Agronomía Mesoamericana <p>Agronomía Mesoamericana journal is a periodical publication (January-April, May-August and September-December) edited in the Universidad de Costa Rica, its objective is to disseminate scientific information 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, especially from Mesoamerica and the Caribbean.&nbsp;</p> <p>&nbsp;</p> <p><strong>URL OAI-PMH</strong>&nbsp;<a href=""></a></p> en-US <p>Those authors/publications as having this journal agree to the following terms:<br>1. The authors retain their copyright and guarantee to the journal right of first publication of his work, which will be simultaneously subject to license recognition of Creative Commons that allows others to share the work provided that its author is indicated and its first publication this journal.<br>2. The authors may take other non-exclusive distribution license agreements version of the published work (for example institutional Telematic put it in a file or publish it in a monograph) provided the initial release indicated in this journal.<br>It allows and encourages authors to disseminate their work on Internet (for example institutional telematic files or on their website) prior to and during the submission process, which can produce interesting exchanges and increase appointments of the published work. (See The Effect of Open Access).</p> (Nancy León Ulate) (Ing. Nancy León Ulate) Wed, 01 May 2019 00:00:00 -0600 OJS 60 Analysis of statistical methods to evaluate the performance of simulation models in horticultural crops <p><strong>Introduction. </strong>Every simulation model must be calibrated and validated, in order to avoid speculative and inaccurate conclusions. The methods to evaluate simulation models are usually applied “by habit”, without specifying &nbsp;basic methodological details which leads to the use of terminology and symbology that could cause confusion <strong>Objective. </strong>The objective in the present study was to analyze the different statistical methods employed to evaluate the performance of simulation models in agriculture, and thus propose which is the most suitable from the practical point of view. <strong>Materials and Methods. </strong>Statistical methods based on difference and regression analysis, between measured and simulated values were analyzed. Regarding the difference analysis group, the used methods were root mean square error (RMSE), mean absolute error (MAE), relative error (RE), adjustment index (<em>d</em>), me bianas error (MBE) and the model efficiency (E). In the case of the regression analysis the intercept, linear regression (b) and determination (R2) coefficients, and the estimation confidence limits were scrutinize. <strong>Results. </strong>The ER, <em>d </em>and E, are measures which objective is the comparison between different models to simulate a given variable, instead of evaluating the performance of the model as such. The root square mean error usually used to evaluate differences between observed and simulated values is different from the RMSE regression. The different cases illustrated with the “Eurotate_N” model demonstrated the apropriate practical application of the regression analysis as statistical tool to evaluate its capacity to simulate fruit yield, volumetric soil moisture, evapotranspiration and dry matter in tomato crop under greenhouse. <strong>Conclusion. </strong>The most appropriate statistical method proposed to evaluate a simulation model in tomato was the regression analysis.</p> Freddy Soto-Bravo, María Isabel González-Lutz ##submission.copyrightStatement## Wed, 01 May 2019 00:00:00 -0600 Endophytic bacteria of Capsicum frutescens antagonistic to Fusarium spp. <p>&nbsp;<strong>Introduction. </strong>In the last decades, there has been an increased on the interest of Tabasco Chilli pepper cultivation in Colombia; however, production limitation has been observed due to phytosanitary problems. Species of the&nbsp;genus <em>Fusarium </em>cause root and stem rots with large losses for farmers; whereby, it is important to find alternatives to vascular wilt management caused by <em>Fusarium </em>spp. <strong>Objective. </strong>The objective of this research was to isolate and characterize endophytic foliar bacteria with <em>in vitro </em>antagonistic potential against <em>Fusarium </em>spp. in Tabasco Chili pepper (<em>Capsicum frutescens</em>) plants. <strong>Materials and methods. </strong>In the period between February 2014 and February 2016, the <em>in vitro </em>antagonistic capacity of 68 bacterial endophytes of leaf tissue <em>C. frutescens</em>, from two municipalities of Valle del Cauca, Colombia, was evaluated. The isolated bacteria were confronted with six pathogenic isolates of <em>Fusarium </em>spp. by dual growth method. <strong>Results. </strong>Fifty of the bacterial isolates showed percentages of inhibition against at least one <em>Fusarium </em>isolate, and of these sixteen had percentages of inhibition above 40 %. The morphology, biochemical profile and molecular characterization allowed to determine that the isolates identified as <em>Bacillus subtillis </em>and <em>Pseudomonas aeruginosa </em>showed inhibition averages between 62 and 89%, high averages compared to those previously reported in other studies. In addition, stand out as new findings of bacteria associated with endophytic plant tissue of <em>C. frutescens</em>, in Valle del Cauca, Colombia, the <em>Enterobacter cloacae</em>, <em>Microbacterium arborescens</em>, and <em>Stenotrophomonas maltophilia </em>species. <strong>Conclusion. </strong>These results constitute a potential source for pathogen management and productivity improvement in tabasco chili pepper in Colombia.&nbsp;</p> Martha Lucia Velasco-Belalcázar, Carlos Alberto Hernández-Medina, Eyder Daniel Gómez-López, Celina Torres-González, Paola Andrea Caro-Hernández ##submission.copyrightStatement## Wed, 01 May 2019 00:00:00 -0600 Climate change perceptions and adaptive responses of small-scale farmers in two Guatemalan landscapes <p><strong>Introduction. </strong>The productivity of certain crops such as coffee (<em>Coffea arabica </em>L.), maize (<em>Zea mays</em>) and beans (<em>Phaseolus vulgaris </em>L.) is expected to decline in Central America because of climate change. This will impact regional economies and livelihoods of smallholder farmers relying on these crops for their food security and livelihoods. There is a need to understand how climate change is already impacting smallholder farmers in Guatemala in order to promote adaptation measures that will allow them to face these impacts. <strong>Objective. </strong>The objectives of this study were to characterize two Guatemalan small-scale agricultural systems, describe farmers’ perceptions of climate change and impacts, and document their adaptation efforts. <strong>Materials and methods. </strong>Structured surveys were carried out in households growing coffee or basic grains in Acatenango and Chiquimula landscapes, two climate change vulnerable landscapes, between June and July 2014. The research was based on farmers’ perceptions of changes in temperature and rainfall, the impacts related to these changes, and the adaptation actions implemented in response to perceived changes. <strong>Results. </strong>Results indicated that 95% of farmers perceived changes in climate, and 81% of them considered these changes to have negatively affected their production. Only 41% of farmers had implemented measures to adapt to these changes, mainly those farmers growing coffee. The implemented adaptation measures differed between landscapes , crops, and usefulness against perceived change with tree planting being the most common adaptation practice to buffer against temperature increases. <strong>Conclusion. </strong>In order to improve the adaptive response ofsmallholder farmers and to promote the use of practices that increase resilience, it is neecessaryto provide more technical, financial and political support to facilitate the adaptation of small farmers facing climate change.