Artículos científicos

URI permanente para esta colecciónhttps://repositorio.inia.gob.pe/handle/20.500.12955/8

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Physiological response of Cinchona officinalis L., the Peruvian national tree, inoculated with native arbuscular mycorrhizal fungi under nursery conditions in the Amazon rainforest
(Universidad Nacional de Tumbes, 2026-06-30) Guelac Santillan, Marly; Huaman Pilco, Angel F.; Zabaleta Santisteban, Jhon A.; Vargas , Raúl; Corazon Guivin, Mike Anderson; Marcelo Bazán, Fátima Elizabeth; Sanchez Santillan, Tito
This study evaluated the agronomic response of Cinchona officinalis L. to inoculation with native arbuscular mycorrhizal fungi (AMF) under nursery conditions in the province of Condorcanqui, Amazonas, at 315 m.a.s.l., an unusually low elevation for a species typically found between 1000 and 3000 m.a.s.l. The main objective was to assess the physiological response of C. officinalis to AMF inoculation in lowland conditions. A completely randomized design was implemented, including five native AMF consortia and one non-inoculated control. Growth and symbiotic parameters such as plant height, dry biomass, mycorrhizal colonization, and spore diversity were measured. Results showed that inoculation with AMF consortia from San Jerónimo and Yambrasbamba significantly enhanced plant growth and symbiosis, indicating a positive effect on early development. These findings suggest that AMF play a key role in facilitating early establishment and seedling performance under low-elevation nursery conditions. This is one of the first reports demonstrating the potential of using native AMF to promote the successful propagation of this important forest species outside its natural altitudinal range, offering a sustainable strategy for conservation and restoration efforts in the Peruvian Amazon.
Predicting Pregnancy After Fixed-Time Artificial Insemination in Goats: Comparative Performance of Multivariable Logistic Regression and Random Forest Models
(MDPI, 2026-08-17) Rodríguez Vargas, Aníbal Raúl; Rivas Flores, Josselin Kelly; Ruiz Chamorro, José Antonio; Galván Cavero, Gerardo Antonio; Mendoza Ordoñez, Gilmar; Ortiz Morera, Narda Cecilia; Cruz Luis, Juancarlos Alejandro
Accurate prediction of pregnancy following fixed-time artificial insemination (FTAI) remains challenging under commercial goat production conditions. This study compared multivariable logistic regression and Random Forest models for pregnancy prediction and used SHAP analysis to characterize predictor contributions. Data from 920 goats subjected to FTAI across four regions of Peru were analyzed using reproductive, hormonal, animal-level, and management variables. Logistic regression was developed after univariable screening, whereas Random Forest models used 500 trees with mtry values of 2, 3, and 4. Models were compared using stratified 10-fold cross-validation with identical folds. The mtry = 4 configuration yielded the highest Random Forest AUC. Logistic regression identified semen type, buck and doe breed, insemination site, and cervical mucus score as independent predictors. Chilled semen was associated with higher pregnancy odds, whereas superficial cervical insemination was associated with lower odds. Logistic regression outperformed Random Forest in discrimination (AUC, 0.761 vs. 0.654), accuracy (0.679 vs. 0.644), and specificity (0.882 vs. 0.782), whereas Random Forest showed higher sensitivity (0.369 vs. 0.278). SHAP analysis identified eCG dose, cervical mucus score, semen type, and insemination site as the most influential predictors. Overall, logistic regression provided superior and more consistent predictive performance, whereas Random Forest offered complementary sensitivity and captured nonlinear predictor contributions. These findings support logistic regression as the more effective predictive approach for pregnancy following FTAI under the conditions studied, with explainable machine learning providing complementary insight into prediction patterns.
Nursery management modulates biomass allocation and early field establishment of Pinus douglasiana Martínez
(MDPI, 2026-08-20) Bernaola Paucar, Rosario Marilu; Ruiz Blandon, Bayron Alexander; Alama Flores, Marcos; Amaringo Córdova, Luiz Paulo; Rodríguez Cangalaya, Nora; Colachagua Calderon, Deysi Alina; Nieto Ramos, Carlos Emérico; Nieto Ramos, Luis Armando; Cuadrado Campó, Walter Javier
Nursery decisions influence the condition of seedlings before outplanting, but their practical value depends on whether those traits remain evident during early field establishment. We evaluated Pinus douglasiana Martínez seedlings grown under eight combinations of container volume, fertilization, and irrigation regime. Seedlings were conditioned for six months in the nursery and then assessed after 12 months under field conditions. Container volume was the clearest source of variation. Compared with 1 L containers, 5 L containers produced seedlings with larger root collar diameter, greater shoot, root, and total biomass, and higher Dickson quality index. Total biomass was 2.2-fold greater in 5 L stock. Final survival was retained as a descriptive field variable and averaged 76.7% in 5 L treatments and 27.5% in 1 L treatments. Correlations based on treatment means associated total biomass with field diameter and descriptive survival, although these patterns were exploratory because only eight treatment means were available. Proline increased mainly under non-continuous irrigation, indicating a water-related nursery response, but it was not aligned with biomass production or first-year field performance. The treatment-level PCA separated biomass and field-growth variables from proline and lignification. These results show that larger containers improved the structural condition of P. douglasiana planting stock, although nursery costs, planting-site constraints, and longer monitoring should be considered before operational adoption.
