Periódicos
URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3352
Navegar
3 resultados
Resultados da Pesquisa
Item Genetic characterization of Xylella fastidiosa isolated from citrus and coffee plants(Escola Superior de Agricultura "Luiz de Queiroz", 2007-09) Miranda, Vicente Savonitti; Farias, Paulo Roberto Silva; Roberto, Sérgio Rufo; Lacava, Pedro MagalhãesThe Citrus Variegated Chlorosis and the Coffee Leaf Scorch are some of the many destructive diseases caused by Xylella fastidiosa, a gram-negative bacterium limited to the xylem of affected plants. As its genetic characterization is still not well established, different isolates of X. fastidiosa from citrus and coffee were evaluated through RAPD (Random Amplified Polymorphic DNA) technique to characterize and classify these isolates based on similarity coefficients. Sixteen isolates of X. fastidiosa were used on this trial, obtained from citrus, coffee and almond. The genetic polymorphism evaluation was performed using six arbitrary 10-base primer pairs. It was possible to establish a dendogram in which the isolates were classified into five groups (A, B, C, D and E). A prevalence of citrus isolates in groups A and D was observed. In groups B and C, there was a prevalence of coffee isolates meanwhile the group D consisted of the almond isolate, solely.Item Selection of Coffea canephora parents from the botanical varieties Conilon and Robusta for the production of intervarietal hybrids(Universidade Federal de Santa Maria, 2018-04) Oliveira, Leilane Nicolino Lamarão de; Rocha, Rodrigo Barros; Ferreira, Fábio Medeiros; Spinelli, Victor Mouzinho; Ramalho, André Rostand; Teixeira, Alexsandro LaraThe objective of this research was to quantify the genetic divergence of potential Coffea canephora parents, with the goal of developing progenies that associate the best traits of the Conilon and Robusta botanical varieties for hybrid vigor expression. Thus, 10 morphological and productive characteristics of 130 clones of Conilon and Robusta botanical varieties and their intervarietal hybrids were evaluated over 2 years. The experiment was conducted in a randomized block design with four replicates of four plants per plot. For selection of parents, the main component analysis was used to associate values with reference points obtained from the average of each botanical variety. The first two principal components allowed for the separation of the botanical varieties representing the variability contained in the original data with 76% for the first year and 69% for the second year. Although, the genotype × years interaction had significant effects, there were minor differences in the grouping from one year to the next, which is associated with the higher repeatability estimates observed in this study. It was observed that crosses with the 16-1-81 I , 9-1-82 L , and 13-1-61 I parents of the botanical variety Robusta and the 167 I , 890 E , and 130 I parents of the Conilon botanical variety presented greater potential for obtaining selection gains.Item Caracterização e uso da variabilidade genética de banco ativo de germoplasma de Coffea canephora Pierre ex Froehner(Editora UFLA, 2013-10) Rocha, Rodrigo Barros; Vieira, Diogo dos Santos; Ramalho, André Rostand; Teixeira, Alexsandro LaraEstratégias eficientes para manipular a variabilidade genética são determinantes para o sucesso dos programas de melhoramento de Coffea canephora. Combinações entre genitores divergentes expressam maior efeito heterótico, devendo a seleção de matrizes considerar, simultaneamente, a divergência genética e o desempenho agronômico superior.Objetivou-se, neste trabalho, quantificar a diversidade genética de acessos de C. canephora do Banco Ativo de Germoplasma da Embrapa Rondônia, visando à identificação de plantas de maior divergência genética e maior potencial produtivo para hibridização. Para isso, entre 1100 acessos foram pré-selecionadas 89 plantas para avaliação dos principais componentes da produção de café beneficiado. Para a quantificação da diversidade genética foi utilizada a técnica de componentes principais, associada a pontos de referência para reunir as informações de divergência genética e de desempenho agrícola em uma única análise. Os acessos selecionados apresentaram expressiva variabilidade genética para os principais componentes de produção, com destaque para os valores de peneira média acima de 17, o que indica uma condição favorável para a realização de cruzamentos controlados visando à seleção de plantas de maior produtividade e tamanho de grãos.