Search Results (155)

Fungal endophytes have emerged as a promising source of bioactive compounds with potent antifungal properties for plant disease management. This study aimed to isolate and characterize fungal endophytes from Antillean avocado (Persea americana var. americana) trees in the Colombian Caribbean, capable of producing bio-fungicide metabolites against Fusarium solani and Fusarium equiseti. For this, dual culture assays, liquid-state fermentation of endophytic isolates, and metabolite extractions were conducted. From 88 isolates recovered from leaves and roots, those classified within the Diaporthe genus exhibited the most significant antifungal activity. Some of their organic extracts displayed median inhibitory concentrations (IC₅₀) approaching 200 μg/mL. To investigate the mechanism of action, in silico studies targeting chitin synthase (CS) were performed, including homology models of the pathogens’ CS generated using Robetta, followed by molecular docking with Vina and interaction fingerprint similarity analysis of 15 antifungal metabolites produced by Diaporthe species using PROLIF. A consensus scoring strategy identified diaporxanthone A (12) and diaporxanthone B (13) as the most promising candidates, achieving scores up to 0.73 against F. equiseti, comparable to the control Nikkomycin Z (0.82). These results suggest that Antillean avocado endophytes produce bioactive metabolites that may inhibit fungal cell wall synthesis, offering a sustainable alternative for disease management. Full article

Soil contamination by heavy metals (HMs) threatens crop productivity, food safety, and ecosystem health, especially in intensively cultivated Mediterranean regions. This study investigated the influence of soil HM contamination on nutrient uptake, photosynthetic traits, and metal bioaccumulation in avocado (Persea americana Mill.) orchards. Twenty orchard sites were sampled, collecting paired soil and mature leaf samples. Soil physicochemical properties and HM concentrations were determined, while leaves were analyzed for macro- and micronutrients, photosynthetic pigments, and metal contents. Bioaccumulation Factors (BAFs) were computed, and multivariate analyses (Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA), Linear Discriminant Analysis (LDA), and Partial Least Squares Regression (PLSR)) were applied to assess soil–plant relationships, complemented by Monte Carlo simulations to quantify probabilistic contamination risks. Results revealed substantial inter-site variability, with leaf Cd and Pb concentrations reaching 0.92 and 3.54 mg/kg, and BAF values exceeding 1 in several orchards. PLSR models effectively predicted leaf Cd (R² = 0.789) and Pb (R² = 0.772) from soil parameters. Monte Carlo simulations indicated 15–25% exceedance of FAO/WHO safety limits for Cd and Pb. These findings demonstrate that soil metal accumulation substantially alters avocado nutrient balance and photosynthetic efficiency, highlighting the urgent need for site-specific soil monitoring and sustainable remediation strategies in contaminated orchards. Full article

Avocado cultivation is expanding rapidly in East Africa, driven by growing market demand, yet planning often relies on farmers’ experience rather than systematic spatial analysis, raising risks of inefficient land and resource use. Therefore, this study applied four species distribution models (SDMs), Generalized Additive Models (GAM), Boosted Regression Trees (BRT), Maximum Entropy (MaxEnt), and Random Forest (RF), along with an ensemble model to map potential avocado suitability in Tanzania. The models were calibrated using 199 Variance Inflation Factor (VIF)-depurated occurrence records from which climatic, edaphic, and topographic predictor variables were extracted. BRT and RF had the best predictive abilities, with AUC values ranging from 0.77 ± 0.20 to 0.81 ± 0.13. The individual models identified Njombe, Iringa, Songwe, Kigoma, Rukwa, Kagera, and Morogoro as regions with high suitability, with more than 30% of each region’s total area predicted to be suitable for avocado production. Moderate suitability (15% to ≤30% of the regional area) was recorded for Kilimanjaro, Arusha, Dodoma, Manyara, Mara, Mbeya, Ruvuma, Tanga, and Katavi, whereas negligible suitability was forecasted for most of the remaining regions by the majority of the models. These findings suggest that heavy investments in avocado production and value chain additions should be directed primarily to regions with high suitability in order to use resources efficiently and minimize investment risks. More targeted, site-specific management should be encouraged in moderately suitable regions, with a focus on helping farmers identify and manage the best avocado sites rather than promoting broad expansion across the country. The findings generated by the ensemble model could be incorporated in the Tanzania Agriculture Climate Adaptation Technology Deployment Programme (TACATDP) to enhance sustainable crop investment, lower production risks, and strengthen the resilience of the avocado sector in the country. Full article

