Agronomía Mesoamericana 2024-01-25T10:03:03-06:00 Nancy León Ulate Open Journal Systems <p>Agronomía Mesoamericana journal is a continued publication with shutdowns in January, May and September. Edited in the Universidad de Costa Rica, its objective is to disseminate original scientific information in Spanish or English language, through the publication of articles, short communications, technical notes and literature reviews, related with food and agriculture sciences from anywhere in the world, emphasized in tropical and subtropical zones. </p> <p>Agronomía Mesoamericana implements interoperability protocols that allow the journal to be harvested by other content distribution systems. It supports this process through the OAI-PMH protocol (Open Archives Initiative Protocol for Metadata Harvesting) that allows the transfer of scientific and open access digital resources. <strong>URL OAI-PMH</strong></p> <p> </p> Rhizobium pusense associated to chickpea (Cicer arietinum L.), in Cuba. 2023-07-18T11:25:08-06:00 Marisel Ortega-García Yoania Ríos-Rocafull Lily Zelaya-Molina Juan Lara-Aguilera Ramón Arteaga-Garibay Maria Caridad Nápoles-García <p><strong>Introduction.</strong> Chickpea has been considered a restricted host species for nodulation, although recent studies describe a greater bacterial diversity associated with the crop, which can enhance our understanding of this symbiosis to obtain efficient isolates in its contribution. <strong>Objective.</strong> To characterize and identify an isolate obtained from chickpea nodules and evaluate its effectiveness under field conditions. <strong>Materials and methods.</strong> The research was conducted in the laboratories of two centers: the Institute of Fundamental Research in Tropical Agriculture "Alejandro de Humboldt," Cuba, and the National Center for Genetic Resources, Mexico, as well as under field conditions in two campaigns to demonstrate its effectiveness in crop interaction in the first center during the years 2018 and 2020. The isolate R3 showed morpho-physiological and biochemical characteristics similar to rizobia and it was taxonomically identified through the sequencing of four genes. For laboratory experiments, a completely randomized design was used, while plant trials were conducted under a randomized block design. The results were subjected to analysis of variance, and means were compared using the Tukey test (p&lt;0.05). <strong>Results.</strong> The isolate R3 showed variability in terms of its morpho-physiological-biochemical characteristics. Furthermore, it exhibited significant differences compared to the other treatments in the growth and yield indicators evaluated in chickpea. <strong>Conclusions</strong>. <em>Rhizobium pusense</em> associated with chickpea nodules was identified for the first time in Cuba. The strain demonstrates positive growth at pH levels between 5.5 and 9.0 and temperature ranges from 29 °C to 38 °C, indicating its tolerance to these factors. Its inoculation in chickpea stimulates nodule formation and increased yield-related variables.</p> 2024-01-09T00:00:00-06:00 Copyright (c) 2024 Marisel Ortega-García, Yoania Ríos-Rocafull, Lily Zelaya-Molina, Juan Lara-Aguilera, Ramón Arteaga-Garibay, Maria Caridad Nápoles-García Fermentation of Trichoderma for biological control using local inputs in Costa Rica 2023-07-18T07:26:14-06:00 Patrick Becker Paul Esker Gerardina Umaña Rojas <p><strong>Introduction.</strong> Supply chain issues have driven up raw material costs and reduced the availability of materials for producing biological control agents. These delays in application could result in increased disease pressure and reduced farm yields. <strong>Objective. </strong>To determine the effect of different amounts of starch and the use of local ingredients for small and commercial-scale fermentation processes for <em>Trichoderma harzianum</em>. <strong>Materials and methods. </strong>All trials took place in San José, Costa Rica, between 2016 and 2018. Flask trials were executed to investigate the potential reduction or elimination of starch in commercial fermentation media. Additionally, fermentation vessel trials were conducted to assess the effectiveness of an alternative local medium, encompassing three treatments: 1) Commercial medium as a control, 2) 10% molasses medium, and 3) 10% molasses mediaum with 0.5% yeast extract. Viable spore counts were performed to determine colony forming units (CFU/mL). <strong>Results. </strong>Reducing starch to 10% of the original medium had no impact on CFU/mL. However, the absence of starch led to uneven growth during fermentation, resulting in solid mycelium accumulations. Molasses medium yielded roughly half the CFU/mL compared to the commercial medium, but it still exceeded the 107 CFU/mL threshold commonly used in studies for biological plant pathogen control. Results from a commercial-scale fermenter mirrored those from pilot-scale fermentation. <strong>Conclusion. </strong>While reducing starch content in the commercial medium didn't affect growth, the absence of starch caused solid mycelium accumulations, potentially posing issues in commercial production. Employing locally sourced molasses medium on a commercial scale appears feasible while maintaining a viable spore count meeting the minimum field-use specifications. Overall, these findings support the use of these media for <em>Trichoderma </em>production in biological control applications.</p> 2024-01-09T00:00:00-06:00 Copyright (c) 2024 Patrick Becker, Paul Esker, Gerardina Umaña Rojas Physiological response of Solanum phureja under water deficit 2023-08-07T10:26:35-06:00 Juan Fernando López-Rendón Pedro Rodríguez-Hernández Diego Hernan Meneses Buitrago Hyrcania-Vanessa Lopez-Peñafiel <p><strong>Introduction.</strong> The parameters of physiological response to drought stress are the conjugation of a series of attributes of slow or fast action. The gas exchange variables are classified as fast-acting, and their level of occurrence or affection depends on the interaction between factors such as genotype, duration and intensity, and the phenological stage of occurrence of the stress. <strong>Objective.</strong> To identify the levels of physiological response of Solanum phureja under progressive water deficit stress.<strong> Materials and methods</strong>. The experiment was conducted between 2019 and 2020, under semi-controlled conditions at the Obonuco Research Center of the Colombian Agricultural Research Corporation, where four potato cultivars were planted, half of the trial was maintained with irrigation at field capacity and the other part was suspended to induce water deficit stress for 15 days, then rehydrated; variables of gas exchange, chlorophyll and photosynthetic efficiency were evaluated every three days. <strong>Results.</strong> Statistically significant differences were presented, with the maximum values of gas exchange in plants of the control treatment with 16.67 µmol m<sup>-2</sup> s<sup>-1</sup> photosynthesis rate (A); 0.34 mol m<sup>-2</sup> s<sup>-1</sup> stomatal conductance (gs) 5.5 mmol m<sup>-2</sup> s<sup>-1</sup> transpiration (E) and in stress 1.17 µmol m<sup>-2</sup> s<sup>-1</sup> (A); 0.013 mol m<sup>-2</sup> s<sup>-1</sup> (gs); 0.29 mmol m<sup>-2</sup> s<sup>-1</sup> (E). As for chlorophyll content, values between 451.7 and 474.69 m<sup>-2</sup> s<sup>-1</sup> were presented with irrigation and without irrigation, respectively.