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Báo cáo sinh học: "Increasing long-term to selection"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Increasing long-term to selection | Genet Sei Evol 1994 26 431-451 Elsevier INRA 431 Original article Increasing long-term response to selection NR Wray ME Goddardt Livestock Improvement Unit Victorian Institute of Animal Science 475 Mickleham Road Attwood Victoria 3049 Australia Received 8 September 1993 accepted 25 May 1994 Summary Selection on estimated breeding value EBV alone maximises response to selection observed in the next generation but repeated use of this selection criterion does not necessarily result in a maximum response over a longer time horizon. Selection decisions made in the current generation have at least 2 consequences. Firstly they influence the immediate genetic response to selection and secondly they influence the inbreeding of the next and subsequent generations. Accumulation of inbreeding has a negative impact on future genetic response through reduction in future genetic variance and a negative impact on future performance if inbreeding depression affects the selected trait. Optimum selection decisions depend on the time horizon of interest. If this is known then a breeding objective can be defined. A selection criterion is proposed in which the positive contributions of a selected group of parents to immediate genetic response determined by their average EBV is balanced against their negative contribution to future genetic response determined by their contribution to inbreeding . The value assigned to the contribution to inbreeding is derived from the breeding objective. Selection of related individuals will be restricted if the detrimental value associated with inbreeding is high restrictions on the selection of sibs however is flexible from family to family depending on their genetic merit. A selection algorithm is proposed which uses the selection criterion to select sires on 3 selection strategies to select on i a fixed number of sires ii a variable number of sires each allocated an equal number of matings or iii a variable number of sires allocated an optimal .