Data/hora: 04/06/2024 16:10:15

Biblioteca(s): 	Embrapa Gado de Corte.	
Data corrente: 	20/04/2009	
Data da última atualização: 	29/07/2011	
Autoria: 	PAGLIARINI, M. S.; RISSO-PASCOTTO, C.; SOUZA-KANESHIMA, A. M. de; VALLE, C. B. do.	
Afiliação: 	Maria Suely Pagliarini, UEM; Claudicéia Risso-Pascotto, UEM; Alice Maria de Souza-Kaneshima, UEM; Cacilda Borges do Valle, CNPGC.	
Título: 	Analysis of meiotic behavior in selecting potential genitors among diploid and artifcially induced tetraploid accessions of Brachiaria ruziziensis (Poaceae).	
Ano de publicação: 	2008	
Fonte/Imprenta: 	Euphytica, Wageningen, Holanda, v. 164, n.1 , p. 181-187, nov. 2008.	
Idioma: 	Inglês	
Conteúdo: 	Sexuality is correlated with diploidy and apomixis with polyploidy in the Brachiaria genus. Brachiaria ruziziensis is a key species in Brachiaria breeding due to its obligate sexuality and intrinsic agronomic qualities. Interspecific crosses in the genus became feasible only when a few diploid accessions of B. ruziziensis were artificially tetraploidized and remained sexual. Hybridization has been done since, using natural tetraploid apomictic accessions of B. brizantha or B. decumbens as pollen donors. Twenty two accessions of B. ruziziensis from the Embrapa Beef Cattle germplasm collection (Campo Grande, MS, Brazil) were cytologically analyzed: 16 are natural diploids (2n = 2x = 18) and six are artificially induced tetraploids (2n = 4x = 36). The meiotic behavior in the 16 diploid accessions varied. The mean of meiotic abnormalities per accession ranged from zero to 24.46%. Meiotic behavior in the induced tetraploid accessions also varied with the mean of meiotic abnormalities ranging from 5.20% to 54.71%. The most common abnormalities observed in both the diploid and the tetraploid accessions, were those related to irregular chromosome segregation. In one tetraploid accession, with a high frequency of those, other irregularities involving chromosome orientation at metaphase plate and chromosome convergence to the poles, a meiotic mutation known as divergent spindle, were recorded. Meiotic behavior should be considered in selecting potential genitors for breeding.	
Palavras-Chave: 	Braquiária; Brasil; Campo Grande; Mato Grosso do Sul; Microsporogêne.	
Thesagro: 	Apomixia; Brachiaria Ruziziensis; Citogenética Vegetal; Meiose; Melhoramento Genético Vegetal; Pastagem; Poliploidia.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Gado de Corte (CNPGC)	
Exemplares: 	CNPGC - (12390-1) - UPC - AP - DD - 631.5305 -  -  - DIS