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Stomatal and Non-Stomatal Leaf Responses during Two Sequential Water Stress Cycles in Young Coffea canephora Plants
Publication . Baroni, Danilo F.; de Souza, Guilherme A.R.; Bernado, Wallace de P.; Santos, Anne R.; Barcellos, Larissa C.de S.; Barcelos, Letícia F.T.; Correia, Laísa Z.; de Almeida, Claudio M.; Verdin Filho, Abraão C.; Rodrigues, Weverton P.; Ramalho, José C.; Rakočević, Miroslava; Campostrini, Eliemar; Faculdade de Ciências e Tecnologia (FCT); GeoBioTec - Geobiociências, Geoengenharias e Geotecnologias; MDPI - Multidisciplinary Digital Publishing Institute
Understanding the dynamics of physiological changes involved in the acclimation responses of plants after their exposure to repeated cycles of water stress is crucial to selecting resilient genotypes for regions with recurrent drought episodes. Under such background, we tried to respond to questions as: (1) Are there differences in the stomatal-related and non-stomatal responses during water stress cycles in different clones of Coffea canephora Pierre ex A. Froehner? (2) Do these C. canephora clones show a different response in each of the two sequential water stress events? (3) Is one previous drought stress event sufficient to induce a kind of “memory” in C. canephora? Seven-month-old plants of two clones (’3V’ and ‘A1’, previously characterized as deeper and lesser deep root growth, respectively) were maintained well-watered (WW) or fully withholding the irrigation, inducing soil water stress (WS) until the soil matric water potential (Ψmsoil) reached ≅ −0.5 MPa (−500 kPa) at a soil depth of 500 mm. Two sequential drought events (drought-1 and drought-2) attained this Ψmsoil after 19 days and were followed by soil rewatering until a complete recovery of leaf net CO2 assimilation rate (Anet) during the recovery-1 and recovery-2 events. The leaf gas exchange, chlorophyll a fluorescence, and leaf reflectance parameters were measured in six-day frequency, while the leaf anatomy was examined only at the end of the second drought cycle. In both drought events, the WS plants showed reduction in stomatal conductance and leaf transpiration. The reduction in internal CO2 diffusion was observed in the second drought cycle, expressed by increased thickness of spongy parenchyma in both clones. Those stomatal and anatomical traits impacted decreasing the Anet in both drought events. The ‘3V’ was less influenced by water stress than the ‘A1’ genotype in Anet, effective quantum yield in PSII photochemistry, photochemical quenching, linear electron transport rate, and photochemical reflectance index during the drought-1, but during the drought-2 event such an advantage disappeared. Such physiological genotype differences were supported by the medium xylem vessel area diminished only in ‘3V’ under WS. In both drought cycles, the recovery of all observed stomatal and non-stomatal responses was usually complete after 12 days of rewatering. The absence of photochemical impacts, namely in the maximum quantum yield of primary photochemical reactions, photosynthetic performance index, and density of reaction centers capable of QA reduction during the drought-2 event, might result from an acclimation response of the clones to WS. In the second drought cycle, the plants showed some improved responses to stress, suggesting “memory” effects as drought acclimation at a recurrent drought.
Dynamics of dry matter accumulation in the berries, beans, and husks of six Coffea canephora genotypes during fruit maturation
Publication . Salvador, Henzo Pezzin; Semedo, José Nobre; Rakocevic, Miroslava; Ramalho, José Cochicho; Partelli, Fábio Luiz; GeoBioTec - Geobiociências, Geoengenharias e Geotecnologias; Cambridge University Press
During the post-harvesting process, coffee berries are dried and separated into green commercial beans and husks. The dynamics of dry matter (DM) accumulation in the berry components along the maturation process are important for the definition of the most adequate moment for the harvest, which is genotype-dependent. The DM accumulation dynamics in the berries, beans, and husks in six Coffea canephora genotypes were studied during the fruit maturation process, with the aim of identifying the fruit harvesting stage when the highest bean yield can be obtained. Berry samples were collected every two weeks at nine maturation stages starting from 33 weeks after flowering (green berry stage). Second-order polynomial regressions were used to analyse berry and bean DM accumulation over time, while temporal husk DM accumulation was compared using ANOVA and the Tukey test. DM accumulation was the highest in the berries and beans following the initial sampling, while the highest husk DM accumulation occurred at the final stages of maturation. In general, DM accumulation of all components increased as fruit maturation progressed, attaining the highest DM values in the final stages of red berries, but occurred earlier for early/medium and medium maturation cycle genotypes. The Beira Rio 8 genotype showed the highest DM accumulation in all components. Bamburral and P1 genotypes showed the lowest berry fresh mass (FM) to bean DM ratios. The A1 genotype showed the greatest berry FM to bean DM ratio, being a genotype with the lowest DM and bean mass performances and bean yield. Our data revealed that not only should the absolute berry and bean yield be considered for highly productive genotype selection but also the bean DM dynamics in the characterization of commercial coffee yield.
