Non-Additive and Sex-Linked Genetic Effects on Egg Production in a Randombred Population ,

NUMEROUS heritability estimates for egg production and egg quality traits are available in the literature. Most of these reports were calculated from matings of dams within sires and, therefore, include a part of the non-additive variance which may have been present in the population. Relatively few researchers have attempted to partition the additive and non-additive genetic variance for these traits. Jerome, Henderson and King (1956) reported that the magnitude of non-additive genetic variance was larger than the additive genetic variance for survivors’ production over a period of a year. Also, the authors reported that the magnitude of non-additive variance was larger for production for 365 days as compared with shorter production periods up to four months. Fuchs and Krueger (1957) reported that non-additive effects appeared to be important in egg production in single and three-way crosses but of questionable magnitude in pure strains.