&nbsp;</p> Bárbara Viguera, Francisco Alpízar, Celia A. Harvey, M. Ruth Martínez-Rodríguez, Milagro Saborío-Rodríguez, Lucía Contreras ##submission.copyrightStatement## Wed, 01 May 2019 00:00:00 -0600 Climate change perceptions and adaptive responses of small-scale coffee farmers in Costa Rica <p><strong>Introduction. </strong>Climate change will affect the distribution, productivity and profitability of coffee production in Central America, negatively impacting national economies and small farmer livelihoods. There is a need to understand how climate change affects small coffee farmers in the region in order to promote measures that allow them to cope with and adapt to these changes. <strong>Objective. </strong>The objective of this study was to describe Costa Rican small-scale coffee systems in two vulnerable agricultural landscapesand explorethe adaptation efforts that coffee farmers have implemented in these two coffee systems. <strong>Materials and methods. </strong>Structured surveys were conducted with coffee-producing households in two highly vulnerable landscapes, Turrialba and Los Santos, in Costa Rica, from March-May 2014. The study was based on farmers’ perceptions of changes in temperature and rain, reported impacts of these changes and the adaptation actions implemented at farm level. <strong>Results. </strong>Ninety-eight percentof farmers perceived changes in local climate and most of them related these changes with impacts on production (increase in pests and diseases, floweringproblems and other reported impacts). Sixty percentof the surveyed farmers had modified the management of their farms in order to reduce climate change impacts. The most common adaptation measures used by farmers were the planting of trees and the increased use of agrochemical inputs, mostly in response to perceptions of increasing temperatures. <strong>Conclusion. </strong>This study highlights the need for greater technical, financial and policy support to help smallholder coffee farmers implement adaptation practices and become more resilient to climate change.&nbsp;</p> Barbara Viguera, Francisco Alpizar, Celia A. Harvey, M. Ruth Martínez-Rodríguez, Milagro Saborío-Rodríguez ##submission.copyrightStatement## Wed, 01 May 2019 00:00:00 -0600 Assessment of counting chambers on boar sperm parameters analyzed by a CASA-Mot system <p><strong>Introduction. </strong>Understanding the variability in sperm kinetic values through different chambers depths, shows the importance to create a standard for quality control methods in the artificial insemination (AI) industry. Objective. The work aimed was to evaluate the spermatozoa kinetic parameters based on different depths of the visualization chamber by means of a commercial system of computer-assisted sperm analysis, CASA-Mot. <strong>Materials and Methods. </strong>Twenty seminal doses of ten pietrain boars were used. The experimental period was from February to July 2017. The Integrated Semen Analyses System (ISAS®v1) with 50 Hz capture frequency was used. ISAS®D4C16 and ISAS®D4C20 counting chambers with a height of 16 and 20 μm respectively and pre-heated to 37 °C were employed. <strong>Results. </strong>Higher values (p&lt;0.05) were found for all kinetic parameters when the height of the counting chamber was 20 μm. The zone effects within the counting chamber were constant between the two heights, and the variations observed in the kinetic parameters were due to a random effect of the boar. When analyzing the zone effect within the counting chamber, the first three fields of analysis showed higher curvilinear and rectilinear velocity (p&lt;0.05) than the following fields, which is attributed to the presence of passive movement (drifting). <strong>Conclusion. </strong>The greater amplitude and volume capacity within the counting chamber (20 μm versus 16 μm), could promote the unrestricted movement of the cells, which would explain the increase in the kinetic values as the chamber height increased. Studies on the technical conditions of seminal analysis should be continued in order to standardize valuation methods with CASA systems.&nbsp;</p> Anthony Valverde, Mónica Madrigal-Valverde ##submission.copyrightStatement## Wed, 01 May 2019 00:00:00 -0600 Extraction of apitoxin with an electric collector in Irapuato, Guanajuato, Mexico <p><strong>Introduction. </strong>The toxin (apitoxin) produced by <em>Apis mellifera </em>bees, is a product with important expectations in the medical industry, due to the therapeutic use in various diseases. <strong>Objetive. </strong>The objective of the present study was to estimate the annual production potential of apitoxin, collected through an automated equipment operating with electrical impulses of 10 s of duration and a voltage of 12 v. <strong>Materials and methods. </strong>Five beehives were used from a beekeeping farm located in Irapuato, Guanajuato, Mexico, where the apitoxin was harvested from August 2016 to June 2017, at biweekly intervals for a period of 20 min at a time, suspending the collection in those periods with abundant flows of nectar, to not affect the production of honey. <strong>Results. </strong>According to the conditions in which&nbsp;this study was developed, the average (± standard deviation) per harvest with biweekly extraction was 52,41±13,83 mg.hive-1, production that was increased to 62,48±1,37 mg.hive-1, considering only colonies with low levels of <em>Varroa destructor </em>infestation. <strong>Conclusion. </strong>The apicultural region where this research was developed, presented potential for the production of apitoxin, being proposed as an additional apicultural product that allows increasing the profitability of the apiary.