Search Results (94)

Unmanned aerial vehicle (UAV)-based multispectral remote sensing has emerged as a promising tool for monitoring crop physiological status and supporting precision disease management. However, the capacity of multispectral vegetation indices to detect foliar diseases under commercial field conditions remains insufficiently understood, particularly in perennial crops grown in humid tropical environments. This study evaluated the potential of UAV-derived multispectral vegetation indices to assess the physiological response of avocado (Persea americana Mill.) canopies affected by anthracnose caused by Colletotrichum fructicola in Amazonas, Peru. Disease incidence and severity were assessed through field evaluations, while multispectral imagery was acquired using a UAV equipped with a MicaSense RedEdge-MX Dual sensor. Vegetation indices including the Normalized Difference Vegetation Index (NDVI), Green Normalized Difference Vegetation Index (GNDVI), Soil-Adjusted Vegetation Index (SAVI), Normalized Difference Red Edge Index (NDRE), Red Edge Chlorophyll Index (CIred-edge), Plant Senescence Reflectance Index (PSRI), and Visible Atmospherically Resistant Index (VARI) were calculated, and their relationships with anthracnose incidence were analyzed using Spearman’s rank correlation. Field observations confirmed a high incidence of foliar anthracnose with a heterogeneous spatial distribution across the orchard. Multispectral imagery successfully characterized spatial variability in the canopy physiological condition, revealing differences in vegetation vigor, chlorophyll-related reflectance, and senescence among experimental blocks. Nevertheless, none of the evaluated vegetation indices showed statistically significant correlations with anthracnose incidence (p > 0.05), indicating that spectral variability primarily reflected the general canopy physiological status rather than a disease-specific spectral response. These findings demonstrate that UAV-derived multispectral vegetation indices are valuable for monitoring spatial variability in the avocado canopy condition but have limited capability for independently detecting anthracnose under humid tropical field conditions. Future studies integrating multi-temporal UAV acquisitions, hyperspectral and thermal imagery, LiDAR, environmental variables, and machine-learning approaches are expected to improve the early detection and spatial prediction of anthracnose in avocado production systems. Full article

Superfoods have gained increasing attention for their nutritional and functional properties, with avocado (Persea americana Mill.) among the most prominent examples owing to its health-promoting compounds. However, avocado cultivation is associated with several challenges, including high water demand, environmental impact, seasonal variability, and post-harvest losses. To address these limitations, in vitro plant cell cultures represent a sustainable and controlled alternative for producing avocado-derived material. In this study, avocado var. Hass callus cultures were established and evaluated as a potential source of functional metabolites. Colourimetric assays performed at different growth stages identified 14-day-old callus as the most enriched in phenolic compounds and antioxidant activity; this material was therefore selected for further analyses. LC–ESI–QTOF–MS/MS profiling revealed a phenolic-rich composition, including flavonoids, proanthocyanidins, galloyl derivatives and phenylpropanoid-related compounds, consistent with vegetative plant tissues. Nutritional analysis showed high moisture content and low lipid levels, differing in composition from the avocado pulp, along with a high content of attention-grabbing nutrients, such as protein and fibre. Overall, although further studies are required to confirm compound identity and assess safety for future applications, avocado calli represent a promising sustainable platform for the production of value-added bioactive compounds. Full article

Avocado (Persea americana Mill.) is gaining economic relevance in Mediterranean regions such as southern Spain. In recent years, production has been severely affected by dieback caused by Botryosphaeriaceae species, a problem intensified under drought conditions. Conventional chemical control has shown limited effectiveness due to the scarce availability of fungicides and the difficulty of targeting pathogens colonizing lignified tissues. This study therefore evaluated eco-friendly control strategies comparing their performance with conventional fungicides and complementary cultural practices within an integrated management framework. Varietal tolerance significantly influenced symptom development and yield, with younger trees (1–2 years old) being more susceptible. Among the tested treatments, potassium silicate (K-Link) was associated with moderate reduction in disease intensity, with decreases in disease index ranging from 5–10%. Other products, including the biostimulant Brotolom^® SOILFORCE (BTL) and the disinfectant Huwa San^® TR50, also showed reductions in disease severity (approximately 5% and up to 14%, respectively), although their effects varied depending on cultivar and season. Cultural practices such as autumn pruning reduced symptoms and improved yield but required greater economic and labor inputs. In contrast, gibberellic acid was highly effective, reducing flowering, improving canopy balance, decreasing dieback incidence by 28%, and increasing yield by 34%. Integrating eco-friendly products, particularly potassium silicate, with targeted cultural practices and gibberellic acid application provides effective and sustainable tools to mitigate avocado dieback under Mediterranean conditions. Full article