<strong> Conclusions.</strong> Stomatic closure was the earliest response to water deficit, and potato plants showed recovery of gas exchange values after the supply of irrigation following stress. Finally, three levels of physiological response were identified: mild, moderate and severe stress according to the intensity and duration of stress, which is useful for future studies and irrigation schedules.</p> 2024-01-09T00:00:00-06:00 Copyright (c) 2024 Juan Fernando López-Rendón, Pedro Rodríguez-Hernández, Diego Hernan Meneses Buitrago, Hyrcania-Vanessa Lopez-Peñafiel Sensitivity of the corn (Zea mays) crop to different periods of controlled water deficit 2023-07-31T10:55:12-06:00 Ana Sáez-Cigarruista Donaldo Morales-Guevara Román Gordón-Mendoza Jorge Jaén-Villarreal Francisco Ramos-Manzané <p><strong>Introduction</strong>. Corn is one of the oldest food grains. With climate change, frequent and severe droughts, available water in the soil will be greatly reduced. Water deficit affects corn crop development to varying degrees, the sensitivity to this stress varies at different stages of development. <strong>Objective</strong>. To identify the phenological stages most sensitive to water deficit in corn. <strong>Materials and methods</strong>. This experiment was conducted during two cycles 2020 and 2021 in El Ejido, Los Santos province, Republic of Panama, under semi-controlled conditions in the grow house greenhouse of the Coronel Segundo de Villarreal Institute. The commercial corn hybrid ADV-9293 was used. Agronomic management was carried out according to the technology generated by the Panama Institute for Agricultural Innovation (IDIAP). Variables such as plant height, leaf length and width, stalk diameter, biomass and yield components such as number of rows per ear, number of kernels per row and mass of 100 kernels were determined throughout the crop cycle. Soil moisture was also determined by the gravimetric method. Water deficit at different stages was generated through drought simulation. <strong>Results</strong>. The control grain yields exceeded the different treatments evaluated with 12.83 t ha<sup>-1</sup>, followed by the treatment with grain filling stress with 10.31 t ha<sup>-1</sup>. Two periods were determined to be more sensitive to water deficit; these are the stages from 20 to 35 and 40 to 55 days after sowing. Water deficit in the different phenological stages of the crop had a negative impact on the relative chlorophyll content. <strong>Conclusion</strong>. The pre-flowering and flowering stages were more sensitive to water deficiency in corn.</p> 2024-01-09T00:00:00-06:00 Copyright (c) 2024 Ana Sáez-Cigarruista, Donaldo Morales-Guevara, Román Gordón-Mendoza, Jorge Jaén-Villarreal, Francisco Ramos-Manzané Commercial microbial inoculants with PGPR on productive and economic variables of common bean (Phaseolus vulgaris L.) 2023-08-01T09:01:50-06:00 Klever Granda-Mora Cristina Correa-Ullauri Yadira Collahuazo-Reinoso Ángel Robles-Carrión <p><strong>Introduction</strong>. In Ecuador, there are few studies on the use of microbial inoculants for sustainable common bean (<em>Phaseolus vulgaris</em> L.) production. <strong>Objective</strong>. To evaluate the effect of inoculation with plant growth-promoting rhizobacteria (PGPR) on productive and economic variables of <em>P. vulgaris.</em> <strong>Materials and methods</strong>. The research was conducted at the La Argelia Experimental Station in Loja, Ecuador, from February to July 2022. Using loamy soil, the common bean cultivar "Mantequilla" was employed in a randomized complete block design with seven treatments and four replications each. The treatments were: T1) absolute control, T2) <em>Bacillus subtilis</em>, T3) <em>Rhizobium leguminosarum</em> bv. viciae, T4) <em>Pseudomonas fluorescens</em> + <em>B. subtilis</em>, T5) R<em>. leguminosarum</em> bv. viciae + <em>B. subtilis</em>, T6) <em>R. leguminosarum</em> bv. viciae + <em>P. fluorescens</em> + <em>B. subtilis</em>, and T7) chemical fertilization. The effect of the treatments on growth, development, and yield components in the evaluated cultivar was assessed. Additionally, an economic analysis of the application of beneficial microorganisms versus chemical fertilization was conducted. <strong>Results</strong>. Treatment T6 (<em>R. leguminosarum</em> bv. viciae + <em>P. fluorescens</em> + <em>B. subtilis</em>) shortened the phenological phases (days), promoted a higher number of nodules, emergence percentage, plant height, leaf area, number of pods per plant, weight of 100 seeds, nitrogen content, and agricultural yield without statistical differences (p&lt;0.05) compared to chemical fertilization (T7). The economic analysis showed that T6 generated higher income and greater profitability compared to chemical fertilization. <strong>Conclusion</strong>. Inoculation with beneficial microorganisms positively affected the productive and economic variables of common beans and can be a valid alternative to the conventional use of chemical fertilizers.</p> 2024-01-10T00:00:00-06:00 Copyright (c) 2024 Klever Granda-Mora, Cristina Correa-Ullauri, Yadira Collahuazo-Reinoso, Ángel Robles-Carrión Biological activity of improved color maize (Zea mays) grown in southern Sonora 2023-07-17T09:31:33-06:00 Francisco Cadena Cadena Joe Luis Arias Moscoso Gilberto Rodríguez Pérez Alejandro García Ramírez Alba Roció Meza Ochoa Dulce A. Cuevas Acuña <p><strong>Introduction</strong>. In Mexico, 85 % of the crops are white maize, 10 % white yellow and 5 % other colours. There are biochemical studies of pigmented native maize, but little information on colour-improved maize. <strong>Objective</strong>. To evaluate the phytochemical content and antimicrobial capacity of two pigmented maize hybrids grown at the Tecnológico Nacional de México-Valle del Yaqui. <strong>Materials and methods</strong>. Extraction of biocompounds from a portion of the maize grown in southern Sonora, Mexico, during the summer-winter 2020 cycle was performed on red and purple maize hybrids. A thirty-part solution of ethanol, acetic acid and water was used. Proximal composition, anthocyanin, polyphenol and flavonoid content were determined by standardised methods. Antioxidant capacity was determined by ABTS (2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid)) and DPPH (2,2-diphenyl-1-picrylhydrazyl) methodologies. In addition, antimicrobial capacity and minimum inhibitory concentration were determined. <strong>Results</strong>. Purple maize showed higher content of anthocyanins (340.98±5.21 mg/100 g) and polyphenols (173.68±24.23 mg gallic acid/100 g) compared to red maize. Flavonoids are more abundant in purple maize (575.10±27.88 mg quercetin/100 g). Both maize hybrids exhibited more than 50 % antioxidant capacity against ABTS and DPPH radicals. Regarding antimicrobial activity, higher inhibition was observed for <em>Escherichia coli</em> and <em>Salmonella</em> (18 % and 47 %), and lower for <em>Staphylococcus aureus</em> and <em>Shigella </em>(19 % and 34 %) compared to gentamicin. <strong>Conclusion</strong>. Purple maize showed higher content of anthocyanins, polyphenols and flavonoids. Both hybrids had more than 50 % antioxidant capacity. Antimicrobial activity was higher against E. <em>coli</em> and <em>Salmonella</em>, but lower against <em>S. aureus</em> and <em>Shigella</em>.