Quantitative Genetics of Autogamous F₂

Abstract

General quantitative genetic properties are derived for the F₂ originating from self-fertilisation of hybrid (F₁) individuals. These results extend and generalise previous restricted knowledge about this F₂. New equations are found for all genotype frequencies, allele frequencies, inbreeding coefficient, genie (additive-genetic) and dominance variances, broadsense and narrowsense heritabilities, and selection potential. The bulk mean is generally lower, and the genotypic variance is generally higher, than those of the F₁ and the allogamous F₂. Genic and dominance variances for the selfed F₂ are very different to the classical counterparts. Their relationships with inbreeding have been investigated, and they are more elaborate than previously considered. The level of inbreeding is constant irrespective of parental combinations, which is different to the inbreeding of an allogamous F₂. Selection potential is generally high, and selection advance generally exceeds bulk inbreeding depression. If selection is assisted by dispersion, the autogamous F₂ may obtain greater genetic advance than its allogamous counterpart for the same selection pressure. Under conditions of spatially separated F₂ swarms, natural selection may be enhanced by selfing.