豚の閉鎖群育種において相対希望改良量に産子数を含めた場合の期待改良量  [in Japanese] Expected Genetic Gains From Desired Change Index in Selection for Increased Litter Size in a Closed Swine Herd  [in Japanese]

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Abstract

相対希望改良量を達成するための家系情報に基づく選抜指数によって, アニマルモデルによる制限付きBLUP法を用いた選抜による育種価の期待改良量E (Δg) を試算した。改良目標形質は, 1日平均増体重 (DG), 背脂肪厚 (BF) および産子数 (LS) とした。家系の情報は, 選抜候補を第0代とし, 4代祖までの選抜候補の直系およびそれらの全きょうだいと半きょうだいの表型価および血縁関係を用いた。選抜候補世代はLSの表型価を持たないものとした。交配は雄1頭に対し雌5頭とし, 腹あたりの選抜候補豚の頭数は2~4頭とした。DG, BF, LSの遺伝率はそれぞれ0.3, 0.5, 0.1, DGとBFの遺伝および表型相関は0.2, LSとDGおよびBF間の相関は0とした。LSの相対希望改良量を小さくした場合, 制限付きBLUP法による各形質のE (Δg) は, DGおよびBFの2形質の選抜指数とLSの表型価に基づく選抜によるE (Δg) に等しくなることが期待された。また, LSの相対希望改良量を大きくした場合, 制限付きBLUP法によるLSのE (Δg) は, LSのみの BLUP 法によるそれに類似することが期待された。さらに, 改良目標に達している形質がある場合, 例えばBFの集団平均が最適値に達している場合, LSのE (Δg) はより大きくなることが期待された。

Selection index based on family information was used to estimate expected genetic gains resulting from selection based on animal model BLUP of breeding values. The breeding objective was to achieve predetermined desired changes for average daily gain (DG), backfat thickness (BF) and litter size at birth (LS). Information for selection was on the candidate's parents and their full and half sibs found in generation F<sub>-1</sub>, grand parents and their full and half sibs found in generation F<sub>-2</sub>, F<sub>-i</sub> was defined as animals in the i<sup>th</sup> generation back. The candidate for selection was found in the current generation F<sub>-0</sub>. Records from F<sub>-0</sub> to F<sub>-4</sub> were used in the present study. All animals were assumed to have one record for DG and BF and each female animal except those in current generation was assumed to have one record for LS. Each male was mated to 5 females. The number of candidates for selection per litter was varied from 2 to 4. The respective heritabilities of 0.3, 0.5 and 0.1 for DG, BF and LS, with genetic and phenotypic correlations between DG and BF of 0.2 were used. No correlations between LS and DG and BF were assumed. When desired change of DG, BF and LS was 2:2:1, estimated genetic gain of each trait using selection on restricted BLUP was as large as that on two-trait selection index for DG and BF and individual phenotype for LS. When desired change of DG, BF and LS was 1:1:2, estimated genetic gain of LS using restricted BLUP was equal to that using single trait BLUP for LS. Furthermore, if the population was at the optimum for BF, larger genetic gain was expected for DG and LS.

Journal

  • Nihon Yoton Gakkaishi

    Nihon Yoton Gakkaishi 36(1), 13-17, 1999-03-10

    The Japanese Society of Swine Science

References:  18

Cited by:  2

Codes

  • NII Article ID (NAID)
    10008285190
  • NII NACSIS-CAT ID (NCID)
    AN10202971
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    0913882X
  • NDL Article ID
    4682706
  • NDL Source Classification
    ZR22(科学技術--農林水産--畜産)
  • NDL Call No.
    Z18-1082
  • Data Source
    CJP  CJPref  NDL  J-STAGE  JASI 
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