Coffee Science
URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3355
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Resultados da Pesquisa
Item Coffee genotypes morphophysiological adaptation under coffee leaf rust biotic stress(Editora UFLA, 2021) Viana, Mariana Thereza Rodrigues; Azevedo, Harianna Paula Alves de; Pereira, Fernanda Aparecida Castro; Carvalho, Milene Alves de Figueiredo; Guimarães, Rubens JoséThe identification of morphophysiological traits responsible for a better plant behavior when infected is useful for cultivar selection, and become crucial for breeding. We investigated the morphophysiological behavior of coffee genotypes before and after inoculation with the pathogen Hemileia vastatrix, causal agent of coffee rust. With multivariate techniques we identified the characteristics that most contribute to total genetic divergence of the geno types. Ten genotypes of Coffea arabica from the Germplasm Bank of Coffee from Minas Gerais were sown in a nursery and then take to a greenhouse with controlled temperature and humidity. After one month of acclimatization, the artificial inoculation with the fungus H. vastatrix was carried out. The anatomical and physiological evaluations were performed 1 day before inoculation and 160 days after inoculation. When the first symptom emerged, plants were evaluated according to a descriptive scale for coffee rust. We observed significant differences in rust severity and ostiole opening between genotypes. Different groups were formed by the K-means method, based on morphophysiological characteristics. This shows that genetic variability exists between the coffee genotypes evaluated before and after inoculation with the pathogen. The most important characteristics that contributed to the total genetic divergence were xylem vessel diameter and stomatal conductance. In conclusion, inoculation with H. vastatrix caused a change in coffee geno types based on morphophysiological characteristics.Item Characterization of coffee cultivars leaf rust-resistant subjected to framework pruning(Editora UFLA, 2018-01) Reis, Estevam Antônio Chagas; Freitas, Tainah; Carvalho, Milene Alves de Figueiredo; Mendes, Antônio Nazareno Guimarães; Rezende, Tiago Teruel; Carvalho, João Paulo FelicoriThe goal of our work was to evaluate physiological and agronomic traits, as well as the relationship between these traits in coffee cultivars coming from a germplasm supposedly resistant to leaf rust, and their response to framework pruning. The experiment was conducted at the Federal University of Lavras in randomized blocks with three replicates, with spacing of 3.5 x 0.7 m and plots of 12 plants. An amount of 25 coffee cultivars was evaluated, from which 23 were considered resistant and two susceptible to leaf rust. Traits analyzed were the plagiotropic branch length and number of nodes, net photosynthetic rate, transpiration rate, water use efficiency, fluorescence and chlorophyll index, leaf area index, leaf rust incidence and yield. Catucaí Amarelo 20/15 cv 479, Araponga MG1 and Tupi IAC 1669-33 cultivars show highly responsive to framework pruning. These cultivars have high yield associated to high net photosynthetic rate, water use efficiency and low transpiration rate. Moreover, the last two cultivars show a low incidence of leaf rust. The Acauã cultivar has a good response to framework pruning, showing high yield associated to lower incidence of leaf rust. Catucaí Vermelho 785/15 cultivar is not responsive to framework pruning because show lower yield, high incidence of leaf rust, low vegetative growth and low water use efficiency.