Understanding how climatic variability shapes the reproductive behavior of perennial crops is essential for improving their adaptation to tropical mountain environments. This study examined the influence of altitudinal and thermal gradients on flowering synchrony in ‘Hass’ avocado (Persea americana Mill.) cultivated across the tropical Andes of Colombia. Climatic variables and phenological stages were monitored across three elevations (2056, 2212, and 2338 m.a.s.l.) during two production cycles. Principal component, confirmatory factor, and circular statistical analyses were applied to integrate multivariate climatic structure with temporal flowering patterns. Results revealed that temperature was the main climatic driver of phenological variability, with significant differences among altitudes. The study revealed an altitudinal thermal–hydric gradient structuring distinct microclimates between 2050 and 2350 m.a.s.l., which determine the synchrony and rate of ‘Hass’ avocado phenological processes. Anthesis was the most environmentally sensitive phase, showing greater stability at intermediate elevations (~2200 m). Multivariate (PCA, CFA, ANOVA) and circular analyses confirmed that accumulated temperature (GDD) effectively predicts phenological progression, defining an optimal altitudinal range for synchrony and productivity in high Andean temperate zones. Full article

The transition towards a circular bioeconomy drives the search for sustainable valorization routes for agricultural waste streams. In this context, lignocellulosic residues from avocado tree prunings (Persea americana Mill.), with a reported high extractives content, represent a promising resource for pyrolytic valorization; however, their thermal behavior remains scarcely studied. This work characterized the chemical composition of whole branches (including bark) by FTIR and evaluated thermal degradation by thermogravimetric analysis (TGA) at five heating rates (10–30 °C/min) in an inert atmosphere. Kinetic analysis of the TGA data employed Friedman, FWO, KAS, Coats–Redfern, and Kissinger models. The Avrami model determined a reaction order of n ≈ 0.28. Among the methods, Coats–Redfern, applied with this n, provided the most consistent description, achieving the best average fit (R² ≈ 0.9878) and the narrowest range of pre-exponential factors (10¹²–10¹⁶ s⁻¹). The Friedman model showed greater dispersion (10¹²–10²² s⁻¹). Average activation energies ranged from 185 to 210 kJ/mol (Kissinger: 171.3 kJ/mol). The thermodynamic parameters confirmed a non-spontaneous, endothermic process (ΔH = 166.4–205.9 kJ/mol; ΔG = 178.8–179.8 kJ/mol). The entropy change (ΔS from –33.8 to 194.1 J/mol·K) reflects the complex solid-to-volatiles transition during pyrolysis. This study establishes a tailored kinetic framework for avocado branch pyrolysis, providing a reliable kinetic description for this biomass and identifying the Avrami–Coats–Redfern method as the most suitable for its accurate modeling. Full article

Alternate (irregular) bearing, characterized by large fluctuations in fruit yield between consecutive years, remains a major constraint to sustainable avocado (Persea americana) production. This study aimed to assess the potential of satellite remote sensing and climatic variables to characterize and predict alternate bearing patterns in commercial orchards in Tzaneen, Limpopo Province, South Africa. Historical yield data (2018–2024) from 46 “Hass” avocado blocks were analyzed alongside Sentinel-2 derived vegetation indices (NDVI, GNDVI, NDRE, CIG, CIRE, EVI2, LSWI) and flowering indices (WYI, NDYI, MTYI). To align temporal scales, all VIs and FIs were aggregated into eight quarterly averages from the two years preceding each yield year and spatially averaged across each orchard block. Climatic predictors including maximum temperature (Tmax), minimum temperature (Tmin), vapor pressure deficit (VPD), and precipitation were screened against historical yields to identify critical periods, with June–October emerging as the most influential months, and these variables were aggregated accordingly to match annual alternate bearing patterns. Five machine learning (ML) algorithms—Random Forest, XGBoost, CATBoost, LightGBM, and TabPFN—were trained and tested using a Leave-One-Year-Out (LOYO) approach. Results showed that VPD, Tmin, and Tmax during the flowering period (July–September) were the most influential variables affecting subsequent yields. TabPFN achieved the highest predictive accuracy (Accuracy = 0.88; AUC = 0.95) and strongest temporal generalization. Spectral gradients between flowering and early fruit drop were lower during “on” years, reflecting stable canopy vigor. This combined use of remote sensing and climatic variables in a ML framework represents a novel approach, and the findings demonstrate that integrating remote sensing and climatic indicators enables early discrimination of “on” and “off” years, supporting proactive orchard management and improved yield stability. Full article

