Agronomía Mesoamericana

Introduction. Chionanthus pubescens Kunth is an endemic tree of southern Ecuador with ornamental uses due to its pink inflorescence in the villages of the region. Objective. To evaluate the effect of aqueous extracts of quinoa mojuelo on the growth of arupo plants (Chionanthus pubescens Kunth) and the incidence of Fusarium sp. Materials and methods. The test was carried out in the province of Chimborazo, Ecuador, during the year 2022.The aqueous extracts of quinoa mullein were obtained using the Soxhlet method, and their concentrations were determined by UV-VIS spectrophotometry. A completely randomized block design with a bifactor arrangement was used, with three levels for factor A (aqueous extract of mojuelo: mother extract (100 %), diluted 50 %, 75 % in sterile distilled water; v/v, and three levels for factor B, (frequency of application: every 7, 14 and 21 days), in total ten treatments (including an absolute control) with three repetitions each. They were evaluated in ten plants selected at random by treatment the morphological variables (height, number of leaves per plant and stem diameter), as well as the incidence of Fusarium sp. Results. The results showed that the concentrations of 50 and 75 % aqueous extract of mojuelo, applied weekly, achieved the best morphological development and the lowest percentage of affectation by Fusarium sp. in arupo (C. pubescens) plants, reflected in the height (16.3 cm), number of leaves (17.8), stem diameter (6.5 cm) and the incidence of the disease (50 %). Conclusions. The aqueous extracts obtained from quinoa mojuelo (Chenopodium quinoa Willd.) applied to arupo plants (Chionanthus pubescens Kunth) in the nursery, reduce the incidence of Fusarium wilt and promote growth in the first stages of development.

Introducción. La antracnosis de Sansevieria, causada por Colletotrichum sansevieriae, representa un riesgo significativo para el cultivo y la exportación de esta planta ornamental. Los métodos efectivos y rápidos de identificación de este patógeno son cruciales para implementar medidas de control que prevengan su propagación a áreas no infectadas. Objetivo. Implementar y optimizar métodos moleculares para la identificación rápida y confiable de C. sansevieriae. Materiales y métodos. Durante 2016, se analizó un fragmento del gen β-tubulina-2 (β-tub2) de C. sansevieriae aislado de una finca local en Alajuela, Costa Rica. Se implementó PCR-RFLP del fragmento parcial del gen β-tubulina-2 (β-tub2) con la enzima MseI (Tru1I). Además, se aplicaron cebadores específicos para la detección de C. sansevieriae y análisis de PCR-RFLP del fragmento amplificado. Resultados. La digestión produjo de manera consistente un patrón de restricción de dos bandas específico para C. sansevieriae. Los cebadores diseñados amplificaron con éxito un fragmento de 383 pb del β-tub2 de todas las cepas de C. sansevieriae probadas. No se observó amplificación de otras especies de Colletotrichum dentro de los complejos C. gloesporioides y C. acutatum, ni de aislamientos de C. truncatum y Fusarium oxysporum. Además, este sitio de restricción, ubicado dentro del amplicón generado por los cebadores específicos para C. sansevieriae, permitió la validación exitosa de la especie mediante digestión. Conclusiones. Ambos métodos basados en PCR demostraron ser lo suficientemente sensibles como para detectar C. sansevieriae en hojas de Sansevieria infectadas de manera natural y artificial sin necesidad de aislar el patógeno en cultivos puros, lo que hace que el proceso diagnóstico sea más eficiente y accesible.

