Agronomía Mesoamericana

Evaluation of ammonium nitrate and flaming for weed management in coffee

2024-10-30T14:28:24-06:00

Introduction. The weeds compete for water, light, and space with the coffee. Therefore, sustainable management practices must be carried out. Objective. To evaluate the effectiveness of weed management with ammonium nitrate and flaming in a coffee system. Materials and methods. This work was carried out from September 26, 2022 to January 10, 2023 at La Hilda coffee farm in San Pedro de Poás, Alajuela, Costa Rica. Two alternative weed control treatments were applied jointly, the first was ammonium nitrate diluted in water, at three doses (0, 150 and 300 kg/ha) and 15 days after spraying (dda) with this fertilizer, flaming was applied at three doses (0, 60 and 120 kg/ha). Applications were made on weeds present in coffee rows following a split-plot design, the large plot was made up of the ammonium nitrate doses, while the small plots were applied with the flaming doses. A chemical control was included with the herbicide glyphosate, also applied with flaming. Each treatment was randomly assigned and replicated six times. Results. The broad leaves were moderately damaged at 25 days after application of nitrate and 10 days after flaming. Both doses of ammonium nitrate slightly damaged Commelina diffusa, and the highest dose of ammonium nitrate without flaming caused moderate damage to broadleaf weeds; flaming without ammonium nitrate provided moderate initial damage to narrowleaf weeds. Conclusions. The herbicidal effect of ammonium nitrate was dependent on flaming but only on broadleaf weeds, C. diffusa was successfully controlled with glyphosate and flaming.

Modeling strategies to determine the effective dose of herbicides

2024-09-30T07:52:10-06:00

Introduction. Dose-response trials are used with the objective of selecting the efficient herbicide dose for the management of weed species. Data analysis of these experiments has been criticized for the use of statistical models that do not fit the distribution of the response variable, failure to specify the original structure of the experimental design, and the preference for partial models instead of fitting a unique model. Nonlinear mixed models are presented as a more accurate alternative for analyzing these experiments. Objective. Determine an effective dose of herbicide using three modeling strategies in dose response trials. Materials and Methods. Two independent experiments were conducted in greenhouses located in Tambor de Alajuela, Costa Rica during 2012 where the fresh weight (PF) in grams (g) of a biotype of Paspalum paniculatum L. was quantified as a function of grams of acid equivalent (GEA) of an applied herbicide, under a randomized complete block design. A four-parameter logistic regression model was used as a basis and three model variants were fitted. Using penalized information criteria [Akaike information criterion (AIC) and Bayesian information criterion (BIC)], the best fitting model was chosen. Results. The strategy that considered the experiment and the block within each experiment as random factors resulted the most precise. This model estimated the confidence interval (95 %) for the mean effective dose of GEA between 335,12 and 384,32 g. Conclusion. Integrating information from independent experiments as random effects within a unique model generated more accurate estimates of the glyphosate’s effective dose.

Effect of Bacillus spp. as a biostimulants for Brassica oleracea var. capitata and Brassica oleracea var. sabellica microgreens

2024-09-23T14:55:08-06:00

Introduction. The Bacillus genus has been used as a biostimulant with positive effects on crop yield and quality. However, there are few studies on its application in microgreens. Objective. To evaluate the effect of B. subtilis (BsC4 and BsPC) and B. thuringiensis (Bt24) as biostimulants on the germination and growth of red cabbage (Brassica oleracea var. capitata) and kale (B. oleracea var. sabellina) microgreens indoor. Materials and Methods. The study was conducted at the Autonomous University of Chihuahua, Mexico, in 2023. Four treatments were assessed: Bt24, BsC4, BsPC, and seedlings without microorganisms (control) on red cabbage and kale seeds, under a completely randomized design (n = 5). Germination was monitored in the first trial, and microgreens development was assessed in the secund. After 15 days, morphological variables, photosynthetic pigments, nitrate content, quality, and yield were measured. Data were analyzed using Analysis of Variance (ANOVA) and Tukey tests (p < 0.05). Results. For kale, Bt24 improved germination speed (31.17 %) and reduced germination time (4.61 %), with no significant effect on red cabbage. In kale, yield increased (62,60 %) with Bt24, particularly in fresh biomass (63.3 %) and cotyledon area (61.57 %). In cabbage, BsC4 increased yield (44.31 %) and improved fresh biomass (42.21 %) and cotyledon area (50.57 %). Nitrate content was highest in lake with BsPC (138.30 %) and in red cabbage with Bt24 (65.14 %), without exceeding safe limits. For visual quality, both crops achieved the “Good” and “Excellent” categories, with no differences between treatments. Conclusions. These results suggest that B. thuringiensis and B. subtilis could be used as growth biostimulants for cabbage and kale microgreens, offering a promising to optimize microgreen production under controlled conditions.

