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 | Acesso ao texto completo restrito à biblioteca da Embrapa Gado de Corte. Para informações adicionais entre em contato com cnpgc.biblioteca@embrapa.br. |
Registro Completo
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Biblioteca(s): |
Embrapa Gado de Corte. |
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Data corrente: |
30/09/2009 |
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Data da última atualização: |
13/10/2009 |
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Autoria: |
UTSUNOMIYA, K. S.; PAGLIARINI, M. S.; VALLE, C. B. do. |
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Afiliação: |
KARINA SAYURI UTSUNOMIYA, UEM; MARIA SUELY PAGLIARINI; CACILDA BORGES DO VALLE, CNPGC. |
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Título: |
Microsporogenesis in tetraploid accessions of Brachiaria nigropedata (Ficalho & Hiern) Stapf (Gramineae). |
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Ano de publicação: |
2005 |
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Fonte/Imprenta: |
Biocell, v. 29, n. 3, p. 295-301, ago./dez. 2005. |
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Idioma: |
Português |
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Conteúdo: |
The genus Brachiaria (Trin.) Griseb. has achieved considerable importance to cattle production systems, as a result of the good production and adaptation of a few cultivars to poor and acid soils of the Brazilian savannas. Many of its species and accessions are polyploid and apomictic, which limits direct hybridization. To assist the breeding program, cytogenetic characterization has been undertaken on the accessions
of Brachiaria collection at the Embrapa Beef Cattle Research Center. In this study, chromosome number and meiotic behavior are reported for the Brachiaria nigropedata (Ficalho & Hiern) Stapf collection. The 20 available accessions are tetraploid (2n = 4x = 36). Chromosomes paired preferentially as bivalents, but quadrivalents were found in high frequencies in some cells. Meiotic behavior was, in general, irregular, and
varied among accessions. Most accessions presented more than 20% of abnormal tetrads. The most common meiotic abnormalities were those related to irregular chromosome segregation due to polyploidy, leading to micronuclei formation in the tetrad stage. A low frequency of other meiotic abnormalities such as the absence of cytokinesis, chromosome stickiness, cell fusion, anaphase bridges, and chromosome transfer among microsporocytes were also recorded in some accessions. Limitations of these accessions for use in hybridization programs are discussed. |
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Palavras-Chave: |
Brachiaria nigropedata; Braquiária. |
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Thesagro: |
Apomixia; Gramínea Forrageira; Melhoramento Genético Vegetal; Pastagem; Poliploidia. |
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Categoria do assunto: |
F Plantas e Produtos de Origem Vegetal |
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Marc: |
LEADER 02075naa a2200229 a 4500
001 1512814
005 2009-10-13
008 2005 bl --- 0-- u #d
100 1 $aUTSUNOMIYA, K. S.
245 $aMicrosporogenesis in tetraploid accessions of Brachiaria nigropedata (Ficalho & Hiern) Stapf (Gramineae).
260 $c2005
520 $aThe genus Brachiaria (Trin.) Griseb. has achieved considerable importance to cattle production systems, as a result of the good production and adaptation of a few cultivars to poor and acid soils of the Brazilian savannas. Many of its species and accessions are polyploid and apomictic, which limits direct hybridization. To assist the breeding program, cytogenetic characterization has been undertaken on the accessions of Brachiaria collection at the Embrapa Beef Cattle Research Center. In this study, chromosome number and meiotic behavior are reported for the Brachiaria nigropedata (Ficalho & Hiern) Stapf collection. The 20 available accessions are tetraploid (2n = 4x = 36). Chromosomes paired preferentially as bivalents, but quadrivalents were found in high frequencies in some cells. Meiotic behavior was, in general, irregular, and varied among accessions. Most accessions presented more than 20% of abnormal tetrads. The most common meiotic abnormalities were those related to irregular chromosome segregation due to polyploidy, leading to micronuclei formation in the tetrad stage. A low frequency of other meiotic abnormalities such as the absence of cytokinesis, chromosome stickiness, cell fusion, anaphase bridges, and chromosome transfer among microsporocytes were also recorded in some accessions. Limitations of these accessions for use in hybridization programs are discussed.
650 $aApomixia
650 $aGramínea Forrageira
650 $aMelhoramento Genético Vegetal
650 $aPastagem
650 $aPoliploidia
653 $aBrachiaria nigropedata
653 $aBraquiária
700 1 $aPAGLIARINI, M. S.
700 1 $aVALLE, C. B. do
773 $tBiocell$gv. 29, n. 3, p. 295-301, ago./dez. 2005.
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