Avocado (Persea americana Mill.) is cultivated in a wide range of environments, from tropical and semitropical to subtropical regions. Its fruit, of high nutritional value, is increasingly demanded worldwide. Spain is the main European producer, but avocado cultivation in certain areas, such as the Canary Islands, requires the genetic identification of West-Indian rootstocks because they often show tolerance to low-quality water and soil salinization. In the present study, eight novel Retrotransposon-Based Insertion Polymorphism assays, derived from previously characterized inter-Primer Binding Site markers, have been developed and evaluated by multiplex PCR across 58 P. americana cultivars. The results showed 100% specificity and sensitivity in detecting the West-Indian genomic component, both in pure and hybrid avocado cultivars. This cost-effective and fast molecular tool provides a valuable resource for characterization and selection programs of avocado cultivars genetically related to the West-Indian horticultural race. Full article

Avocado trees (Persea americana Mill.) grown in Mediterranean conditions are exposed to high temperatures and intense solar radiation during summer, factors that can severely compromise plant water status and key physiological processes. To minimize these stressful conditions, the use of shade nets is an agronomical technique that permits the creation of an optimal microclimate for crop development. Thus, the aim was to evaluate the effects of shade netting on the physiological response of young avocado trees commercially grown under Mediterranean climatic conditions. The main results showed similar circadian rhythms of plant water status under both crop systems (open-air and shaded) in both seasons. However, the use of shading nets altered the circadian rhythm of leaf gas exchange. In summer, stomatal conductance (g_s) remained significantly more open after midday in shaded trees, allowing higher leaf transpiration (E_leaf) and cooler leaf temperature (T_leaf). A similar daily pattern was observed in chlorophyll a fluorescence parameters, including the effective quantum yield of photosystem II (ΦPSII) and the electron transport rate (ETR), with the lowest values occurring at midday. In shaded plants, ΦPSII and ETR remained higher after midday than in open-air, suggesting a lower photochemical inhibition of photosynthesis caused by heat stress and photoinhibition. Thus, the use of shade nets represents an agronomic alternative technique for cultivating avocados in Mediterranean climate conditions. Full article

Zygotic embryogenesis is a key process in the development and propagation of avocado (Persea americana). Plant growth regulators, particularly auxins and cytokinins, play a crucial role in regulating this process. In this study, a transcriptomic analysis was performed to identify and characterize the expression of genes related to biosynthesis, transport, signaling, or response to auxins and cytokinins during different stages of embryonic development, as defined by the varying sizes of collected fruits. Additionally, several transcription factors and genes related to embryogenesis were analyzed. The results reveal dynamic patterns of gene expression that suggest a coordinated interaction between these PGRs in embryo formation and differentiation. This study provides key insights into the molecular mechanisms that regulate avocado zygotic embryogenesis, with potential applications in biotechnology and plant propagation. Full article

Avocado (Persea americana Miller), a crop of major economic importance in Mexico, is threatened by several quarantine pests, and recent reports have suggested that the lance fly Neosilba batesi (Diptera: Lonchaeidae) may be responsible for significant yield losses. To clarify the role of this species, we surveyed avocados from six localities in Veracruz State on the Gulf coast of Mexico and identified lance flies using both morphological and molecular tools. None of the symptoms previously attributed to N. batesi infestation in Hass avocado were observed in any of the fruits inspected across the six localities. However, 90 fruits displayed clear signs of borer attack by Conotrachelus spp. or other primary pests, and 64 of these damaged fruits (60%) yielded lance flies. Hass avocados were rarely infested and hosted only N. batesi, whereas creole avocados (P. americana var. drymifolia) were hosts to N. batesi, N. glaberrima, N. recurva, and N. flavitarsis and an undescribed species (Neosilba sp.3) that was detected by analysis of the COI gene sequences of males. Additionally, Lonchaea cristula was reported for the first time emerging from creole avocado. Each avocado yielded an average of between 2.3 and 21.0 adult lance flies. Infestation was more frequent and numerous in fruits collected from the ground than in those harvested directly from trees, supporting the idea that lance flies preferentially exploit pre-damaged or fallen fruits. Indeed, lonchaeid eggs were frequently observed deposited on the periphery or inside oviposition holes created by other pests. Overall, our results indicate that Neosilba spp. act as secondary invaders in Veracruz, with no evidence of N. batesi behaving as a primary pest in this region. None of the avocados were infested by species of Tephritidae and none of the Neosilba species we identified appear to pose a threat to avocado production in Mexico. This study highlights the value of combining morphological and molecular tools for species identification and underscores the importance of differentiating between primary and secondary invaders in the context of avocado pest management. Full article

