Revista de la Facultad de Agronomía de la Universidad del Zulia

Detection of Diaporthe sp. in cacao plants (cv. CCN 51) in Guayas Province, Ecuador

José Vera-Rodríguez — 2025-10-08

Cacao cultivation contributes significantly to the global economy. However, a decline in production is evident due to the presence of pathogens, especially within the fungi kingdom, where some remain unidentified. The objective of this study was to identify the presence of Diaporthe sp. in cacao plants of the CCN-51 cultivar in Ecuador. Samples of cacao branches with symptoms of rot and necrotic tissue were collected (cankers). The samples were disinfected and processed in the Microbiology Laboratory of the Milagro State University, Ecuador. Cambium fragments were cultured on potato dextrose agar (PDA) and incubated at 27°C. After culture purification, morphological characterization and molecular identification were performed using ITS and EF1-α barcoding methods. The sequences were compared with the NCBI GenBank database for validation. A phylogenetic analysis was performed between the strains found and those reported in Puerto Rico and Australia. Morphological identification placed the isolates within the genus Diaporthe, which was confirmed molecularly. Phylogenetic analysis demonstrates marked genetic diversity among isolates within the genus Diaporthe. These findings suggest that Diaporthe spp. is prevalent in Ecuadorian cacao plantations and that molecular methods are effective for its identification. The presence of this pathogen implies the need for management strategies to mitigate its impact on cacao production.

Soil characteristics under different crops in mountain environments in Pamplona, Norte de Santander

Ana González-Pedraza — 2025-10-08

Agricultural intensification in mountain regions can alter soil quality and compromise its ecosystem functionality. Accordingly, this study evaluated the influence of land use on the physical, chemical, and biological properties of soils in agricultural and forest systems located in the Monteadentro district, municipality of Pamplona, Norte de Santander. During the 2019 rainy season, five land-use types were analyzed: strawberry, pea, tree tomato, pasture, and natural forest. In 1,000 m² plots, composite soil samples were collected at 0–10 cm depth to determine texture, volumetric water content (VWC), bulk density (BD), pH, electrical conductivity (EC), total organic carbon (TOC), and soil basal respiration (SBR). Both univariate and multivariate statistical analyses were applied (ANOVA, Kruskal–Wallis, correlations, and PCA). The results showed that land use significantly affected soil properties. Forest soils exhibited more favorable conservation conditions, with higher TOC content (2.8 %) and lower BD (0.7 g·cm^-3), in contrast to agricultural soils, which presented higher BD, lower VWC and TOC, and higher SBR, likely associated with more labile organic substrates and organic matter degradation. Principal Component Analysis identified two main gradients: a physical–textural gradient (clay, VWC, EC, sand) and a biochemical–structural gradient (silt, pH, TOC, SBR), which differentiated land-use systems according to their degree of disturbance. These findings emphasize the need to implement conservation-oriented management strategies and regular soil monitoring in order to preserve soil functionality in mountain ecosystems.

General, specific combining ability, and heritability in potato genotypes (Solanum tuberosum L.) for agronomic traits

Doris Marmolejo-Gutarra — 2025-10-16

Potato (Solanum tuberosum L.) is a key crop in Peru due to its nutritional value and its potential for agronomic genetic improvement, which justifies further research in the selection of promising parents and crosses. This study aimed to estimate general combining ability (GCA), specific combining ability (SCA), and heritability for key agronomic traits: plant height, earliness, and the number and weight of tubers per plant, under the climatic conditions of Huancayo, Peru. Sixteen F₁ families derived from a full diallel cross (Griffing's model I, method I, fixed effects) among four parents (Mariva, Redondo, Redondo Achatado, and Oblongo) were evaluated. The trial was conducted using a randomized complete block design with three replications. The analysis included ANOVA, estimates of GCA, SCA, and reciprocal effects. Highly significant differences (p < 0.01) were detected among the combinations. Mariva showed the highest GCA for plant height (5.266), while the Redondo Achatado × Redondo cross exhibited the highest SCA (6.404); for earliness, the GCA of Redondo Achatado (0.056) and the SCA of Redondo Achatado × Mariva (0.952) were outstanding; regarding tuber number per plant, Redondo had the highest GCA (3.258) and the Redondo × Redondo Achatado cross the highest SCA (8.982); for tuber weight, Redondo had the best GCA (0.107) and Oblongo × Redondo the highest SCA (0.449). Heritability ranged from 0.419 to 0.596, indicating moderate to high genetic variation. The high values of GCA and SCA, along with the observed heritability, confirm the potential of these parents to improve potato yield.