&nbsp;</p> Carlos Manuel Bucio-Villalobos, Oscar Alejandro Martínez-Jaime ##submission.copyrightStatement## Wed, 01 May 2019 00:00:00 -0600 Validation and determination of equations prediction weight for Ibero-American horses in Costa Rica <p><strong>Introduction. </strong>A limitation in production systems is the weighing of animal, an activity that is performed empirically or with the use of weight estimation tapes which generate overestimates. <strong>Objective. </strong>The objective was&nbsp;to validate fourteen weigh predictive equations in Ibero-American horses, and develop the breed’s own equations for Costa Rica. <strong>Material and methods. </strong>The investigation was carried out between the months of September 2016 and March 2017. Allometrics measurements of weight (kg), length (cm), height at the withers (cm), thoracic perimeter (cm), umbilical perimeter (cm), and age (months) of 152 animals (male and female) registered in the Asociación Centroamericana de Criadores de Caballos de raza iberoamericana, were taken. As a result on the analysis of the information, a growth curve was developed for males (y= 94.54 ln(X) 6 47.14; R2=0.858) and females (y=82.09 ln(x)+86.81; R2=0.744). <strong>Results. </strong>From the equations evaluated, it was determined that twelve allowed to predict the weight of the animal when it is a colt (p&lt;0.05), five when it is considered young (p&lt;0.05), six when it is in the process of dressage (p&lt;0.05), and six it when it is adult (p&lt;0.05).According to the equation used, weight overestimates of animals between 29.84kg and 168.17kg live weight were determined. Similarly, the developed equations make use of the body measurements and age of the animals, with overestimates of weight between 0.67 and 2.17 kg per animal, which allowed having a better weight prediction and thus improving the determination of the nutritional requirements, dosages of veterinary products, and the handling of the animals. <strong>Conclusion. </strong>Two equations were generated to estimate the weight of the Ibero-American horses, as well as discarding the equations available in the literature, which did not allow an estimation of the weight according to the productive stage of the animal.</p> Grethel Solano-Mora, Rodolfo WingChing-Jones ##submission.copyrightStatement## Wed, 01 May 2019 00:00:00 -0600 Inhibition of mycelial growth of fungi associated with anthracnose in yam (Dioscorea alata) <p><strong>Introduction. </strong>Yam is a tuber affected by a large number of organisms such as viruses, bacteria and fungi, being <em>Colletotrichum</em>, which causes anthracnose, the most important. <strong>Objective. </strong>The objective of the present research was to determine, through an <em>in vitro </em>test, the inhibition exerted by commercial fungicides on the mycelial growth of seven fungal isolations that had been obtained from foliar lesions in yam. <strong>Materials and methods. </strong>The study was carried out at the Instituto Tecnológico de Costa Rica, in the period between October 2016 and June 2017. Ten fungicides —azoxystrobin, benomyl, benzotiazol, carbendazine, chlorothalonil, mancozeb, mancozeb + copper oxychloride, methylthiophanate, propiconazole, and propineb— were evaluated at different concentrations, on five isolates of <em>Colletotrichum</em>, one of <em>Bipolaris </em>and one of <em>Mycoleptodiscus</em>. With this purpose, two tests were performed; in the first, the growth of the isolates in PDA was analyzed in five different concentrations of each fungicide. The results obtained were subsequently used in the second test to calculate the percentage of inhibition of mycelial growth (PICM) of each isolation. <strong>Results. </strong>The results indicate that, in the concentrations used and with the fungal isolates studied, no treatment reached 100 % inhibition. Propineb was the most effective fungicide on the fungus <em>Mycoleptodiscus </em>sp., with a PICM of 64.51, carbendazim had a similar behavior on <em>Colletotrichum truncatum </em>with a PICM of 43.83, and propiconazole had it on <em>Colletotrichum gloeosporioides </em>with a PICM of 49.79. Azoxystrobin was not effective at any concentration on any isolation. <strong>Conclusion. </strong>The results obtained suggest that the pathogens associated with anthracnose in Costa Rican yam plantations could be developing resistance to fungicides.&nbsp;</p> Cinthia Arce-Araya, Ingrid Varela-Benavides, Sergio Torres-Portuguez ##submission.copyrightStatement## Wed, 01 May 2019 00:00:00 -0600 Effectiveness of arbuscular mycorrhizal fungi inoculated on Canavalia ensiformis L. in Calcaric Histosol soils <p><strong>Introduction. </strong>In recent years, significant results have been obtained in Cuba in the joint management of efficient strains of arbuscular mycorrhizal fungi (AMF) and <em>Canavalia ensiformis </em>L., in different types of soils. However, there are no reports about the effectiveness of strains of AMF in Calcaric Histosol soils, which are highly represented in the central and eastern areas of the country. <strong>Objective. </strong>The objective of this research was to compare the effectiveness of four AMF strains inoculated in <em>C. ensiformis </em>seeds in in Calcaric Histosol soils. <strong>Materials and methods. </strong>Plants through seed coatings inoculated and a non-inoculated control were evaluated; <em>C. ensiformis </em>L. was used as plant host in a complete randomized design with four repetitions per treatment during two consecutive years. Sixty days after <em>C. ensiformis </em>seeding, the biomass production; N, P and K contents; percentage of total mycorrhizal colonization; and the reproduction of mycorrhizal spores were evaluated. <strong>Results. </strong>For all variables, there was a positive and differentiated response between the different strains, and the highest values (p≤0.05) were obtained with the inoculation of <em>Rhizoglomus intraradices </em>/ INCAM-11. The high amounts of spores produced by the inoculation with <em>R. intraradices </em>/ INCAM-11 were indicative of to the possibilities of using Jackbean as a way to introduce efficient strains in this edaphic condition. <strong>Conclusion. </strong>The results obtained allow to include Calcaric Histosol soils, with pH&gt;7.5, in the group of soils in which <em>R. intraradices </em>/ INCAM-11 behaves as an efficient strain.</p> jaime Enrique Simó-González, Ramón Rivera-Espinosa, Luis Alberto Ruiz-Martínez, Geysi Díaz-Roche, Michel Ruiz-Sánchez ##submission.copyrightStatement## Wed, 01 May 2019 00:00:00 -0600 Structure and impact of taxonomic diversity on cocoa of Soconusco, Chiapas, México <p><strong>Introduction. </strong>The cultivation of cocoa in Mexico is an exportable item that guarantees the subsistence of thousand families. The state of Chiapas is one of the most important producers; however, even the yields are low due to different factors. These can be minimized with appropriate agroforestry design that responds to the requirements of the crop. <strong>Objective. </strong>The objective of this work was to evaluate the structure of taxonomic diversity in cocoa plantations, and analyze its influence on the crop in Soconusco, Chiapas, Mexico. <strong>Materials and methods. </strong>The research was carried out from January to May 2018 in thirteen municipalities: Cacahoatán, Tuxtla Chico, Frontera Hidalgo, Metapa, Suchiate, Tapachula, Huixtla, Tuzantán, Huehuetán, Escuintla, Acacoyagua, Acapetagua and Mapastepec. Representative plots of 50x20 m were established, in which the present species were counted and classified taxonomically. The diameter at chest height (DAP) and total height (Ht) were evaluated. An analysis was made to define the strata (lower, middle and upper) in the vertical structure of the agroforestry system, and considerations were made about the influence of the results on the cocoa. <strong>Results. </strong>35 tree species were determined with 199 plants belonging to twenty-two families. The most important species were <em>Cordia alliodora</em>, <em>Tabebuia rosea </em>and <em>Pouteria sapota</em>. <strong>Conclusion. </strong>The shade tree species registered in the vertical and horizontal structure of the agroforestry cocoa systems of the Soconusco region, Chiapas, generated an excess of shade equivalent to an average in the region of 14.16 % of the total illumination, and the consequent competition for light among the species studied, including cocoa cultivation.