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 | Acesso ao texto completo restrito à biblioteca da Embrapa Pecuária Sul. Para informações adicionais entre em contato com cppsul.biblioteca@embrapa.br. |
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Registro Completo |
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Biblioteca(s): |
Embrapa Caprinos e Ovinos; Embrapa Pecuária Sul. |
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Data corrente: |
25/11/2002 |
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Data da última atualização: |
25/11/2002 |
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Tipo da produção científica: |
Artigo em Periódico Indexado |
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Autoria: |
BENAVIDES, M. V.; MAHER, A. P. |
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Título: |
Quantitative genetic studies on wool yellowing in Corriedale sheep. II. Clean wool colour and wool production traits: genetic parameter stimates and economic returns. |
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Ano de publicação: |
2000 |
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Fonte/Imprenta: |
Australian Journal of Agricultural Research, v. 51, n. 2, p. 191-196, 2000. |
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Idioma: |
Inglês |
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Conteúdo: |
The potential for improvement of clean wool colour (CWC) in Corriedale sheep via selection was examined. The heritability, and phenotypic and genetic correlations, of CWC, brightness (Y), greasy (GFW) and clean (CFW) fleece weights , yield percentage (Yield), mean fibre diameter (MFD), and visual colour score were estimated from 440 progeny of 19 sires of a Corriedale flock using restricted maximum likelihood (REML) procedures with average information algorithm (AIREML).
The heritability of CWC was estimated at 0.27+-0.13. Clean wool colour showed strong positive genetic correlations with CFW and MFD. Visual colour score and CWC were also positively genetically correlated. As expected, direct selection criteria against MFD, CWC, or visual colour score would reduce CWC; however, direct selection M against MFD would improve clean wool colour with negligible reductions on CFW, thus resulting in small economic gains.
Several selection indices were calculated having either CFW, MFD, and CWC or CFW and MFD as selection criteria. The b-values of an unrestricted index were estimated at I1 =+ 1.15 CFW + 0.13 MFD + 0.43.CWC, with positive correlated responses for all 3 breeding objective traits (CFW, MFD, and CWC). A second index, where CFW was restricted to nil genetic change, was estimated at: I2 = + 0.14 CFW - 0.02 MFD + 0.01 CWC. This index was expected to cause a negligible genetic gain for CWC (-0.04 Y-Z units/head.year). To avoid economic losses with the reduction on CFW, a third selection index was calculated where CWC was restricted to nil change. The index was estimated at I3 = +0.61 CFW - 0.07 MFD + 0.02 CWC with expected increases in CFW and decreases in MFD. Selection indices with (a) CFW and MFD (4) and (b) CFW, MFD, and visual colour score (15) as selection criteria would increase CFW, MFD, and CWC at the same rates observed in I1. MenosThe potential for improvement of clean wool colour (CWC) in Corriedale sheep via selection was examined. The heritability, and phenotypic and genetic correlations, of CWC, brightness (Y), greasy (GFW) and clean (CFW) fleece weights , yield percentage (Yield), mean fibre diameter (MFD), and visual colour score were estimated from 440 progeny of 19 sires of a Corriedale flock using restricted maximum likelihood (REML) procedures with average information algorithm (AIREML).
The heritability of CWC was estimated at 0.27+-0.13. Clean wool colour showed strong positive genetic correlations with CFW and MFD. Visual colour score and CWC were also positively genetically correlated. As expected, direct selection criteria against MFD, CWC, or visual colour score would reduce CWC; however, direct selection M against MFD would improve clean wool colour with negligible reductions on CFW, thus resulting in small economic gains.
Several selection indices were calculated having either CFW, MFD, and CWC or CFW and MFD as selection criteria. The b-values of an unrestricted index were estimated at I1 =+ 1.15 CFW + 0.13 MFD + 0.43.CWC, with positive correlated responses for all 3 breeding objective traits (CFW, MFD, and CWC). A second index, where CFW was restricted to nil genetic change, was estimated at: I2 = + 0.14 CFW - 0.02 MFD + 0.01 CWC. This index was expected to cause a negligible genetic gain for CWC (-0.04 Y-Z units/head.year). To avoid economic losses with the reduction on CFW, a thi... Mostrar Tudo |
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Palavras-Chave: |
Melhoramento genético; Raça Corriedale; Viabilidade econômica. |
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Thesagro: |
Lã; Ovino; Parâmetro Genético. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 02578naa a2200205 a 4500
001 1528897
005 2002-11-25
008 2000 bl uuuu u00u1 u #d
100 1 $aBENAVIDES, M. V.
245 $aQuantitative genetic studies on wool yellowing in Corriedale sheep. II. Clean wool colour and wool production traits$bgenetic parameter stimates and economic returns.$h[electronic resource]
260 $c2000
520 $aThe potential for improvement of clean wool colour (CWC) in Corriedale sheep via selection was examined. The heritability, and phenotypic and genetic correlations, of CWC, brightness (Y), greasy (GFW) and clean (CFW) fleece weights , yield percentage (Yield), mean fibre diameter (MFD), and visual colour score were estimated from 440 progeny of 19 sires of a Corriedale flock using restricted maximum likelihood (REML) procedures with average information algorithm (AIREML). The heritability of CWC was estimated at 0.27+-0.13. Clean wool colour showed strong positive genetic correlations with CFW and MFD. Visual colour score and CWC were also positively genetically correlated. As expected, direct selection criteria against MFD, CWC, or visual colour score would reduce CWC; however, direct selection M against MFD would improve clean wool colour with negligible reductions on CFW, thus resulting in small economic gains. Several selection indices were calculated having either CFW, MFD, and CWC or CFW and MFD as selection criteria. The b-values of an unrestricted index were estimated at I1 =+ 1.15 CFW + 0.13 MFD + 0.43.CWC, with positive correlated responses for all 3 breeding objective traits (CFW, MFD, and CWC). A second index, where CFW was restricted to nil genetic change, was estimated at: I2 = + 0.14 CFW - 0.02 MFD + 0.01 CWC. This index was expected to cause a negligible genetic gain for CWC (-0.04 Y-Z units/head.year). To avoid economic losses with the reduction on CFW, a third selection index was calculated where CWC was restricted to nil change. The index was estimated at I3 = +0.61 CFW - 0.07 MFD + 0.02 CWC with expected increases in CFW and decreases in MFD. Selection indices with (a) CFW and MFD (4) and (b) CFW, MFD, and visual colour score (15) as selection criteria would increase CFW, MFD, and CWC at the same rates observed in I1.
650 $aLã
650 $aOvino
650 $aParâmetro Genético
653 $aMelhoramento genético
653 $aRaça Corriedale
653 $aViabilidade econômica
700 1 $aMAHER, A. P.
773 $tAustralian Journal of Agricultural Research$gv. 51, n. 2, p. 191-196, 2000.
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