Endozoochory by goats and white-tailed deer: type of ruminant affect recovery and germination of Neltuma pallida seeds
(MDPI, 2026-08-20) Salinas Marcos, Jorge Daniel; Cruz Luis, Juancarlos Alejandro; Aguirre Terrazas, Lucrecia
The "algarrobo" (Neltuma pallida) is a key tree species in the seasonally dry tropical forests in Equatorial Pacific coast of South America, currently at risk. Its regeneration depends on endozoochorous dispersal, in which seeds are ingested and later defecated by animals, helping to release and scarify them. We compared the role of the native white-tailed deer (Odocoileus virginianus peruvianus) and the introduced goat (Capra hircus) in seed dispersal. Seeds were recovered from the dung of both species after experimental feeding and from grazing goats in a fruiting N. pallida forest. Seed recovery was higher in deer dung (9.34%) than in goat dung (3.06%), and retention time was shorter in deer than in goats (peak at 48 and 84 h respectively). Only passage of seeds through the deer's digestive tract significantly improved cumulative germination (63% vs. 44%) and germination rate (time to reach 25% germination, T25 = 8.98 days). Meanwhile, the passage of seeds through the goat's digestive system reduced germination rate under experimental conditions (T25 = 19.25 days) but slightly increased it under forest conditions (T25 = 12.81 days), where goats ingest fruits constantly. Differences in seed recovery and germination are explained by the morphophysiological traits of ruminants. In conclusion, both goats and deer contribute to seed dispersal. White-tailed deer enhances seed germination (~66%), whereas goats maintain seed viability (~44%) and exhibit a longer seed retention time. During peak fruiting, alternating grazing between high-fruiting and degraded areas is recommended to maximize seed incorporation into the soil.
Molecular analysis of the diversity of nitrogen-fixing and phosphate-solubilizing bacteria in Neltuma pallida (Humb. & Bonpl. ex Willd.) Kunth
(Facultad de Ciencias Agropecuarias, Universidad Nacional de Trujillo, 2026-08-17) García León, Mack Frank; Córdova Campos, José Stalyn; Garcia Garcia, Segundo Melecio; Ruiz Polo, Archi Alejandro; Mialhe Matonnier, Eric Louis; García Seminario, Ramón; Mogollón Farias, César Augusto
La identificación de bacterias fijadoras de nitrógeno y solubilizadoras de fosfato atmosféricas emerge como una alternativa de fertilización sostenible al uso de agroquímicos que contaminan el medio ambiente. El objetivo de esta investigación fue analizar molecularmente la diversidad de bacterias fijadoras de nitrógeno y solubilizadoras de fosfato en Neltuma pallida. Se recolectaron muestras de suelo rizosférico de árboles jóvenes de Neltuma pallida ubicados en el campo de prácticas del programa de Ingeniería Forestal y Ambiental de la Universidad Nacional de Tumbes, en la localidad de Garbanzal. Las bacterias se aislaron del suelo, se caracterizaron morfológicamente y se evaluaron en ensayos de fijación de nitrógeno inoculando 5 µL de suspensiones bacterianas (1×10⁸ UFC/mL) por triplicado en medio de cultivo ASHBY. Posteriormente, se seleccionaron los aislados con mayor fijación de nitrógeno para ensayos de solubilización de fosfato, los cuales se inocularon en medio NBRIP suplementado con azul de bromofenol (25 ppm), utilizando la misma concentración bacteriana. El análisis de datos se realizó con el software R Studio. Finalmente, se realizó la identificación de los aislados mediante la secuenciación del gen 16S rRNA y se establecieron las relaciones evolutivas a través de un árbol filogenético. En total, se aislaron 50 cepas bacterianas, de las cuales 41 tenían la capacidad de fijar nitrógeno atmosférico. Entre estas, 10 destacaron por su alta eficiencia de fijación y, de estas, cinco también mostraron la capacidad de solubilizar fosfato. Sin embargo, solo dos cepas exhibieron alta eficiencia en ambas funciones. Las relaciones filogenéticas agruparon las especies en tres clados (Firmicutes, Proteobacteria y Bacteroidetes). Las especies identificadas con doble capacidad (fijación de nitrógeno y solubilización de fosfato) fueron Bacillus megaterium, Erwinia spp., Bacillus flexus, Bacillus amyloliquefaciens y Pantoea spp., mientras que aquellas que solo fijaban nitrógeno incluían Bacillus endophyticus, Olivibacter spp., Pantoea septica y Lysinibacillus xylanilyticus.