Avocado (Persea americana Mill.) is one of the most widely consumed fruits worldwide. The tree species is traditionally classified into three botanical races: Mexican, Guatemalan, and West Indian (with a potentially distinct Colombian genepool). However, previous studies using molecular markers, such as AFLPs, microsatellites (SSRs), and GBS-derived SNP markers, have only partially resolved this racial divergence, especially in the hyper agrobiodiverse region of northwest South America. Therefore, in order to confirm genetic identity and origin of “criollo” avocado cultivars in the region, as well as to improve their traceability as rootstocks for the Hass variety, we performed low-coverage whole genome resequencing (lcWGS) on 205 ex situ conserved tree samples, comprising 42 commercial varieties and 163 “criollo” trees from various provinces in Colombia. This characterization yielded a total of 64,310,961 SNPs at an average coverage of 4.69×. Population structure analysis using principal component analysis (PCA) and ADMIXTURE retrieved at least five genetic clusters (K = 5), partly confirmed by Bayesian phylogenetic inference. Three clusters matched the recognized Mesoamerican botanical races (Mexican, Guatemalan, and West Indian), and two clusters reinforced the distinctness of two novel Andean and Caribbean Colombian genetic groups. Finally, in order to retrieve high-quality SNP markers for racial screening, a second genomic dataset was filtered, consisting of 68 avocado tree samples exhibiting more than 80% ancestry to a given racial cluster, and 9826 SNPs with a minimum allele frequency (maf) of 5%, a minimum sequencing depth (SD) of 10× per position, and missing data per variant not exceeding 20% (i.e., variants with genotypes present in at least 80% of the samples). This racially segregating high-quality subset was analyzed against the racial substructure using linear mixed models (LMMs), enabling the identification of 254 SNP markers associated with the five avocado genetic races. The previous candidate SNPs may be leveraged by nurseries and producers through a high-throughput SNP screening system for the racial traceability of seedling donor trees, saplings, and rootstocks. These genomic resources will support the selection of regionally adapted elite rootstocks and represent a landmark in Colombian horticulture as the first large-scale lcWGS-based characterization of a local avocado germplasm collection. Full article

Avocado is a unique fruit in which of seven-carbon (C7) sugars (notably D-mannoheptulose and perseitol) dominate the carbohydrate profile at harvest. Despite growing interest in sugar-mediated ripening processes, limited comparative data exist across cultivars. This work characterises the dynamic changes in non-structural carbohydrates in the mesotecarp of three commercially relevant avocado varieties—Bacon, Fuerte, and Hass—across four defined ripening stages, from unripe to overripe, with five biological replicates per stage. Using a validated hydrophilic interaction liquid chromatography–mass spectrometry (HILIC–MS) method, we quantified five key sugars and assessed their evolution through ripening. Concentrations varied among the studied samples within the following ranges: D-mannoheptulose, 0.4–49 mg/g dry weight (DW); perseitol, 0.5–23 mg/g DW; glucose, 0.8–5.3 mg/g DW; fructose, 0.6–4.5 mg/g DW; and sucrose, 0.5–3.4 mg/g DW. C7 sugar levels consistently declined, while C6 sugars increased—primarily between the intermediate and ready-to-eat stages—with distinct cultivar-specific patterns. Bacon maintained elevated C7 concentrations for a longer period; Fuerte exhibited a rapid transition from C7 to C6 sugars; and Hass displayed a more gradual and balanced shift. Multivariate analysis (partial least squares discriminant analysis, PLS-DA) effectively discriminated between cultivars at each ripening stage, confirming cultivar-specific metabolic signatures. These findings offer new insights into avocado carbohydrate metabolism, emphasising variety-dependent pathways that could inform breeding strategies, optimise postharvest ripening protocols, and support the nutritional characterisation of different avocado cultivars. Full article

