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Registro Completo |
Biblioteca(s): |
Embrapa Milho e Sorgo. |
Data corrente: |
02/04/2002 |
Data da última atualização: |
19/10/2023 |
Autoria: |
GUIMARAES, P. E. de O. |
Afiliação: |
PAULO EVARISTO DE O GUIMARAES, CNPMS. |
Título: |
Effects of a long-term recurrent selection program on the genetic structure of the BSSS maize population. |
Ano de publicação: |
2001 |
Fonte/Imprenta: |
2001. |
Páginas: |
99 p. |
Idioma: |
Inglês |
Notas: |
Tese (Doutorado) - Iowa State University, Ames. |
Conteúdo: |
Evaluating of Recurrent Selection (RS) programs can lead to increase knowledge of methods, populations, and traits and give support for better management of breeding programs. The objective herein was to evaluate the effects of seven cycles of half-sib selection followed by seven cycles of S2 selection on the genetic structure of BSSS maize population. Individuals from BSSSP (progenitor lines), BS13(S)CO (original S2 selection), and BS13(S)C7 (7th S2 cycle) cycles were genotyped based on a sample of 105 RFLP loci. Measures of genetic variation within (expected heterozygosity, number of allelles, average frequency of the most common allele, and proportion of polymorphic loci) and among (Principal Component Analysis and Nei's genetic distance, NGD) cycles of selection indicated BSSSP has a considerable genetic variability, substantial loss a variation and increase of divergence over the cycles of selection, greatest loss of diversity occurred during the HS selection program, future cycles of RS are predicted to have narrow genetic variation, and low average effective population size was an important factor in loss of genetic variation. Changes in allele frequencies for about 30% of the loci cannot be explained by genetic drift alone, suggesting that selection also was an important factor of variation. The majority of loci in C0 and C7 were in H-W equilibrium. Progenitor lines Illinois Hy had a lower NGD to C0 and C7 and five of its unique had frequencies significantly increased in later generations, indicating a selective advantage over the cycles of RS. Hybrid Hy x LE 23 showed the lowest NGD to C0 and C7 populations. NGD among parental lines was not a good predictor of single-crosses yield performance. A founder effect observed herein may explain partially reduced genetic gains during the S2-selection period reported in other studies. Limited RFLP diversity in BS13(S)C7 suggests this population may not have enough genetic variability to sustain significant long-term genetic gains per se for grain yield. RFLP data were useful tools to evaluate this RS program. However, much more information could be obtained about recurrent selection programs by integrating of molecular (a standard set of marker loci) and phenotypic data. MenosEvaluating of Recurrent Selection (RS) programs can lead to increase knowledge of methods, populations, and traits and give support for better management of breeding programs. The objective herein was to evaluate the effects of seven cycles of half-sib selection followed by seven cycles of S2 selection on the genetic structure of BSSS maize population. Individuals from BSSSP (progenitor lines), BS13(S)CO (original S2 selection), and BS13(S)C7 (7th S2 cycle) cycles were genotyped based on a sample of 105 RFLP loci. Measures of genetic variation within (expected heterozygosity, number of allelles, average frequency of the most common allele, and proportion of polymorphic loci) and among (Principal Component Analysis and Nei's genetic distance, NGD) cycles of selection indicated BSSSP has a considerable genetic variability, substantial loss a variation and increase of divergence over the cycles of selection, greatest loss of diversity occurred during the HS selection program, future cycles of RS are predicted to have narrow genetic variation, and low average effective population size was an important factor in loss of genetic variation. Changes in allele frequencies for about 30% of the loci cannot be explained by genetic drift alone, suggesting that selection also was an important factor of variation. The majority of loci in C0 and C7 were in H-W equilibrium. Progenitor lines Illinois Hy had a lower NGD to C0 and C7 and five of its unique had frequencies significantly increase... Mostrar Tudo |
Palavras-Chave: |
Maize. |
Thesagro: |
Melhoramento; Milho; Zea Mays. |
Thesaurus Nal: |
breeding. |
Categoria do assunto: |
