Scientia Agropecuaria

Detección del tizón tardío en folíolos de papa usando imágenes tomadas con dron y técnicas de Deep Learning

2025-06-05T01:53:24+00:00

Phytophthora infestans causa una de las enfermedades más devastadoras del cultivo de papa, también conocida como tizón tardío. Dado que la identificación temprana de este patógeno es crucial para el control efectivo de la enfermedad, este estudio tuvo como objetivo proponer una metodología automatizada para la identificación de sus lesiones en foliolos de papa, utilizando redes neuronales convolucionales llamadas "Mask R-CNN". Las evaluaciones se llevaron a cabo durante la temporada de lluvias, en cultivos realizados por agricultores en la localidad de Huasahuasi, en los Andes centrales del Perú. Se tomaron cien fotografías (5472 × 3078 píxeles) con un vehículo aéreo no tripulado (UAV) Phantom 4 Pro a una altitud de 3 m en cultivos con una incidencia de tizón tardío entre 2 y 3. Las imágenes se dividieron en cuatro partes y luego pasaron un riguroso control de calidad, dando como resultado 200 fotos (1825 × 1369 píxeles). Del total, el 75% se utilizó para el entrenamiento del modelo y el 25% para su validación. Los modelos se evaluaron en condiciones reales, utilizando métricas como la precisión y la recuperación. Se determinó que la red neuronal Mask R-CNN, basada en la arquitectura de red neuronal profunda ResNet 101, ofrece una precisión y efectividad aceptables (73,5%) en la identificación de lesiones de tizón tardío a nivel de foliolo. Esta metodología constituye una contribución significativa a la agricultura de precisión en los Andes, al validar una herramienta no invasiva capaz de superar las limitaciones topográficas de la zona. Su aplicación práctica optimizaría el uso de fungicidas mediante la detección dirigida, promoviendo así sistemas de producción de papa más sostenibles y rentables para los agricultores locales.

Screening commercial disinfectants to strengthen on-farm biosecurity for the prevention of Fusarium wilt of banana Tropical Race 4 in Ecuador

2026-02-16T13:03:10+00:00

Bananas (Musa spp.), often reported together with plantains, are among the most traded fruit commodities worldwide, particularly in terms of export volume and value, with Ecuador recognized as the leading global exporter, supplying approximately one quarter of the total international trade. However, its production is increasingly threatened by climate change and fungal diseases such as Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense Tropical Race 4 (Foc TR4). To support preventive management strategies against Foc TR4, this study evaluated the in vitro efficacy of nine commercial disinfectants available in Ecuador—including quaternary ammonium compounds (QACs), oxidizing agents, aldehydes, and alkaline substances—against conidia and chlamydospores of several Foc race 1 strains (VCG0120) as a model organism. Different concentrations and contact times were tested in the presence and absence of organic matter. Chlamydospores exhibited higher resistance than conidia, requiring greater concentrations for inhibition. Aldehyde formulations and QACs achieved the lowest minimum inhibitory concentrations (<1,000 ppm) and remained effective under organic load and variable contact times. These findings emphasize the need to select disinfectants with consistent efficacy under field-relevant conditions to ensure the application of proper biosecurity measures.

Reemplazo parcial de Artemia sp. por Moina sp. como alimento vivo y destete temprano con una dieta comercial: efectos sobre el crecimiento, la supervivencia y la histología digestiva de alevines de paiche (Arapaima sp.)

2026-02-16T13:17:03+00:00

El paiche (Arapaima sp.) es una especie emblemática de la Amazonía peruana, cuya producción sostenible sigue limitada por la escasa disponibilidad de alevines en cautiverio. El objetivo del presente estudio fue evaluar el reemplazo parcial de Artemia sp. por Moina sp. durante la fase de alimento vivo y el efecto del destete temprano con una dieta comercial para trucha sobre el crecimiento, la supervivencia y la histología del sistema digestivo. Se realizó un ensayo de 37 días con seis tratamientos por triplicado, definidos por tres tallas de destete (3, 3,5 y 4 cm de longitud total) y dos regímenes de alimento vivo (100% Artemia sp. o 50% Artemia sp. + 50% Moina sp.). Todos los grupos fueron destetados con la misma dieta comercial. El reemplazo del 50% de Artemia sp. por Moina sp. no comprometió el desempeño inicial. Sin embargo, los alevines destinados al destete a 4 cm presentaron una reducción del crecimiento mientras permanecieron exclusivamente con alimento vivo, lo que sugiere limitaciones del protocolo de alimentación viva a esa talla. El destete a 4 cm se asoció con mejores indicadores de crecimiento y supervivencia que los destetes a 3 y 3,5 cm. No obstante, la dieta comercial resultó inapropiada para el destete temprano, evidenciándose a nivel histológico mediante alteraciones como obstrucción del lumen, deterioro de las vellosidades e hiperplasia del epitelio intestinal. En conjunto, estos resultados subrayan la necesidad de desarrollar dietas específicas para el paiche, adaptadas a sus requerimientos durante las etapas tempranas.

