Revista Ceres
URI permanente para esta coleção${dspace.url}/handle/123456789/9884
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Item Variability of photosynthetic performance among improved genotypes of Coffea canephora(Universidade Federal de Viçosa, 2025-05-09) Colodetti, Tafarel Victor; Tomaz, Marcelo Antonio; Rodrigues, Wagner Nunes; Christo, Bruno Fardim; Martins, Lima Deleon; Cavatte, Paulo CezarThis study evaluated the variability of photosynthetic performance of 27 improved genotypes of Conilon coffee, cultivated in the Southern of the Espírito Santo State. The photosynthetic performance was based on the measurement of gas exchange rates and chlorophyll in the period most favorable to the photosynthetic activity and in different stages of the reproductive cycle: flowering, fruit initiation, grain formation and fruit maturation; being expressed as the average (weighted by the number of days) along the phenological stages of the third reproductive cycle of the plants. It was possible to verify the existence of sufficient variability to differentiate the photosynthetic performance among the 27 genotypes throughout the reproductive cycle, even starting from a group of already improved genotypes. Among the physiological parameters, the rate of carbon assimilation, stomatal conductance and the transpiration rate stood out as parameters for the study of variability, mainly due to their contributions to the clustering of genotypes. The genotype 108 is highlighted due to its high photosynthetic rate, associated with higher relative content of chlorophyll, as well as reasonable water use efficiency. The genotypes 205, 206 and 305 stood out in terms of water use and carbon assimilation.Item The management of orthotropic stems modulates the photosynthetic performance and biomass allocation of productive plants of Arabica coffee(Universidade Federal de Viçosa, 2020) Colodetti, Tafarel Victor; Rodrigues, Wagner Nunes; Brinate, Sebastião Vinícius Batista; Martins, Lima Deleon; Cavatte, Paulo Cezar; Tomaz, Marcelo AntonioDue to the possibility of enhancing the physiological responses by modulating the architecture of coffee trees, the objective of the study was to analyze the leaf gas exchanges and biomass allocation of Arabica coffee cultivated with different numbers of orthotropic stems. The experiment was carried out in a plantation located in Santa Teresa-ES, Brazil, cultivated with spacing of 2.5×1.0 m, using the cultivar Catuaí Vermelho IAC44. The gas exchange rates were monitored along stages of the phenological cycle (2014/2015), following a split-plot scheme, 3×3 (number of orthotropic stems per plant in three levels: 1, 2 and 3; and the phenological stages in three levels: flowering, fruit formation and maturation). The allocation of biomass in the plagiotropic branches was also analyzed during the phenological stage of fruit maturation. The management of the number of orthotropic stems affected the photosynthetic responses and biomass allocation of coffee trees. Under the studied conditions, cultivating the plants with two orthotropic stems created conditions which promoted the photosynthetic responses. Keeping more stems promotes the availability of leaves per amount of produced fruits in the plagiotropic branches, allowing the plant to sustain the production with less metabolic earing.