Search Results (88)

Melatonin (N-acetyl-5-methoxytryptamine) is a regulatory molecule with potential to increase plant tolerance to water stress by modulating stomatal function, redox balance, and photosynthetic efficiency. However, its physiological effects depend on dose, species, and stress intensity, and studies on Coffea canephora under recurrent drought are scarce. This study evaluated the effects of exogenous melatonin (0, 100, 200, 300, and 400 µM) on young plants of conilon coffee genotype 02 (Clone V12) subjected to three consecutive cycles of water deficit and rehydration. The experiment was conducted in a greenhouse using a randomized block design, with evaluations of gas exchange, water potential, and biomass allocation. Melatonin improved physiological recovery after rehydration, particularly at 100 and 300 µM during the second stress cycle, when photosynthesis reached values similar to the irrigated control. The 400 µM treatment maintained root dry mass close to the control under prolonged deficit, suggesting preferential biomass allocation to the root system. Overall, melatonin effects were more pronounced during recovery than stress, indicating a possible priming action. These results highlight the potential of melatonin as a phytoprotective agent in C. canephora, although responses depend on dose and stress cycle. Full article

The efficiency of converting ripe fruits into processed beans is an economically relevant component of Coffea canephora production systems, yet its genetic parameters remain poorly characterized in studies that do not partition the genotype × year (G×Y) interaction. This study estimated genetic parameters for five processing efficiency traits, namely grain proportion (% grain), husk proportion (% husk), fruit fresh mass per grain mass (FWM/GW), fruit fresh mass per bag (FWM/bag), and fruit volume per bag (FVol/bag), in 48 C. canephora genotypes (40 Robusta, 8 Conilon) evaluated over two crop years (2023–2024) in Jaguaré, Espírito Santo, Brazil. Bayesian inference via MCMC (brms) revealed that the genotype × year variance component exceeded the genotypic variance in 79–97% of posterior samples across the 48 genotypes evaluated over two crop years, a result that should be interpreted within the context of this restricted temporal window, with median heritabilities of 0.27–0.50 (95% credible intervals spanning up to 0.66 units, reflecting the uncertainty inherent to the two-year evaluation window) and genotypic correlations of 0.19–0.38 between years, indicating low consistency of genetic merit across crop seasons. Bayesian probability of consistent superiority identified Z21 as the genotype with the highest predictability for FWM/bag (prob. $=0.846$ at 20% selection intensity), while VR3 showed a favorable profile across four traits simultaneously. The multi-trait model with unstructured covariance estimated a negative genetic correlation between % grain and FWM/bag (${\widehat{r}}_g=-0.87$), suggesting potential for indirect selection. UPGMA clustering based on Mahalanobis distance (CCC $=0.813$) yielded six divergence groups that did not coincide with the botanical classification Conilon/Robusta. In this single-location, two-year study, temporal instability was the predominant source of uncertainty in the selection for processing efficiency in C. canephora under restricted evaluation windows. under restricted evaluation windows. Accordingly, the highlighted genotypes should be interpreted as priority candidates for validation in multi-environment, multi-year networks, rather than as definitive cultivar recommendations, given that the short evaluation window limits the generalizability of genotypic rankings. Full article

Chemical differentiation of coffee species is essential for quality control, authenticity verification, and the prevention of mislabeling in the coffee industry. This is particularly relevant in Panama, a recognized producer of specialty coffees such as Geisha, where studies on chemical characterization remain limited. This study investigated the phenolic composition, antioxidant activity, and caffeine content of roasted coffee as potential chemical markers for differentiating Coffea arabica and Coffea canephora. Ultrasound-assisted hydroethanolic extraction was optimized using the response surface methodology, with temperature, ethanol concentration, and extraction time as the experimental variables. The optimized extraction parameters were established at 75 °C, 44% ethanol, and 25 min, resulting in high recovery of the total phenolic content, total flavonoid content, and antioxidant activity (ABTS and DPPH assays). Under these conditions, C. canephora samples obtained higher levels of phenolic compounds, antioxidant activity, and caffeine content than C. arabica. Pearson’s correlation analysis showed significant associations among phenolic compounds, caffeine content, and antioxidant activity. PCA explained 90.5% of the total variance and clearly discriminated between the two species, mainly based on differences in caffeine content and antioxidant activity. HCA confirmed this classification and revealed subgroups within C. arabica, particularly among the Geisha varieties. PLS-DA achieved complete separation between species, with zero classification error under cross-validation. These results indicated that combined chemical and multivariate approaches can be used to differentiate and assess the authenticity of coffee, particularly in underexplored production regions such as Panama. Full article