The valorization of agro-industrial byproducts has emerged as an important strategy to improve resource efficiency and promote circular food systems. This study evaluated avocado (Persea americana Mill.) seed as a functional ingredient for frankfurter-type sausages using extrusion followed by enzyme-assisted wet milling. Extrusion modified the techno-functional properties of avocado seed flour, increasing the water absorption index from 2.87 to 3.91 g/g while reducing the oil absorption index from 2.12 to 1.84 g/g. In addition, extrusion reduced the total acetogenin content by approximately 82.8% (11.99 to 2.07 mg/g), indicating a substantial reduction of these endogenous compounds. When incorporated at a concentration of 1% (w/w) to replace commercial soy fiber, avocado seed ingredients produced frankfurter-type sausages with low cooking losses (1.67–3.77%), stable water activity (0.979–0.990), and an acceptable instrumental hardness (1.01–1.41 N) over 35 days of refrigerated storage. Consumer sensory evaluation (n = 106) showed comparable or higher flavor and overall acceptability scores for sausages containing avocado seed flour relative to the control formulation. These findings demonstrate that extruded avocado seed flour can function as a viable upcycled ingredient for emulsified meat products, supporting circular bioeconomy approaches for the development of value-added foods of animal origin. Full article

Soil salinity is a major environmental constraint affecting avocado (Persea americana Mill.) productivity. In this study, we evaluate the physio-morphological and molecular responses of two avocado varieties, drymifolia (sensitive) and americana (tolerant), subjected to increasing NaCl concentrations for 60 days. Our results reveal distinct adaptive strategies. While salinity reduced total biomass in both genotypes, var. americana exhibited superior resilience, characterized by preferential biomass allocation to the root system. Ion analysis demonstrated that tolerance was not mediated by K⁺ homeostasis, but rather by the differential management of toxic ions. var. americana effectively sequestered chloride Cl⁻ in the roots, whereas var. drymifolia exhibited a breakdown of the exclusion mechanism at 60 mM NaCl, with shoot Cl⁻ concentrations exceeding those of the root, leading to severe toxicity. At the molecular level, qPCR analysis of the Na⁺ transporters PaHKT1 and PaSOS1 showed no expression pattern correlated with salt stress. Bioinformatic assessment revealed significant structural divergences and a lack of conserved functional domains in these proteins. These findings challenge the applicability of the classical sodium-exclusion model (typical of Liliopsida and Magnoliopsida) to avocado. We conclude that salt tolerance in this Lauraceae species is primarily driven by root-mediated Cl⁻ exclusion rather than canonical Na⁺ transport pathways. Full article

Leaves of Persea americana Mill. are a potential source of bioactive compounds; however, current knowledge is limited by the lack of studies that simultaneously evaluate multiple cultivars and leaf developmental stages under comparable field conditions, as well as by inconsistent sampling criteria across studies. This study aimed to assess how leaf developmental stage and cultivar influence phenolic composition and antioxidant activity in avocado leaves grown under field conditions. Total polyphenols, total flavonoids, quercetin-3-O-galactoside, and chlorogenic acid were selected as representative compounds due to their relevance in plant defense and antioxidant capacity. These compounds, together with antioxidant activity, were quantified in young expanding (E1) and fully expanded (E6) leaves of seven avocado cultivars using spectrophotometric methods and HPLC-DAD, and analyzed through two-way ANOVA. Results showed that leaf developmental stage significantly influenced flavonoid content, chlorogenic acid, and antioxidant activity, which were consistently higher in E1 leaves. In contrast, total polyphenol content exhibited cultivar-dependent responses, increasing toward E6 only in specific genotypes, while quercetin-3-O-galactoside remained stable across developmental stages but varied among cultivars. Overall, the results indicate that phenolic metabolism in avocado leaves is regulated by both developmental stage and genotype in a compound-specific manner, with no consistent pattern associated with racial background. From a practical perspective, these findings provide a basis for selecting leaf material according to the intended application: young leaves for higher antioxidant capacity and flavonoid content, and specific cultivars at advanced stages for higher total polyphenol accumulation, supporting the functional valorization of avocado leaves as a source of bioactive compounds. Full article