</p> <p> </p> 2024-01-09T00:00:00-06:00 Copyright (c) 2024 Francisco Cadena Cadena, Joe Luis Arias Moscoso, Gilberto Rodríguez Pérez , Alejandro García Ramírez , Alba Roció Meza Ochoa , Dulce A. Cuevas Acuña Pelletized Mucuna pruriens and Trichoderma harzianum applied to tomato (Solanum lycopersicum L.) as an amendment and biocontrol agent 2023-07-26T09:33:39-06:00 Arnaldo Martínez-Alfaro Andrés Zuñiga-Orozco <p><strong>Introduction.</strong> In organic agriculture, green manure and biocontrollers are used as methods for fertilization and pest control. However, the independent application of these inputs increases production costs. A pelleted formulation is proposed to allow for the simultaneous application of both inputs. <strong>Objective.</strong> To evaluate the effect of pelletized Mucuna pruriens L. inoculated with <em>Trichoderma harzianum</em> Rifai on nutritional contribution, agricultural yield, and the regulation of <em>Fusarium oxysporum</em> f. sp<em>. lycopersici</em> in tomato (<em>Solanum lycopersicum</em> L.). <strong>Materials and methods</strong>. The experiment was conducted during the year 2022 in Tablón del Guarco, Cartago (Costa Rica), using a randomized complete block design with seven treatments and seven replicates. Two formulations (A and B) of biopellet (M. pruriens + zeolite + <em>T. harzianum</em>) were applied at three dosages (15, 30, 50 g/plant). <em>T. harzianum</em> was added at a rate of 5 g/kg of biopellet. Applications of each treatment were conducted every 15 days for a total of eight applications. At the time of planting, <em>F. oxysporum</em> was inoculated (100 mL/plant with a concentration of 1 x 10<sup>3</sup> CFU). <strong>Results</strong>. The application of biopellet achieved a yield and weight of high-quality fruits similar to the commercial control. There were no significant differences among treatments for second and third-quality fruits. The technical efficiency in controlling <em>F. oxysporum </em>reached 97.6% with biopellet. This amendment increased the levels of C, N, and organic matter in the soil and affected the nutritional content of the plant foliage in the first 60 days after sowing. <strong>Conclusions</strong>. The biopellet has the capacity to make chemical and organic contributions to the soil, which improves the nutrition of the tomato crop. Some dosages had a similar performance to the commercial control. It is a biocontrol alternative against <em>F. oxysporum</em> and compatible with <em>T. harzianum</em>. The dosage and composition of this amendment must be studied in depth for the partial or total replacement of chemical fertilization in the crop.</p> 2024-01-09T00:00:00-06:00 Copyright (c) 2024 Arnaldo Martínez-Alfaro, Andrés Zuñiga-Orozco Evaluation and estimation of calibration curves of devices to measure soil moisture 2023-06-19T09:38:48-06:00 Aquileo Daniel Gonzalez de León Luis Alberto Sandoval Mejía Gloria Elizabeth Arévalo-Valderrama Oriana Michelle Gómez Brian Stiven Caro <p><strong> </strong></p> <p><strong>Introduction. </strong>Adaptation measures to climate change require informed decision-making. However, small-scale agriculture shows low technology adoption rates due to their cost and lack of connectivity. <strong>Objective.</strong> To evaluate three low-cost prototypes of small-scale agriculture devices for soil moisture measurement in different soil textures, determine the respective calibration equations, and assess the effects of electrical conductivity and temperature on moisture measurement. <strong>Materials and methods.</strong> Three measurement and recording prototypes for soil moisture were evaluated in soils with variations in clay/sand content and electrical conductivity in productive plots at Zamorano University in Honduras and a demonstration farm in Popayán, Colombia during the first quarter of 2022. Commercial sensors were used as a reference to compare the performance of the prototypes through regression analysis of hourly sensor readings over 90 days. Electrical conductivity (dS/m) and temperature variables were collected to determine their influence on moisture reading accuracy. <strong>Results.</strong> The soil moisture measurement devices showed better performance in soils with lower sand content. The measurement from the devices overestimated moisture readings by 0.19 to 0.52 percentage points for each additional degree of soil temperature. Additionally, for each additional dS/m of electrical conductivity, the reading needed adjustment by 8 to 55 percentage points. <strong>Conclusions.</strong> Prototype A was the most accurate device, while prototype B was the most precise compared to commercial sensors. Soil moisture devices performed best in soils with lower sand content. All three evaluated models performed best in loamy soil with a medium clay content.</p> <p><strong>Keywords: </strong>calibration equations, volumetric content, conductivity, textural differential.</p> 2024-01-09T00:00:00-06:00 Copyright (c) 2024 Aquileo Daniel Gonzalez de León, Luis Alberto Sandoval Mejía, Gloria Elizabeth Arévalo-Valderrama, Oriana Michelle Gómez, Brian Stiven Caro Varroasis and nosemosis in Apis mellifera hives in the municipality of Tomalá, Honduras 2023-06-12T08:08:56-06:00 Daneri Jasael Pineda Nataren Elder Leonel Videz Byron Flores Somarriba <p><strong>Introduction.</strong> Beekeeping in Honduras is an important activity for the livestock sector, threatened by the presence of pests and diseases that affect the development and production of hives. <strong>Objective.</strong> To determine the parasitic load of <em>Varroa destructor</em> and <em>Vairimorpha</em> (<em>Nosema</em>) spp associated with hygienic behavior, productivity, and presence of other pests in <em>Apis mellifera</em> hives in the municipality of Tomalá, department of Lempira, Honduras. <strong>Materials and methods.</strong> A descriptive cross-sectional study was carried out on 57 samples of hives from 19 apiaries, analyzed with the screening method to determine the infestation rate of <em>Varroa destructor</em>. To find the average infection rate of <em>Vairimorpha</em> spp spores, the Cantwell method was used. In addition, the association between parasite loads and variables such as yield, use of chemical control, hygienic behavior, and presence of other pests was determined, through a stratified analysis according to the history of the use or not of treatment against <em>Varroa</em> spp. Data were analyzed using measures of central tendency and the Shapiro Wilk test. The determination of associations was performed by means of no parametric Mann Whitney U and Kruskal Wallis tests. <strong>Results.</strong> The infestation rate for <em>V. destructor</em> in the dispersion and larval phases were 3.48 % and 6.82 % respectively, the history of applying chemical treatment did not show an association with the infestation rate of <em>V. destructor</em> in larvae or in adults (p≥0.05), the presence of the small hive beetles (SHBs) was associated with a greater infestation of <em>V. destructor</em> in larvae (p˂0.007) in hives that had not received treatment. The range of infection of <em>Vairimorpha</em> spp was found within the very light classification with 50,000.00 (IC 50,000.00-260,000.00) spores per sample, the load of <em>Vairimorpha</em> spp did not show an association with the variables (p≥0.05). <strong>Conclusion.