Introduction. In previous studies related to the inclusion of Palmiche flour, nuts of the royal palm (Roystonea regia) in the diet of broiler chickens, it was observed that it improved quality indicators related to lipid composition in thighs, legs, breasts and abdominal fat. Objective. To evaluate the effect of palmiche flour consumption on chemical and sensorial attributes of chicken meat. Materials and methods. The study was carried out at the Institute of Animal Science, located in the province of Mayabeque, Cuba in the months of January to February 2023 for 35 days. Forty-eight day old male animals were used. The experimental treatments consisted of the control group and the inclusion of 5, 10 and 15 % of royal palm nuts. Moisture and ash content were determined in thighs and breast. In the control and 15 % treatments, qualitative analysis of the attributes color, smell, flavor, dryness, hardness and juiciness was carried out. The overall quality was quantitatively evaluated. Results. Humidity increased in the treatments that included 5 and 10 % of royal palm nuts compared to the control and 15 %, which did not differ significantly from each other (69.92 and 70.45 vs 65.70 and 65.71 %, respectively). Flavor intensity and overall quality were improved by including the 15 % royal palm nuts in thighs and breast. Conclusions. The consumption of royal palm nuts at 15 % did not affect the chemical attributes of the meat, nevertheless, it improves the sensory characteristics, flavor and overall quality of thighs and breasts of broiler meat.

Introduction. Isolation and manipulation of rumen cellulolytic bacterial consortia (CBC) improve fiber degradation under in vitro conditions. Objective. To obtain CBC from different substrates and to simulate the manipulation of ruminal microbiota (RM) by means of an in vitro gas production test. Objective. Obtain CBC from different substrates and simulate the manipulation of ruminal microbiota (RM) by in vitro gas production test. Materials and methods. The experiment was conducted from January to June 2024 at the Autonomous University of Guerrero, Cuajinicuilapa, Guerrero, Mexico. CBC were obtained from rumen fluid in selective culture media using ground sawdust (CBCa), Mulatto grass stalk (CBCt) and ground Mulatto grass (CBCm) as substrate. Two in vitro assays were performed: a) Evaluation of obtained CBCs and, b) Addition of CBCs to MR. In both, partial biogas production was measured from 0 to 24 h, 24 to 48 h and 48 to 72 h, as well as cumulative production. Dry matter degradation (DMD) and cellulolytic enzyme activity (CEA) were measured at 24, 48 and 72 h. The variables were analyzed in a design based on the design of the CBCs. The variables were analyzed in a completely randomized design. Results. In trial 1, CBCa produced higher cumulative biogas (p<0.05); DMD at 24 and 72 h was higher for CBCa (p<0.05); DMD at 48 h and AEC showed no difference between CBCs (p>0.05). In trial 2 they showed that the addition of CBCs to the RM did not modify the partial biogas production, the DMS at 24, 48 and 72 h, nor the CEA at 24 and 48 h (p>0.05); but the addition of CBCm increased 13.8 and 36.3 % the cumulative biogas production and CEA at 72 h. Conclusion. The CBCs obtained from the mulatto grass allow manipulation of the RM after in vitro simulation under the specific conditions of the present study.

Introduction. Glyphosate (GLI) is a common herbicide that, when applied in excess, can affect both broadleaf weeds and weeds. Plant growth promoting bacteria can promote GLI resistance and protection of agricultural crops. Objective. To evaluate the toxicity of GLI on the root, stem and root + stem of Pisum sativum (snow pea) in sandy loam soil, with the presence of the bacteria Ochrobactrum anthropi and Pseudomonas aeruginosa individually and in a bacterial consortium made up of both microorganisms. Materials and methods. The experiment was carried out in a greenhouse in Lima, Peru. A completely randomized design (CRD) was performed with 32 treatments, whose soil was mixed with GLI and subjected to edaphological analysis. Four treatments were controls, 12 contained soil with O. anthropi and P. aeruginosa individually and in a bacterial consortium, and 16 treatments also contained P. sativum. Results. P. sativum exposed to 8.71 mL L-1 and 17.42 mL L-1 of GLI showed a significant reduction in growth, particularly in fresh shoot and root biomass, but the application of a bacterial consortium reversed this effect, improving growth. GLI altered soil pH and electrical conductivity, although organic matter did not change. Soil available potassium increased with GLI, but bacteria reduced this effect, and available phosphorus increased in the presence of P. sativum and GLI at 17.42 mL L-1. Conclusions. GLI at the highest concentrations affected shoot and root growth of P. sativum, but bacterial inoculation attenuated this effect and modified soil properties. This underlines the relevance of the interaction between herbicide, microorganisms, and soil parameters in agriculture.