Economic valuation of non-timber forest products from the tropical dry forest: Ethnic-Pijao, Natagaima-Tolima, Colombia

2024-09-20T17:48:34-06:00

Introduction. Non-timber forest products from the tropical dry forest (TSF) offer multiple benefits and are considered an alternative for the sustainable use of forests and the socioeconomic development of local communities. Nevertheless, little is known about its economic value, limiting the visibility and exploitation of its potential and functionality. Objective. To assess the economic benefits of non-timber forest products from BST for the Pijao indigenous population of Natagaima-Tolima, Colombia. Materials and methods. This study was carried out in the municipality of Natagaima-Tolima, Colombia, during the first half of 2023. Data was collection through semi-structured interviews with 95 indigenous people from the rural sector, integrating social, ethnobotanical and economic variables. For the economic evaluation, the costs required for the acquisition of the product (CRAP), gross profit (BBr) and net profit (Bn) were established, supported by direct, indirect and contingency market valuation methods. Results. 570 reports were registered, 66 species of the tropical dry forest (TSF) were identified, which offer 122 NTFPs, distributed in eight categories of use (food, medicinal, forage, oil, construction, domestic, artisanal and magical-religious). In turn, these offer a total Bn of $ 8,591 /year, with a CRAP of 1.4 and a Bn per person of $ 1.34 /year. The categories of medicinal use, food and forage provide the greatest economic benefits considering that they contribute 79,5 % ($ 6.830,9 /year) of the total net income. Conclusions. NTFPs from tropical dry forests provide important socio-economic benefits to the livel

Perception and management of mango (Mangifera indica L.) dieback in Actopan, Veracruz, Mexico

2024-09-03T16:30:10-06:00

Introduction. Dieback is a serious disease reported in mango-producing regions of Mexico; however, there is no information on the perception and management of this disease by mango producers. Objective. To assess the perception of mango producers in the municipality of Actopan, Veracruz, Mexico regarding dieback disease, to evaluate the management practices they implement, and to describe their socioeconomic and production characteristics. Materials and methods. The research was conducted in the municipality of Actopan, Veracruz, Mexico in the years 2021–2022. Semi-structured interviews with 45 questions were applied to mango producers. The socioeconomic characterization of the producers, plot management, recurrent diseases, and the perception and management of mango dieack were addressed. The data obtained from the surveys were analyzed using various multivariate and descriptive statistical tools. Results. The majority of the producers were men (94 %) with a wide age range, predominantly older adults and young adults. A cluster analysis identified three distinct groups of producers: small (SPM,56 %), medium (MPM,16 %), and large (LPM,28 %) mango producers, each with specific characteristics regarding cultivated area, agronomic management, and yield (M = 8,54 ± 3,75 t/ha). The mango dieback was widely recognized by all surveyed producers; the main symptoms associated with the disease: gummosis, branch rot, and trunk rot. Only 18.75 % of the producers implement some type of specific management or control of mango dieback, mainly through chemical and mineral fungicides. Conclusions. For mango producers in Actopan, Veracruz, dieback is a highly important disease in their cultivation. They carry out some basic management strategies; however, these have not been efficient, which has led to an interest in the development of new and better control tools.

Morphological characterization of advanced lines of pepper (Capsicum annuum L.) from central Mexico

2024-08-23T15:07:39-06:00

Introduction. Of the five cultivated species of pepper, Capsicum annuum L. is the most important in the world, with great demand in the food, medicine, and cosmetology industries, among others. Mexico has the greatest diversity of cultivated types, highlighting jalapeño, guajillo, ancho, serrano and habanero. However, there are farmers who plant native materials that need to be studied and preserved, such as mulato and chilaca. There are no improved commercial cultivars for some types, such as chilaca, so producers depend on the seed they produce. Objective. Morphologically characterize advanced lines of different types of C. annuum from central Mexico. Materials and methods. The work was carried out in the spring summer 2022 and 2023 cycles, at the Bajío Experimental Station, Celaya, Gto., Mexico. In 32 advanced lines of C. annumm, 42 traits were evaluated based on UPOV guidelines (International Union for the Protection of New Varieties of Plants) and the IPGRI (International Plant Genetic Resources Institute) guide. The data obtained were analyzed using descriptive statistics and subjected to a cluster and correspondence analysis. Results. Morphological variation showed that fifteen plant, leaf and fruit traits were decisive in differentiating types and lines of chili. Based on similar traits, they were placed in five groups with the cluster analysis, where groups I and III were made up of three types of chilies and six traits presented the highest positive eigenvectors. Conclusions. The observed diversity revealed determining morphological characteristics to differentiate types and lines of chili peppers, which undoubtedly must complete their genetic improvement process.

