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Provedor de dados:  Scientia Agricola
País:  Brazil
Título:  Microsporogenesis in Brachiaria bovonei (Chiov.) Robyns and B. subulifolia (Mez) Clayton (Poaceae)
Autores:  Risso-Pascotto,Claudicéia
Pagliarini,Maria Suely
Valle,Cacilda Borges do
Data:  2009-10-01
Ano:  2009
Palavras-chave:  Brachiaria
Chromosome number
Breeding program
Resumo:  Some African species of Brachiaria have been introduced into the Americas and became the most important forage for pastures in the tropics. New cultivars can be obtained either from direct selections from the natural existing variability in the germplasm collections or from interspecific hybridizations. Polyploidy is predominant in the genus Brachiaria and correlated with apomixis which complicates hybridization. The objective of cytological studies underway on the Brachiaria germplasm collection at Embrapa Beef Cattle is to determine the chromosome number and meiotic behavior of accessions. For the breeding of Brachiaria species, compatible sexual and apomictic accessions need to be identified. Microsporogenesis was evaluated in two accessions of Brachiaria bovonei (BO01 and BO05) and one accession of B. subulifolia (SU01). BO01 is pentaploid (2n = 5x = 45), BO05 is tetraploid (2n = 4x = 36), and SU01 is hexaploid (2n = 6x = 54), derived from x = 9. Meiotic abnormalities typical of polyploids, characterized by precocious chromosome migration to the poles in metaphases, laggard chromosomes in anaphases, and micronuclei in telophases and tetrads, were recorded in high frequency in all the accessions generating unbalanced gametes. Both accessions of B. bovonei presented chromosome stickiness. The results are discussed in the view of the Brachiaria breeding program objectives.
Tipo:  Info:eu-repo/semantics/article
Idioma:  Inglês
Editor:  São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Relação:  10.1590/S0103-90162009000500015
Formato:  text/html
Fonte:  Scientia Agricola v.66 n.5 2009
Direitos:  info:eu-repo/semantics/openAccess

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