</strong> The results suggest that varroasis is an important disease for in the municipality of Tomalá, department of Lempira, Honduras, associated with hygienic behavior and the presence of SHBs in the hives. butNosemosis presented a very light infection.</p> 2024-01-09T00:00:00-06:00 Copyright (c) 2024 Daneri Jasael Pineda Nataren, Elder Leonel Videz, Byron Flores Somarriba Ovulation induction in cows with Kisspeptin-10 in an estrus synchronization protocol 2023-07-17T08:34:48-06:00 Jorge Víctor Rosete Fernández Abraham Fragoso Islas Rubén Santos Echeverría Ángel Ríos Utrera <p><strong>Introduction.</strong> In prepubertal heifers, Kisspeptin-10 has stimulated the secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and in postpartum lactating cows, it has stimulated LH secretion without evidence of inducing ovulation. <strong>Objective.</strong> To induce ovulation using Kisspeptin-10 or gonadotropin-releasing hormone (GnRH) in beef-producing cows under subtropical conditions in Mexico. <strong>Materials and methods.</strong> he study was conducted in the northeastern region of the state of Puebla from 2020 to 2021, involving 252 crossbred Bos taurus x Bos indicus cows. The estrous synchronization protocol involved the insertion of an intravaginal device impregnated with progesterone (1.9 g) and intramuscular injection of 2 mg of estradiol benzoate (day 0). On day seven, the intravaginal device was removed, and cows were immediately intramuscularly injected with 0.150 mg of D-cloprostenol. On the following day (day eight), Kisspeptin-10 was as effective as GnRH in inducing ovulation. 56 hours after the removal of the intravaginal device (day nine), cows were intramuscularly injected with GnRH or Kisspeptin-10. Cows were assigned to four treatments: T1, 100 µg of GnRH (positive control), T2, T3, and T4 with 500 µg, 1000 µg, and 1500 µg of Kisspeptin-10, respectively. Ovulation was detected via ultrasonography four days post-treatment. The response variable evaluated was the ovulation rate. Data were analyzed using generalized linear models with a logit link function. <strong>Results.</strong> Ovulation rates obtained with T1 and T4 were statistically equal (99.9%; p&gt;0.05) and higher (p&lt;0.05) than those achieved with T2 (98.5%) and T3 (88.4%), with the latter two being statistically equal (p&gt;0.05).<strong>Conclusion.</strong> Kisspeptin-10 was as effective as GnRH in inducing ovulation.</p> 2024-01-09T00:00:00-06:00 Copyright (c) 2024 Jorge Víctor Rosete Fernández, Abraham Fragoso Islas, Rubén Santos Echeverría, Ángel Ríos Utrera Perception of farmers on the management of fungal diseases of soybeans (Glycine max x (L.) Merr.) in Paraguay 2023-06-06T10:37:41-06:00 Gabriela Giuliana Caballero-Mairesse Flávio Henrique Mendes Andrea Alejandra Arrua Horacio Daniel Lopez-Nicora Guillermo Andrés Enciso-Maldonado <p><strong>Introduction. </strong>Paraguay is the sixth largest producer and third largest exporter of soybeans (<em>Glycine max x</em> (L.) Merr.) globally, making this crop of paramount socio-economic importance in the country. However, its productivity can be adversely affected by diseases caused by phytopathogenic fungi. Additionally, phytosanitary information regarding soybean cultivation in Paraguay is limited.<strong> Objective. </strong>To understand farmers' perceptions of the the primary soybean diseases and their management.<strong> Materials and methods. </strong>Between April and May 2022, we administered a questionnaire in Google Forms format, consisting of both open and closed-ended multiple-choice questions, to 45 soybean producers aged between 30 and 50 years. These producers cultivate areas ranging from 200 to 1000 hectares in the departments of Alto Paraná, Itapúa, and Caaguazú in Paraguay. <strong>Results. </strong>Among the respondents, 56% considered Asian soybean rust (Phakopsora pachyrhizi) as the most significant phytosanitary issue associated with soybean cultivation, followed by late-season diseases (LSD) such as brown spot (<em>Septoria glycines</em>) and frogeye leaf spot (<em>Cercospora kikuchii</em>). Respondents reported using three to four fungicide applications as a disease control measure, with their choice based on the type of product formulation. A majority of respondents noted that both the cost and frequency of applications increased over time. Additionally, 53% mentioned that biological fungicides are a viable alternative for integrated disease management.<strong> Conclusion. </strong>The responses obtained in this study provide valuable insights into the disease management tactics perceived by soybean producers in Paraguay, underscoring the significance of Asian soybean rust and late-season diseases. Nevertheless, further research is necessary to explore all aspects of pathogen management thoroughly.</p> 2024-01-09T00:00:00-06:00 Copyright (c) 2024 Gabriela Giuliana Caballero-Mairesse, Flávio Henrique Mendes, Andrea Alejandra Arrua, Horacio Daniel Lopez-Nicora, Guillermo Andrés Enciso-Maldonado Resilience capacity of coffee agroecosystems in Tezonapa, Veracruz, Mexico 2023-07-17T08:13:23-06:00 Ismael Quiroz Guerrero Arturo Pérez-Vázquez Cesáreo Landeros Sánchez Felipe Gallardo López Joel Velasco Velasco Griselda Benítez Badillo <p><strong>Introduction.</strong> Coffee agroecosystems have a great environmental, social, and economic importance in subtropical regions of Mexico, but it is vulnerable to unexpected crisis such as climate change. In recent history, it has been documented that the coffee agroecosystem presents a constant process of self-organization based on adaptation and learning in the face of various adverse scenarios. <strong>Objective.</strong> Therefore, the aim was to determine the resilience capacity of the coffee agroecosystem in the central region of the Veracruz state. <strong>Materials and methods</strong>. The research was carried out in Tezonapa, Veracruz, Mexico from December 2017 to November 2018. 52 interviews with coffee farmers were conducted to measure the resilience index, made up of 30 variables corresponding to seven factors (social, economic, technological, infrastructure, communications, institutional and environmental). Resilience was estimated on a scale of 0-1, where values close to zero represent low resilience and close to one, high resilience. Data were analyzed using descriptive statistics and Kruskal-Wallis and, Chi-squared tests. <strong>Results.</strong> Statistically significant differences (p&lt;0,05) were found for the indicators of the economic (0,06) and technological (0,22) dimensions, with the least contribution to resilience. On the contrary, social (0,78) and environmental (0,74) dimensions had a greater contribution to resilience determined by the altitudinal gradient. <strong>Conclusion.</strong> The indicators with the greatest contribution to the resilience capacity of the coffee agroecosystem are those of social and environmental dimensions, and with low contribution the economic and technological dimensions capacity.</p> 2024-01-10T00:00:00-06:00 Copyright (c) 2024 Ismael Quiroz Guerrero, Arturo Pérez-Vázquez, Cesáreo Landeros Sánchez, Felipe Gallardo López, Joel Velasco Velasco, Griselda Benítez Badillo Effect of macronutrient omission on cadmium uptake in rice seedlings 2023-07-25T10:08:24-06:00 Manuel Danilo Carrillo Zenteno Juan Xavier Valarezo Karina Peña Salazar Wuellins Durango Yelitza García-Orellana <p><strong>Introduction.