Decoding the chloroplast genome of the Amazonian fruit Myrciaria dubia (camu-camu): molecular evolution and comparative genomics across the order Myrtales
(Springer Nature, 2026-08-14) Castro, Juan C.; Leonardo, Diego A.; Cobos, Marianela; Vargas, Jhon A.; Paredes, Jae D.; Adrianzén, Pedro M.; Castro, Carlos G.; Imán Correa, Sixto Alfredo; Rodriguez, Hicler N.; Marapara, Jorge L.; Maddox , J. Dylan
Myrciaria dubia (camu-camu) is an economically important Amazonian fruit species with severely limited genomic resources despite growing commercial interest and conservation needs. This study sequenced, assembled, and comprehensively analyzed the complete chloroplast (cp) genome of M. dubia and performed comparative genomic analyses across the order Myrtales, including codon usage, codon decoding mechanisms, repetitive elements, nucleotide diversity, and phylogenetic reconstruction. The cp genome spanned 158,664 bp with a typical quadripartite organization: a large single-copy region (LSC = 87,640 bp), a small single-copy region (SSC = 18,324 bp), and paired inverted repeats (IRA/IRB = 26,350 bp each). Functional annotation identified 135 genomic features, comprising 84 protein-coding genes, 37 tRNA genes, eight rRNA genes, and five pseudogenes. Codon usage analysis revealed a strong AT bias (62.50%), with 30 preferred codons (RSCU >1.0) predominantly ending with A/T nucleotides. Codon decoding analysis assigned all 61 sense codons to five mechanistic categories, collectively achieving complete codon coverage across all 23 Myrtales accessions. Repetitive element analysis identified 69 simple sequence repeats in M. dubia (91.3% mononucleotide, predominantly adenine motifs in LSC intergenic spacers) and 439 long dispersed repeat pairs (97.5% palindromic, concentrated in the inverted repeat regions). Nucleotide diversity varied significantly across structural regions (SSC, mean π = 0.173; LSC, mean π = 0.084; IRA/IRB, mean π = 0.010–0.015), with the highest diversity window (π = 0.240) located in the SSC at approximately 117.7 kb. SWAN analysis of 78 protein-coding genes identified rpl22, ycf1, matK, ndhF, and ndhD as the most variable loci, with no gene exceeding ω = 1.0, indicating a pervasive purifying selection. Comparative analysis across 19 Myrtaceae accessions demonstrated complete gene collinearity and conserved IR boundary arrangement, with divergence concentrated in the SSC intergenic regions. Phylogenetic analysis positioned M. dubia as a sister species to Plinia trunciflora within the Myrteae tribe, nested in a well-supported monophyletic Myrtaceae clade (bootstrap = 100%).
Evaluación agronómica de tres ecotipos locales de cañihua (Chenopodium pallidicaule Aellen) en la comunidad altoandina de Huarcapata, Espinar – Cusco
(Facultad de Ciencias Agrarias - Universidad Nacional del Altiplano, 2026-08-12) Mamani Aguilar, Mery Maribel; Tuni Ramos, Rosa Agustina; Huisa Huarca, Marck Oscar
El objetivo de la investigación fue evaluar el rendimiento y caracterizar morfológicamente tres ecotipos locales de cañihua (Chenopodium pallidicaule Aellen) en condiciones agroclimáticas altoandinas, durante la campaña agrícola 2024-2025; en Huarcapata, Espinar Cusco a 4045 msnm se evaluaron los ecotipos "Yauri", "Toclla" y "Tocroyo" bajo un diseño de bloque completo al azar con tres repeticiones. Se midió el rendimiento de grano (kg/ha) y se caracterizaron variables morfológicas (forma de hoja, altura, dehiscencia, color de perigonio y pericarpio, forma del grano) siguiendo descriptores estandarizados del IPGRI/PROINPA. El análisis estadístico incluyó ANOVA y prueba de Tukey (p<0.05). Los resultados indican diferencias significativas (p<0.01) en rendimiento y altura. "Toclla" presentó el mayor rendimiento 1920 kg/ha y altura 37 cm, con dehiscencia persistente grado 7. "Yauri" rindió 1800 kg/ha y "Tocroyo" 1280 kg/ha, ambos con dehiscencia regular grado 5. Los tres ecotipos mostraron hábito de crecimiento "lasta" y forma de grano sub-lenticular, con variabilidad en colores. El ciclo fenológico fue de 158 días. Se concluye que los ecotipos, especialmente "Toclla", superan ampliamente el rendimiento promedio, demostrando alto potencial productivo y adaptación a condiciones agroclimáticas adversas, la baja dehiscencia es un carácter valioso para la cosecha. Estos resultados destacan la importancia de la selección de ecotipos locales para mejorar la sostenibilidad del cultivo en los Andes.