The cryopreservation of the germplasm of livestock species: A step towards sustainability

2024-08-06T11:45:31-06:00

Introduction. Climate change has led to the need to modify the way of production in livestock systems. Objective. Review the state of the art on the cryopreservation of sperm from livestock species and its possible repercussions on sustainable development. Development. Scientific articles from 2000 to 2024 were reviewed from Web of Science, Scopus and ScienceDirect. Sperm freezing can be considered as a way to optimize the reproduction of animals, however, during the process the formation of reactive oxygen species (ROS) can be stimulated, which promote lipid peroxidation of the membrane, which can cause damage. at a structural and molecular level that compromise the sperm functionality and the fertilizing capacity of the male gamete. The success of cryopreservation of sperm from livestock species can be improved by including extrinsic factors such as the addition of antioxidants, centrifugation or selection of the type of freezing. This reproductive biotechnology is associated with artificial insemination (AI) and the combination of these techniques has made it possible to optimize the profitability of livestock systems through continuous genetic improvement. Conclusions. The optimization of cryopreservation of the germplasm of species of zootechnical interest has allowed for an increase in the productivity and efficiency of livestock systems, as well as the possibility of species conservation, which are key factors to achieve sustainability.

Efficiency of botanical extracts from Jatropha curcas for the control of Trialeurodes vaporariorum (Hemiptera: Aleyrodidae)

2024-07-26T10:09:00-06:00

Introduction. Trialeurodes vaporariorum (Westood)is considered as a main pest of ornamental and horticultural crops, especially under greenhouse. In order to perform an effective management of this pest, different kind of techniques and methods such as the implementation of botanical extracts must be integrated. Objective. To evaluate the efficacy of botanical extracts made with Jatrophas curcas for the control of Trialeurodes vaporariorum in laboratory conditions. Materials and methods. The study was carried out in the Entomology Laboratory of the Research Center in Crops Protection, implementing an adaptation to the methodologies described by Liu and Stanly (1995) and Ibrahim and Mostafa (2018), where was evaluated the efficacy, median lethal concentration (LC50) and median lethal time (LT50) of botanical extracts made of leaves, stems and seeds of two accessions of Jatropha curcas L. at concentrations of 50, 100, 150 and 200 g/L on T. vaporariorum Results. The lower values of LC50 (1.52 g/L), LT50 (61.01 hours) and the greater values of efficacy (greater than 65 %) were achieved with the leaf’s extracts, however only the LT50 values were significant differences. Concentration was the most important factor in the calculation of efficacy according to the Akaike information criteria (AIC), it was estimated that the efficacy increased by 0.15 % for each unit of concentration. None of the extracts caused phytotoxicity on Solanum melongena L. plants. Conclusions. The leaf extracts are a promissory choice for the control of T. vaporariorum; nevertheless, it is needed to determine the compounds of Jatropha’s leaves that induce mortality.

Exploratory single crosses of purple maize for pericarp and cob pigment production

2024-08-07T14:24:28-06:00

Introduction. Plant based pigments could replace artificial pigments and consume healthy food products. Objective. To evaluate in the field and laboratory exploratory purple grain and cob maize single cross hybrids (CSE), formed with random lines, to analyze the integration of the B-49N x B-41N heterotic pattern. Material and methods. The research was carried out in Tepatitlán, Jalisco, Mexico during 2021-2022, CSEs were formed between six S₅ lines from population B-49N and four S₃ from B-41N with purple grain and cob. The crosses and five controls were evaluated in 2022 in the same location. A randomized complete block experimental design with three repetitions was used. Plot size, a row of 4 m long, 0,8 m wide and 0,16 m between plants with 25 plants per row. Plant and ear data were taken. In seven crosses total anthocyanin content in grain (CATg) and cob (CATo) were evaluated. Analysis of variance and tests of means were performed on all variables using the statistical SAS program. Results. There were 12 CSEs with the same yield (p < 0,05) as the white control, but with purple grain and cob, significant variation (p < 0,05) in anthesis (from 80 to 90 days), stem lodging (from 0 to 12,6 %). and ear grade (from 1,5 to 2,7). The grain of the CSEs was soft to very soft, and there was not association between yield and high CATg and CATo contents. Conclusion. CSE results show positive progress in the integration of the heterotic purple maize pattern B-49N x B-41N, but, in the future, the anthocyanin content in grain and cob, and grain hardness, should be increased.

