| Abstract: | Populations of M.persicae from glasshouses in Britain were found to have a structurally heterozygous chromosome complement. Biometric data from somatic metaphase chromosomes, and the pairing configurations of chromosomes at spermatocyte meiosis, indicate either a simple or a reciprocal translocation involving autosomes 1 and 3. All except one of the clones started from these populations showed high levels of esterase activity indicative of resistance to organophosphorus insecticides. The British translocated clones were all androcyclic in reproductive character, but of several distinct genotypes. A similar or identical translocation was found in seven out of nine clones started from M.persicae collected in the field in Japan. The translocation was present in Japanese M.persicae of all reproductive categories, being somehow maintained in the sexual breeding system of the aphid. In breeding experiments, translocation heterozygosity was inherited independently from colour and reproductive characters. The translocation was also found in a sample of M.persicae from southern California. |
