Data/hora: 22/06/2024 08:49:51

Biblioteca(s): | Embrapa Gado de Corte.
Data corrente: | 10/07/2009
Data da última atualização: | 20/07/2023
Autoria: | MENDES-BONATO, A. B.; RISSO-PASCOTTO, C.; PAGLIARINI, M. S.; VALLE, C. B. do.
Afiliação: | ANDREA BEATRIZ MENDES-BONATO, UNIVERSIDADE ESTADUAL DE MARINGÁ; CLAUDICÉIA RISSO-PASCOTTO, UNIVERSIDADE ESTADUAL DE MARINGÁ; MARIA SUELY PAGLIARINI, UNIVERSIDADE ESTADUAL DE MARINGÁ; CACILDA BORGES DO VALLE, CNPGC.
Título: | Chromosome number and meiotic behaviour in Brachiaria jubata (Gramineae).
Ano de publicação: | 2006
Fonte/Imprenta: | Journal of Genetics, Bangalore, v. 85, n. 1, p. 83-87, Apr. 2006.
Idioma: | Inglês
Notas: | Research note.
Conteúdo: | The production of new genetic variability through hybridization has been undertaken in Brachiaria, an important forage grass genus of African origin widely used in pastures in the Brazilian tropics. Although the genus comprises about 100 species, only a few of them present favourable agronomic attributes and are explored. In the genus Brachiaria, the majority of species and accessions are polyploid and apomictic, which makes breeding through hybridization more complex. Sexuality has been found in diploids and eventually among tetraploids with normal meiosis. Brachiaria jubata presents good forage value and adaptation to riverbanks and lake margins, and is therefore relevant to pasture systems in the tropics. Furthermore, the most interesting form of resistance to spittlebugs?antibiosis?was identified in one accession of B. jubata. Thus its interest in the Brazilian breeding programme lies in the possibility of using hybridization to transfer high resistance to this insect to susceptible accessions. This paper reports chromosome numbers and meiotic behaviour in 21 accessions of this species as a tool in selecting promising ones for crossing. Only one accession was found to be diploid; the others were tetraploid. Microsporogenesis was normal in the diploid accession, while among the tetraploid ones, irregular chromosome segregation leading to unbalanced gamete formation was common but variable. Pollen fertility among tetraploid accessions was high.
Palavras-Chave: | Brachiaria jubata; Braquiária.
Thesagro: | Citogenética; Gramínea Forrageira; Meiose; Melhoramento Genético Vegetal; Pastagem; Poliploidia.
Thesaurus Nal: | Chromosome number; Meiosis; Microsporogenesis.
Categoria do assunto: | --
Registro original: | Embrapa Gado de Corte (CNPGC)
Exemplares: | CNPGC - (12534-1) - UPC - AP - -- - 462/01 -  - 462/01 - DIS