&nbsp;</p> Gicli Manuel Suarez-Venero, Carlos Hugo Avendaño-Arrazate, Pablo Amin Ruiz-Cruz, Paulina Estrada-de-los-Santos ##submission.copyrightStatement## Wed, 01 May 2019 00:00:00 -0600 Absorption of nutrients in rice in an inceptisol soil under irrigation in Coclé, Panamá <p><strong>Introduction. </strong>Nutrients content in rice (<em>Oryza sativa</em>) plant during its different phenological stages is affected by nutrients content in soil, dose and fertilizers source, varieties, and implemented cropping systems. <strong>Objective. </strong>The objective of this research was to determine the extraction of macro and micro nutrients from two rice varieties in each phenological stage, in an Inceptisol soil under irrigated conditions. <strong>Materials and methods. </strong>The study was developed in Penonome, Cocle, Panama in the 2015 and 2016 agricultural cycles. The IDIAP FL 106-11 and IDIAP FL 137-11 varieties were used. Plants samples were taken every fifteen days since germination with four repetitions&nbsp;using a frame of 0.25 m X 0.25 m. A regression analysis was performed to determine the nutrients extraction per crop stage. <strong>Results. </strong>IDIAP FL 106-11 variety yielded 31.7 t.ha-1 of dry matter and the IDIAP FL 137-11 about 26.9 t.ha-1; grain yield was similar with 5.5 t.ha-1 and 5.3 t.ha-1, respectively. There were significant differences about nutrients extraction between the different phenological stages in both varieties (p&lt;0.001). IDIAP FL 106-11 extracts more N, K, Mn, Zn, and Cu than IDIAP FL 137-11, which absorbed more P, Ca, Mg, and Fe. Nutrients importance order, based on extracted quantity, was K&gt;N&gt;Ca&gt;P&gt;Mg&gt;Mn&gt;Fe&gt;Zn&gt;Cu. In a study conditions, IDIAP FL 106-11 requires greater amounts of nutrients to produce a ton of grain than IDIAP FL 137-11. <strong>Conclusion. </strong>Each variety presented nutrient different absorption implying an adjustment in the fertilization plans that are currently handled.&nbsp;</p> Luis Alberto Barahona-Amores, José Ezequiel Villarreal-Núñez, Walker González-Carrasco, Evelyn Itzel Quiro-Mclntire ##submission.copyrightStatement## Wed, 01 May 2019 00:00:00 -0600 Evaluation of two-sex determining systems in papaya plants (Carica papaya) Pococí hybrid <p><strong>Introduction. </strong>Papaya growers prefer hermaphrodite plants for their fruit characteristics, but they must wait until the beginning of flowering to identify and select plants. Currently, it is possible to determine the sex of papaya plants&nbsp;in the seedling stage using molecular markers. <strong>Objective. </strong>The objective of this research was to compare the vegetative and productive growth of papaya plants Pococí hybrid, sexed by two systems: conventional (CS) and molecular (MS). <strong>Materials and methods. </strong>For the conventional sexing system the traditional method of farmers sowing was used, which consists of planting three seedlings and determine the sex by visual inspection, eliminate female plants and leave a hermaphrodite plant per sowing site. In the molecular sexing system, sex was determined in the seedbed based on the molecular markers, and then a hermaphrodite plant was established per planting site. The trial was conducted on the farm of a papaya producer located in the Rita de Guapiles, Limon province, Costa Rica, between March and October of 2010. <strong>Results. </strong>No significant differences were observed for plant height and stem diameter with both sexing systems, indicating that the period of initial competition to which the seedlings were subjected in the SC system did not affect vegetative development. For the productive variables, significant differences were found between both sexing systems. SM plants presented flowering and fruit set at an earlier age. The total production and fruit quality were similar between both treatments. <strong>Conclusion. </strong>The sex-determining procedure did not influence the growth, development, and yield of the plants under this study condition, which indicates the possibility of using SM plants for cultivation of the Pococí hybrid.&nbsp;</p> Walter Vicente Barrantes-Santamaría, Carlos Loría-Quirós, Luis Gómez-Alpízar ##submission.copyrightStatement## Wed, 01 May 2019 00:00:00 -0600 Phenotypic stability of genotypes Lolium sp. in the high tropic of Nariño, Colombia <p><strong>Introduction. </strong>The species of the Lolium genus represent an important component in the bovine feeding in several regions of Colombia, however, in the high tropic of Nariño, one of the main dairy basins of the country, there is little knowledge about the performance of the cultivars managed by the producers; there are no stability studies that allow us to know which of the cultivars offered in the market behave better in a specific location, which affects the&nbsp;farmers’ economy. <strong>Objective. </strong>The objective of this research was to determine the phenotypic stability of the yield of green forage (RFV) and dry matter (RMS) in ryegrass, in the dairy basin of the high tropic of Nariño. <strong>Materials and methods. </strong>Between 2016 and 2017, ten ryegrass genotypes were evaluated in Pasto, Cumbal, and Sapuyes. The experiments were established under a randomized complete block design with four repetitions. For the analysis of adaptability and stability of RFV and RMS, the model proposed by Eberhart and Russell, and the analysis of principal additives effects and multiplicative interactions (AMMI) were used. <strong>Results. </strong>The Tetralite II, Bóxer, Bestfor Plus, and Aubade genotypes had the highest green forage yields (7.52-8.34 t.ha.cut-1) and dry matter (1.29-1.37 t.ha.cut-1) in the three environments studied. With the Eberhart and Russell model, for RFV, these genotypes were classified as the best response in favorable and predictable environments, and by RMS they were also predictable, but Aubade and Bestfor Plus were classified with good response in all environments, and Bóxer and Tetralite II, with better response only in favorable environments. <strong>Conclusion. </strong>The AMMI model allowed to identify the Pasto municipality as the most favorable environment, and the Bóxer and Tetralite II genotypes as those with the best performing in this environment.&nbsp;</p> Máryory Maricela Cadena-Guerrero, Mario Augusto García-Dávila, Edwin Castro ##submission.copyrightStatement## Wed, 01 May 2019 00:00:00 -0600 Allometric correlation in Hylocereus costaricensis y H. monocanthus (pitahaya): a tool to quantify growth <p><strong>Introduction. </strong>Dragon fruit plant (Pitahaya) is a cactacea family plant, it grows naturally in dead trees or stakes in seasonally dry areas, and it has an out-of-order architecture in the growth for being and epiphyte and hemiepiphyte plant, its green steams are structures that play the role of steam-leaf. Currently, in Costa Rica, there is little information on the growth and quantification of dragon fruit morphometry. <strong>Objective. </strong>The objective of this work was to relate non-destructive variables with destructive variables to develop a useful tool for the use growth projections in dragon fruit in Costa Rica. <strong>Materials and methods. </strong>The study was carried from 2016 to 2017. Stems from plants sown in soil and substrates were randomly sampled. The following were evaluated: longitude, basal, medium and apical thickness (A), leaf area (indirect method) and biomass (fresh weight, dry weight and moisture percentaje) for each stem. A database was built and it’s linear regressions were calculated, and the site variability (clay soil, loam soil and nurseries) was compared with Kruskal Wallis (α=0.05) test. <strong>Results. </strong>Linear regressions showed highly significant correlation (r2= 0.97) with the significative correlation (r2=0.85) with dry weight and that the longitude by width presented a foliar area. Two mathematical criteria were determined, to generate better fit equation for more accurate projections of variables. The weight showed significative differences (α=0.01) according to stem growth sites. <strong>Conclusion. </strong>Linear regression showed high precision (r2= 0.85) in some growth variables in dragon fruit steams, wich could be an effective tool to generate crop growth quantification.