Chemical composition, ruminal fermentation and greenhouse gases of diets with different levels of poultry manure

Roselia Ramírez — 2025-09-26

The use of poultry manure in tropical cattle farming is common and although many aspects of this resource have been studied, it is important to generate information on the effects of including it in comprehensive diets. The objective of this work was to know the chemical, fermentative, greenhouse gas (GHG) production and costs characteristics of diets that include poultry manure. Three diets (treatments) made with local ingredients (30, 15 and 0 % poultry manure) were evaluated. For each treatment, crude protein values and ruminal degradation, ash, fiber fractions, fermentation kinetics and fractions, GHG production and cost per kilogram were estimated. The results, except costs, were analyzed using the GLM procedure. Protein and fiber values were similar (P>0.05) in all treatments while ash was higher (P<0.05) in those containing manure. The values of Vm, Fm and FT were similar (P>0.05) in all treatments. In relation to GHG, the highest methane values occurred in T3 (P<0.05) and those diets that included poultry manure were up to 20 % more economical. The inclusion of poultry manure in diets achieves protein contributions to the rumen similar to those achieved with diets based on which this byproduct was not included, as well as a greater contribution of ash without affecting ruminal fermentation activity, but it does reduce methane production and diet costs.

Physical properties of sausage analogues made with quinoa and cañihua flours, by extrusion

Jordan Aviles — 2025-10-08

Sausages are widely consumed meat products around the world. The objective of this research was to evaluate the physical properties (color, texture, cooking performance, diameter reduction) and acceptability of sausage analogues prepared from meat analogues using high-moisture extrusion. Two sausage analogues were prepared, including mixtures of quinoa flour (QF) and cañihua flour (KF) with soy protein isolate in different proportions, SA-1 (15 % QF, 15 % KF) and SA-2 (25 % QF, 15 % KF). Color was evaluated by image analysis; texture by texture profile analysis; cooking yield and diameter reduction by weight and dimension ratios. For comparison purposes, commercial chicken and pork sausages were used. SA-1 had a hardness of ~64 N, ~0.30 cohesiveness, ~0.65 elasticity, and ~14 N chewiness, values similar to chicken sausages. The color of SA-1 and SA-2 was similar to chicken sausages, with a hue of ~318° and saturation between 12.54 and 15.89 %. The cooking yield of SA-1 was ~93 %, higher than that of commercial sausages (~86 %). Sensory evaluation of SA-1 was comparable to that of pork and chicken sausages. SA-1 had physical properties similar to commercial chicken sausages, demonstrating the possibility of producing this type of product.

Spring onion (Allium fistulosum L.) farmer’s system typologies of Maracaibo municipality, Zulia State, Venezuela

Arlenis Albornoz — 2025-10-08

In Venezuela, spring onions are the most widely consumed edible leafy vegetable. Their production is concentrated in small settlements where the interaction of farmers with social, technical, economic, environmental, and territorial factors gives rise to a different types of production systems. The study aimed to typify the spring onion production systems in the municipality of Maracaibo, Zulia state, Venezuela. A sample of 53 farmers was considered, to whom was applied a structured questionnaire with sociodemographic, labor, technology, territory, natural environment, and socioeconomic enviroment information. The groups were formed using multivariate techniques (Principal Components and K-Means Clustering) and were compared using Chi-square. The four groups were: 1. Mixed Family Production Systems (MFS = 36 % of the sample), centered on family labor, that combined agricultural crops with small-scale animal husbandry and the use of organic fertilizer. 2. Intensive technology systems (ITS = 23 %), where chemical fertilizers (nitrogen and phosphorus) were used intensively. 3. Family polyculture systems (SPF = 28 %) cultivated spring onion and other crops (cilantro, cassava, and plantain) for commercial sales. 4. Technified polyculture systems (SPT = 13 %), which were labor-intensive, planted large areas of spring onions and other crops (plantain and “topocho”), performed a more efficient use of inputs, and pests control. These findings help to understand specificities of each typology, that allow personalized implementation of agricultural development strategies, addressing specific factors for each group.