Brazil, as one of the world’s leading fruit producers, faces increasing challenges arising from climate change, particularly in avocado cultivation, where excessive solar radiation and high temperatures impair plant metabolism, yield, and fruit quality. This study evaluated the use of a calcium and magnesium hydroxide-based sunscreen in mitigating heat stress in eight-year-old ‘Hass’ avocado trees. The experimental design was a randomized complete block design in a 4 × 8 factorial arrangement, with five replicates. Sunscreen applications were performed at full bloom and at the initial fruit development stage (18 mm). Leaf temperature, fruit drop rate, yield-related traits, fruit classification, and the percentage of fruit lesions were evaluated. Applications of the calcium and magnesium hydroxide-based sunscreen at concentrations of 3.0% and 4.5% (w/v) reduced leaf temperature and improved fruit biometric attributes compared to the control, although the maximum fruit diameter was achieved at the 2.6% concentration. The 4.5% sunscreen concentration reduced leaf temperature and fruit drop in ‘Hass’ avocado trees by 1.5 °C and 24.5%, respectively, compared with the control and decreased the percentage of small and damaged fruits. The application of sunscreen improved fruit weight and the percentage of fruits with higher market value, while the fruit diameter presented higher values at intermediate concentrations. Full article

Monitoring avocado (Persea americana Mill., cv. Semil-34) in tropical mountain landscapes of Cambita, San Cristóbal, Dominican Republic is inherently complex due to the pronounced topographical and climatic heterogeneity that modulates the crop’s ecophysiological responses, specifically vegetative vigor, carbon allocation, and the synchronization of reproductive flushes. This study integrates 5-year (2020–2025) Sentinel-2 time series, ERA5-Land climatic variables (air temperature, total precipitation, and radiation), and geomorphometric covariates to explain variability in yield and fruit quality. Multispectral indices, including the Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), Normalized Difference Red Edge (NDRE), and Normalized Difference Moisture Index (NDMI), were analyzed using Partial Least Squares Regression (PLSR) to characterize phenological dynamics and rank dominant predictors. The results revealed coherent spectral phenological trajectories; however, a significant inverse relationship was detected between canopy vigor and yield during reproductive phases. High vegetation index values were significantly and negatively associated with lower production (r = −0.58, p < 0.0021), reflecting a potential source–sink imbalance. Topography functioned as a structural filter, regulating root drainage and productive stability across the landscape. While yield variability was partially explainable (R² = 0.38), internal fruit quality, measured as dry matter content, exhibited comparatively high environmental stability. A central contribution of this research lies in identifying the “vigor paradox” in cv. Semil-34 and the suggestion that topography may exert a stronger influence than direct spectral signals under tropical hillside conditions. These findings provide an exploratory framework for anticipating yield and fruit quality through satellite remote sensing or UAVs, supporting site-specific management decisions in mountain agricultural systems. Full article

The avocado oil industry discards residues from the peeling and destoning steps primarily as mixtures with high biofunctional potential. Extracts from a residual avocado oil industry (RAOI) mixture were evaluated for the effects of green technologies Naviglio^® (rapid solid–liquid dynamic extraction), ultrasound, and maceration on their functional compounds and biological activity. The Naviglio^® extract excelled for total flavonoid content (7.29 ± 1.09 mg QE/g), minimum inhibitory concentration (MIC) against Escherichia coli (25 mg/mL) and Staphylococcus aureus (25 mg/mL), and minimum bactericidal concentration (MBC) against Staphylococcus aureus (50 mg/mL), with similar anti-inflammatory activity and total phenolic content (17.32 ± 0.59 mg GAE/g) than the maceration extract. Maceration was superior in seven polyphenol contents, β-sitosterol (9135.87 ± 468.83 mg/kg), and antioxidant activities (116.71 ± 16.09, 63.85 ± 3.97 and 49.63 ± 1.83 µmol TE/g for ABTS, FRAP and DPPH, respectively). At the evaluated MIC and MBC, the Naviglio^® extract was non-toxic, while maceration and ultrasound extracts were moderately toxic; at the anti-inflammatory concentrations tested, the Naviglio^® and ultrasound extracts were non-toxic. Naviglio^® and ultrasound extracts have pharmaceutical potential as antioxidants and anti-inflammatory agents, while the macerated extract is a potential source of β-sitosterol. For the first time, Naviglio^® technology was applied to RAOI mixtures, and the biological properties of the extracts were evaluated. Full article

