Use este identificador para citar ou linkar para este item: http://repositorio.ufla.br/jspui/handle/1/11865
Título: Mecanismos da eliminação cromossômica em híbridos de Pennisetum purpureum e P. Glaucum e relações genômicas em Pennisetum spp.
Título(s) alternativo(s): Mechanisms of chromosome elimination in hybrids of Pennisetum purpureum and P. glaucum and genomic relations in Pennisetum spp.
Autores: Davide, Lisete Chamma
Torres, Giovana Augusta
Torres, Giovana Augusta
Techio, Vânia Helena
Azevedo, Ana Luisa Souza
Vicini, Lyderson Facio
Palavras-chave: Capim elefante
Milheto
Plantas – Melhoramento genético
Eliminação cromossômica
Elephant grass
Milhet
Plant breeding
Chromosome elimination
Pennisetum spp.
Data do documento: 5-Out-2016
Editor: Universidade Federal de Lavras
Citação: REIS, G. B. dos. Mecanismos da eliminação cromossômica em híbridos de Pennisetum purpureum e P. Glaucum e relações genômicas em Pennisetum spp. 2016. 96 p. Tese (Doutorado em Genética e Melhoramento de Plantas)-Universidade Federal de Lavras, Lavras, 2016.
Resumo: Napier grass (Pennisetum purpureum Schumach) is a specie with allopolyploid A’A’BB genomes and 2n = 4x = 28 chromosomes, while pearl millet (Pennisetum glaucum L. (R.) Br.) is a diploid specie with genome AA and 2n = 2x = 14 chromosomes. Interspecific hybridization is used as an alternative in the breeding program of Napier due the proximity between these species. The interspecific hybrid is triploid, sterile, with AA’B genomes and 2n = 3x = 21 chromosomes. In order to restore the fertility of the triploid hybrid and facilitate the use of genetic combination of Napier grass and pearl millet in breeding programs, duplication of chromosomes is necessary producing hexaploid plants with 2n = 6x = 42 chromosomes and genomes AAA’A’BB. The population of hexaploid individuals has been subjected to cycles of selection and gains on the size and viability of the seeds have already been observed. However, mixoploidy resulting from chromosomal elimination has been observed frequently in poliploidy hybrids. To date, works with duplicated hybrids have showed that there are irregularities in both somatic and germinative cells and chromosomal elimination is related to the induction of polyploidy and is biparental. While the triploid hybrids have stable somatic chromosome number, hexaploide hybrids exihibited variation in chromosome number, with plants that tend to eliminate more chromosomes than others. However, is still unknown which causes leading to elimination. Another aspect unknown with respect to the Napier grass is the origin of the genome B. Previous studies have shown that there is a high degree of homology between A genome of pearl millet and A’ genome of Napier grass and, in a less proportion, between these and the B genome. Nevertheless, the donor of B genome is still unkown. So, the aim of this work was to evaluate the cytogenetic mechanisms involved in chromosome elimination in partial synthetic hexaploid hybrids of Napier grass and pearl millet and to identify species that present homologous/homeologous genomes to B genome of Napier grass. It was observed that the centromeres dysfunction is a cause of disposal and not repaired DNA breakages that result in chromosomal fragments of synthetic hybrids. In addition, it was found that P. glaucum, P. violaceum and P. schweinfurthii must have genomes with high homology/similarity, possibly sharing the same A genome, while P. purpureum and P. flacidum would share the B genome, and to a lesser extent in P. vilosum and P. orientale should contain the genome A’ of P. purpureum.
URI: http://repositorio.ufla.br/jspui/handle/1/11865
Aparece nas coleções:Genética e Melhoramento de Plantas - Doutorado (Teses)



Os itens no repositório estão protegidos por copyright, com todos os direitos reservados, salvo quando é indicado o contrário.