Elite Stevia rebaudiana clones for sustainable tropical highland cultivation: Agronomic traits and glycoside profiles

2025-08-18T13:16:09+00:00

Stevia rebaudiana Bertoni (Bertoni) is a high-value source of non-caloric sweeteners, yet its genotype-specific performance under tropical highland conditions remains insufficiently documented. Eleven elite stevia clones grown in the tropical highlands of Indonesia were evaluated, integrating agronomic performance with the steviol glycoside profile. A random block design with four replicates was implemented across three harvests. Majalengka exhibited the greatest plant height (45.06 cm) and total biomass (21.32 g plant⁻¹), while Karang Anyar and Garut also exceeded 20 g plant⁻¹, indicating robust vegetative growth. Dry leaf yield ranged from 4.98 to 14.00 g plant⁻¹, with Majalengka, Karang Anyar, and TIA-001A among the highest-yielding genotypes. High-performance liquid chromatography (HPLC) identified Garut as the leading clone in total glycoside content (346.78 mg g⁻¹), with the highest concentrations of stevioside (75.91 mg g⁻¹, 7.59%) and rebaudioside A (26.40 mg g⁻¹, 2.64%). However, its Reb A/stevioside ratio (0.35) was lower than that of TIA-006 (0.74), TIA-003 (0.54), and Karang Anyar (0.52), which exhibited more favorable sweetness profiles. TIA-003 combined high glycoside content (286.58 mg g⁻¹, 28.66%) with environmental stability, despite moderate leaf yield. Pujon and TIA-002A showed consistent glycoside profiles suitable for herbal and blended extract applications, while Karang Anyar demonstrated dual potential for leaf yield and sweetener quality. These findings identify Garut, TIA-003, and Karang Anyar as priority genotypes for glycoside extraction and agro-industrial scaling, while Majalengka and TIA-001A offer biomass advantages for whole-plant utilization. These findings offer genotype-specific insights to guide breeding programs and facilitate agro-industrial deployment in tropical highland stevia systems.

Sustainable livestock farming: Estimating forage biomass with RPAS and 3D modeling

2025-09-17T21:52:39+00:00

An alternative to support sustainable and technological livestock farming is using aerial images through Remotely Piloted Aircraft Systems (RPAS). This method has demonstrated effective outcomes in assessing agricultural variables including height, volume, and biomass across vegetation and crops like pastures. The study was carried out at Nero farm in southern Ecuador. The objectives of this research were: i) demonstrate the validity of the aerial imagery method with traditional field methods for characterizing grassland agronomic parameters (height, volume, and biomass) and ii) evaluate which of the variables studied (height and volume) is the best predictor of grass fresh mass and dry mass. The first methodology consists of collecting in filed (paddock) height and volume of grass using a frame of 1 m², then biomass was measured in laboratory. For the second method, aerial images were obtained through RPAS and processed to generate digital surface model (DSM) and digital terrain model (DTM). Finally, linear models were performed with respective R² and error. The height and volume of grass of both methods represent up to 98% of data variability (p < 0.0001), also, the measures of central tendency and dispersion were so similar. Regarding the models of fresh and dry mass with height and volume digital of grass representing over 40% (p < 0.05), the digital height being the best predictor for dry (R²: 48%) and fresh mass (R²: 42%). This research revalidates the effectiveness use of aerial images in important crops from Ecuador.

Fusarium in banana from Ecuador: A morphological, molecular and pathogenic study as a control strategy

2026-03-04T14:37:53+00:00

Fusarium oxysporum f. sp. cubense is associated with wilting in banana cultivation. The soil-dwelling phytopathogenic fungus has caused devastating consequences worldwide. The races that affect bananas are 1, 2 and 4, the latter very feared because of the epidemics caused since its identification, and because to date an effective control against the pathogen has not been determined. Therefore, the objective of the research was to isolate and characterize morphologically using four culture media, and molecularly the fungus in order to evaluate its pathogenicity with in vitro and greenhouse tests. 20 symptomatic samples were collected from an apple variety banana plantation. Subsequently, isolations were made from vascular tissue. The morphological identification of the isolates obtained was decisive to use a single strain for subsequent analysis and trials due to the similarity of the isolate’s strains. These strains were characterized by a cottony white mycelium that gradually changed to purple. Microscopy identified macroconidia, microconidia and chlamydospores. Molecular analysis was performed through the genes: translation elongation factor TEF1α, and Rpb2. The strain (Fus banana) was identified as F. oxysporum f. sp. cubense, accessions TEF1α (PV682586), Rpb2 (PV682587). The results were expressed in terms of incidence and severity. The medium malt extract registered a higher incidence reaching 99%. Regarding the distribution of severity, a progressive pattern in the intensity of symptoms was observed. The results obtained constitute consistent scientific support for future studies that are oriented towards the development of reliable diagnostic tools, the evaluation of pathogenicity in banana materials and the design of integrated management strategies against this pathogen with high economic and phytosanitary impact.