</strong> The edaphoclimatic conditions of Ecuador are ideal for growing rice, yields are higher than the world average, but its agronomic management leads to an increase in cadmium in the soil, which can reach the grain by translocation, which affects its safety. <strong>Objetive.</strong> To evaluate the absorption of cadmium through the omission of macronutrients technique in six soils of Ecuador and its effect on the vegetative development of rice crops. <strong>Materials and methods.</strong> The trial was carried out at the Pichilingue Tropical Experimental Station of the National Institute of Agricultural Research, Ecuador, during 2018. Nine treatments were studied: 1) Without fertilization and without Cd (control 1), 2) without fertilization and with Cd (Control 2), 3) Complete fertilization and six omission treatments of one nutrient at a time, a completely randomized block design of experiments, divided plots and three repetitions was used. The variables evaluated were those related to the production of dry matter in the root and aerial part. For the comparison between means, the Tukey test was used (p&lt;0.05). <strong>Results.</strong> The omissions of nutrients (N and P) led to reduced Cd absorption, which decreased dry matter production, particularly in very acidic or alkaline soils such as in Sucumbíos (pH 4) and Guayas (pH 7, 9), respectively. <strong>Conclusions.</strong> The absorption of cadmium in rice plants was reduced to a greater extent with the omission of the macronutrients N and P, mainly in the soils of Sucumbíos, Los Ríos, El Oro and Manabí, the nutrient omission technique also affecting the production of dry matter and yields, also observing that a pH below 5 or higher than 7.9 affects the absorption of cadmium in the soils studied.</p> 2024-01-10T00:00:00-06:00 Copyright (c) 2024 Manuel Danilo Carrillo Zenteno, Juan Xavier Valarezo, Karina Peña Salazar, Wuellins Durango, Yelitza García-Orellana Cattle feedlot market in Mexico: a network approach 2023-04-28T11:50:32-06:00 Nicolás Callejas-Juárez <p><strong>Introduction</strong>. The cattle movement network for cattle for fattening in Mexico is complex. The motive, volume, origin and destination of the animals moved determine the economic structure and market network. <strong>Objective</strong>. Analyze the market structure of the national beef cattle market network for fattening in Mexico from 2017 to 2021. <strong>Materials and Methods</strong>. The study considered all head of cattle mobilized for fattening in 956 municipalities of origin (supply) and 1,173 municipalities of destination (demand) within Mexico from 2017 to 2021. The market structure was analyzed with economic, density and centrality measures of the Social Network Analysis (SNA). <strong>Results</strong>. The beef cattle mobilization network for fattening consisted of 31 origins and 32 destinations, an annual average of 3.9 million head of cattle mobilized and 73.6 head of cattle per mobilization. The most important states for cattle movement, in origin and destination, were Chiapas and Durango. In all cattle origins and destinations, a high concentration of steers for fattening was found, because they had low centrality and density measures of the entire network. Likewise, both in origin and destination, Veracruz and Durango were the most influential. <strong>Conclusions</strong>. The cattle market network in Mexico has a high density and low centrality structure. The degree of specialization, both in origins and destinations, is low. Supply is concentrated in the southeast and demand in the north and center of the country.</p> 2024-01-08T00:00:00-06:00 Copyright (c) 2024 Nicolás Callejas-Juárez Alelopathy of Cenchrus clandestinus on common bean (Phaseolus vulgaris L.) germination 2023-04-12T08:31:20-06:00 Sugey Velasco-Villabona Enrique Quevedo-García Amanda Lucía Chaparro-García <p class="p2"><strong>Introduction. </strong>Weeds are one of the main problems in agricultural productivity due to their interactions with crops, such as alelopatic effects on germination. <strong>Objective. </strong>To evaluate the allelopathy of kikuyo grass (<em>Cenchrus </em><em>clandestinus</em>) on the germination of beans (<em>Phaseolus vulgaris </em>L.) variety ICA Cerinza. <strong>Materials and methods. </strong>The study was conducted at the Quality Control Laboratory of the Universidad de Pamplona, Central Campus, Pamplona, Norte de Santander, Colombia, from May to August 2022. To each experimental unit (Petri dishe) with 12 been seeds, 6 mL of kikuyo aqueous extract (leaf, stem, and root) at three concentrations (1, 2.5, and 5 %), plus a control (0 %), were added, totaling 12 treatments. From day 0 to 12, the number of germinated seeds (NGS) was recorded, and the germination rate index (GRI) and germination index (IG) were calculated. The biomolecular profile of the aqueous extract was determined using the Fourier-transform spectroscopy. A completely randomized experimental design with a factorial arrangement (3x4), with repeated measures in each experimental unit, was employed. The intersuject factors were the organ type and concentration, while the intrasubject factor was the evaluation time (12 days). <strong>Results. </strong>Significant differences (p&lt;0.001) were observed for NSG among treatments due to the concentration of the aqueous extract, as well as for IG, while GRI depended on the organ (p&lt;0.05) and concentration (p&lt;0.001), both negatively affected as the concentration increased. The infrared spectrum of the extract determined the presence of polyphenols, nitriles, and siloxanes. <strong>Conclusión. </strong><em>C. clandestinus </em>affected NGS, GRI, and GI of <em>P. vulgaris</em>, with an allelopathic effect of the leaf aqueous extract at higher concentrations. Polyphenols, nitriles, and siloxanes associated with allelopathic effects were identified in the aqueous extracts.</p> 2024-01-25T00:00:00-06:00 Copyright (c) 2024 Sugey Velasco-Villabona, Enrique Quevedo-García, Amanda Lucía Chaparro-García Herbicide selectivity in sweet potato (Ipomoea batatas (L.) Lam.) Criollo variety 2023-03-31T11:36:15-06:00 Franklin Herrera-Murillo Grettel Picado-Arroyo <p class="p2"><strong>Introduction.</strong> Sweet potato (<em>Ipomoea batatas</em> (L) Lam.) is sensitive to weed competition, and chemical control in Costa Rica is challenging due to limited local information on herbicide selectivity. <strong>Objective.</strong> To determine the selectivity of six herbicides applied at different stages of development to Criollo sweet potatoes and their effect on coverage, biomass, and crop yield. <strong>Materials and methods.</strong> Between August and December 2021, three experiments were conducted at the Fabio Baudrit Moreno Agricultural Experimental Station, Universidad de Costa Rica, Alajuela,<br />Costa Rica. Herbicides were applied (in kg a.i. ha<sup>-1</sup>) as follows: a) Experiment 1: 0.36 of metribuzin, 1.50 of<br />pendimethalin, 0.48 of clomazone, 0.075 of halosulfuron, 1.00 of linuron, and 1.25 of metolachlor, applied six days after planting (dap) in a randomized block design with four repetitions; b) Experiment 2: 1.00 of linuron and 0.36 of metribuzin 0.36, applied at -1, 15 and 30 dap, in a randomized block design with a 2x3 factorial arrangement and three repetitions; and c) Experiment 3: 0.075 of halosulfuron and 0.36 of metribuzin, mixed with 0.125 of fluazifop-p-butyl<br />in a randomized block design with three repetitions. Weeding was performed at 15 and 30 dap in all cases. Results.