Genotypic Performance of Coffea canephora at Transitional Altitudes for Climate-Resilient Coffee Cultivation
Publication . Jordaim, Renan Baptista; Colodetti, Tafarel Victor; Rodrigues, Wagner Nunes; Salles, Rodrigo Amaro de; Amaral, José Francisco Teixeira do; Maciel, Laiane Silva; Partelli, Fábio Luiz; Ramalho, José Cochicho; Tomaz, Marcelo Antonio; GeoBioTec - Geobiociências, Geoengenharias e Geotecnologias; Faculdade de Ciências e Tecnologia (FCT); MDPI - Multidisciplinary Digital Publishing Institute
The Coffea canephora market has grown significantly, driven by its economic relevance and improvements in beverage quality. Developing varieties adapted to local edaphoclimatic conditions is essential for supporting smallholder farmers, increasing productivity, and ensuring quality in the face of environmental challenges. This study evaluated 27 genotypes under two irrigation regimes using a split-plot design in a completely randomized block arrangement, with four replicates and three plants per plot. Growth and yield parameters were assessed. Genotypes 102, 103, 105, 106, 202, 209, 301, 303, and 305 showed significantly higher yields under full irrigation—up to 60% greater than under minimal irrigation—demonstrating strong responsiveness to water availability. In contrast, genotypes 203 and 206 performed better under minimal irrigation, with 29% higher yields, suggesting lower water requirements or greater drought tolerance. These findings highlight the potential for selecting genotypes suited to transitional altitudes that can benefit from targeted irrigation strategies. The combined use of irrigation and altitude-specific cultivation represents a viable and necessary approach to maximizing genetic potential, optimizing water use, and enhancing the sustainability of C. canephora cultivation in regions facing climate variability.
Optimizing Herbicide Use in Fodder Crops with Low-Cost Remote Sensing and Variable Rate Technology
Publication . Conceição, Luís Alcino; Silva, Luís; Dias, Susana; Maçãs, Benvindo; Sousa, Adélia M. O.; Fiorentino, Costanza; D’Antonio, Paola; Barbosa, Sofia; Faugno, Salvatore; DCT - Departamento de Ciências da Terra; GeoBioTec - Geobiociências, Geoengenharias e Geotecnologias; MDPI - Multidisciplinary Digital Publishing Institute
The current Common Agriculture Policy (CAP) foresees a reduction of 50% in the use of herbicides by 2030. This study investigates the potential of integrating remote sensing with a low-cost RGB sensor and variable-rate technology (VRT) to optimize herbicide application in a ryegrass (Lolium multiflorum Lam.) fodder crop. The trial was conducted on three 7.5-hectare plots, comparing a variable-rate application (VRA) of herbicide guided by a prescription map generated from segmented digital images, with a fixed-rate application (FRA) and a control (no herbicide applied). The weed population and crop biomass were assessed to evaluate the efficiency of the proposed method. Results revealed that the VRA method reduced herbicide usage by 30% (0.22 l ha−1) compared to the FRA method, while maintaining comparable crop production. These findings demonstrate that smart weed management techniques can contribute to the CAP’s sustainability goals by reducing chemical inputs and promoting efficient crop production. Future research will focus on improving weed recognition accuracy and expanding this methodology to other cropping systems.
Reflectance-based assessment of nitrogen status in ryegrass and mixed ryegrass-clover intercropping fodder crops
Publication . Silva, Luís; Barbosa, Sofia; Carita, Teresa; D'Antonio, Paola; Lidon, Fernando Cebola; Conceição, Luís Alcino; DCT - Departamento de Ciências da Terra; GeoBioTec - Geobiociências, Geoengenharias e Geotecnologias; Elsevier BV
Effective nitrogen (N) management is essential for optimizing crop yields and minimizing environmental impacts, particularly in semi-arid regions where climate risks and natural resource constraints complicate decision-making. These low-energy systems require precise N strategies tailored to their unique challenges. This study evaluated a sensor-driven data analysis workflow for assessing N status in ryegrass-based fodder crops under semi-arid conditions and identified the most effective bands and vegetation indices (VIs) for use. Field trials conducted at Herdade da Comenda in Portugal employed a split-plot design, testing three N topdressing rates (0, 120, and 200 kg ha⁻¹) across varying crop types and irrigation systems. Both physical and remote measurements of crop parameters and N nutrition indicators were taken to address the limitations of current approaches in these conditions. The study found that vegetation pixels dominate spectral imagery, making additional filtering, such as ExG masks, unnecessary at ryegrass tillering and stem-elongation in ryegrass-based fodders. This simplification reduces processing time, costs, and digital footprints. Key VIs—NDRE, RERVI, and CIRE—proved robust for monitoring variables such as crop type, growth stage, and N treatments, showing strong correlations with N status indicators (NNI and CNI). Additionally, the study contrasted the efficiency of the entirely remote NNI method with the enhanced accuracy of the hybrid CCCI-CNI approach, providing valuable insights for tailored N management in semi-arid systems.
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Fundação para a Ciência e a Tecnologia
Programa de financiamento
Concurso de avaliação no âmbito do Programa Plurianual de Financiamento de Unidades de I&D (2017/2018) - Financiamento Programático
Número da atribuição
UIDP/04035/2020