Sex-Linked and Maternal Effects in the Diallel Cross

Abstract

The diallel cross has been used frequently in plant experiments to partition the genetic variation into general and specific combining abilities of inbred lines. The statistical models developed for analysis of diallel crosses in plants have been used in a number of studies of diallel crosses in mammals and poultry, without due consideration to the presence and effect of the sex chromosomes. Two statistical models for the analysis of the modified diallel cross, one assuming maternal effects and one assuming no maternal effects, were compared for male and female progeny of both male homogametic species and female homogametic species. It was found that neither statistical model is adequate to separate the effects of sex-linked genes from both maternal and autosomal additive genetic effects when data on only one sex of progeny are analyzed. Utilization of estimates from both statistical models provides a crude estimate of sex-linked, maternal, and additive autosomal effects only in the case of female progeny of male homogametic species such as poultry.