Genetic and environmental effects on production of dairy goats under semi-intensive tropical conditions

2024-07-26T09:37:28-06:00

Introduction. The study of factors affecting the productive performance of dairy goats under tropical conditions is essential for optimal resource utilization. Objective. To quantify the impact of genetic and environmental factors affecting the productive performance of dairy goats under semi-intensive tropical conditions. Materials and Methods. The study was conducted at the Finca Experimental Santa Lucía (FESL) of the Universidad Nacional (UNA), Heredia, Costa Rica. The experimental period spanned from January 2007 to December 2023. A total of 15,686 daily milk weighing records were analyzed from 191 dairy goats of Saanen (S) and Saanen×Toggenburg (S×T) crossbreeds. A Generalized Linear Mixed Model was used to evaluate the effect of various predictor variables on daily milk production, and standard lactation curves were fitted for different genetic and environmental conditions using the Wood function. Results. Highly significant effects (p<0.001) of variables such as parity number, year of kidding, lactation week, buck category, number of offspring, season, and month of kidding on milk production were determined. For primiparous goats of S and S×T breeds kidding in the rainy season, daily peak milk productions of 2.46 and 2.54 kg were estimated, reached in weeks 6.4 and 5.9, with persistencies at the end of lactation of 86 % and 84 %, respectively. Conclusions. Being multiparous goats and the availability of feed with higher nutritional content during the rainy season are factors associated with higher milk production. Lactation curves revealed different patterns in milk production between primiparous and multiparous goats, as well as between different kidding seasons and breed types. The study provides valuable information for commercial validation and optimization of themanagement of lactating goats in semi-intensive tropical conditions.

Environmental impact of the broiler production chain under conventional systems

2024-09-18T06:52:18-06:00

Introduction. Broiler production is an activity of growing economic importance worldwide, but it entails a significant environmental impact. Objective. To assess the environmental impact of the broiler production chain under conventional systems. Material and methods. Assessment was performed through a “cradle to gate” Life Cycle Analysis (LCA). Base parameters were obtained from a poultry farm located in San Ramón, Alajuela, Costa Rica, between January and December 2021. The functional unit of the LCA was a metric ton of chicken meat (MT CM) and the impact categories included were established based on the ReCiPe 2016 v.1.1 system, with characterization factors evaluated at the midpoint level under a hierarchical perspective. Results. The estimated environmental impacts, in equivalent units per MT CM, were the following: global warming: 5208 kg CO2-eq, terrestrial acidification: 52.6 kg SO2-eq, marine eutrophication: 4.19 kg Neq, freshwater eutrophication: 2.47 kg P, land use: 5238 m2 crop year, water consumption: 3962 m3, terrestrial ecotoxicity: 1831 kg 1,4-DCB, marine ecotoxicity: 2.79 kg 1,4-DCB, freshwater ecotoxicity: 8.49 kg 1,4-DCB, human toxicity (carcinogenic): 1.13 kg 1,4-DCB, human toxicity (non-carcinogenic): 84.4 kg 1,4-DCB, fine particulate matter formation: 8.15 kg PM2.5, fossil resource depletion: 246.1 kg oil, ozone formation (ecosystem health): 10.8 kg NOx, ozone formation (human health): 10.7 kg NOx, and stratospheric ozone depletion: 0.043 kg CFC11. Conclusions. The processes with the greatest contribution to the environmental impacts evaluated in this study were the production of feed, fertilizers and fuels, as well as the management of farm waste. Most of the environmental impact attributable to the broiler production chain occurs outside of Costa Rica.

Jackfruit (Artocarpus heterophyllus Lam.) agroindustrial waste in animal feeding: Systematic review

2024-08-05T11:05:51-06:00

Introduction. Nowadays, food industry innovation has carried out thousand tons of agroindustry waste that affect negative of ambient sustainability, so it is important to take actions to contribute to decrease waste, to use the bioactive compounds present in them to taking advantage. Objective. To conduct a literature review on the nutrients and bioactive compounds present in the main parts of jackfruit (peel, pulp and seed), to addition this fruit to feeding animals. Development. A systematic review was carried out based on experimental articles located in databases such as: ScienceDirect, Wiley, Google Scholar, Scopus and Springer Link. A search equation was used for this purpose. The results showed that the different parts of jackfruit present nutrients (proteins, carbohydrates, minerals) and bioactive compounds (polyphenols, flavonoids, polysaccharides, phenols, etc.) that have proven to have a positive effect when added to the feed of production animals (broilers, sheep and goats). Conclusion. The addition of jackfruit to feed animal production favor the weight gain, improving digestibility, stimulating the immune system and decrease feed production cost.