Growth dynamics, harvest performance, and biomass partitioning of lettuce cultivars under contrasting hydroponic configurations: Implications for sustainable protected horticulture
(Acadlore Publishing Services Limited, 2026-06-10) Capcha Inga, Paola Veronica; Oliva Rojas, Luis; Chumbimune Vivanco, Sheyla Yanett; Amézquita León, Carlos Alberto; Paz Monge, Michel; Ortega Quispe, Kevin Abner
White Boston, Waldmann's Green, and Black Rose—grown in pyramidal nutrient film technique (NFT), floating raft (FR), and semihydroponic (SH) configurations. The experiment included 36 units and 192 plants. Nondestructive measurements were performed at 30 and 60 days after sowing, followed by destructive harvest measurements at 60 days. Temporal changes and cultivar responses were evaluated separately within each configuration because hydraulically independent units differed among configurations; between-configuration patterns were interpreted descriptively. Most temporal changes were similar among cultivars. At harvest, cultivar-dependent responses were configuration-specific and involved morphology, leaf fresh weight, total dry matter content, and biomass allocation. Total fresh and dry weight did not differ significantly among cultivars within any configuration. Nevertheless, FR–White Boston showed the highest numerical total fresh weight (189.96 ± 48.90 g plant⁻¹), whereas FR–Black Rose showed the greatest leaf fresh-weight proportion (81.0%). Waldmann's Green showed comparatively high total dry matter content, including 5.18% in FR, where cultivar differences were statistically supported. The first two principal components explained 56.9% of the total variance and revealed overlapping multivariate patterns among configuration × cultivar combinations. Overall, cultivar performance depended on the trait and cultivation configuration: White Boston was associated with higher numerical fresh biomass, Black Rose with greater leaf biomass allocation, and Waldmann's Green with comparatively higher dry matter content. These findings provide an agronomic basis for cultivar selection in protected hydroponic production.
Effect of planting density on the agronomic performance and forage potential of Vicia sativa L. in the high Andes of Peru
(Springer Nature, 2026-08-11) Quiñones Trejo, Robert Adrián; Samaniego Vivanco, Tomas Daniel; Hurtado, Samuel; Solórzano Acosta, Richard Andy
In the high Andean regions of Ancash, Peru, limited high-protein forage during dry seasons challenges livestock feeding. A locally adapted ecotype of common vetch (Vicia sativa L.) grows spontaneously and shows resilience to harsh conditions. This study evaluates its agro-morphological traits, forage and seed yields, and chemical composition to assess its potential as a sustainable forage resource for improving livestock nutrition in the region. This study was conducted using a completely randomized design with four plant spacing treatments: 10 cm, 20 cm, 30 cm, and 40 cm, maintaining a fixed row spacing of 30 cm. Seeds were collected from smallholder agricultural fields during the dry season. The highest plant densities, particularly 10 and 20 cm spacing, produced greater dry biomass. The forage biomass contained nitrogen (5.08%) and potassium (2.03%), with crude protein and crude fiber at 26.27 and 22.82%, respectively. Seed analysis revealed a crude protein content of 25.45%, corresponding to an estimated energy contribution from protein of 102 kcal. Based on these findings, Vicia sativa L. demonstrates strong potential as a forage crop and a viable alternative for smallholder farmers in the high Andean regions of Ancash, particularly during dry seasons, serving as an economical and accessible protein source for livestock feed.
Phenotypic diversity and selection of promising accessions of Cucurbita spp. from Peruvian germplasm
(Springer Nature, 2026-07-27) Celestino Avelino, Doris; Morales Luis, Jhunior; Lazaro Justo, Nilton Yefre; García Gantu, Ricardo Noel; Cueva Carhuatanta, César Aldair; Marcelo Salvador, Mavel Nansi
The genus Cucurbita spp. is native to the Americas, and Peru is one of its main centers of diversity. This crop represents a strategic resource for food security due to its adaptability and nutritional value. The objective of this study was to evaluate phenotypic diversity and select promising accessions of Cucurbita spp. conserved in the INIA Germplasm Bank (Peru). A total of 107 accessions were characterized using agromorphological descriptors (18 qualitative and 15 quantitative). Genetic variability parameters, correlation analysis, and multivariate analysis were estimated. Fruit size-related traits, including fruit length, width, and weight, exhibited high broad-sense heritability (H2 > 60%), suggesting high potential for selection. Correlation analysis revealed significant positive associations between fruit size and seed traits, and negative associations with total soluble solids, suggesting a trade-off between fruit size and sugar concentration. Likewise, the earlier-maturing accessions tended to produce larger fruits and seeds. Principal component analysis (PCA) explained 65.9% of the total variation, indicating that diversity is determined by characteristics related to fruit size, internal structure, and seed traits. Cluster analysis classified the accessions into four phenotypically distinct clusters. A multi-criteria index allowed for the selection of promising accessions in different species, notably PER1011008, PER1003595, and PER1010999 in C. ficifolia; PER1010939, PER1003572, and PER1010934 in C. maxima; PER1003584, PER1010957, and PER1010973 in C. moschata; and PER1010982, PER1010985, and PER1010987 in C. pepo. These results highlight the high value of Peruvian Cucurbita germplasm as a source of genetic diversity and as a basis for the targeted selection of ideotypes with potential in plant breeding programs focused on productivity, quality, and diversification of uses.