Endophytic bacteria isolated from the medicinal plant kratom (Mitragyna speciosa): Morphological, biochemical, and molecular characteristics, and their potential use as plant growth promoters

2026-03-04T14:46:26+00:00

Endophytic bacteria live within and colonize plant tissues, forming symbiotic interactions that often enhance host growth, health, and stress tolerance without causing harm. This study aimed to isolate endophytic bacterial strains from the medicinal plant ‘kratom’ (Mitragyna speciosa), characterize their biological functions by analyzing morphological, biochemical, and molecular properties, and evaluate their plant growth-promoting potential. The research followed standard procedures for isolating and analyzing the production of plant growth-promoting compounds, including indole-3-acetic acid, 1-aminocyclopropane-1-carboxylate deaminase, siderophores, cellulase, nitrogen fixation, and phosphate solubilization, and for assessing their effects on soybean in planta, including bacterial root colonization and plant growth. Of the isolates tested by 16S rDNA sequencing, five were successfully identified, belonging to Chromobacterium alkanivorans (2), Bacillus methylotrophicus (1), Stenotrophomonas maltophilia (1), and Chromobacterium violaceum (1). Quantitative assays showed that the bacterial isolates produced 13.35 – 24.11 g mL^-1 of indole acetic acid, 20.77 – 24.95 μg mL^-1 of inorganic phosphate solubilization activity, 63.34 – 84.29 U mL^-1 of acid phosphatase, and 2.92 – 4.86 U mL^-1 of cellulase. Qualitative tests confirmed that each isolate produced siderophores, nitrogenase, 1-aminocyclopropane-1-carboxylate deaminase, indole acetic acid, cellulase, and both organic and inorganic phosphate solubilization. Greenhouse experiments demonstrated that all bacterial isolates promoted plant growth, increasing soybean shoot length by 17.71% to 54.17%, root length by 14.36% to 39.34%, and total dry weight by 2.24% to 56.71% compared to controls. These findings support the potential application of endophytes as biofertilizers in sustainable agriculture, highlighting their capacity as plant growth-promoting bacteria.

Biogeography and climate change threats of supersect. Tacsonia (subgenus Passiflora), in Peru

2025-07-03T15:22:10+00:00

Supersection Tacsonia (Passiflora L.) is a high-Andean lineage whose geographic restriction and environmental specialization make it particularly vulnerable to ongoing climate change. However, broad-scale evidence integrating distribution patterns, endemism, protection coverage, and future habitat stability remains limited for the Peruvian Andes. Here, we assessed the spatial distribution, richness patterns, habitat associations, and climate-driven vulnerability of Tacsonia species in Peru. We compiled 1,758 georeferenced occurrence records for 25 Tacsonia species (including one unidentified taxon) spanning elevations of 1,500–4,500 m and summarized richness across administrative regions, elevation bands, and latitudinal/longitudinal gradients. We also evaluated protection coverage by intersecting records with the national protected-area system and developed ecological niche models to estimate current suitability and potential losses under climate-change scenarios. Most records occurred between 3,000 and 3,500 m, and 23 species were found between 2,500 and 3,000 m. Cusco concentrated the highest number of observations (543) and species richness (14), followed by Cajamarca (226 records; 11 species). Richness peaks were detected around 6°, 7°, and 13°S and 72°, 75°, and 77°W. Thirteen species are endemic to the Peruvian Andes, including five restricted to Cusco, La Libertad, and Amazonas. Tacsonia species occupy multiple Andean ecosystems (Tropical Dry Forest, Páramo, Puna, Yungas, and Andean Dry Forest), with P. tripartita occurring across all habitat types. Occurrences were recorded within several protected areas (Alto Mayo, Pui Pui, Manu, Río Abiseo, Huascarán, Yanachaga-Chemillén, Calipuy, Cotahuasi, Pampa de Ayacucho, Machu Picchu, and Ampay), including endemic taxa such as P. amazonica, P. huamachucoensis, P. parvifolia, P. peduncularis, P. trifoliata, P. trisecta, and P. weigendii. Niche models indicated high current suitability along northern slopes and across the central and southern eastern Andes (AUC = 0.94), but projected climate change could reduce suitable habitat by ~20%–60% by 2100.