Data/hora: 16/06/2024 23:48:02

Biblioteca(s): 	Embrapa Gado de Corte.	
Data corrente: 	30/03/2011	
Data da última atualização: 	29/01/2018	
Autoria: 	RICCI, G. C. L.; PAGLIARINI, M. S.; VALLE, C. B. do.	
Afiliação: 	G. C. L. RICCI, Departamento de Biologia Celular e Genética, Universidade Estadual de Maringá, Maringá, PR, Brasil; M.S. PAGLIARINI, Departamento de Biologia Celular e Genética, Universidade Estadual de Maringá, Maringá, PR, Brasil; CACILDA BORGES DO VALLE, CNPGC.	
Título: 	Genome elimination during microsporogenesis in two pentaploid accessions of Brachiaria decumbens (Poaceae)	
Ano de publicação: 	2010	
Fonte/Imprenta: 	Genetics and Molecular Research, v.9, n.4, p. 2364-2371, 2010.	
Idioma: 	Inglês	
Conteúdo: 	Polyploidy is a prominent and significant force in plant evolution, taking place since ancient times and continuing until today. Recent cytogenetic studies in the genus Brachiaria using germplasm collected from wild African savannas in the 1980s revealed that most species and accessions within species are polyploid. Diploid, tetraploid, and pentaploid accessions have been found. We found asynchronous meiosis during microsporogenesis, followed by genome elimination, in two pentaploid (2n = 5x = 45) accessions (D53 and D71) of a hardy, invasive pasture grass, introduced from Africa to Brazil, Brachiaria decumbens. In these accessions, chromosomes paired as 18 bivalents and nine univalents during diakinesis, suggesting that these accessions resulted from a recent event of natural hybridization. The lack of chromosome associations in the genomes suggests that these accessions resulted from hybridization between two genotypes that are not closely related, with low genome affinity and with different meiotic rhythms. This supposition is reinforced by the meiotic behavior of the nine univalents, which were always laggard in relation to the other chromosomes and eliminated as micronucleiin microspores. The behavior of these accessions, which have an odd level of ploidy and confirmed genome elimination, supports the general assumption that a polyploid accession can undergo a new event of polyploidization by natural hybridization (neopolyploidyzation). This evidence for natural hybridization in Brachiaria shows that this is a wild genus in an ongoing evolutionary process.	
Palavras-Chave: 	Hibridação natural; Microsporogênese.	
Thesagro: 	Brachiaria Decumbens; Gramínea Forrageira; Melhoramento Genético Vegetal; Pastagem.	
Categoria do assunto: 	F Plantas e Produtos de Origem Vegetal	
URL: 	http://ainfo.cnptia.embrapa.br/digital/bitstream/item/171758/1/Genome-elimination-during-microsporogenesis.pdf	
Registro original: 	Embrapa Gado de Corte (CNPGC)	
Exemplares: 	CNPGC - (13843-1) - UPC - AP - DD -  -  - SP 003/005 - DIS