A tool for predicting live weight in Huacaya alpacas from southern Peru
(ResearchersLinks Ltd, England, UK, 2026-07-23) Churata Huacani, Roxana; Canaza Cayo, Ali William; Amarilho Silveira, Fernando; Rodriguez Huanca, Francisco Halley; Marchezan Barchet, Fernanda; Fonseca de Freitas, Rilke Tadeu; Núñez Pérez, Herbert Jesús
The aim of this study was to identify the most suitable model for predicting live weight using both original body measurements (BM) and principal component scores (PC), and to assess the relationship between body measurements (BM) and live weight (LW). LW and BM of Huacaya alpacas (n = 117) were collected from the Quimsachata Center of the National Institute of Agricultural Innovation in Peru. The following BM, including LW, withers height (WH), croup height (CH), thoracic circumference (TC), abdominal circumference (AC), cannon-bone length (CL), neck-base circumference (NBC), cannon circumference (CC), tail insertion length (TIL), rump width (RW), tail insertion circumference (TIC), body width (BDW), rump length (RL), forelimb length (FL), body length (BDL), back length (BKL), were taken. Principal component analysis (PCA) was utilized to extract and clarify the correlation between LW and their BMs. Regression equations relating LW to BM and their PCs were computed. Additionally, the root mean squared error (RMSE), Bayesian information criterion (BIC), Akaike information criterion (AIC), and coefficients of multiple determination (R²) were used to assess the models. Four components were extracted from the PCA of BM and LW, which accounted for 67.3% of the total variance. The prediction model for LW, utilizing two PCs, showed the highest R² as well as the lowest BIC, AIC and RMSE values in contrast to models based on the original measurements. The findings suggest that this method is a viable alternative for predicting live weight and may be useful in breeding programs, as well as in the design of management and selection strategies for Huacaya alpacas from Peru.
Mapping of coffee cultivation based on land use/land cover in the tropics of Cajamarca (Peru): An integration of Sentinel data, machine learning, and Google Earth Engine
(Elsevier B.V., 2026-08-12) Barboza, Elgar; Aragon, Amanda; Pizarro, Samuel; Roman Peña, Alcides; Adams, Brandon; Delgado, Ellen; Cotrina Sanchez, Alexander; Tariq, Aqil; Medina Medina, Angel; Tuesta Trauco, Katerin; Rivera Fernandez, Abner; Zabaleta Santisteban, Jhon; Ocaña, Candy; Madden, Marguerite
Coffee cultivation is a strategic economic activity in the Andean-Amazonian region of Peru, characterized by its diversity of production systems and complex landscape. In this study, a methodological approach based on multitemporal mapping of land cover and land use (LULC) was developed to identify coffee crops by integrating optical satellite imagery (Sentinel-2) and radar data (Sentinel-1), as well as topographic variables, processed on the Google Earth Engine (GEE) platform, with supervised classification based on the Random Forest (RF) algorithm. The study area covered the provinces of Jaen and San Ignacio (Cajamarca), the main coffee-growing areas in the country's north. A time series of satellite data from 2019 to 2024 was used, considering two climatic seasons (dry and wet). The 69 spectral, textural, and topographic variables were evaluated but subsequently reduced to 22 using the Variance Inflation Factor (VIF). The classification distinguished 11 LULC classes, including shade-grown and non-shade-grown coffee, achieving an overall accuracy of over 84% and a Kappa index of 0.90. The binary coffee maps made it possible to quantify and analyze the spatial dynamics of the crop in both provinces, showing a growing trend toward shade-grown coffee, especially in San Ignacio. The proposed approach proved to be operational for mountainous tropical areas with high cloud cover.