<br />Root yield was not affected in any of the three experiments. Experiment 1: Only halosulfuron caused mild damage to the plants; no herbicide affected above-ground biomass production. Experiment 2: Only linuron and metribuzin applied at 15 and 30 dap caused mild damage. Experiment 3: The mixtures caused temporary damage to the plants. <strong>Conclusions.</strong> The evaluated herbicides were selective to the Criollo sweet potatoes, and did not affect the yield of<br />marketable storage roots. Only halosulfuron caused mild damage in all application forms, and metribuzin and linuron<br />only in late applications.</p> 2024-01-08T00:00:00-06:00 Copyright (c) 2024 Franklin Herrera-Murillo, Grettel Picado-Arroyo Zinc oxide supplementation as a substitute to antibiotics in pigs (Sus scrofa domestica) 2023-06-26T08:44:36-06:00 Cristian Barría Richard Mudarra Reggie Guerra <p><strong>Introduction. </strong>There is a high human concern about resistance to antibiotics due to their inappropriate use as growth promoters in animal husbandry. <strong>Objective.</strong> To evaluate the effect of a high level of zinc as a substitute to antibiotics in nursery pigs. <strong>Material and methods.</strong> The study was carried out from June to August 2022 in the province of Chiriqui, Panama. The experimental period consisted of three phases with 14 days each. The nursery pigs (n= 54) were distributed to one of three treatments with six replicates per treatment and three pigs per replicate. The treatments were: 1) control diet, which was formulated to meet the nutritional requirements for nursery pigs; 2) similar to treatment 1, plus 200 mg of amoxicillin /kg of feed and 40 mg of florfenicol /kg of feed during phase 1 (P1) and phase 2 (P2), respectively; and 3) similar to treatment 1, plus 2000 ppm and 1600 ppm of zinc during P1 and P2, respectively. In phase 3 (P3), all pigs were fed a common diet. <strong>Results.</strong> The supplementation of zinc improved the average daily gain in all phases. Pigs fed zinc diet had better F:G ratio in P2 compared to pigs fed antibiotic diet (p&lt;0.05). A higher concentration of hemoglobin and percentage of monocytes was found in pigs fed with higher level of zinc than the other treatments. (p&lt;0.05). Furthermore, Pigs fed the antibiotic, or the control diet had a lower percentage of fecal dry matter compared to those supplemented with zinc. (p&lt;0.05).<strong> Conclusion.</strong> The supplementation of high levels of zinc exerted improvements, in comparison to the antibiotic, in terms of hemoglobin concentration, incidence of diarrhea and weight gain in pigs during 42 days after weaning.</p> 2024-01-09T00:00:00-06:00 Copyright (c) 2024 Cristian Barría, Richard Mudarra, Reggie Guerra Evolution of the brown spot (Septoria glycines) in different soybean (Glycine max) production systems 2023-03-28T14:31:43-06:00 M. Lavilla A. Peper <p class="p2"><strong>Introduction. </strong>The main control measure for brown spot (BS) caused by <em>Septoria glycines </em>is through the application of foliar fungicide. However, the management of the disease could be accomplished through cultural and genetic practices. <strong>Objective. </strong>To analyze the evolution of BS in soybean under different production systems. <strong>Materials and methods. </strong>This study was conducted for two consecutive years (2020 and 2022), in Pergamino, Buenos Aires, using the soybean cultivar DM46i20. The management variables studied were cover crops (CC), rotations (Rt), and timing of foliar fungicide application (MAFF). The evaluated pathometric variable was the area under the progress curve of plant height with symptoms (ABCPAPS), and the quantitative physiology variable was grain yield (R) in kg/ha. <strong>Results. </strong>Agronomic management practices had a significant effect (p≤0.05) on R and ABCPAPS. CC and MAFF were independent variables and showed a significant response (p&lt;0.0001) on R. On the other hand, there was a significant triple interaction (p&lt;0.0001) among CC, Rt, and MAFF for ABCPAPS, and therefore, the data were explained based on this relationship. <strong>Conclusions. </strong>The implementation of cover crops, crop rotations, and foliar fungicide significantly reduced (p≤0.05) the evolution of BS in soybean cultivation. There was a significant negative correlation (p≤0.05) between soybean yield and the area under the progress curve of the plant height with BS symptoms.</p> 2024-01-08T00:00:00-06:00 Copyright (c) 2024 M. Lavilla, A. Peper Typification of cocoa-producing farms (Theobroma cacao L.) in Montes de María and La Mojana, Colombia 2023-03-29T07:30:09-06:00 Antonio María Martínez-Reina Liliana María Grandett-Martínes Rafael Segundo Novoa-Yanez Judith del Carmen Martínez-Atencia José Luis Contreras-Santos Emel Enrique Berrio-Guzman <p><strong>Introduction.</strong> The cocoa production system is an integral part of Colombian agriculture in the subregions of Montes de María and La Mojana in the department of Sucre. There is currently no evidence in the literature regarding a<br />characterization and typification of the study of this production system. <strong>Objective.</strong> To analyze the socio-economic and technological aspects of cocoa cultivation in the Montes de María and La Mojana subregions and define homogeneous<br />groups of producers sharing similar characteristics that serve as recommendation domains.<strong> Materials and methods.</strong> Surveys were designed and conducted among farmers in the Montes de María and La Mojana region during 2019. Twenty-two farmers were selected through deterministic sampling. The analysis involved the typification of farmers<br />using the distance method and Ward’s hierarchical clustering. <strong>Results.</strong> Three groups of farmers were identified. Group GI exhibited a low technological level, with farmers having incomplete primary education and low yields (420 kg ha<sup>-1</sup>). Group GII consisted of farmers with incomplete secondary education, achieving higher yields than GI (491 kg ha<sup>-1</sup>) and incorporating practices like formation and maintenance pruning. Group GIII had a higher level of education, used technological options such as improved planting materials and crop management techniques, and obtained the highest yields among all farmers (550 kg ha<sup>-1</sup>). <strong>Conclusion.</strong> The typified farms displayed differences among the groups, concluding that group G3 achieved the highest yields per hectare, attributed to the adoption of new technologies.</p> 2023-11-13T00:00:00-06:00 Copyright (c) 2023 Antonio María Martínez-Reina, Liliana María Grandett-Martínez, Rafael Segundo Novoa-Yanez, Judith del Carmen Martínez-Atencia, José Luis Contreras-Santos, Emel Enrique Berrio-Guzman Predictive model of the severity of leaf blight by Cercospora kikuchii using meteorological variables 2023-03-13T14:36:54-06:00 M. Lavilla M. Martínez A. Ivancovich A. Díaz-Paleo <p><strong>Introduction.</strong> In integrated disease management, it is important to incorporate elements such as economic<br />damage thresholds, monitoring, and risk forecasting systems, which constitute tools to define disease control strategies. <strong>Objective.