This paper presents a dataset for a comparative analysis of direct (spectrophotometric) and indirect (multispectral imagery-based) methods for quantifying crop leaf chlorophyll content. The dataset originates from a study conducted in the Department of Cauca, Colombia, a region characterized by diverse agricultural production. Data collection focused on seven economically important crops, namely coffee (Coffea arabica), Hass avocado (Persea americana), potato (Solanum tuberosum), tomato (Solanum lycopersicum), sugar cane (Saccharum officinarum), corn (Zea mays) and banana (Musa paradisiaca). Sampling was conducted across various locations and phenological stages (healthy, wilted, senescent), with each leaf subdivided into six sections (A–F) to facilitate the analysis of intra-leaf chlorophyll distribution. Direct measurements of leaf chlorophyll content were obtained by laboratory spectrophotometry following the method of Jeffrey and Humphrey, allowing for the determination of chlorophyll A and B content. Simultaneously, indirect estimates of leaf chlorophyll content were obtained from multispectral images captured at the leaf level using a MicaSense Red-Edge camera under controlled illumination. A set of 32 vegetation indices was then calculated from these multispectral images using MATLAB. Both direct and indirect methods were applied to the same leaf samples to allow for direct comparison. The dataset, provided as an Excel (.xlsx) file, comprises raw data covering laboratory-measured chlorophyll A and B content and calculated values for the 32 vegetation indices. Each row of the tabular dataset represents an individual leaf sample, identified by plant species, leaf identifier, and phenological stage. The resulting dataset, containing 16,660 records, is structured to support research evaluating the direct relationship between spectrophotometric measurements and multispectral image-based vegetation indices for estimating leaf chlorophyll content. Spearman’s correlation coefficient reveals significant positive relationships between leaf chlorophyll content and several vegetation indices, highlighting its potential for a nondestructive assessment of this pigment. Therefore, this dataset offers significant potential for researchers in remote sensing, precision agriculture, and plant physiology to assess the accuracy and reliability of various vegetation indices in diverse crops and conditions, develop and refine chlorophyll estimation models, and execute meta-analyses or comparative studies on leaf chlorophyll quantification methodologies. Full article

The bacterial diversity of soils cultivated with avocado (Persea americana M.) is influenced by different factors, perhaps the most decisive being the type of agronomic management used by farmers. In conventional agronomic management (CM), high doses of agrochemicals are applied, in contrast to organic agronomic management (OM), where organic fertilizers are used. This alters the diversity and abundance of soil microorganism populations, which in turn affects crop health. This study aimed to isolate and morphologically characterize rhizospheric bacteria from avocado trees under different agronomic management systems (CM and OM). For the bacterial isolates, their ability to promote plant growth in vitro was determined through biochemical tests for phosphorus and calcium solubilization and nitrogen fixation. In addition, their in vivo effect on tomato (S. lycopersicum) growth was evaluated, and their antagonistic capacity against Fusarium sp. was assessed. The results showed differences in the quantity, diversity, and morphologies of bacterial isolates depending on the type of agronomic management. A higher Shannon diversity index was found in OM (2.44) compared to CM (1.75). A total of 35 bacterial isolates were obtained from both management types. A greater number of isolates from OM soils exhibited in vitro PGP activity; notably, eight isolates from OM plots showed phosphate-solubilizing activity, compared to only one from CM plots. Furthermore, although all isolates demonstrated nitrogen fixing capacity, those from OM orchards produced significantly higher nitrate levels than the control (Azospirillum vinelandii). On the other hand, inoculation of tomato plants with bacterial isolates from OM soils increased plant height, root length, and total fresh and dry biomass compared to isolates from CM soils. Likewise, OM isolates exhibited greater antagonistic activity against Fusarium sp. These findings demonstrate the impact of agronomic management on soil bacterial populations and its effect on plant growth and protection against pathogens. Full article

The growing emphasis on sustainability and circular economy strategies has driven increasing interest in the valorization of agro-industrial by-products. Among these, the peel and seed of avocado (Persea americana), typically discarded during processing, have emerged as promising sources of bioactive compounds, particularly phenolic constituents with recognized antioxidant capacity. This review critically examines the current scientific literature on the phytochemical composition, antioxidant activity, and potential health benefits associated with avocado peel and seed. In addition, it explores recent technological advances in extraction methods and highlights the applicability of these by-products in the formulation of functional foods, nutraceuticals, and other health-related products. Challenges related to safety, bioavailability, and regulatory aspects are also discussed. By consolidating available evidence, this work supports the potential of avocado peel and seed as valuable functional ingredients and contributes to sustainable innovation in the food and health industries. Full article