&nbsp;</p> Gabriel Garbanzo-León, Greddin Chavarría-Pérez, Edgar V. Vega-Villalobos ##submission.copyrightStatement## Wed, 01 May 2019 00:00:00 -0600 Lipid profile in milk of grazing cows in the colombian dry tropics <p><strong>Introduction. </strong>The composition of fat in bovine milk has relevance in human health, where polyunsaturated fatty acids such as conjugated linoleic acid (ALC c9 t11) have positive effects (anticarcinogenic, antidiabetogenic). There are investigations regarding the effect of bovine feeding on milk quality in temperate zones (above 2200 m.a.s.l.), but few in the Colombian low tropics (below 1500 m.a.s.l.). <strong>Objetive. </strong>The objective of this work was to evaluate the effect of three grasses Mulato II, Tanzania, and Toledo on production, composition, and lipid panel in the milk of Gyr x Brown Swiss cows in the first-second-and three-third of lactation. <strong>Materials and methods</strong>. The study was conducted from May to June 2013 in the city council of San Diego, Cesar, Colombia. Two groups of nine animals were selected (three cows in each third lactation stage), and one cow was assigned to each grass in a replicated 3 x 3 Latin Square design. <strong>Results. </strong>Milk production was similar (p&gt;0.05) in evaluated grasses and decreased (p&lt;0.05) as the lactation advanced. The concentration of milk fat and protein was higher (p&lt;0.05) in Tanzania and Mulato II, although in the second-third there was a higher content (p&lt;0.05) of polyunsaturated acids, compared to Toledo. The lactation trimester did not affect (p&gt;0.05) milk composition. There was higher fed (p&lt;0.05) concentration of conjugated linoleic acid and polyunsaturated fatty acids in milk fat in cows fed with Tanzania and Toledo forage. <strong>Conclusion. </strong>Feeding dual-purpose cows with Tanzania and Toledo grasses could have positive effects on human health, due to the healthier lipid panel of the milk produced.&nbsp;</p> José Edwin Mojica-Rodríguez, Edwin Castro-Rincón, Juan Evangelista Carulla-Fornaguera, Carlos Eduardo Lascano-Aguilar ##submission.copyrightStatement## Wed, 01 May 2019 00:00:00 -0600 Frequency and cutting height on Panicum maximum cv Gatton Panic <div class="page" title="Page 1"> <div class="layoutArea"> <div class="column"> <p><strong>Introduction.</strong> Livestock activity is developed in grazing as the main food resource. In central and northern Argentina new planted pastures are being used with higher biomass production and ability to keep forage quality longer. Objective. The objective of this study was to evaluate the production of dry matter (kg MS.ha-1), number of buds, and relation leaf:stem (H:T) of Panicum maximum cv. Gatton panic in two heights, three cutting frequencies, and two sampling periods. <strong>Materials and methods.</strong> The study was developed between April 2011 and May 2012. Two heights (0,15 and 0,30 m) and three cut-off frequencies (30, 45 and 90 d) were evaluated in two periods (90 and 180 d), using a completely randomized design with a factorial arrangement: 2 x 3 x 2. <strong>Results.</strong> Interaction between the variables (A) x height frequency (F) was found. The highest dry matter (MS) production was observed with the lowest height and the highest cutting frequency (0.15 m and 90 d) with 1877.2 kg MS.ha-1. For the number of buds the interaction A x F showed difference (p&lt;0.05) for the combination of 0.30 m and 30 d, while the leaf - stem ratio (H:T) was affected by the interaction A x F. The best H:T ratio was obtained with the intermediate frequency and the higher height. <strong>Conclusion.</strong> The greatest MS production was obtained with the highest cutting frequency, in the shortest time, and with the lowest height. The highest number of buds was obtained with the lowest frequency, the shortest time, and the highest height; in addition the best H:T ratio was obtained with intermediate and low frequency, the shortest time, and the highest cutting heights.</p> </div> </div> </div> Leandro Pablo Schnellmann, Juan José O. Verdoljak, Aldo Bernardis, Juan Carlos Martínez-González, Sonia Patricia Castillo-Rodríguez ##submission.copyrightStatement## Wed, 01 May 2019 00:00:00 -0600 Calibration and validation of Veris MSP3 on two soils in Guanacaste, Costa Rica <p><strong>Introduction. </strong>It is necessary to implement and validate precision agriculture (PA) technologies in tropical regions. <strong>Objective. </strong>The objective of this study was to calibrate and validate Veris MSP3 equipment in two different fields located in Guanacaste, Costa Rica. <strong>Materials and methods. </strong>The data obtained by the sensors integrated into the Veris MSP3 equipment was correlated with laboratory analysis of soil samples with the intent to develop simple or multiple linear&nbsp;regressions to predict soil texture, organic matter, nitrogen in the soil, total cation exchange capacity, and pH, in order to obtain a model that best suits each of the parameters. <strong>Results. </strong>The regressions that resulted with the best models were: i) apparent electrical conductivity (CEa) with soil texture, ii) optic ratio and slope with organic matter, iii) optic ratio with N, iv) CEa with total cation exchange capacity (total CIC), and v) Veris pH with pH in water and KCl. The higher determination coefficient was obtained between CEa and sand percentage with r2 of 0,82. In addition, the r2 for the rest of parameters ranged from 0,28 to 0,82. <strong>Conclusion. </strong>The calibration method used gave reasonably precise correlations (r2≥0,55) for soil texture at depth from 0 to 30 cm and organic matter variables. However, from 30 to 90 cm soil texture, N, total CIC, and pH anoter calibration methodology should be considered because of imprecise correlations (r2≤0,55).</p> Wanderson Novais, José Carlos Rodríguez-Mejías, Johan Perret, Carlomagno Soto, José Eduardo Villalobos, Carol Lucía Fuentes, Karim Abdalla ##submission.copyrightStatement## Wed, 01 May 2019 00:00:00 -0600 Azotobacter chroococcum and Azospirillum lipoferum as biostimulants in Ipomoea batatas Lam. culture <div class="page" title="Page 2"> <div class="layoutArea"> <div class="column"> <p><strong>Introduction.</strong> The excessive use of nitrogen fertilizers in sweet potato crops contributes to the ecosystems contamination; to reduce this effect and improve crop productivity, the incorporation of plant growth promoting rhizobacteria (PGPRs) in the strategies of crop managment constitute a sustainbale tool. <strong>Objective.