Improving Accuracy of Heritability Estimates from Diallel and Triallel Matings in Poultry

ACCURACY in estimating heritabilities may be improved by increasing the number of parents, by choosing the most appropriate mating system, and by increasing the number of progeny. Goodman and Jaap (1960) concluded that, within closed populations, heritability estimates from 50 sets of diallel matings consisting of 200 families with the equivalent of four full sibs per family, were superior to estimates from 30 triallel sets consisting of 270 families with full-sib families of two individuals. The two strains of New Hampshire used in that report had long closed-flock histories and the additive genetic effects on eight-week weight were low compared with reports in the literature. Non-additive genetic effects were very low or non-existent. Also, the parents used in that study had been intensely selected for growth. Weights of the spleen and the bursa of Fabricius in baby chicks from a randombred population were chosen for the tests to be reported …