Inoculation with Trichoderma in Coffea arabica seedlings: Effects on morphological indices and seedling quality under nursery conditions
(MDPI, 2026-08-04) Camacho Villalobos, Alina Alexandra; Amaringo Córdova, Luiz Paulo; Ucañay Ayllon, Tatiana Mildred; Salgado Veramendi, Noelito; Flores Jaramillo, Jhoffre David; Aldava Pardave, Uriel
Microbial inoculants such as Trichoderma have been proposed as sustainable tools to improve seedling quality in coffee nurseries; however, their effectiveness may vary according to formulation and genotype. This study evaluated three treatments: a solid Trichoderma formulation (1 kg m−3 of substrate) based on a multispecies consortium (T. harzianum, T. asperellum, and T. viride; 5 × 109 conidia g−1), a liquid formulation of T. harzianum (1 × 108 CFU mL−1; 1 L m−3 of substrate), and a non-inoculated control, using three Coffea arabica varieties (Catimor, Marsellesa, and Gran Colombia) under controlled nursery conditions. A linear mixed model was applied, considering variety and inoculant type as fixed effects and replicates as random effects. The results show that the biostimulant response is strongly modulated by the variety × inoculant interaction. The solid formulation was superior in promoting the expansion of the photosynthetic apparatus, increasing leaf area by 24.6%. In turn, the liquid formulation optimized structural vigor, increasing stem diameter by 17.3% and reducing slenderness by 13.1%. Inoculation reduced the lignification index by 10.4%, favoring dynamic vegetative growth. These improvements were integrated into the Dickson Quality Index, which reached values of 0.41–0.70, greatly exceeding the critical threshold of 0.20 for medium- to high-quality seedlings. It is concluded that Trichoderma acts as a physiological compensator that harmonizes plant architecture, although its efficacy depends on specific compatibility with the genotype, which is essential for ensuring the successful establishment of coffee plants under field conditions.
Influence of thermal comfort in housing facilities on the increase in live weight of guinea pigs (Cavia porcellus) in the high Andean region of Puno, Peru
(Malque Publishing, 2026-08-03) Calatayud Mendoza, Alfredo Pelayo; Belisario Quispe, German; Huaquisto Ramos, Edilberto; Mamani Cato, Ruben Herberht; Coaquira Yucra, Martha Adela; Zeballos Cabana, Julio Cesar; Mamani Flores, Adderly
The high-altitude region of Puno is characterized by a pronounced daily thermal oscillation, which poses a challenge for the production of guinea pigs (Cavia porcellus), a species that is highly sensitive to microclimatic variability. This study analyzed the association between the thermal conditions of the houses and the weight gain of guinea pigs, considering both the mean level of the Temperature-Humidity Index (THI) and its intraday stability, measured by the thermal amplitude THI. The research followed a quantitative, non-experimental and longitudinal design, using productive and environmental data from INIA's Illpa Experimental Center. A total of 36 Peru breed guinea pigs housed in three pre-existing and independent facilities were evaluated, with weight records collected every 14 days between November 2023 and February 2024 (216 observations). The climatic variables were monitored by digital sensors that recorded measurements every 15 minutes. The results show that a higher intraday thermal amplitude of the Temperature and Humidity Index (THI) is negatively and statistically significantly associated with weight gain. On the other hand, no statistically significant association was detected between the mean level of the THI and weight gain under the observed conditions. This result does not imply the absence of a possible biological effect of the average THI, but rather that this effect could not be statistically identified within the thermal range and the period analyzed. Likewise, males showed greater weight gains than females, while the estimated coefficient for age was negative, although it did not reach statistical significance in the linear mixed model. Overall, the results suggest that intraday thermal stability may be related to productive performance; however, they do not allow us to conclude that it is more important than the average level of the THI or that it constitutes the only determining factor of weight gain (p<0.001).
Impact of three field-practical thawing methods on bovine semen motility, viability, and membrane and acrosome integrity at 0 and 2 hours post-thaw
(Sociedade de Medicina Veterinária do Estado do Rio de Janeiro (SOMVERJ), 2026-08-04) Pozo Curo, Alfredo; Bellido Quispe, Dionet Keny; Tacza Paquiyauri, Katherine Milagros; Sobero Ballardo, Rogelio; Rodríguez Zamora, Luis Arturo; Contreras Huamaní, Mijail; Youngs, Curtis R.
The effectiveness of artificial insemination with frozen semen depends largely on semen quality, which can be influenced by the thawing method. This study evaluated the effect of three field-practical semen thawing methods on bovine sperm motility, viability, and plasma membrane and acrosome integrity at 0 and 2h post-thaw. The treatments were: T1 (water at 37 °C), T2 (axilla at 36.1°C), and T3 (room temperature at 23.4 °C). A total of 42 frozen semen straws was analyzed. Motility was assessed using a CASA system, viability was evaluated with Hoechst/propidium iodide staining, and plasma membrane and acrosome integrity were examined using the hypoosmotic swelling (HOS) test and Coomassie blue (CB) staining, respectively. Statistical analysis included ANOVA and t-tests. At 0h, thawing using a water bath (T1) or the axilla (T2) resulted in higher (P < 0.05) total motility, progressive motility, rapid motility, and number of rapidly motile sperm compared to thawing at room temperature (T3). Thawing using a water bath also resulted in higher (P<0.05) sperm viability and percentage of HOS+/CB+ cells at 0h than thawing with T2 or T3. At 2h, post-thaw, T1 resulted in superior (P<0.05) total motility, progressive motility, rapid motility, and viability compared with T2 and T3 thawing methods. Holding samples from 0 to 2h reduced sperm quality parameters in all three thawing methods. In conclusion, thawing semen in warm water at 37 °C yielded better sperm quality parameters at both 0 and 2h post-thaw than thawing in the axilla or at room temperature.