The expanding use of Conilon and Conilon × Robusta hybrids in Brazilian coffee cultivation contrasts with the scarcity of information on the genetic variability underlying their physical yield attributes. This study quantified genetic variability and estimated genetic parameters for fresh fruit mass and volume, fruit-to-bean ratio, and bean and husk proportions in 48 Coffea canephora genotypes, compared the discriminatory power of gravimetric and volumetric metrics in classifying processing efficiency, and identified genotypes combining high bean proportion and genetic divergence for use in breeding programs. A randomized complete block design with three replications was used. The fruit mass required to produce a 60 kg bag of processed coffee (FMM/bag) ranged from 205.29 to 251.46 kg bag⁻¹, representing an 18% difference between the most and least efficient groups identified by the Scott-Knott test. High heritability was found for bean proportion (90.74%) and FMM/bag (84.58%), confirming strong genetic control over fruit-to-bean yield. Mass-based metrics showed greater discriminatory power than volumetric ones, forming four distinct groups versus two. Conilon genotypes tended toward greater yield efficiency. The observed variation indicates exploitable genetic variability for selective gains, with direct implications for crossing strategies and post-harvest processing optimization in C. canephora. Full article

The main commercial species of coffee is Coffea arabica; however, it is highly susceptible to biotic and abiotic factors. For this reason, scions of Coffea arabica species are used on robusta (Coffea canephora) rootstocks since grafting can modify the organoleptic, nutraceutical, and nutritional characteristics of crops. The objective of this study was to evaluate the effects of five roasting degrees (light, medium light, medium, medium dark, and dark) in two varieties of Coffea arabica species (Colombia Rojo and Costa Rica 95) and their respective grafts on C. canephora variety Romex. The concentrations of acrylamide, caffeine, and chlorogenic acids were analyzed using HPLC, and the nutrient content was analyzed using plasma induction atomic emission spectrophotometry. The graft of the Colombia Rojo variety with the medium dark roast had the highest concentration of caffeine (1.523%). The same variety with the light roast had the highest concentration of chlorogenic acid (3.088 mg g⁻¹), while the highest acrylamide content (336.70 ng g⁻¹) was found in the same variety with the medium light roast. The roasting degree, variety, and grafting of coffee influence the organoleptic, nutraceutical, and nutritional contents of coffee infusions. Full article

Premium coffee depends on high-quality beans, influenced by a combination of genetic, environmental, and postharvest factors. This review summarizes the mechanisms underlying coffee bean quality, with an emphasis on the genetic differences between Coffea arabica and Coffea canephora, as well as the integrated roles of environmental conditions, agronomic practices, including nutrient and shade management, and postharvest processing technologies. The allotetraploid genome of C. arabica is influenced by homoeologous exchanges and subgenome-biased expression (such as decreased DXMT activity that reduces caffeine), which contribute to its complex flavor profile. Key lipid metabolism genes, particularly FADS2, play a critical role in regulating lipid metabolism. The effects of altitude (1600–2000 m) and shade influence various metabolic pathways. Cooler temperatures promote sugar accumulation, while excessive shading hinders carbon assimilation and the development of flavor precursors. Postharvest processing significantly influences flavor, where microbial or enzymatic treatments enhance sensory attributes. In addition, methods like natural, washed, or honey processing modulate various nonvolatile compounds, impacting lipid emulsification and aroma retention. Multi-omics analyses suggest that MYB proteins play a key role in regulating pathways involved in caffeine, chlorogenic acids, and terpenes. Effective hermetic packaging prevents oxidation, thereby preserving freshness. Overall, superior coffee quality stems from synergistic interactions across genetic, ecological, agronomic, and processing factors, highlighting the need for the development of an integrated strategy to support the sustainable production of premium coffee. Full article

