Data/hora: 04/06/2024 02:24:25

Biblioteca(s): 	Embrapa Gado de Corte.	
Data corrente: 	01/02/2010	
Data da última atualização: 	01/02/2010	
Autoria: 	FUZINATTO, V. A.; PAGLIARINI, M. S.; VALLE, C. B. do.	
Afiliação: 	VERIDIANA APARECIDA FUZINATTO, UEM; MARIA SUELY PAGLIARINI, UEM; CACILDA BORGES DO VALLE, CNPGC.	
Título: 	Meiotic behavior in progenies from a hybrid between B. ruziziensis and B. brizantha (Poaceae).	
Ano de publicação: 	2009	
Fonte/Imprenta: 	In:SIMPÓSIO INTERNACIONAL SOBRE MELHORAMENTO DE FORRAGEIRAS, 2., 2009, Campo Grande, MS. [Anais]... Campo Grande, MS: Embrapa Gado de Corte, 2009. II SIMF. Comitê editorial: Liana Jank; Lucimara Chiari; Rosângela Maria Simeão Resende.	
Páginas: 	3 p.	
Descrição Física: 	1 CD-ROM.	
Idioma: 	Inglês	
Notas: 	Resumo C 07.	
Conteúdo: 	In the last three decades, the extensive use of some Brachiaria cultivars created directly from the natural genetic variability has placed Brazil as the major beef cattle exporter in the world. Interspecific hybridization is difficult to accomplish because only a few species are compatible (VALLE; SAVIDAN, 1996; VALLE; PAGLIARINI, 2009). Compatibility has been found among some species of the Group 5 (RENVOIZE et al., 1996): B. brizantha, B. decumbens and B. ruziziensis. Due to correlation between polyploidy and apomixis, Brachiaria breeding is not easy. Polyploid accessions with desirable agronomic characteristics are apomictics (VALLE; SAVIDAN, 1996), and sexuality is found only in diploid accessions. To overcome the barrier between sexual diploid and apomictic tetraploid accessions, Ferguson and Crowder (1974) proposed to create a cross-compatible, sexual tetraploid plant by doubling the chromosome number. The barrier was overcome a decade later, in Belgium, when diploid accessions of B. ruziziensis were tetraploidized with colchicine (SWENNE et al., 1981). In the genus Brachiaria, apomixis is pseudogamic, which means that viable gametes are necessary to fertilize the secondary nucleus of the embryo sac to guarantee endosperm development to produce healthy seeds (VALLE; SAVIDAN, 1996). But, in the genus, polyploidy is highly correlated with abnormal meiosis (MENDES-BONATO et al., 2002a; RISSOPASCOTTO et al., 2006).  Previous cytogenetic analysis of F1 generations of B. ruziziensis x B. brizantha hybrids (RISSO-PASCOTTO et al., 2005) have been conducted and revealed that they differ in amount and kinds of meiotic abnormalities, indicating that selection for meiotic stability is possible among them. In this study, we analyzed for the first time, the microsporogenesis of six progenies of a crossing between a sexual tetraploidized accession of B. ruziziensis and a natural tetraploid of B. brizantha, in attempt to select apomictic progenies with high meiotic stability and high seed production to be released as new cultivars.	
Palavras-Chave: 	Braquiária.	
Thesagro: 	Brachiaria Brizantha; Brachiaria Ruziziensis; Gramínea Forrageira; Melhoramento Genético Vegetal; Pastagem.	
Categoria do assunto: 	K Ciência Florestal e Produtos de Origem Vegetal	
Registro original: 	Embrapa Gado de Corte (CNPGC)	
Exemplares: 	CNPGC - (12926-1) - UMT - PL - CD - CD-105 - SIM -  - DIS