Data/hora: 12/06/2024 09:20:11

Biblioteca(s): | Embrapa Gado de Corte.
Data corrente: | 16/04/1997
Data da última atualização: | 06/09/2007
Autoria: | VALLE, C. B. do; SAVIDAN, Y. H.
Afiliação: | EMBRAPA. Centro Nacional de Pesquisa de Gado de Corte (Campo Grande, MS).
Título: | Genetics, cytogenetics and reproductive biology of Brachiaria.
Ano de publicação: | 1996
Fonte/Imprenta: | In: MILES, J.W.; MAASS, B.L.; VALLE, C.B. do, ed. Brachiaria: biology, agronomy and improvement. Cali: CIAT / Brasilia: EMBRAPA-CNPGC, 1996.
Páginas: | p.147-163.
Série: | (CIAT. Pblication, 259).
ISBN: | 958-9439-57-8
Idioma: | Inglês
Notas: | CNPGC.
Conteúdo: | Two essentials for breeding new cultivars of Brachiaria are germplasm devirsity and information on basic biological aspects of major species. This paper reviews current knowledge on the cytological behaviour, mode of reproduction and its inheritance, and crossing compatibility of different species. The two of major agronomic importance - B. decumbens and B. brizzantha-are tetraploid (2n = 4X = 36) and apomictic, that is, the embryo is produced without fusion of male and female gametes. Apomixis, although not common, is found throughout the plant kingdom and is often associated with polyploidy. Hence, it is frequently accompanied by meiotic anomalies leading to reduced pollen  fertility. Sexuality has been found at the diploid level in these species and in B.ruziziensis, and is generally associated with regular chromosome pairing and division. As a breeding tool, apomixis affers several advantages, because it associated fixation of hybrids vigor with seed propagation. Apomictic hybrids breed true, and  superior genotypes can be rapidly incresed by seed. The discovery of completeley sexual plants in cross-compatible species of Brachiaria and the development of pratica clearing techniques for the observation of ovules prompted studies of inheritance of apomixix. Results suggest a simple, monogenic control of model of reproduction, with apomixis dominant over sexuality. These investigations open up promising new possibilities for manipulating apomixis in breeding programs.
Palavras-Chave: | Biology; Brachiaraia; Melhoramento genetico; Pasture.
Thesagro: | Apomixia; Biologia; Citogenética; Pastagem; Reprodução.
Thesaurus Nal: | apomixis; breeding; cytogenetics; reproduction.
Categoria do assunto: | --
Registro original: | Embrapa Gado de Corte (CNPGC)
Exemplares: | CNPGC - (6370-1) - UMT - PL - -- - 633.2 - M643b - 1997.00005 - DIS