Centro de Ciências Agrárias
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11727
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Resultados da Pesquisa
Item Variabilidade de genótipos de milho quanto à composição de carotenoides nos grãos(Pesquisa Agropecuária Brasileira, 2009-02) Cardoso, Wilton Soares; Paes, Maria Cristina Dias; Galvão, João Carlos Cardoso; Rios, Sara de Almeida; Guimarães, Paulo Evaristo de Oliveira; Schaffert, Robert Eugene; Borém, AluízioO objetivo deste trabalho foi caracterizar e avaliar a variabilidade quanto ao teor e perfil de carotenoides nos grãos de 134 genótipos de milho (Zea mays), com vistas à utilização em programas de biofortificação. Os materiais foram provenientes dos campos experimentais e do Banco Ativo de Germoplasma da Embrapa Milho e Sorgo, Sete Lagoas, MG. São cultivares e híbridos comerciais, linhagens-elite e outros acessos escolhidos com base na coloração amarelo-alaranjada do endosperma. A quantificação do teor de carotenoides totais, carotenos e xantofilas mono-hidroxilada e di-hidroxilada dos grãos foi realizada por método cromatográfico-espectrofotométrico. As médias encontradas nos grãos foram 22,34µ gg-1 de carotenoides totais, 2,55µ gg-1 de carotenos, 3,86µ gg-1 de xantofilas mono-hidroxiladas e 15,93µ gg-1 de xantofilas di-hidroxiladas. Os genótipos foram agrupados em 18 grupos pelo método de Tocher. O germoplasma da Embrapa possui potencial para ser usado em programas de desenvolvimento de linhagens de milho biofortificadas, quanto ao total de carotenoides pró-vitamina A.Item Classificação de populações de milho quanto à eficiência e resposta ao uso de fósforo(Acta Scientiarum. Agronomy, 2010-04) Miranda, Glauco Vieira; Fidelis, Rodrigo Ribeiro; Pelúzio, Joênes Mucci; Galvão, João Carlos CardosoO presente trabalho teve como objetivo selecionar os genótipos mais eficientes na absorção e utilização de fósforo em solos de cerrado na safrinha. O ensaio foi constituído de 47 tratamentos (genótipos) e foi conduzido na área experimental da Universidade Federal do Tocantins, Campus de Gurupi. Para simular ambientes com baixo e alto nível de fósforo, foram utilizadas doses de 25 e 113 kg ha-1 de P2O5 na semeadura, respectivamente. Para identificar os cultivares adequados aos ambientes, utilizou-se metodologia que sugerem a classificação das cultivares quanto à eficiência no uso e resposta a aplicação do fósforo (eficiência e resposta). Concluiu-se que os genótipos eficientes na absorção e utilização de fósforo e responsivos ao incremento de P foram UFVM77-0331, UFVM77-0307, UFVM77-0333, UFVM77-0381, UFVM77-0313, UFVM77-0305, UFVM77-0377 e UFVM77-0345.Item Combining ability of tropical maize cultivars in organic and conventional production systems(Ciência Rural, 2011-05) Oliveira, Lucimar Rodrigues de; Miranda, Glauco Vieira; DeLima, Rodrigo Oliveira; Souza, Leandro Vagno de; Galvão, João Carlos Cardoso; Santos, Izabel Cristina dosThe objectives were to identify maize germplasm for the organic productions system and to compare the genetic effects of the grain yield of maize cultivars in organic and conventional production systems. Diallel crosses were made between six maize cultivars and the hybrid combinations were evaluated in conventional and organic production systems. The hybrid combinations produced different grain yields in the two production systems. The interaction between general combining ability and production systems was significant for grain yield, ear height and number of ears. This indicates that the additive genetic effects differ in organic and conventional production systems. The specific combining abilities (SCA) were significant for grain yield and plant height, indicating a significant difference between the non-additive effects. However, the SCA x production systems interactions were not significant for those traits. It was concluded that for the development of maize cultivars for the organic production system, selection must be made in the specific environment for the expression of favorable alleles that confer advantages for adapting to this system; the general combining ability of genitors is different for the two production systems, but the specific combining ability isn’t different in organic and conventional systems.Item Genetic variability and heterotic groups of brazilian popcorn populations(Euphytica, 2007-10-25) Miranda, Glauco Vieira; Souza, Leandro Vagno de; Galvão, João Carlos Cardoso; Guimarães, Lauro José Moreira; Melo, Aurélio Vaz de; Santos, Izabel Cristina dosThe development of successful advanced lines and cultivars in maize is dependent on parental selection and assignment to defined heterotic groups. So, the objectives of this study were to evaluate genetic variability and identify heterotic groups among Brazilian popcorn varieties. Thus, diallel crosses of advanced generations of the popcorn hybrids, IAC 112 and Zélia, and of three open-pollinated popcorn varieties, RS 20, Branco, and SAM were performed. Ten hybrid combinations, the five parents, and five check treatments were arranged in a block design with four replicates in two tropical-zone locations (CWb climate). Both additive and non-additive effects were important for grain yield, plant height, ear height, and husk cover. For popping expansion, only the additive effects were important. Hybrid combinations between the local variety (Branco) and F2 populations (IAC 112 and Zelia) resulted in the third and fourth highest values for popping expansion. The best grain yields were obtained with hybrid combinations involving SAM. Cultivars Zélia, IAC 112, and RS 20 increased popping expansion, whereas cultivar Branco increased grain yield of hybrid combinations. The following conclusions may be drawn: Brazilian popcorn populations have reduced heterosis and genetic variability to popping expansion in relation commercial cultivars; there is genetic variability among Brazilian popcorn populations that allows the exploitation of additive and non-additive effects for grain yield; it is possible to increase grain yield by using local varieties; but it would be difficult to obtain commercial hybrids from local varieties because they have poor performance for popping expansion.