tailieunhanh - Báo cáo sinh học: "Restricted multistage selection indices"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Restricted multistage selection indices | 193 Genet Sei Evol 1997 29 193-203 Elsevier Inra Original article Restricted multistage selection indices c Xie s Xu Department of Botany and Plant Sciences University of California Riverside CA 92521-0124 USA Received 12 November 1996 accepted 3 April 1997 Summary - Multistage selection index is an important extension to single stage selection index for genetic improvement of multiple traits. Recently a multistage selection procedure referred to as selection index updating has been developed. This procedure combines several desired aspects of independent culling and selection index. In this study we directly extend selection index updating to cases of restricted multistage selection indices by imposing restrictions for solving index coefficients. 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 possibility of imposing restrictions on different stages is also discussed. A numerical example is given to illustrate the calculation of restricted multistage selection indices. independent culling multistage selection restricted selection index sequential selection Resume Index contraints dans la selection à étapes. L index de selection à plusieurs etapes est une extension importante de I index de selection à une seule étape. Recemment Xu et Muir ont développé une procedure de selection à plusieurs étapes appelêe index de selection avec mise à jour. Cette procedure combine plusieurs aspects intéressants de la selection sur index et de la selection à niveaux indépendants. Dans cette étude nous étendons directement la mise à jour des index de selection au cas d index de selection à plusieurs étapes en imposant des restrictions pour trouver les coefficients des index. Les index correspondants contraignent les progrểs génétiques à être nuls ou à être dans des rapports donnés pour des caractères OU des combinaisons de .