This open access book focuses on the linear selection index (LSI) theory and its statistical
properties. It addresses the single-stage LSI theory by assuming that economic weights are
fixed and known - or fixed but unknown - to predict the net genetic merit in the phenotypic
marker and genomic context. Further it shows how to combine the LSI theory with the
independent culling method to develop the multistage selection index theory. The final two
chapters present simulation results and SAS and R codes respectively to estimate the
parameters and make selections using some of the LSIs described. It is essential reading for
plant quantitative geneticists but is also a valuable resource for animal breeders.