Coffea canephora cultivation areas in Brazil are frequently exposed to successive cycles of water deficit, triggering plant stress responses. In addition to water deficit, increased air temperature can act as a second stress factor. The recurrence of these stress factors may induce plant tolerance mechanisms, potentially mitigating future stress responses even of a different stress nature. We hypothesized that repeated cycles of water deficit can trigger tolerance mechanisms that make C. canephora leaves more resilient to supra-optimal temperatures. To test this hypothesis, young C. canephora plants were grown under non-limited water conditions for seven months (Ψ_mSoil > −20 kPa), after which they were subjected to two consecutive cycles of water deficit (Ψ_mSoil < −300 kPa), followed by rehydration. Two clones were used, ‘A1’ and ‘3V’, previously classified as drought sensitive and tolerant, respectively, considering the dynamics of physiological and architectural responses. After the second cycle, leaf discs were collected from completely expanded leaves formed during the two stress cycles and exposed to heat treatments (35 °C, 40 °C, 45 °C, 50 °C, and 55 °C) for 15 min in a water bath. Chlorophyll a fluorescence emission was then monitored, and the results were analyzed using OJIP transient kinetics and the JIP_Test. High temperatures induced negative changes in both OJIP kinetics and JIP_Test-derived parameters. A significant increase in F₀ and a reduction in F_M were observed mainly at 50 °C and 55 °C, due to changes in the stages of the OJIP curve. These changes impacted the “energy connectivity” and consequently the electron transport along the electron transfer chain (ETC), increasing energy dissipation, as confirmed by the JIP_Test variables. Despite the high temperature impacts, previous water deficit induced heat tolerance in clone ‘A1’, while it increased sensitivity in clone ‘3V’. This study suggests that selecting drought-resistant varieties should consider their subsequent response to short high-temperature stress to avoid cross-sensitivity caused by selecting for a single environmental factor. Full article

Coffea canephora is economically and socially important for small-scale agriculture in Northern Brazil. To identify genotypes adapted to Amazonian edaphoclimatic conditions, clones of the species have been evaluated across multiple locations in Amazonas. Introducing genetically selected materials into comparable environments may promote consistent productivity gains in the short and medium term. In this context, the aim of this study was to assess the genetic diversity of different C. canephora genotypes using microsatellite markers, which will support the development of superior genotypes adapted to Amazon conditions. A total of 43 C. canephora genotypes were analyzed. Leaves were collected for genomic DNA extraction and were standardized and amplified by PCR using microsatellite primers. Genotyping was performed via capillary electrophoresis, allowing for the determination of allele sizes. Genetic structure was inferred, and genetic diversity parameters were estimated. The average observed heterozygosity (H_O = 0.64) exceeded the expected heterozygosity (H_E = 0.53), and the average inbreeding coefficient (f = −0.19) indicated an excess of heterozygotes. The results revealed high genetic variability among the evaluated genotypes. These findings highlight the broad genetic diversity of C. canephora, reinforcing its potential as a genetic basis for selection and the development of cultivars adapted to the environmental conditions of the Amazon. Full article

Expanding Coffea canephora cultivation to transitional altitudes offers a promising strategy to sustain coffee production under climate change. This study evaluated 27 genotypes cultivated under two water management regimes (fully and minimally irrigated) at 650 m altitude in Espírito Santo, Brazil, over eight harvests (2018–2025). A split-plot design was analyzed using a three-way mixed model (REML/BLUP) to estimate genetic parameters and predicted genotypic values. Adaptability and stability were assessed using the harmonic mean of relative performance of genotypic values (HMRPGV) and weighted average of absolute scores (WAASB) and integrated into a multi-trait selection index. Significant genotypic and temporal effects were detected, while the interaction between genotypes and water management regimes was non-significant, indicating consistent performance under different water regimes. Broad-sense heritability was moderate, with high selective accuracy. Genotypes 108 and 203 achieved the highest predicted yields (91.4 and 86.8 bags ha⁻¹) and superior adaptability. The multi-trait index identified six outstanding genotypes—108, 203, 201, 306, 303, and 302—combining high yield, broad adaptability, and temporal stability, resulting in an expected genetic gain of 8.17% in relation to the original population. These findings demonstrate that selected C. canephora genotypes are well adapted to transitional altitudes, supporting breeding programs for climate-resilient and high-yielding crops. Full article

