RESTRICTED MULTISTAGE SELECTION INDEXES

Multistage selection index is an important extension to single stage s election index for genetic improvement of multiple traits. Recently, a multistage selection procedure, referred to as selection index updati ng, has been developed. This procedure combines several desired aspect s of independent culling and selection index. In this study, we direct ly extend selection index updating to cases of restricted multistage s election indices by imposing restrictions for solving index coefficien ts. The resulting indices restrict genetic changes to zero or to some proportion in the chosen characters or linear functions of characters. As such, it makes multistage selection indices more flexible. The pos sibility of imposing restrictions on different stages is also discusse d. A numerical example is given to illustrate the calculation of restr icted multistage selection indices.