Avocado (Persea americana Mill.) is one of the most widely consumed fruit tree crops worldwide, with cultivation expanding rapidly beyond its Mesoamerican and northwest South America center of origin. In emerging secondary diversity centers such as East Africa, farmers have long propagated seedling naturalized populations that may hold valuable reservoirs of genetic diversity, yet these resources remain underexplored. To help fill this gap, this study developed the first genomic resources for avocados in Tanzania, where avocado has a long history of introduction and diversification dating to the first Arab incursions and Catholic missionary missions. Low-coverage whole-genome resequencing (lcWGS) data were obtained from 95 trees sampled in Tanzania across the low- to mid-altitude Morogoro region (n = 25) and the Southern Highlands—i.e., the Iringa (n = 20), Mbeya (n = 30) and Ruvuma (n = 20) regions. In order to guide racial assignation, sequences were merged with NCBI-available lcWGS data from 205 avocado trees, including 42 commercial varieties, with reported ancestry. Population stratification as inferred via maximum likelihood phylogenetic inference, genetic principal component analysis, and ADMIXTURE unsupervised clustering suggested that the sampled Tanzanian avocado trees were genetically closer to the West Indian race and more distant from the northwest South American Caribbean and Andean groups. Additionally, while the trees from the low- to mid-altitude region of Morogoro were almost exclusively West Indian type, some trees from the Southern Highlands aligned more closely with West Indian × Guatemalan and West Indian × Mexican hybrids. These trends were equally supported by a subset of 10,460 high-coverage (10×) SNP markers. Together these findings clarify the dynamics of avocado diversification in a secondary center in East Africa, spanning recent introductions from a single Mesoamerican race, adaptation to a wide range of locally geographic conditions, and farmer-driven selection matching local tribal preferences. Characterizing these locally adapted resources is key for identifying underrepresented yet promising provenances, developing resilient and sustainable horticultural production systems, and safeguarding the species’ global genetic heritage. Full article

The export of Hass avocado (Persea americana Mill.) from Colombia requires accurate determination of harvest maturity, currently assessed through destructive dry matter (DM) measurements that are wasteful and limited in throughput. The objective of the article is to propose a low-cost, non-destructive approach to determine the maturity of the Hass avocado crop based on machine learning techniques. The approach consists of a low-cost, non-invasive bioimpedance spectroscopy system operating in the 1–10 kHz range, featuring a custom Analog Front End (AFE) and a tetrapolar surface probe to mitigate skin contact resistance, which collects data for predictive models of avocado maturity. To evaluate the quality of the approach, a longitudinal field study (n = 100) was conducted in a commercial orchard in Cundinamarca, Colombia, tracking complex impedance features—Magnitude, Phase Angle, Resistance, and Reactance—of tagged fruits over 8 weeks across four measurement timepoints. The predictive performance of a classical chemometric model (PLS-DA), non-linear classifiers (SVM, Random Forest), and a temporal Deep Learning (LSTM) architecture was compared using a Stratified Group K-Fold Cross-Validation scheme to prevent data leakage across fruits from the same tree. The 4-electrode configuration successfully isolated mesocarp impedance, identifying the 5–7.2 kHz band as the most sensitive to physiological maturation. In turn, the LSTM model achieved a mean accuracy of 92.0% and an AUC of 0.94, outperforming the other models by 4.0% in mean accuracy. The results demonstrate that modeling the temporal trajectory of impedance, rather than single-point measurements, improves harvest maturity classification in Hass avocados, providing a scalable, low-cost alternative to destructive testing. Full article

Avocado (Persea americana Mill) is a crop of significant economic importance in Ecuador, facing major threats from insect pests such as Monalonion velezangeli (Hemiptera: Miridae), which can reduce production by up to 42%. This study evaluated the effectiveness of six treatments based on physical barriers and biorational products within an integrated pest management (IPM) framework in an experimental avocado orchard (cv. Fuerte) in Pichincha, Ecuador. The treatments included pyrethroid, kaolin, mineral oil, combinations of kaolin and mineral oil, fruit bagging and a water control. The Kruskal–Wallis analysis revealed significant differences among treatments (T = 23.10, df = 6, p = 0.000765). Fruit bagging and a pyrethroid emerged as the most effective strategies, with mean pest damage incidences of 10.33 and 9.17%, respectively, while the control treatment showed the highest pest damage incidence (32.83%). The combination of mineral oil and kaolin demonstrated intermediate efficacy, acting as a physical barrier that interferes with the pest’s feeding and oviposition behaviours. Although fruit bagging proved highly effective, its adoption in commercial systems is limited by cost and time requirements. Full article