</strong> Develop a predictive model of the severity of Cercospora leaf blight (TFC) using meteorological variables for the north of the province of Buenos Aires, Argentina. <strong>Materials and methods.</strong> There were data on the incidence<br />and severity of TFC corresponding to five relevant Pergamino, Buenos Aires, soybean production cycles (2013-2017) in different reproductive stages R1 to R7. The dependent variable was the probability of occurrences of categorized levels of the rate of increase (TI) of the severity of TFC caused by C. kikuchii. The elements and meteorological variables used were daily records of maximum and minimum temperature, precipitation, and relative humidity. The<br />nonparametric Kendall Tau-b coefficient TI of connection between the TI binary categorized levels of TFC severity and the weather variables was calculated. <strong>Results.</strong> The meteorological variables with the greatest consequences in relation to the TI of the TFC were those related to relative humidity (DHR, MOJRO, DHRT). The inclusion of a thermal variable (GDTmax) was important for the adjustment of the predictive model. <strong>Conclusion.</strong> It was possible to develop a TFC severity prediction model that included two meteorological variables, one related to relative humidity<br />days and another thermal related to a maximum temperature limit for the development of the disease. To validate and strengthen the proposed model, it is necessary to have more severity data over the years.</p> 2023-07-14T00:00:00-06:00 Copyright (c) 2023 M. Lavilla, M. Martínez, A. Ivancovich, A. Díaz-Paleo Allelopathy of Panicum maximum Jacq. on Euphorbia heterophylla L. and Amaranthus dubius Mart. in laboratory 2023-03-09T08:48:59-06:00 Lisette Alonso Sánchez Leónides Castellanos González Isabel Ortega Meseguer <p class="p1"><strong>Introduction.</strong> Delving into the allopathic effects of weeds on agricultural crops and other weeds is of great importance in establishing management strategies. <strong>Objective.</strong> To evaluate the allelopathic effect of residues from<br /><em>Panicum maximum</em> Jacq. rhizomes on<em> Euphorbia heterophylla</em> L. and <em>Amaranthus dubius</em> Mart. in pre and postemergence.<br /><strong>Materials and methods.</strong> Four experiments were conducted in completely randomized design 5x5 at the Plant Health Laboratory in Cienfuegos, Cuba, in 2020. The allelopathic capacity of<em> P. maximum</em> rhizome residues<br />against <em>E. heterophylla</em> and <em>A. dubius</em> was evaluated in pre-emergence and post-emergence applications. Five treatments were assessed: 0, 40, 60, 80, and 100 g of <em>P. maximum</em> plants rhizomes fractioned per 2 kg of soil, with five repetitions (plastic pots). Rhizomes were obtained from plants in the flowering and fruiting stage at three months of age. At 12 days from the treatment, the percentage of emergence and/or survival, radicle, and hypocotyl length were compared. Analysis of variance and mean comparisons using Tukey’s test (p≤0.05) were performed using SPSS (vers. 15). <strong>Results.</strong> When comparing the treatment effect against <em>E. heterophylla</em>, a significant reduction in emergence in pre-emergence and a decrease in survival percentage and hypocotyl length in post-emergence were observed, while<br />against <em>A. dubius</em>, there was a reduction in emergence and survival, and a significant decrease in radicle and hypocotyl<br />length pre and post-emergence. <strong>Conclusions.</strong> The negative allelopathic effect (P&lt;0.05) of<em> P. maximum</em> residues on<br />both<em> E. heterophylla</em> and <em>A. dubius</em> was confirmed.</p> 2023-11-13T00:00:00-06:00 Copyright (c) 2023 Lisette Alonso Sánchez, Leónides Castellanos González, Isabel Ortega Meseguer Strawberry (Fragaria ananassa) seedlings formation under different intensities of violet, blue and red LED light 2023-03-17T07:12:55-06:00 Jorge Eric Ruiz Nieto Ana Isabel Mireles Arriaga Jesús Hernández Ruiz María Isabel Laguna Estrada Adolfo Rafael López Núñez José Luis Zárate-Castrejón <p><strong>Introduction.</strong> Seedlings formation under controlled conditions is essential for growing species of importance as strawberry. Since the artificial LED lighting technologic has allowed greater control of light, the variation of components such as the wavelength and intensity can be manipulated to form seedlings with different characteristics. However, it is necessary to generate original scientific information for the development of precise and efficient practices on light control. <strong>Objective.</strong> The aim of the present study was to evaluate the strawberry seedlings formation under different intensities of violet, blue and red LED light. <strong>Material and methods. </strong>The study was performed in 2020 at the Plant Genetics Laboratory of the Agronomy Department of the Universidad de Guanajuato, in the municipality of Irapuato, in the state of Guanajuato, Mexico. Seeds were recovered from San Andreas cultivar fruits and seedlings were formed under violet, blue and red LED light at high, medium, and low intensities. Color determination of cotiledon area, chroma saturation index and Hue angle were performed. Physiotechnical variables, chemical and antioxidant activity were measured. <strong>Results.</strong> The most suitable treatments were violet light of high and medium intensities; as well as blue light of high intensity, due to the germination percentage exceeded at least 60 %. Seedlings did not lengthen or thin, presented the largest cotyledons areas and the highest chlorophyll concentrations. In addition, these light treatments consumed 31.2 % less electrical energy on average. <strong>Conclusions.</strong> Besides the white light, the most suitable treatments for strawberry seedlings formation were violet light at high and medium intensities, as well as blue light at high intensity. It is suggested that the violet and blue light treatments be evaluated in other cultivars to confirm the beneficial effect on the strawberry seedlings. Red light limited germination and the highest antioxidant activity was observed in this treatment.</p> 2024-01-09T00:00:00-06:00 Copyright (c) 2024 Jorge Eric Ruiz Nieto, Ana Isabel Mireles Arriaga, Jesús Hernández Ruiz, María Isabel Laguna Estrada, Adolfo Rafael López Núñez, José Luis Zárate-Castrejón The creole bovine of Nunkini, Campeche, Mexico a zoogenetic resource at risk 2023-03-24T11:29:51-06:00 Guadalupe de Jesús Cruz-Clemente Raciel Javier Estrada-León Ángel Carmelo Sierra-Vásquez Víctor Hugo Severino-Lendechy Ángel Trinidad Piñeiro-Vázquez Jorge Carlos Bojórquez-Cat <p><strong>Introduction. </strong>Creole cattle raising is practiced in rural areas with difficult characteristics for the management of the species.<strong> Objective. </strong>To describe the production system and the socio-cultural and technical-economic factors that affect the production of Nunkiní Creole cattle (<em>Bos taurus</em>).<strong> Materials and methods. </strong>The study was conducted from November 2020 to October 2021, in nine livestock production units of Nunkiní, municipality of Calkiní, Campeche, Mexico. The information was obtained from an interview questionnaire with social, cultural, technical and economic study variables, applied to selected producers. Data were analyzed using descriptive statistics and ANDEVA.