly, paternally derived centromeres and the attached chromatin are eliminated. (4) Crossing over occurs in the male Hessian fly prior to elimination of the chromatin.