The Heritability of Body Weight in Turkeys

THE basis for genetic improvement of any population is genetic variation within that population. The type of breeding plan to be used and the improvement possible from selection on a phenotypic basis are determined by the degree of heritability of the character involved. The purpose of this study is to estimate the heritability of body weight in turkeys at various ages. The influence of environment on the expression of a complex physiological character such as growth no doubt varies with age. Since heritability is that proportion of total variance due to additive genetic variance, a change in the environmental influence, which is included in total variance, would result in a change in heritability. In the case of body weight, it is not certain that inheritance up to 8 or 12 weeks of age is the same as that responsible for later body weight or ultimate body weight. Schnetzler (1936) found…