Molecular characterization and first report of entomopathogenic nematodes from carob forests in Tumbes, Peru
(Agrociencia Uruguay, 2026-08-07) Riojas Gonzales, J.M.; Castillo Carrillo, P.S.; Cornejo Hidalgo, R.E.; Mogollón Farias, Cesar Augusto; Garcia Garcia, Segundo Melecio; Temoche Socola, V.T.; Ruiz Polo, Archi Alejandro; Gutierrez Reynoso, Dina Lida; Fernandez Huaytalla, Elizabeth; Cordova Campos, José Stalyn
Given their ability to attack and eliminate insects that impact various ecosystems, entomopathogenic nematodes (EPNs) are considered effective biological pest control agents. However, there are few studies focused on their identification or their association with forest species such as the carob tree. The objective of the present study was to isolate and molecularly identify entomopathogenic nematodes from carob tree (Neltuma spp.) forests in Tumbes, Peru. One-kilogram soil samples were collected from ten localities located across four districts in the Tumbes region. In each soil sample, Galleria mellonella Linnaeus 1758 (Lepidoptera: Pyralidae) larvae were exposed as bait for the detection and isolation of EPNs. Exposure times were controlled at 12, 24, 48, 72, and 84-96 hours. The isolated nematodes were morphologically characterized, and their genomic DNA was extracted. The 18S ribosomal DNA (rDNA) gene was amplified via polymerase chain reaction (PCR). Six of the ten evaluated soils showed G. mellonella infection, with a positive correlation between exposure time and infection rate. However, due to marked infectivity divergences (where samples 02 and 06 exhibited the highest percentages), three representative strains were selectively isolated from soil samples 02, 05, and 06. Subsequent morphological characterization and molecular identification determined their taxonomic identity as Heterorhabditis bacteriophora and Heterorhabditis indica. This finding represents the first report of EPNs associated with carob tree plantations in northern Peru and highlights their pathogenic potential against insect larvae. It is recommended that the nematodes identified at the species level be considered in integrated pest management (IPM).
Determinants of compost quality across 12 agroecological zones of Peru: the role of regional organic waste and climatic conditions
(Frontiers Media S.A., 2026-07-02) Hermoza Ayme, Nilton Alexander; Aldava Pardave, Uriel; Ortíz Dongo, Luis Felipe; Palomino Espinoza, Claudio Carlos; Altamirano Quispe, Brandon Santiago; Collavino Cortez, Ulises Ronald; Ore Valeriano, Ruddy Adely; Reza Carlin, Luis Joel; Calle Iparraguirre, Nander Oriol; Peña López, Yerly Marquito; Abensur Diaz, Giancarlos Israel; Suasaca Curo, Abel; Cunyas Camayo, Joseph Michael; Solórzano Acosta, Richard Andi
Introduction: Composting is a cornerstone of the circular economy in agriculture; however, its efficacy is often undermined by limited knowledge regarding how agroclimatic variability influences compost quality under real-world conditions in megadiverse countries such as Peru. Methods: We monitored twelve composting processes over a 16-week period, established at agricultural experimental stations across 12 agroecological zones in Peru—spanning the arid coast, the high Andes, and lowland/high-jungle environments. The study utilized locally representative organic residues and employed a multisite observational design analyzed via generalized linear mixed models (GLMM). Results: High-Andean sites, characterized by low ambient temperatures and quinoa residues, exhibited the highest organic carbon retention and biological stability. In contrast, lowland jungle stations showed accelerated mineralization and suboptimal organic matter content (≈12%), failing to meet national standards. In coastal regions, guinea pig manure helped minimize lead accumulation; however, arsenic concentrations exceeded international safety limits (40 mg kg⁻¹) at certain stations. Furthermore, fixed effects (climate and process parameters) explained more than 67% of the variation in organic matter and nitrogen, while the agroecological context accounted for ≈23% of the variability in yield. Discussion: These findings indicate that compost quality is driven by non-linear interactions between temperature, humidity, pH, electrical conductivity, and regional residue composition, demonstrating that "one-size-fits-all" protocols fail to capture these complex dynamics.
