Meiose em hÃbridos hexaplÃides de capim elefante e milheto / Meiosis in hexaploid hybrids between elephant grass and pearl millet

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

A strategy of the breeding programs of the elephant grass (Pennisetum purpureum 2n = 2x = 28), is the hybrid production between elephant grass and pearl millet (P. glaucum, 2n = 2x = 14), originating triploids hybrids and sterile, however presenting forage quality and providing the obtaining of cultivars superiors to intensify the dairy production. The sterility of triploid hybrid, due to impairing of the chromosomes in meiosis, constitutes a barrier to breeding programs, because it disables your propagation through seeds. Fertility can be restored by doubling the chromosomes. This made possible propagation through seeds. However, is common after doubling chromosome, the instability of the material due to the chromosome elimination. This work describes meiosis of ten hexaploids hybrid between elephant grass and pearl millet, being five from american origin and five national, aiming to assess the hybrid regarding the meiotic stability and pollen grain viability. The most frequent abnormalities were incorrect pairing during diakinesis, early ascension of chromosomes during metaphase, irregular segregation during anaphase and formation of micronucleus in telophase and in tetrads. Such abnormalities in the research compromise pollen fertility by generating aneuploids gametes, presenting low pollen viability rates so much for staining as germination in vitro. ParaÃso hybrid (commercial cultivar), in spite of present high rate of meiotic irregularities, presented 49.96% of viability for the staining tests and 86.17% for germination in vitro. The use of those hybrids in breeding programs of elephant grass is discussed.

ASSUNTO(S)

viabilidade do pÃlen hÃbridos hexaplÃides meiÃtic irregularity citologia vegetal irregularidades meiÃticas hexaploid hÃbridy pennisetum meiose meiosis pennisetum polen viability

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