The main characteristics of the large number of coffee species are differences in aroma and caffeine content. Labeled blends of Coffea arabica (C. arabica) and Coffea canephora (C. canephora) are common to broaden the flavor profile or enhance the stimulating effect of the beverage. New emerging species such as Coffea liberica (C. liberica) further increase the variability in blends. However, significant price differences between coffee species increase the risk of unlabeled blends and thus influence food quality and safety for consumers. In this study, a prototypic hyphenation of trapped headspace-gas chromatography-ion mobility spectrometry-quadrupole mass spectrometry (THS-GC-IMS-QMS) was used for the detection of characteristic compounds of C. arabica, C. canephora, and C. liberica in green and roasted coffee samples. For the discrimination of coffee species with IMS data, multivariate resolution with multivariate curve resolution–alternating least squares (MCR-ALS) prior to partial least squares–discriminant analysis (PLS-DA) was evaluated. With this approach, the classification accuracy, as well as sensitivity and specificity, of the PLS-DA model was significantly improved from an overall accuracy of 87% without prior feature selection to 92%. As MCR-ALS preserves the physical and chemical properties of the original data, characteristic features were determined for subsequent substance identification. The simultaneously generated QMS data allowed for partial annotation of the characteristic volatile organic compounds (VOC) of roasted coffee. Full article

Grafting is a strategy to mitigate biotic and abiotic stresses in coffee systems. However, initial compatibility indicators between Coffea arabica scions and C. canephora rootstocks under controlled conditions remain insufficiently documented. We evaluated the physiological and morphological compatibility of four C. arabica cultivars (Bourbon, Geisha, Catuai, and Villa Sarchí) grafted onto C. canephora (Robusta) rootstock in a tropical highland nursery in the Peruvian Amazon. Seven physiological and six morphological variables were measured. Statistical analyses included one-way ANOVA and Kruskal–Wallis tests with Bonferroni post hoc comparisons. Two physiological parameters were significantly higher in Villa Sarchí grafts than in Robusta: PSII quantum yield (+0.044 units; p < 0.05) and electron transport rate (+14.702 µmol e⁻ m⁻² s⁻¹; p < 0.05); by contrast, net photosynthesis, stomatal conductance, intercellular CO₂ concentration, and transpiration did not differ, and maximum PSII efficiency was similar among treatments (p = 0.509). Conversely, no morphological trait showed significant differences, and graft-take was high across all combinations. The results support the use of Coffea robusta as a rootstock for these four cultivated varieties, thereby offering the possibility of improving their resilience in tropical highland regions. Full article

Plant growth-promoting bacteria (PGPB) associated with Coffea arabica L. and Coffea canephora Pierre ex Froehner offer a viable strategy to reduce synthetic inputs and enhance resilience in coffee agroecosystems. This review synthesizes evidence from the past decade on rhizosphere-associated and endophytic taxa, their plant growth-promotion and biocontrol mechanisms and the resulting agronomic outcomes. A compartment-specific core microbiome is reported, in the rhizosphere of both hosts, in which Bacillus and Pseudomonas consistently dominate. Within endophytic communities, Bacillus predominates across tissues (roots, leaves and seeds), whereas accompanying genera are host- and tissue-specific. In C. arabica, endophytes frequently include Pseudomonas in roots and leaves. In C. canephora, root endophytes recurrently include Burkholderia, Kitasatospora and Rahnella, while seed endophytes are enriched for Curtobacterium. Functionally, coffee-associated PGPB solubilize phosphate; fix atmospheric nitrogen via biological nitrogen fixation; produce auxins; synthesize siderophores; and express 1-aminocyclopropane-1-carboxylate deaminase. Indirect benefits include the production of antifungal and nematicidal metabolites, secretion of hydrolytic enzymes and elicitation of induced systemic resistance. Under greenhouse conditions, inoculation with PGPB commonly improves germination, shoot and root biomass, nutrient uptake and tolerance to drought or nutrient limitation. Notable biocontrol activity against fungal phytopathogens and plant-parasitic nematodes has also been documented. Key priorities for translation to practice should include (i) multi-site, multi-season field trials to quantify performance, persistence and economic returns; (ii) strain-resolved omics to link taxa to functions expressed within the plant host; (iii) improved bioformulations compatible with farm management and (iv) rationally designed consortia aligned with production goals and biosafety frameworks. Full article