Pathogenicity and frequency of Fusarium species associated with the pineapple plant and fruit in Costa Rica

2024-07-10T07:20:42-06:00

Introduction. Costa Rica is one of the largest producers and exporters of pineapple worldwide, however, production and post-harvest handling are difficult due to phytosanitary problems caused by fungi of the genus Fusarium. Objective. To determine the pathogenicity of different Fusarium species associated with the pineapple plant and fruit, and their frequency in the main production areas of Costa Rica. Material and methods. The experiments were performed at the University of Costa Rica, San Jose, from 2015 to 2019. Pathogenicity tests were carried out using inoculation with six Fusarium species, in bracts, peduncles, and fruits of pineapple, and it was verified using Koch´s postulates. By collecting 120 isolates, the frequency of Fusarium species in the producing areas was established. Results. All Fusarium species caused damage to bracts. The largest lesions were caused by F. oxysporum. In fruit, internal lesions were observed in the pulp with F. ananatum, and a correlation between lesion size and the concentration of inoculated conidia, was found. In the peduncle and pulp, lesion diameter varied among Fusarium species. Regarding frequency, all Fusarium species were present in the Huetar Norte region, and F. ananatum was more abundant in all producing regions, except for the Brunca region. Conclusions. All the species analyzed were pathogenic in the pineapple crop, in bracts, peduncles, and fruit, where F. oxyporum and F. ananatum caused the greatest lesions. The presence in all pineapple areas, the pathogenic potential, and the production of mycotoxins determine the importance of taking precise measures to control and prevent the dispersion of the species of this genus.

Functional ingredients and innovative dairy products: Scientific and technological review

2024-09-04T10:35:46-06:00

Introduction. Understanding consumer behavior in the dairy sector is essential for enhancing competitiveness and defining strategies to meet their requirements and needs. Reviewing scientific information and patents allows for the identification of trends in the addition of functional compounds to dairy products, serving as a critical input for innovation in the food industry. Objective. To identify and analyze trends in the incorporation of functional compounds in dairy products by integrating perspectives from scientific articles and patent analyses. Development. Reviews of both sources revelated a greater application of functional ingredients in yogurt, which opens opportunities for implementation and research in other fermented products such as skyr. Scientific articles indicates an increasing focus on incorporating functional ingredients from unconventional sources into yogurt, ice cream, and cheese. Notable trends include the addition of antioxidants, and proteins, fat reduction, and the substitution of additives. Patents show a tendency toward the incorporation of nutrients, with protein addition being a recurring feature, as well as the inclusion of probiotics, minerals, and antioxidants. Another frequent trend in patents is the optimization of production processes to achieve clean labeling and improve sensory characteristics. The development of dairy products for specific populations is an emerging trend evidenced in the documented strategies. Conclusions. Key trends identified in the dairy industry include an emphasis on fermented products such as yogurt, improved production efficiency, and the addition of functional nutrients aligned with consumer requirements. Both sources highlighted the addition of proteins and antioxidants. An emerging trend identified in the analysis is personalized nutrition, which focuses on using functional nutrients tailored to specific populations groups.

Strategies in developing tropical maize hybrids.

2024-06-17T08:12:58-06:00

The strategies in a hybrid development program should be so oriented to achieve short, medium and long term objectives. The germplasm source utilized is quite important and should possess desirable agronomic traits with good plant and ear height characteristics along with good stalk quality to allow development of good progenitors. To achieve these objectives, it is imperative to introduce new strategies and modifications in the conventional systems to obtain higher efficiency. In this presentation various aspects are discussed relating to germplasm source oriented towards hybrids, integration and introduction of new schemes of population improvement parallel to hybrid development, production of vigorous and productive lines using diversified and efficient strategies, precise characterization of lines in inbred-line evaluation trials, combining ability in crosses with testers, identification of new hybrids during various stages of hybrid development, prediction of new hybrids with less number of single crosses, use of inbred lines in forming new populations as well as heterotic groups and synthetics. Options for developing single cross hybrids to add efficiency in the future are discussed.

Some considerations for the organic production of vegetables.

2024-06-17T07:54:46-06:00

This article is based on a Bibliographical Compilation where the ecosystemic problems, generated by the scientific and technological advances in modern agriculture, are analyzed. The basic principles ruling the organic, bilological, alternative or ecological agriculture are defined, emphasizing the importance of maintaining and improving the soil as the basic component of organic production, adducing that a well nourished plant is most resistant to any plague. Diseases, insects, weeds and nematodes are also mentioned, giving emphasis to practices of integrated plague management.

The phytogenetic resources: an option for the agricultural development in the American Tropics.

