Data/hora: 16/06/2024 09:34:41

Biblioteca(s): | Embrapa Gado de Corte.
Data corrente: | 10/08/2011
Data da última atualização: | 16/11/2011
Autoria: | BOLDRINI, K. R.; ADAMOWSKY, E. de V.; MESSAGE, H.; CALIXTO, V.; PAGLIARINI, M. S.; VALLE, C. B. do.
Afiliação: | Kellen Regina Boldrini, UEM; Eleniza de Victor Adamowski, UEM; Hugo Message, UEM; Vergílio Calisto, UEM; Maria Suely Pagliarini, UEM; CACILDA BORGES DO VALLE, CNPGC.
Título: | Meiotic behavior as a selection tool in the breeding of Brachiaria humidicola (Poaceae).
Ano de publicação: | 2011
Fonte/Imprenta: | Euphytica, v.182, n. 3, p.317-324, Dec. 2011.
Idioma: | Inglês
Conteúdo: | Brachiaria humidicola is a tropical grass that grows in seasonally swampy grasslands in Africa. In Brazil, two apomictic cultivars (2n = 54) of this species are widely used as pastures in poorly drained soils. The recent discovery of a sexual polyploid accession (2n = 36) in the germplasm collection at the Embrapa Beef Cattle Research Center allowed intraspecific hybridization with the objective of broadening the genetic variability and selection of superior genotypes in this species. Hybridization, however, depends on accessions with the same ploidy level. Cytological analyses of 55 accessions revealed that 19 apomictic accessions also presented 2n = 36 chromosomes. Chromosome pairing in hexavalent association at diakinesis and metaphase I suggested that the basic chromosome number for this species is x = 6. Cytological analysis revealed abnormalities in variable frequencies in the meiosis of these hexaploid (2n = 6x = 36) accessions. The most common were those related to irregular chromosome segregation which led to unbalanced gamete formation, but chromosome stickiness was also recorded. These results clearly demonstrate the value of cytogenetics in the choice of genitors and for superior hybrids to be obtained in the breeding of this species. For that both the ploidy level and the frequency of abnormalities need to be considered, besides other favorable agronomic characteristics.
Thesagro: | Brachiaria Humidicola; Melhoramento Genético Vegetal; Pastagem.
Categoria do assunto: | K Ciência Florestal e Produtos de Origem Vegetal
Registro original: | Embrapa Gado de Corte (CNPGC)
Exemplares: | CNPGC - (14012-1) - UPC - AP - DD -  -  -  - DIS