Autoria: BOLDRINI, K. R.; PAGLIARINI, M. S.; VALLE, C. B. do

Resumo: Brachiaria humidicola (Poaceae), originally from Africa, is an economically important pasture plant in tropical South America. An accession of B. humidicola (H038) collected from the wild African savanna (Mbeya, Tanzania) showed irregular microsporogenesis. This meiotic behavior was consistent with an allopolyploid origin. Multivalent chromosome association at diakinesis gave tri- to octavalents, associated with two nucleoli in some cells. Six non-congregated univalents in metaphase I and anaphase I, along with previous lines of evidence for x = 6 in B. humidicola, confirm H038 as a nonaploid accession, 2n = 9x = 54. Asynchrony in the genome during microsporogenesis also corroborated this assumption. Its putative origin could be a cross between two related species with different rhythms in meiosis. The meiotic behavior of this accession reinforces the hypothesis of the existence of a new basic chromosome number (x = 6) for Brachiaria. The use of this accession in the breeding of this important forage grass for the tropics is discussed.

Ano de publicação: 2009

Tipo de publicação: Artigo de periódico

Unidade: Embrapa Gado de Corte

Palavras-chave: Brachiaria Humidicola, Braquiária, Gramínea Forrageira, Melhoramento Genético Vegetal, Pastagem