2024-06-17T07:49:32-06:00

The Central American agriculture shows a low productivity in most of the cultivated crops, apparently due to a lack of improved varieties and a reduced used of cultural practices. The Central American region has climatic, topographic, edaphic and social characteristics that could allow a more integral development and exploitation of the autochthonous phytogenetic resources. Nonetheless, in spite of the significance that it has to the farmer and the industry, there is little research and information on the use and of cultural practices of some potential species of American origin. A better knowledge of the genetic diversity, seasonal production, quality, supply and demand of the products, will allow for the preparation of a list of the phytogenetic potential which is still preserved. The most important incentive of any crop is its economic profitability. On this way, the economic factor promotes the basis for developing an increased production, improve quality and open new alternatives to the farmer and the industry. If a new crop is not profitable, it is rejected inmediately; but on the other hand, if a crop is highly profitable, it is almost imposible to restrain its diffusion. The recognition and conscience drawn by the reasonable use of the "genetic resources" on the national, regional and world level, as an essential base for a dynamic and rational agriculture, by far justifies the programs of the countries in the American Tropics to join their efforts in the preservation and promotion of the genetic diversity.

Aerobiology: a new research area.

2024-06-17T07:38:28-06:00

A workshop to address the science of aerobiology was held at Michigan State University‘s Kellog Biological Station on October 10-13, 1992. The purpose of the workshop was to bring together scientistis and to our-reach specialists from diverse disciplines to advance the understanding of aerobiology and improve the capability to predict the atmospheric movement of biota. Biota important to agriculture, forestry, human health and the envirommental move in predictable atmospheric transport events. The workshop participants discussed the principles of long-distance atmospheric transport of biota, formulated strategies to share diagnostic technologies and information systems, and concluded that science is positioned to make major advances in forecasting the movement of arthropods, plant viruses, fungi, and bacteria; birds and human allergens. A North American alliance for aerobiology research is being accelerate research advances in the important area of science. Approximately 70 nationally and internationally recognized scientists from agriculture, medicine, engineering, physics, eviromental science, and systems science participated in the workshop. The workshop generated (1) a set of generic foci and scientific hypotheses that will serve as guidelines to conceptualize and direct research in aerobiology, (2) recommendations for networking biological, atmospheric, and other environmental monitoring networks for in forecasting aerobiological transport events, (3) recommendations for utilizing existing electronic networks to link scientistis with agencies and institutions with and tools, (4) recommendations for developing an information database on an electronic comunications network to facilitate access to aerobioogical information, and (5) the establishment of an organizational, structure for the Alliance for Aerobiological Research (AFAR)with a governing board to serve the membership.

Biotechnology and the agricultural field.

2024-06-17T07:24:41-06:00

This article summarizes how the modern biotechnology techniques can be used as a tool to make the traditional animal and plant breeding methodologies more efficient. The advantages and disadvantages of using these techniques were analyzed at each stage of the selection process of the breeding program. We compared the ease of handling and time saving obtained when the biotechnology component is integrated in the process used by the breeder. The new techniques analyzed were: a- Tissue and organ culture; b- Genetic transformation; c- Molecular genetic markers. Likewise, the current interest of multinational corporations on the potential of the agriculture modified by the biotechnology and the further concentration of knowledge and intellectual rights was analyzed. The importance for the Latin American countries to rule as a group and to share a common criteria in order to legislate in favor of the intellectual rights and biosafty was also emphasized. This legislation would allow a harmonic development of biotechnology among our countries.

Characterization of the nopal (Opuntia spp.) production system in the Huasteca region of Tamaulipas, Mexico

2024-06-21T11:17:39-06:00

Introduction. In Tamaulipas, Mexico, environmental conditions are suitable for nopal (Opuntia spp.) production; however, yields are lower than the national average. Objective. To characterize the nopal production system in the Huasteca Tamaulipeca region and identify the main issues that limit production. Materials and methods. A diagnosis of the nopal production system in the Huasteca Tamaulipeca region was conducted through 28 interviews with 65 questions, divided into three sections: a) producer identification, b) characterization of the family production unit, and c) technical-productive characterization and commercialization. Results. Producers’ ages ranged from 37 to 78 years, with an average schooling of 6.5 years. A total of 32 % of the producers do not receive technical assistance, 57.1 % work on land under the ejido system (communal land tenure), 82.1 % sell their products to intermediaries, and 100 % do not use agricultural machinery for their activities. Conclusions. Most nopal producers in the Huasteca Tamaulipeca region are older adults with experience in nopal cultivation. Nopal production in the region is carried out traditionally, under rainfed conditions, without infrastructure, and with little technical support. The main issues identified were low prices due to limited product demand and a lack of technical assistance for crop management.