This study evaluated the genetic diversity of 33 Coffea canephora genotypes through morphophysiological and molecular analyses, aiming to identify promising genotypes for pre-breeding purposes in the southern region of Espírito Santo, Brazil. Cutting-propagated seedlings were evaluated 120 days after planting, considering height, stem and crown diameter, number of leaves, fresh and dry shoot and root weight, chlorophyll content, and root characteristics. Molecular analysis was performed on 32 genotypes; one was excluded due to absent DNA, and 18 ISSR markers were used. Morphological data were analyzed by ANOVA, Scott–Knott’s mean test, principal component analysis, and cluster analysis. The results revealed significant diversity among genotypes. The first two principal components explained 75.5% of the total variability. Genotypes 2, 3, 4, 5, 6, 10, 32, and 33 stood out as those that produced the most vigorous seedlings. Molecular analysis also revealed genetic diversity among genotypes, with the formation of 16 groups, while the morphophysiological analysis revealed four groups. The Mantel test demonstrated a small but significant positive difference (r = 0.228; p = 0.018) between the genetic and morphophysiological distances of the genotypes. This diversity indicates that the genotypes evaluated are promising for use in C. canephora breeding programs. Full article

Chitinases have been demonstrated to enhance plant resistance to fungi in various pathosystems. Although there is evidence of the effectiveness of these proteins in coffee–fungus interactions, no genome-wide identification or characterization of coffee chitinases has been performed. In this study, we employed phylogenetic analysis, domain architecture, gene structure analysis, and subcellular localization to identify and characterize putative genes and proteins in the genomes of Coffea arabica and its progenitors, Coffea canephora and Coffea eugenioides. A total of 113, 47, and 69 putative chitinase proteins were identified in C. arabica, C. canephora, and C. eugenioides, respectively. These chitinases were classified according to their catalytic domains, GH18 and GH19, and into Classes I, II, III, IV, and V, as determined through phylogenetic analysis based on the Arabidopsis thaliana classification. Furthermore, based on orthologous analysis, we identified ten, six, and seven putative chitinases associated with fungal defense responses in C. arabica, C. canephora, and C. eugenioides, respectively. These findings are valuable for future studies focusing on coffee chitinases, particularly on genetic programs involved in plant pathogen resistance. Full article

This study investigates the solubility correlation of oil extracted from Sabah green Robusta coffee (Coffea canephora) beans through supercritical carbon dioxide (SC-CO₂) extraction. Sabah, recognized as the largest coffee-producing region in Malaysia, serves as a significant source of Robusta beans for this research. The solubility of coffee bean oil was evaluated under varying pressures (10–30 MPa) and temperatures (40–80 °C). The maximum solubility, 2.681 mg/g CO₂, was recorded at 30 MPa and 40 °C, whereas the lowest solubility, approximately 0.440 mg/g CO₂, occurred at 20 MPa and 80 °C. A clear inverse relationship between solubility and temperature was observed, with solubility decreasing as temperature increased to 80 °C. Conversely, elevated pressure, particularly at 30 MPa, enhanced solubility due to the increased density and solvent power of SC-CO₂. Experimental data exhibited strong agreement with Chrastil’s equation, yielding a relatively low percentage error of 3.37%, compared with 14.57% for the del Valle-Aguilera model. These findings demonstrate the reliability of Chrastil’s model in predicting the solubility of Sabah green coffee bean oil in SC-CO₂. Overall, the research highlights the potential of SC-CO₂ extraction as a sustainable, solvent-free approach for obtaining high-quality coffee oil extracts, with promising applications in the food industry and possible extension to the recovery of other bioactive compounds in food processing. Full article