</strong> The objective of this research was to incorporate the bacterial strains Azotobacter chroococcum IBCR19 and Azospirillum lipoferumIBSC7 in the nitrogen fertilization, and to evaluate their effect on the yield and bromatological composition of sweet potato tuberous roots (Ipomoea batatas Lam). <strong>Materials and methods.</strong> The study was made in the municipality of Corozal (Sucre, Colombia) during the months of June to October of 2017. An experimental area of 840 m2 was used where twenty-four plots with apical cuttings of the 15020078 accession were established, and distributed under a completely randomized design with an increased factorial arrangement (3x2+2). Root dry matter, yield, and bromatological composition of sweet potato roots were evaluated. <strong>Results.</strong> Fresh yield and root dry matter showedsignificant differences (p≤0.05) among the treatments, where the application of A. chroococcum IBCR19 and 75% of nitrogen fertilization reached the highest average values of yield and dry matter of 12.18 t.ha-1 y 2.92 t.ha-1, respectively.Similarly, the protein and ethereal extract concentrations differed significantly (p≤0.05) between the inoculatedtreatments in relation to the absolute control. <strong>Conclusion.</strong> Based on the results obtained, it can be inferred that the inoculation with A. chroococcum IBCR19 reduced the nitrogen fertilization levels by 25% and constitutes a promising strain as a biostimulant.</p> </div> </div> </div> Diana Beatriz Sánchez-López, Jazmín Vanessa Pérez-Pazos, Lily Lorena Luna-Castellanos, Joaquín Alfonso García-Peña, Amaury Aroldo Espitia-Montes ##submission.copyrightStatement## Wed, 01 May 2019 00:00:00 -0600 A look back in time: genetic improvement of coffee through the application of biotechnology <div class="page" title="Page 2"> <div class="layoutArea"> <div class="column"> <p><strong>Introduction.</strong> Coffee (Coffea spp) is one of the most important crops worldwide, providing economic livelihood to millions of people in developing countries. There are more than 130 species of the Coffea genus, but only three species are commercially cultivated: Coffea arabica L. (2n=4x=44), Coffea canephora P. (2n=2x=22), and Coffea liberica L. (2n=2x=22). Which present limitations for their genetic improvement through conventional programs because of their perennial nature and differences in level of ploidy and incompatibility. Additionally, there are important characteristics such as resistance to pests or pathogens, which are not present in the available germplasm.Genetic engineering techniques have been used to solve this barrier, and significant advances have been generatedduring the last decades. <strong>Objective.</strong> The objective of this work was to provide an overview of the methodologies and advances in coffee genetic improvement through time, and ends with perspectives about the use of new technologies that have emerged in recent years. <strong>Development.</strong> The improvement began with the selection by crosses andinterspecific backcrosses, to move to the selection assisted by molecular markers. Subsequently, the culture and fusionof protoplasts was reported, with the disadvantage in the regeneration process. Genetic engineering through physical (electroporation and biolistics), and biological techniques (A. tumefaciens and A. rhizogenes) helped to overcome the limitations of regeneration, although the optimization processes are still laborious, so, new technologies for editing genomes such as CRISPR-Cas9, can solve problems of time and work in the laboratory for the crop. <strong>Conclusion.</strong>The improvement of coffee began three decades ago and has progressed mainly since the beginning of transgenictechnologies, and with the new techniques of specific modification of genes, the crop will benefit in the coming years.</p> </div> </div> </div> Jimmy Villalta-Villalobos, Andrés Gatica-Arias ##submission.copyrightStatement## Wed, 01 May 2019 00:00:00 -0600 Probiotics and their mechanism of action in animal feed <div class="page" title="Page 1"> <div class="layoutArea"> <div class="column"> <p><strong>Introduction.</strong> In the livestock production for commercial purposes, additives are frequently used to increase the effectiveness of nutrients present in the food, its availability, and absorption in the gastrointestinal tract, as well as modulate the intestinal flora of animals and promote their growth and productivity. Antibiotics have been among the most used additives in recent decades animal production worldwide. <strong>Objective.</strong> The aim of this literature review was to describe the use of probiotics as additives in animal nutrition, as an alternative to the use of antibiotics as growth promoters in commercial livestock production. <strong>Development.</strong> This compilation analyzes the current definition of probiotics accepted by the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) it also describres the microorganisms allowed as probiotics in animal nutrition in Costa Rica and the United States. Additionally,the main mechanisms of action in productive animals are explained. Probiotics are living organisms that when administered in adequate amounts confer a benefit to the health of the host, this effect must be proven and overcome the effect given by the placebo. The microorganisms used as probiotics in animal nutrition should not be pathogenic for animals, and should be resistant to the processes of food and feed elaboration. It has been reported that the benefit of probiotics in productive animals is mainly due to the fact that these promote the microbial balance in the digestive tract and the modulation of the immune system, resulting in an increase in the digestion and absorption of nutrients and decreasing the incidence of infectious diseases. <strong>Conclusion.</strong> The use of different probiotics in productive animals to increase productivity and animal health, has been proven in different commercial livestock species and its use is promising as a growth promoter instead of antibiotics.</p> </div> </div> </div> Andrea Molina ##submission.copyrightStatement## Wed, 01 May 2019 00:00:00 -0600 Mealybugs (Hemiptera: Pseudococcidae) and their impact on the Musaceae crop <p class="Resumen"><strong><span class="CharOverride-2">Introduction. </span></strong>The mealybug (Hemiptera: Pseudococcidae) is known for its importance at commercial level, it can affect all stages of development on agricultural crops and cause harvest losses.&nbsp;<strong><span class="CharOverride-2">Objective.</span></strong> The aim of this bibliographical review was to synthesize the main aspects related to taxonomy, biology, damage to host plants, geographic distribution and the impact of the mealybug on Musaceae.