-- |
URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/item/90316/1/T-Paulo-Evaristo.pdf
|
Marc: |
LEADER 02820nam a2200193 a 4500 001 1485209 005 2023-10-19 008 2001 bl uuuu m 00u1 u #d 100 1 $aGUIMARAES, P. E. de O. 245 $aEffects of a long-term recurrent selection program on the genetic structure of the BSSS maize population.$h[electronic resource] 260 $a2001.$c2001 300 $a99 p. 500 $aTese (Doutorado) - Iowa State University, Ames. 520 $aEvaluating of Recurrent Selection (RS) programs can lead to increase knowledge of methods, populations, and traits and give support for better management of breeding programs. The objective herein was to evaluate the effects of seven cycles of half-sib selection followed by seven cycles of S2 selection on the genetic structure of BSSS maize population. Individuals from BSSSP (progenitor lines), BS13(S)CO (original S2 selection), and BS13(S)C7 (7th S2 cycle) cycles were genotyped based on a sample of 105 RFLP loci. Measures of genetic variation within (expected heterozygosity, number of allelles, average frequency of the most common allele, and proportion of polymorphic loci) and among (Principal Component Analysis and Nei's genetic distance, NGD) cycles of selection indicated BSSSP has a considerable genetic variability, substantial loss a variation and increase of divergence over the cycles of selection, greatest loss of diversity occurred during the HS selection program, future cycles of RS are predicted to have narrow genetic variation, and low average effective population size was an important factor in loss of genetic variation. Changes in allele frequencies for about 30% of the loci cannot be explained by genetic drift alone, suggesting that selection also was an important factor of variation. The majority of loci in C0 and C7 were in H-W equilibrium. Progenitor lines Illinois Hy had a lower NGD to C0 and C7 and five of its unique had frequencies significantly increased in later generations, indicating a selective advantage over the cycles of RS. Hybrid Hy x LE 23 showed the lowest NGD to C0 and C7 populations. NGD among parental lines was not a good predictor of single-crosses yield performance. A founder effect observed herein may explain partially reduced genetic gains during the S2-selection period reported in other studies. Limited RFLP diversity in BS13(S)C7 suggests this population may not have enough genetic variability to sustain significant long-term genetic gains per se for grain yield. RFLP data were useful tools to evaluate this RS program. However, much more information could be obtained about recurrent selection programs by integrating of molecular (a standard set of marker loci) and phenotypic data. 650 $abreeding 650 $aMelhoramento 650 $aMilho 650 $aZea Mays 653 $aMaize
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Registro original: |
Embrapa Milho e Sorgo (CNPMS) |
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Biblioteca(s): |
Embrapa Gado de Leite. |
Data corrente: |
26/03/2009 |
Data da última atualização: |
15/05/2024 |
Tipo da produção científica: |
Artigo em Periódico Indexado |
Circulação/Nível: |
Local - B |
Autoria: |
FURLONG, J.; VERNEQUE, R. da S.; MARTINS, J. R. de S.; PRATA, M. C. de A. |
Afiliação: |
John Furlong, Embrapa Gado de Leite; Rui da Silva Verneque, Embrapa Gado de Leite; João Ricardo de Souza Martins Instituto de Pesquisas Veterinárias Desidério Finamor Fepagro RS; Márcia Cristina de Azevedo Prata, Embrapa Gado de Leite. |
Título: |
O carrapato dos bovinos: saiba como combater esse inimigo. |
Ano de publicação: |
2008 |
Fonte/Imprenta: |
Revista Leite Integral, v. 3, p. 18-31, 2008. |
Idioma: |
Português |
Notas: |
Caderno especial 6. |
Thesagro: |
Carrapaticida; Carrapato; Gado Leiteiro; Sanidade Animal. |
Categoria do assunto: |
L Ciência Animal e Produtos de Origem Animal |
URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/doc/596518/1/O-carrapato-dos-bovinos.pdf
|
Marc: |
LEADER 00592naa a2200205 a 4500 001 1596518 005 2024-05-15 008 2008 bl uuuu u00u1 u #d 100 1 $aFURLONG, J. 245 $aO carrapato dos bovinos$bsaiba como combater esse inimigo.$h[electronic resource] 260 $c2008 500 $aCaderno especial 6. 650 $aCarrapaticida 650 $aCarrapato 650 $aGado Leiteiro 650 $aSanidade Animal 700 1 $aVERNEQUE, R. da S. 700 1 $aMARTINS, J. R. de S. 700 1 $aPRATA, M. C. de A. 773 $tRevista Leite Integral$gv. 3, p. 18-31, 2008.
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