Optimum selection intensities in artificial selection programmes: an experimental evaluation

Abstract

SUMMARYAn experimental evaluation of Robertson's (1970) theory concerning optimum intensities of selection for selection of varying durations has been carried out using published results from a long term selection study inDrosophila. Agreement of predicted rankings of treatments with expectations was excellent for low values oft/T(generations/total number scored) but poor for larger values oft/T. This was due to the 20% selection intensity treatments responding worse than expected and the 40% treatments relatively better than expected. Several possible reasons for the discrepancies exist but the most likely explanation is considered to be the greater reduction in effective population size due to selection in treatments with more intense selection.