&nbsp;<strong><span class="CharOverride-2">Development. </span></strong>Most of the generes have a wide geographical distribution. Can be transported during the shipment of the crop to be exported, slipping away from the phytosanitary regulations, with a high risk of introduction as a pest of economically important crops to other countries. To identify the individual at species level, adult females are used, males and nymphs lack of the necessary characteristics for their classification. Within the Pseudococcidae family, <span class="CharOverride-3">Pseudococcus elisae</span> (Borchsenius) stands out as one of the first species identified in the Musaceae crop. The State Phytosanitary Service &nbsp;of the Ministry of Agriculture and Livestock &nbsp;from Costa Rica, declared by the end of 2013 and the beginning of 2014, a phytosanitary emergency due to the increase of <span class="CharOverride-3">P. elisae</span>, however there are records of up to twenty-four species as vectors of banana streak virus, belonging to fourteen genera with different origins. The feeding period where the transmission, occurs, is associated with the mealybug species and the environmental conditions. At the same time that they inject toxins, the sugary liquids are secreted from the phloem of the plant, which serves as a means for the establishment of fungi on the surface of the attacked organsthat cause several physiological damages to the crop. <strong><span class="CharOverride-2">Conclusion.</span></strong> For this reason, it is of great importance to consider related aspects to taxonomy, biology, host plants and the geographical distribution of the different species of the mealybug to develop appropriate strategies that control the pest propagation.</p> <p>&nbsp;</p> Melissa Palma-Jiménez, Mónica Blanco-Meneses, César Guillén-Sánchez ##submission.copyrightStatement## Tue, 01 Jan 2019 00:00:00 -0600 Chlorogenic acids present in coffee: antioxidant and antimicrobial capacity <p><strong><span class="CharOverride-2">Introduction.</span></strong> Chlorogenic acids are present in the different parts of the coffee fruit; they are mainly esters of trans-cinamic acid possessing antioxidant activity, hypoglycemic, antiviral, hepatoprotective and nutraceutical, among others. <span class="CharOverride-2"><strong>Objective.</strong> </span>The objective of this study was to analyze and summarize the information available in the scientific literature concerning the antioxidant and antimicrobial activity present in coffee and its derived processing by-products. <strong><span class="CharOverride-2">Development.</span></strong> Derived products of coffee processing (pulp, mucilage, parchment, “silver skin”), are in many occasions underutilized, even though they possess significant quantities of chlorogenic acids. These by-products are then considered promissory sources of chlorogenic acids which may be useful for pharmaceutical, cosmetic and food industries. These products exhibit important antioxidant and antimicrobial activity especially against Gram positive microorganisms. In Costa Rica, the research focused on the exploitation of the discarded by-products of coffee processing is still incipient, although it could be a suitable alternative for coffee processing industries to give added value to these by-products. <span class="CharOverride-2"><strong>Conclusion.</strong> </span>There is scientific evidence that indicates that both, the coffee beans and its derived processing by-products have phenolic compound that benefit human health.</p> Evelyn Carolina Chaves-Ulate, Patricia Esquivel-Rodíguez ##submission.copyrightStatement## Tue, 01 Jan 2019 00:00:00 -0600 Polyethylene glicol 8000 to identify corn tolerant to water stress during germination <p><strong><span class="CharOverride-2">Introduction. </span></strong>The availability of water for agricultural production is essential. The production of corn, subject to the rainy season, in Mexico exceeds 70%. In the agricultural regions of the Yucatan, productions are reported in conditions of low rainfall or very erratic precipitation, which can cause total losses. A critical condition for the establishment of a crop is to have the necessary humidity that allows germination. <strong><span class="CharOverride-2">Objective.</span> </strong>The aim of the present work was to evaluate maize materials under simulated water stress conditions through osmotic solutions in order to identify those that can tolerate these conditions.<strong><span class="CharOverride-2"> Materials and methods. </span></strong>The study was carried out in the Campo Experimental Mococha of the Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias, during 2017; including the germination and establishment phase. Twenty-five maize materials were used under a completely random design with a factorial arrangement. A germination test was performed under simulated two stress conditions by means of the PEG 8000 (-0.50 and -0,75 MPa), also a control (0 MPa) was used. Four replicates of twenty-five seeds were done. The seeds were exposed for 24 h to the PEG 8000, subsequent, irrigations were done with distilled water. The seeds were exposed for 24 h to PEG 8000, later, the seeds were irrigated with distilled water. The germinated seeds were counted on the seventh day and reported as germination percentage. In a sample, of ten seedlings of each repetition, length and weight were measured, separately, from the aerial part and the root.<strong><span class="CharOverride-2"> Results. </span></strong>From the evaluated materials, the hybrids H-563, H-565 and H-568 endured a stress of -0.5 MPa, and the H-520, H-567 and HEV3B hybrids presented germination with -0.75 MPa and stood out in all the variables evaluated. <strong><span class="CharOverride-2">Conclusion. </span></strong>It is possible to identify materials that will tolerate stress conditions during the germination stage.</p> Maria Alma Rangel-Fajardo, Noel Gómez-Montiel, Jorge Ismael Tucuch-Haas, Dianelly de la Cruz Basto-Barbudo, Antonio Villalobos-González, Johnny Abraham Buros-Díaz ##submission.copyrightStatement## Tue, 01 Jan 2019 00:00:00 -0600 Genetic analysis of tropical Beauveria and Metarhizium associated with sugar cane insects <p class="Resumen"><strong><span class="CharOverride-4">Introduction.</span></strong> Entomopathogenic fungi are used as biopesticides to control invertebrate pests in agriculture. The generation of genetic information and its geographic relationships are important for diversity studies and for the protection of biological resources. <strong><span class="CharOverride-4">Objective. </span></strong>The aim of this study was to analyze the allelic diversity and the genetic and geographic relationships of several isolates of <span class="CharOverride-5">Beauveria</span> and <span class="CharOverride-5">Metarhizium</span> from Departamento de Investigación y Extensión de la Caña de Azúcar (DIECA) of Liga Agrícola Industrial de la Caña de Azúcar (LAICA). <span class="CharOverride-4"><strong>Materials and methods.</strong></span> This research was performed in DIECA and Universidad Nacional in 2014 and 2015. Fourteen and thirteen isolates of <span class="CharOverride-5">Beauveria</span> and <span class="CharOverride-5">Metarhizium</span>, respectively, were cultured from various Hymenoptera and Coleoptera insects of Costa Rica and Brazil. The isolates were analyzed using primer pairs that amplified simple sequence repeat (SSR) markers; twelve specific to<span class="CharOverride-5"> Beauveria</span> and thirteen specific to<span class="CharOverride-5"> Metarhizium</span>. Geographic and genetic correlation matrices were tested using a Mantel test.<strong> <span class="CharOverride-4">Results</span>.