Inbreeding Effective Population Size Under Some Artificial Selection Schemes. II. Normal Distribution of Breeding Values

Abstract

Two selection systems, truncation selection followed by a balanced mating (truncation selection) and a selection scheme that assigns mating frequencies to individuals according to their breeding values (weighting system), were compared with respect to inbreeding effective population size. This comparison was made with the condition that both selection schemes give the same expected performance of selected individuals (selection differential). Breeding values of selected individuals were assumed to be normally distributed on a performance scale. Two functions, linear and Beta, were used to represent weighting systems. The results showed that (1) depending on the distribution of breeding values, inbreeding effective population number of some weighting systems can be greater than that of a truncation selection that generates the same selection differential, and (2) because the difference in inbreeding effective population size using different systems can be substantial, it is worth examining for the presence of desirable weighting systems in practical tree breeding situations. For. Sci. 35(2):303-318.