<strong> Results. </strong>Cattle raising was carried out only by men (100 %), with an average age of 58.44 years. The average years of experience in the activity was 34.61. Young producers had more schooling and less experience; they were in charge of the production units of higher technological level. The size of the livestock production unit varied from five to twenty-two cattle (mean of 14). Feeding management was based on a transhumance scheme, where from May to December they were free-ranging on ejido lands and from January to April they were semi-stabled, with grazing in cultivated pastures supplemented with agricultural residues. With the zootechnical management implemented by the producers, an average pregnancy rate of 83 % was obtained. The main product marketed was fresh meat in cuts directly to the consumer, with an average price of 2.675 USD$/kg.<strong> Conclusion.</strong> It is extensive traditional system that takes advantage of the common use of grasslands. With experienced producers, but of adulthood, of minimum investment and serves to strengthen the family economy. However, this activity has been threatened by the lack of revaluation of Creole cattle and the introduction of exotic breeds in the area to maximize production.</p> 2024-01-09T00:00:00-06:00 Copyright (c) 2024 Guadalupe de Jesús Cruz-Clemente, Raciel Javier Estrada-León, Ángel Carmelo Sierra-Vásquez, Víctor Hugo Severino-Lendechy, Ángel Trinidad Piñeiro-Vázquez, Jorge Carlos Bojórquez-Cat Climatic factors in the development and production of cocoa in Ursulo Galvan, Veracruz, Mexico 2023-04-17T14:32:38-06:00 Ignacio Garay-Peralta Manuel Villarruel-Fuentes Antonio Luna Díaz-Peón Rómulo Chávez-Morales Jesús Herrera-Alarcón <p class="p2"><strong>Introduction. </strong>Cocoa cultivation in tropical areas is a commercially viable agroecological alternative that allows for productive diversification and sustainable soil management through the use of organic fertilization. <strong>Objective. </strong>To evaluate the development of four cocoa varieties (INIFAP 4, INIFAP 8, INIFAP 9, and Almendra Blanca) under the climatic conditions of the Úrsulo Galván region, Veracruz, Mexico. <strong>Materials and methods. </strong>An experiment was conducted between winter (December 2021) and summer (June 2022), using a completely randomized design with four treatments and ten replications. Conventional agronomic management was employed, with the addition of 10 kg of compost per tree, followed by 3 kg of vermicompost. At four months into the study, 50 g of urea, 50 g of ammonium diphosphate, and 50 g of potassium chloride were incorporated. The study included analysis of variance and Tukey’s tests (α 0.05). <strong>Results. </strong>Statistical equality was found for height, diameter, and number of branches. The cocoa’s response to temperature, precipitation, relative humidity, and wind showed that these factors influenced the expression of its productive potential, as well as its morphology and yield, without adapting to the climatic conditions under study. <strong>Conclusion. </strong>The development of the studied varieties was homogeneous based on the climatic conditions of the Ursulo Galvan region, with the Almendra Blanca variety standing out.</p> 2024-01-08T00:00:00-06:00 Copyright (c) 2024 Ignacio Garay-Peralta, Manuel Villarruel-Fuentes, Antonio Luna-Díaz Peón, Rómulo Chávez-Morales, Jesús Herrera-Alarcón Radiosensitivity of three tomato varieties (Solanum lycopersicum L.) irradiated with Cobalt-60 gamma rays 2023-04-17T14:13:02-06:00 Jorge Enrique Jaén Villarreal María Caridad González Cepero Ismael Camargo Buitrago Ana Elida Sáez Cigarruista Rodolfo Guillama Alonso José Ángel Guerra Murillo <p class="p2"><strong>Introduction. </strong>Tomato (<em>Solanum lycopersicum </em>L.) is considered one of the most important crops in the world. Genetic improvement of tomatoes has employed different methods to generate variability, and mutation the induction of mutations is one of the techniques used to obtaining improved varieties. The first step in using this tool is studying radiosensitivity to determine the irradiation dose to be used. <strong>Objective. </strong>To determine the radiosensitivity and the dose of cobalt-60 gamma rays to be used in three tomato varieties. <strong>Materials and methods. </strong>This research was conducted in January 2020 at the Instituto Nacional de Ciencias Agrícolas of Cuba. Seeds of three tomato varieties were irradiated with cobalt-60 gamma rays, with doses ranging from 100 Gy to 900 Gy, at intervals of 100 Gy; an unirradiated control was also used. The percentage of germination, plant height, and seedling survival were evaluated. <strong>Results. </strong>It was observed that higher irradiation dose reduced germination, survival, and plant height. The IDIAP T-7 and IDIAP T-9 varieties reduced germination at a dose of 400 Gy, while the DINA RPs cultivar reduced germination at 300 Gy. Genotypes showed survival values below 50 % at a dose of 800 Gy. Height reduction began at doses of 200 Gy for IDIAP T-7, 300 Gy for DINA RPs, and 400 Gy for IDIAP T-9. <strong>Conclusion. </strong>The DL-50 doses were identified as 692, 588, and 630 Gy, and the GR-50 doses were 407, 467, and 380 Gy for the IDIAP T-7, IDIAP T-9, and DINA RPs varieties, respectively. The GR-50 dose of each variety was selected for the mutation breeding program.</p> 2024-01-08T00:00:00-06:00 Copyright (c) 2024 Jorge Enrique Jaén Villarreal, María Caridad González Cepero, Ismael Camargo Buitrago, Ana Elida Sáez Cigarruista, Rodolfo Guillama Alonso, José Ángel Guerra Murillo Downy mildew of quinoa (Peronospora variabilis): A review on disease response and treatment 2023-05-22T08:22:23-06:00 Víctor Chávez-Centeno Juan Luis Mancilla-Condor Leonor Neda Carbajal-Cuadros <p><strong>Introduction. </strong>Quinoa downy mildew is a disease that causes great economic losses and has been little studied, so research on the response of quinoa to the disease and forms of treatment is a topic that should be investigated in greater depth. <strong>Objective.</strong> To describe how downy mildew infection affects the quinoa plant and the non-traditional methods used to control this disease. <strong>Development</strong><strong>.</strong> A systematic search was carried out to compile the results associated with <em>P. variabilis</em> in quinoa (<em>Chenopodium quinoa </em>Wild.) under various conditions. The analysis determined that factors such as incidence, severity and tolerance to downy mildew disease were highly dependent on quinoa grain variety and altitude (with its climatic conditions). Plant height and yield per hectare were influenced by soil conditions, pest and disease treatment used, and planting day. <strong>Conclusions.</strong> The incidence and severity of downy mildew depended on the quinoa variety worked with. Other factors such as altitude or humidity also influenced the progress of the disease, causing an infection rate close to 90 % in environments with high humidity. Non-conventional methods for treating downy mildew were infusions of plants such as chamomile and garlic, with positive results in the short term; however, they did not outperform conventional treatments with chemical fungicides.</p> 2024-01-09T00:00:00-06:00 Copyright (c) 2024 Víctor Chávez-Centeno, Juan Luis Mancilla-Condor, Leonor Neda Carbajal-Cuadros