</strong> All <span class="CharOverride-5">Beauveria</span> primer pairs generated products, while only eight of the thirteen <span class="CharOverride-5">Metarhiziu</span>m pairs generated products. Several sets of <span class="CharOverride-5">Beauveria</span> primers were highly informative, but only one of the pairs was moderately informative in<span class="CharOverride-5"> Metarhizium</span>. Five <span class="CharOverride-5">Beauveria </span>primer pairs generated unique genetic profiles in eight of the fourteen isolates (57%). Genetic relationships revealed two major clades among the <span class="CharOverride-5">Beauveria</span> isolates, where one of these clades separated into two smaller groups. <span class="CharOverride-5">Metarhizium</span> isolates were closely related, except for one (Mal12). A linear model explained 26% of the variability of the correlation between the genetic distances and the geographic distances found in <span class="CharOverride-5">Beauveria</span> isolates, however, no relationships were found in <span class="CharOverride-5">Metarhizium</span> isolates. <strong><span class="CharOverride-4">Conclusion. </span></strong>A greater number of markers or different molecular marker technologies would be necessary to distinguish the isolates from the collection. The information in this work is useful for diversity studies and protection of intellectual property. Herein, we also consider search strategies to encounter diverse fungi.</p> <p>&nbsp;</p> Alejandro Vargas-Martínez, José Daniel Salazar-Blanco, Allan González-Herrera, Ramón Molina Bravo ##submission.copyrightStatement## Tue, 01 Jan 2019 00:00:00 -0600 Ecosystem-Based Adaptation Governance for coffee smallholders in Central America <p><span class="CharOverride-3"><strong>Introduction.</strong> </span>Agricultural practices based on good management of ecosystems are promoted as a good adaptation strategy for the productive activities of coffee smallholder farmers in the Central American region. The dissemination of information on innovations, techniques, instruments, etc. between organizations and producers is key to expand and consolidate the use of these practices. <span class="CharOverride-3"><strong>Objective.</strong> </span>The objective of this study was to identify the structure of information-dissemination governance that can help expand and consolidate the use of Ecosystem-based Adaptation (EbA) practices in agriculture. <strong><span class="CharOverride-3">Materials and methods. </span></strong>Three productive landscapes distributed in three countries (Honduras, Guatemala and Costa Rica) were analysed, characterized by predominantly small-scale coffee growing farmers. For each of these landscapes, the actors that exchange information between the national scale and the level of the producers were identified. Interviews were conducted to characterize the information flows and their possible relevance to promote EbA in the productive systems of coffee producers. <strong><span class="CharOverride-3">Results.</span></strong> It was identified both key actors and gaps in the network of organizations that inhibit the transmission of information between scales and sectors. In Costa Rica, the capacity for intermediation of information across sectors and scales is spread between State entities and competitive producer organizations. In Honduras, intermediation capacities are distributed among some civil society organizations that work at local levels closely with producers and governmental organizations that work at the national level. In Guatemala, the intermediation capacities are mainly distributed among governmental, civil society and private organizations, mainly at the national level.<strong> <span class="CharOverride-3">Conclusion.</span></strong>The analysis of networks in these coffee landscapes suggests that although all three countries have a similar institutionalization of the coffee sector, in two the dissemination of information to promote EbA would benefit at intermediate and local scales to promote learning among producers.</p> Raffaele Vignola, Marco Otarola, Francisco Alpizar, Pavel Rivera ##submission.copyrightStatement## Tue, 01 Jan 2019 00:00:00 -0600 Antibiosis of proteins and metabolites of three species of Trichoderma against paraguayan isolates of Macrophomina phaseolina <p class="Resumen"><span class="CharOverride-3">Introduction. </span><span class="CharOverride-4">Macrophomina phaseolina</span> is a necrotrophic fungus that is difficult to control. Biocontrol agents, like the species of the genus <span class="CharOverride-4">Trichoderma</span>, are an alternative for the management of crop diseases caused by this plant-pathogen.<strong><span class="CharOverride-3"> Objective.</span> </strong>The objective of the present work was to determine the antibiosis capacity of <span class="CharOverride-4">Trichoderma</span> <span class="CharOverride-4">arundinaceum</span>, <span class="CharOverride-4">T. brevicompactum</span> and <span class="CharOverride-4">T. harzianum</span>, against two isolates of <span class="CharOverride-4">M. phaseolina</span>. <span class="CharOverride-3"><strong>Materials and methods.</strong> </span>Experiments were carried out from October 2015 to March 2016. Three reference strains of <span class="CharOverride-4">Trichoderma</span> were used: <span class="CharOverride-4">T. arundinaceum</span> (IBT40837), <span class="CharOverride-4">T. brevicompactum</span> (IBT40841) and <span class="CharOverride-4">T. harzianum</span> T34 (CECT2413); and two isolates of <span class="CharOverride-4">M. phaseolina</span> (FCQ6 and FCQ9). Direct confrontation and antibiosis assays were performed, and profiling of proteins and metabolites secreted from <span class="CharOverride-4">Trichoderma</span>. <strong><span class="CharOverride-3">Results.</span></strong>The <span class="CharOverride-4">Trichoderma</span> species significantly inhibited the growth of both <span class="CharOverride-4">M. phaseolina</span> isolates in the direct confrontation assay, cellophane and/or dialysis membrane. In the direct confrontation trial, the greatest inhibition of fungal growth was observed at 96 h. <span class="CharOverride-4">M. phaseolina</span> isolated from sesame (<span class="CharOverride-4">Sesamum indicum</span> L. cultivar Escoba blanca) allowed the evaluation of the antifungal activity of the molecules of high and low molecular weight even up to 120 h. <span class="CharOverride-4">T. arundinaceum</span> maintained 100% growth inhibition in both cellophane and dialysis membrane indicating that low molecular weight metabolites were enough for complete growth inhibition of this <span class="CharOverride-4">M. phaseolina</span> isolate. In contrast, <span class="CharOverride-4">T. brevicompactum</span> and <span class="CharOverride-4">T. harzianum</span> demonstrated the importance of high molecular weight molecules for the maintenance of antifungal activity. In addition, the complexity of secondary metabolites and proteins secreted by the three <span class="CharOverride-4">Trichoderma</span> species was demonstrated. <strong><span class="CharOverride-3">Conclusion. </span></strong>This work is the first description of the antifungal activity of <span class="CharOverride-4">T. arundinaceum</span> and <span class="CharOverride-4">T. brevicompactum</span> against <span class="CharOverride-4">M. phaseolina</span> and also highlights the potential of fungi isolated from native soil as a biological alternative for the control of plant-pathogenic fungi of agricultural importance.</p> <p>&nbsp;</p> Alberto Anastacio Cubilla-Ríos, Dani Daniel Ruíz-Díaz-Mendoza, María Cristina Romero-Rodríguez, María Eugenia Flores-Giubi, Javier Enrique Barúa-Chamorro ##submission.copyrightStatement## Tue, 01 Jan 2019 00:00:00 -0600