Selection for Heterozygotes during Inbreeding

Abstract

RYE is normally an outbreeding species. When the plants are forced to inbreed by self-pollination, the progeny, being more homozygous, are, as is usual in such species, less vigorous and less fertile than the heterozygotes which comprise a normal population. Since heterozygotes are superior in this way to the homozygotes, it could be expected that, during the course of inbreeding, natural selection would favour to some extent the more heterozygous genotypes. To test this assumption, we have made use of chromosome structural changes where genotypes heterozygous and homozygous for the chromosome segments involved are easily distinguished.