Effect of ozone on the postharvest quality of blackberry (Rubus adenotrichos) during storage

2024-06-12T11:47:03-06:00

Introduction. Blackberries are highly perishable fruits due to their soft skin and susceptibility to fungal diseases, such as gray mold caused by Botrytis cinerea. Ozone is a gas that can extend the shelf life and protect the fruit from the growth of B. cinerea. Objective. To evaluate the effect of gaseous ozone application on the physicochemical characteristics and postharvest quality parameters of fresh blackberries during storage. Materials and methods. This study was carried out at the National Center for Food Science and Technology of the Universidad de Costa Rica in 216. Blackberries (Rubus adenotrichos) of the “Vino con espinas rojas” variety were used. The fruits were inoculated with B. cinerea and treated with gaseous ozone at a range of 50-200 μg L^-1for 150 min once a day over 0, 2, 4, 7, and 10 days of storage at 2 °C. Additionally, a control treatment (without ozone) was applied. Various physicochemical characteristics (color, total soluble solids, titratable acidity, and hardness) and postharvest quality parameters (percentage of damaged fruit and fruit infected with B. cinerea) were evaluated. Results. Storage time significantly affected (p < 0.05) all the parameters analyzed, regardless of ozone application. No effect of ozone on the physicochemical parameters was observed. However, ozone treatment influenced the percentage of damaged fruit (p = 0.0067) and fruit affected by B. cinerea (p < 0.0001). After 10 days, ozone-treated fruits showed a lower percentage of fruit affected by B. cinerea (78.95 ± 1.08 %) compared to untreated samples (96.07 ± 2.19 %). Conclusion. Ozone application could be an effective method for maintaining blackberry quality, extending storage time, and improving resistance to fungal deterioration.

Insects as protein supplements for livestock production: a sustainable and efficient alternative

2024-06-21T07:45:49-06:00

Introduction. The agricultural sector faces the challenge of finding sustainable alternatives for animal feed, given the growing demand for food and environmental problems. Objective. To document the outstanding nutritional characteristics of insects and their potential as a food alternative for livestock production. Methodology. A bibliographic search was conducted in the Science Direct database, based on terms related to the consumption and production of animal feed and its environmental impact. Development. The nutritional profile of insects is remarkable due to their content of proteins (32 to 74 %), essential amino acids (8 to 39 %), healthy fats (6 to 21 %), and vitamins and minerals (up to 278.3 mg per 100 g of dry matter). The high digestibility of their nutrients makes them an important option to complement the animal diet. However, their use carries risks such as allergies, contamination, and nutritional imbalances, which can be minimized with proper hygiene practices, ensuring the quality of insects used, and complying with relevant regulations. Conclusions. Insects are an important source of proteins, amino acids, fats, and minerals, with quality comparable to other traditional sources such as soybeans, wheat, improved grasses, and other legumes. The use of insects represents an innovative and sustainable alternative for animal diet, as it provides a balanced and nutritious food source, benefiting both animals and the environment. Successful adoption requires a balance between nutritional and environmental advantages and the costs associated with production and regulation.

Survival or traditional statistics? Purple corn (Zea mays L.) premix shelf life estimation

2024-07-08T14:55:05-06:00

Introduction. Because the development process of a food product is not complete until its useful life is known, the development of a novel product food product such as the purple flour corn pancake premix raises the need of determining it. Objective. Estimate the shelf life of a pancake premix based on pujagua corn flour (Zea mays L.), through a storage study, using linear regression and Weibull distribution data analysis to compare both methodologies. Materials and methods. The study was carried out at the National Center for Food Science and Technology (CITA) of the University of Costa Rica, between 2018 and 2023. The storage study of the pancake premix was carried out with three repetitions, in a chamber at 25 °C and control samples at -18 °C for 7,5 months, considering nine sampling times and 26 days sampling frequency. For the pancakes, the critical sensory variables chewiness and atypical flavor were analyzed; the atypical odor variable was selected for the premix. A liking test was carried out with consumers (n=100).With these and the obtained from trained panel, two useful life values were calculated, one with the cut-off point method using linear regressions and another using the Weibull distribution. Results. The sensory variable determinant of the premix shelf-life was chewiness. With the first methodology, a useful life value of 124 days was estimated and with the second, a value of 265 days at 25 °C was obtained. Conclusions. The cut-off point method is more conservative and sensitive to the selected critical variables. The method using Weibull distribution was more practical, but care must be taken when evaluating products that are little familiar or about which consumers have little information.

Effects of postharvest abiotic stress on the accumulation of bioactive compounds

2024-08-22T07:33:31-06:00

Introduction. Abiotic stress in plants has been studied for many years from agricultural and physiological perspective, generating interest in its application during postharvest stages to induce desirable changes as a basis for the development of functional foods. Objective. To investigate and synthesize information related to the application of postharvest abiotic stress treatments in fruits and vegetables in order to evaluate their impact on the bioactive compounds content. Development. This review was developed in Costa Rica from March 2023 to January 2024 and describes the main effects of applying controlled abiotic stress during postharvest. The includes physical damage, exposure to high or low temperature, application of chemical substances, and irradiation in fruits and vegetables, with special attention to the accumulation of bioactive compounds generated as defense substances or through secondary metabolism. Conclusions. The available information suggests an effect on the accumulation of bioactive compounds, the sensory and general quality of the product, the type of treatment used, and storage conditions. The application of treatments to induce controlled abiotic stress should consider the intensity of stress, as excessive levels hinder subsequent use of the material as raw input for developing functional foods. Therefore, studies on treatments that allows important accumulation of compounds of interest in a specific product, suitable for the use as an raw material in functional food development, should also adedess their effects on relevant quality aspects. Aditionally, the effects of time and storage conditions on the concentration and stability of these compounds should be considered.