Woody tissue diseases of avocado (Persea americana Mill. var. Hass) pose a major phytosanitary threat due to their chronic progression, late symptom expression, and severe impact on tree stability and productivity. Although white rot has traditionally been attributed to saprobic basidiomycetes, increasing evidence suggests corticioid fungi may act as facultative pathogens in agricultural systems. This study examined corticioid basidiomycetes associated with white rot in stems and branches of avocado in Michoacán, Mexico. Field surveys revealed consistent symptoms of structural weakening, branch dieback, and wood decay. Fungal isolates obtained from symptomatic tissues and sporomes were characterized morphologically and identified through ITS-based phylogenetic analyses. Representative isolates of Grammothele spp. and Dentocorticium portoricense were evaluated in pathogenicity assays under controlled conditions. All isolates reproduced field symptoms, confirming pathogenicity, though aggressiveness varied. D. portoricense exhibited the highest incidence, severity, and AUDPC values, indicating greater virulence, while Grammothele isolates showed slower, moderate progression. Phylogenetic analyses provided robust support for D. portoricense, whereas Grammothele was resolved at genus level. Integration of field, pathogenicity, and molecular data demonstrates corticioid fungi are not merely secondary saprotrophs but relevant pathogens in avocado white rot. These findings highlight the need to include corticioid fungi in diagnostic, monitoring, and management strategies for trunk and branch diseases. Full article

Accurate and non-destructive assessment of plant nutritional status remains a key challenge in precision agriculture, particularly under dynamic physiological conditions such as dehydration. Therefore, this study focused on developing an integrated nutritional assessment framework for avocado (Persea americana Mill.) leaves across progressive dehydration stages using spectral analysis. A novel nutritional function index (NFI) was innovatively constructed using an entropy-weighted multi-criteria decision-making approach. This unified assessment metric integrated critical physiological indicators, such as moisture content, nitrogen content, and chlorophyll content estimated from soil and plant analyzer development (SPAD) readings. To enhance the prediction accuracy and interpretability of NFI, innovative vegetation indices (VIs) specifically tailored to NFI were systematically constructed using exhaustive wavelength-combination screening. Optimal wavelengths identified from short-wave infrared regions (1446, 1455, 1465, 1865, and 1937 nm) were employed to build physiologically meaningful VIs, which were highly sensitive to moisture and biochemical constituents. Feature wavelengths selected via the successive projections algorithm and competitive adaptive reweighted sampling further reduced spectral redundancy and improved modeling efficiency. Both feature-level and algorithm-level data fusion methods effectively combined VIs and selected feature wavelengths, significantly enhancing prediction performance. The stacking algorithm demonstrated robust performance, achieving the highest predictive accuracy (R2V = 0.986, RMSEV = 0.032) for NFI estimation. This fusion-based modeling approach outperformed conventional single-model schemes in terms of accuracy and robustness. Unlike previous studies that focused on isolated spectral predictors, this work introduces an integrative framework combining entropy-weighted feature synthesis and multiscale fusion learning. The developed strategy offers a powerful tool for real-time plant health monitoring and supports precision agricultural decision-making. Full article

In this study, we conducted a comprehensive characterization of avocado accessions from the Canary Islands, focusing on molecular, morphological, phenological, and agronomic traits. A total of 311 trees were initially prospected across Tenerife, La Palma, Gran Canaria, and La Gomera Islands. DNA was extracted from young leaves, and genetic diversity was assessed using 28 microsatelites primers, 14 of which were highly polymorphic, revealing 6937 amplified fragments, 137 of which were polymorphic. The average polymorphism percentage was 85.68%, with an expected heterozygosity of 0.68, indicating high genetic diversity. A dendrogram based on genetic data identified four main groups, two of which are closely related to the most widely cultivated avocado cultivars: ‘Hass’, ‘Fuerte’, and ‘Pinkerton’. Morphological analysis (over three years), using 91 descriptors, revealed a clear differentiation between accessions, with several groups corresponding to specific commercial cultivars. Morphotypes that deviated from the main groupings were specimens obtained through sexual propagation. Principal component analysis revealed that fruit characteristics such as length-to-diameter ratio, seed size, and fruit weight were the most discriminating traits, consistent with findings in the Persea genus. These results highlight the genetic and morphological diversity within the Canary Islands avocado germplasm, providing valuable insights for future breeding and conservation efforts. Full article