Genetic control of the pest lepidoptera: Gamma-ray induction of translocations between sex chromosomes of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae)

Abstract

The method suggested by Strunnikov for genetic control of the pest Lepidoptera is based on the release of males, which are trans-heterozygous for two sex-linked recessive lethal mutations. For construction of such males, it is necessary to have females in which a part of the Z chromosome is translocated onto the W chromosome so that wild-type alleles of this translocation protect females from the lethal mutations. In the present study, the induction and isolation of the required translocations have been investigated in Ephestia kuehniella Zeller. Translocations were induced by means of γ-irradiation in oocytes of 4 different age groups of pupae, and in adult female oocytes. Doses of 25, 50, 75 or 100 Gy were used. Detection of translocations was performed using the sex-linked recessive mutation dz. A total of 12 mutant lines has been isolated. In 4 of these lines, females were proved to possess the required T( W; Z) translocation. In the other lines, unexpected phenotypes were segregated in atypical ratios; the genetic mechanism which could explain this fact remains to be clarified. In addition, the optimal stage of female development and the adequate dose of γ-radiation for the induction of T( W; Z) translocations are discussed.