Osmosonication parameters affect Salmonella Typhimurium and Lactobacillus rhamnosus reductions in solutions and fruit juices

2024-08-14T15:23:03-06:00

Introduction. Sonication followed by storage in high osmotic pressure, referred to as osmosonication, can significantly reduce microbial loads in food products. Understanding the parameters that influence these reductions is essential. Objective. To evaluate the effect of osmosonication parameters on the reduction of Salmonella Typhimurium and Lactobacillus rhamnosus in model solutions and fruit juices. Materials and methods. This study was conducted at the Universidad de Costa Rica, San José, Costa Rica between January and December 2012. Completely randomized experiments were designed for both model solutions and fruit juices, with data analyzed using ANOVA. The parameters evaluated included amplitude (20, 25, 30, 35, and 40 %), sonication time (10, 20, and 30 minutes), percentage of pulsations time (90, 50, 10, and 0), pectin content (0, 0.5, and 1,0 %), and cellulose content (0, 0.15, and 0.30 %), pH (2.5; 3.5; 4.5; 5.5, and 6.5) or natural juice pulp content. Results. L. rhamnosus demonstrated greater resistant to osmosonication treatments compared to S. Typhimurium. Microbial reductions increased with higher sonication times and amplitudes. The percentage of pulsations time did not significantly influence bacterial reductions. Lower pH values resulted in reduced bacterial resistance to osmosonication. Neither pectin nor cellulose content significantly affected the resistance of either microorganism to osmosonication. Similar treatments applied to fruit juices (blackberry, pineapple, apple, and coconut water) showed that microbial reductions for both bacteria were influenced by the type of juice, likely due to varying pH levels. These effects was also bacteria-dependent. Pulp content affected bacterial resistance to osmosonication, with the impact varying by bacterial species. Conclusions. Osmosonication parameters such as amplitude, time, pH, and the pulp content influence the reduction of Salmonella Typhimurium and Lactobacillus rhamnosus in model solutions and fruit juices.

Bactris guineensis, an underutilized Costa Rican palm fruit: juice processing and its nutritional profile

2024-09-16T09:37:05-06:00

Introduction. Bactris guineensis is a crop that produces visually appealing fruits resembling purple-black grapes with round seeds. This palm species naturally thrives in the lowland regions of tropical America. However, limited information available about this fruit. Objective. To investigate the nutritional composition, bioactive compound content, antioxidant capacity, and aroma profile of the huiscoyol fruit grown in Costa Rica, as well as to evaluate the effects of juice processing (enzymatic maceration and thermal treatment) on its bioactive compounds and antioxidant capacity. Materials and methods. Fruits were collected from randomly selected palms and bunches in Guanacaste Conservation Area, specifically in Palo Verde and Cañas, during peak harvest years (2007, 2011, 2014, and 2016). Nutritional composition, bioactive compound content, antioxidant capacity, and aroma and polyphenol profiles were analyzed. Juices were prepared using thermal treatment, enzymatic maceration, and a combination of both methods. The bioactive compound content and antioxidant capacity were assessed following each treatment. Results. Huiscoyol fruit exhibited high fiber content [7.3 ± 2.5 g per 100 g of fresh weight (fw)], and significant potassium content (307 ± 98 mg per 100 g fw). Anthocyanin levels ranged from 28.3 to 47.9 mg per 100 g fw, with cyanidin-3-O-rutinoside as the predominant compound. Total polyphenol content varied between 219 and 1,013 mg gallic acid equivalents per 100 g fw. Vitamin C content reached a maximum of 48 mg per 100 g fw. Antioxidant capacity, as measured by H-ORAC, ranged from 6,690 to 14,688 μmol Trolox equivalents per 100 g fw. Enzymatic maceration and thermal treatments applied to the juice did not significantly affect the bioactive compounds content or antioxidant activity (p > 0.05). Conclusion. Huiscoyol fruit demonstrate nutritional and antioxidant potential, making it promising ingredient for funtional beverages. Its bioactive components, such as polyphenols and anthocyanins, showed remarkable stability under thermal and enzymatic processing conditions.