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

2025-10-08T22:27:33+00:00

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

2025-10-08T23:38:07+00:00

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

2025-10-16T19:53:19+00:00

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.

Morphometric and phenotypic characteristics of eight genotypes of Coffea arabica L. during vegetative development

2025-11-06T23:36:07+00:00

Coffee production represents an important source of employment and economic dynamism for the south of the province of Manabí, so it is appropriate to identify the genotypes with the best morphological behaviour. The objective of the research was to evaluate the morphological and phenotypic variables of eight genotypes of Coffea arabica L. ("café arabica") in their third year of vegetative development, in order to identify the best morphological attributes for large-scale multiplication. A total of 348 plants of coffee genotypes Acawa, Catimor, Catucaí, Sarchimor, Bourbon yellow, Bourbon red, Manabi and Catuaí were evaluated. For the statistical analysis of the metric variables, a completely randomised design was used and linear regression, and for the analysis of the phenotypic variables, the chi-square statistical analysis was applied. The results showed highly significant differences (P<0.01) in all quantitative and qualitative variables. The genotype Acawa showed a better response for leaf length and branch length, Manabí 01 had greater petiole length and stem diameter; Catuaí showed greater number of branches, number of nodes and plant height, Bourbon yellow showed greater length between branches and greater internode length. As for the analysis of the qualitative variables, the colour of young leaves, the Bourbon revealed a reddish brown colour, the other genotypes are green; the leaf shape is oval, except for the Sarchimor that showed obovate leaves.

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

2025-09-26T18:00:44+00:00

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.

Phylogenetic relationships of Yucatan hairless pig with Asian and European breeds by mitochondrial DNA D-loop

2025-11-05T23:58:20+00:00

In Mexico native pig genotypes exist whose populations face serious threats to survival. One of them is the Yucatan hairless pig (YUCMEX), for which limited information is available regarding its current conservation status. This study aimed to determine the phylogenetic relationship of YUCMEX with Iberian, wild pigs (WB), European, Asian, and commercial pigs using the mtDNA D-loop region. A total of 31 YUCMEX sequences and 77 mitochondrial haplotypes from GenBank were analyzed, aligned to reference sequence AJ002189. The study fragment, trimmed between positions 15435 and 15977, resulted in 543 base pairs. Genetic distances were calculated to compare YUCMEX with the other pig groups. Phylogenetic trees were constructed using the Neighbor-Joining method with Kimura's two-parameter distance and 1000 bootstrap replicates. Additionally, a principal component analysis (PCA) was performed based on evolutionary distances. Among the 108 sequences analyzed, 41 variable sites and 44 haplotypes were identified. YUCMEX individuals grouped into four haplogroups (HA, HB, HC, HD), showing lower D-loop diversity and genetic distance from the Duroc breed. European and Asian haplotypes formed seven phylogenetic groups, clearly separating both regions. The YUCMEX haplogroups clustered into three lineages close to WB from Portugal and Spain but were distinct from Asian pigs and Eastern European WB haplotypes. These findings confirm the European—specifically Iberian—origin of the Yucatan hairless pig.

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

2025-10-08T21:15:09+00:00

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.

Proximal and physicochemical characterization of fruits from promising avocado genotypes in three areas in the Dominican Republic

2025-11-04T18:04:52+00:00

Characterization is one of the main factors to be considered for the use of any raw material to be industrialized and commercialized, and its quality depends on its origin. The objective of this research was to evaluate the fruit characteristics of promising avocado genotypes in the Dominican Republic, for which two studies were carried out. The first study evaluated the effect of genotype (Popenoe, Criollo, and Hass) and the second evaluated the effect of production area (north, central, and southeast Dominican Republic) on proximal (moisture, protein, lipid, and ash content) and physicochemical (titratable acidity, pH, water activity (aw), and soluble solids) characteristics of avocado pulp. Completely randomized designs with four replicates per study factor were performed. An analysis of variance was carried out, and Tukey's test was applied with a reliability of 95 %. The results show that fat, protein, and pH can vary according to genotype. Criollo avocados had lower fat content (6.40 %) and their protein percentage was statistically similar (p<0.05) to Hass and higher than Popenoe. The pH ranged from 5.96 (Criollo) to 6.98 (Hass). Production areas can influence the protein content, titratable acidity, and water activity (aw) in avocados. Those with the highest protein content are produced in the southeast, while those with the lowest acidity and highest water activity (aw) are produced in the central zone. These results corroborate the need to characterize genotypes and the origin of raw materials for industrialization and commercialization.

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

2025-10-10T00:43:49+00:00

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.