Random Forest-based spatial distribution from heavy metals and associated with ecological and health risk assessment in agricultural soils of the Mantaro Valley, Peru
(Elsevier B.V., 2026-07-31) Orellana Mendoza, Edith; Cosme de la Cruz, Roberto Carlos; Quispe Coquil, Violeta; Mendoza Delgado, Katia; Valero Maraví, Sheila; Rojas León, Ángeles; Ccopi Trucios, Dennis; Pizarro Carcausto, Samuel Edwin
Heavy metal (HM) contamination of agricultural soils in Andean valleys poses a critical threat to ecological integrity, food safety, and human health. This study assessed the spatial distribution, contamination levels, ecological and health risk (non-carcinogenic and carcinogenic) associated with Zn, Pb, Cu, Cd, and As in agricultural soils of the Mantaro Valley in the central Andes of Peru. A total of 306 topsoil samples were analyzed. Random Forest (RF) was used to model the spatial distribution of HM concentrations, integrating spectral, climatic, topographic, edaphic, and distance-related covariates. The RF models showed consistent but element-specific predictive performance. The values of R² ranged from 0.76 to 0.89, with the highest values for Pb and As and the lowest for Cu. Spatial predictions should be interpreted with consideration of the irregular sampling design and inherent uncertainties in spatial extrapolation. Mean concentrations of Zn, Pb, Cu, As, and Cd reached 1347.87, 439.91, 201.71, 90.69, and 4.27 mg kg⁻¹, respectively, exceeding both regulatory thresholds and local geochemical background values. Contamination indices revealed marked enrichment, particularly for As and Cd. Ecological risk was primarily driven by Cd and As, with 70.10% and 61.41% of samples classified as very high ecological risk for these elements, respectively. The comprehensive potential ecological risk index indicated a critical scenario with 71.7% of samples exceeding the very high-risk threshold. Human health risk assessment identified As as the main contributor to both non-carcinogenic and carcinogenic risks, with children showing higher vulnerability than adults. These findings delineate priority agricultural areas where ecological risk and arsenic-related carcinogenic risk overlap, underscoring the urgent need for targeted soil monitoring, exposure reduction, and locally adapted risk management strategies in the Mantaro Valley.
Spatial variation of acidic sodic soils in high-andean environments and theoretical estimation of gypsum requirement
(John Wiley, 2026-06-03) Quispe Matos, Kenyi Rolando; Hermoza Ayme, Nilton Alexander; Mejia Maita, Sharon Yahaira; Ccosi Mamani, Elvis David; Miranda Quispe, Dalmecio; Choquechambi Apaza, Luz Aleida; Choquehuanca Murillo, Katherin Heidy; Carrasco Ordoñez, Edgar Raddy; Cuellar Condori, Néstor Edwin
High-Andean forage systems are characterized by extensive management of cultivated forages, primarily through rotation of forage oats (Avena sativa) and alfalfa (Medicago sativa), under marginal edaphoclimatic conditions. Within this context, soil sodicity severely constrains the productivity of these systems in the districts of Ayaviri and Macarí, Melgar Province, Peru. However, spatially explicit information on gypsum requirements (GR) for sodic-soil reclamation remains unavailable. To address this gap, this study aimed to: (i) develop a weighted Soil Quality Index (SQIw) for sodic soils, (ii) delineate sodicity-affected areas across districts, soil classes and environmental conditions and (iii) generate high-resolution maps of gypsum requirements using regression kriging (RK). A total of 1273 soil samples were analysed in high-altitude areas of Ayaviri and Macarí. Key sodicity-related variables included exchangeable sodium percentage (ESP), clay flocculating charge and Modified Soil-Adjusted Vegetation Index (MSAVI) selected through Pearson correlation and principal component analysis to construct the SQIw, while regression kriging was used to generate spatially explicit gypsum requirement maps. Results showed wide variability in pH and ESP, reflecting heterogeneous sodicity conditions across the study area, with Macarí presenting higher soil quality (SQIw = 0.61) than Ayaviri (SQIw = 0.44). Sandy loam soils and acid saline–sodic soils exhibited the greatest vulnerability. Regression kriging achieved high predictive accuracy for GR estimation (R² = 0.97 in Ayaviri; R² = 0.85 in Macarí), enabling precise delineation of priority intervention zones. The resulting GR maps provide a robust basis for site-specific gypsum application, improving amendment efficiency, reducing unnecessary costs and supporting sustainable sodicity management in vulnerable High-Andean agroecosystems.
A new species of Neorthopleura (coleoptera: cleridae: korynetinae) from northern Peru
(Springer, 2026-06-30) Chuquibala-Checan, Beimer; Hernández May, Manuel A.; Leavengood, John M. Jr.; Tineo Flores, Daniel; Goñas Goñas, Malluri
Neorthopleura pomahuacensis Hernández-May, Chuquibala-Checan and Leavengood, sp. nov. (Coleoptera: Cleridae: Korynetinae) from Pomahuaca, Peru, is described. This beetle species is named after the locality where it was collected. Similar species are discussed and the lectotype of N. suturalis (Chevrolat, 1874) is illustrated for comparison.

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