Agronomía Mesoamericana 2020-02-25T10:07:30-06:00 Nancy León Ulate Open Journal Systems <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 in Spanish or English language, through the publication of articles, short communications, technical notes and literature reviews, related with food and agriculture sciences from anywhere in the world, emphasized in tropical and subtropical zones, especially from Mesoamerica and the Caribbean.&nbsp;</p> <p>&nbsp;</p> <p><strong>URL OAI-PMH</strong>&nbsp;<a href=""></a></p> Fatty acids composition of genotypes of Jatropha curcas L., in Colombia 2020-01-29T08:24:59-06:00 Luis Fernando Campuzano-Duque Fernando Cardeño-López <p><strong><span class="CharOverride-4">Introduction.</span></strong> <span class="CharOverride-5">Jatropha curcas </span>L. (JC) is a specie with the potential to use its oil as a biofuel and its quality is recognized by the composition of the fatty acids present. <strong><span class="CharOverride-4">Objective.</span> </strong>The objective of this work was the identification and quantification of fatty acids of JC genotypes of the Jatropha Colombia Collection.<strong><span class="CharOverride-4"> Materials and methods. </span></strong>During the years 2012-2014 the experiment was conducted in Espinal-Tolima, Colombia, in a randomized complete block design with fifteen genotypes. The lipid profile of the genotypes was determined by chromatography GC-MS and GC-FID. <strong><span class="CharOverride-4">Results. </span></strong>Ten types of fatty acids were detected in the oil: five saturated (myristic, palmitic, margaric, stearic, arachidic); three monounsaturated (palmitoleic, oleic and eicosenoic), and two polyunsaturated (linoleic and linolenic). The proportion was higher in monounsaturated acids (45.44 %) and polyunsaturated acids (34.18 %) and lower in saturated acids (20.37 %). In the monounsaturated, the oleic predominated (44.62 %); in polyunsaturated linoleic (33.95 %) and in saturated palmitic (12.41 %) and stearic (7.43%). The results found allowed the classification of JC oil as monounsaturated-polyunsaturated (oleic-linoleic), which coincided with what was reported worldwide. <strong><span class="CharOverride-4">Conclusion.</span></strong> Based on the lipid profile, it can be inferred that the oil of the fifteen genotypes evaluated in Colombia is suitable for use as biodiesel.</p> 2020-01-01T00:00:00-06:00 ##submission.copyrightStatement## Detection of the 35S promoter by real-time PCR as a transgenicity indicator in food and Gossypium sp. 2020-01-01T09:54:21-06:00 Karen Oviedo-Bolaños Jaime García-González Stefany Solano-González Claudio Martínez-Debat Carolina Sancho-Blanco Rodolfo Umaña-Castro <p><span class="CharOverride-2"><strong>Introduction.</strong> </span>Genetically modified crops (GMC) are of particular interest due to their impact on the global economy. Therefore, as a general concern, many countries have established some regulations in regards to genetically modified organisms (GMOs). In Costa Rica, the cultivation of GMOs has been practiced since 1991; however, there´s a lack of studies that monitor the execution and compliance with the biosafety regulations. <strong><span class="CharOverride-2">Objective.</span></strong> The objective of the present study was to identify the presence or absence of transgenicity in processed foods for human and animal consumption, as well as in cotton seeds. <span class="CharOverride-2"><strong>Material and methods.</strong> </span>The real-time PCR technique was used to target the 35S promoter sequence, derived from the cauliflower mosaic virus (CaMV), as a marker to detect the presence of transgenes in processed foods for human and animal consumption as well as in wild or cultivated cotton seeds collected nearby a GM cotton farm in May 2017. <span class="CharOverride-2"><strong>Results.</strong> </span>In the analyzed samples there was a high incidence of an 82 bp fragment, corresponding to the 35S promoter sequence, being absent only in organic corn crops and their derivatives (tortillas, corn powder). Results suggest the presence of GMO traces in the Costa Rican food market, additionally it reveals the urgency of implementing adequate labeling for food traceability. Furthermore, the presence of transgenic cotton in the vicinity of a GM cotton farm was identified, suggesting the relevance of surveillance in aspects of biosafety and genetic manipulation of crops. <strong><span class="CharOverride-2">Conclusion. </span></strong>The presence of traces for GMOs in Costa Rican processed food, demonstrates the importance of continuing this monitoring to provide enough elements for a critic discussion about food traceability and potential transgene flow into wild plant material.</p> 2020-01-01T00:00:00-06:00 ##submission.copyrightStatement## Selection criteria in tomato lines with determinate growth habit 2020-01-01T09:54:21-06:00 Esteban Burbano-Erazo Iván Javier Pastrana-Vargas Julián Roberto Mejía-Salazar Franco Alirio Vallejo-Cabrera <p><strong><span class="CharOverride-2">Introduction. </span></strong>The selection of genotypes with a determined growth habit in tomato should contemplate adequate selection criteria to increase the efficiency of the plant breeding program.<strong> <span class="CharOverride-2">Objective. </span></strong>The objective of this research was to estimate selection criteria for “chonto” tomato lines with determined growth habit. <span class="CharOverride-2"><strong>Materials and methods.</strong> </span>The research was developed in the Universidad Nacional de Colombia campus Palmira in 2016, using seven determinate habit growth lines (D) and a control with undetermined habit growth. The heritability in a broad sense (h<span class="CharOverride-3">2</span>g), coefficient of environmental variation, coefficient of genetic variation, selection efficiency, and genetic gain was determined, in morphologic, phenological, quality fruit, fruit shape, and productions parameters using the RELM/BLUP process, from the SELEGEN software. <span class="CharOverride-2"><strong>Results.</strong> </span>Three ranges of h<span class="CharOverride-3">2</span>g were found, the first with values of h<span class="CharOverride-3">2</span>g greater than 0.76, the second between 0.53 and 0.38, and the third with a value less than 0.38. The highest values of h<span class="CharOverride-3">2</span>g were for final height plant with 0.92, height plant to harvest with 0.88, production per plant with 0.83, days to flowering with 0.83, fruit number with 0.82, and days to harvest with 0.82. For genetic gain it was found that the control presented the highest values within the main parameters for final height plant, plant height to harvest, internode length, days to harvest, crop duration, soluble solids content, number of fruits per plant, weight fruit, and plant production; however, in some parameters such as height and phenology for effects of selection by habit of determined growth lower values were better. <span class="CharOverride-2"><strong>Conclusion.</strong> </span>Genetic parameters were evidenced that could be considered as selection criteria for “chonto” tomato lines with determined growth of habit.</p> 2020-01-01T00:00:00-06:00 ##submission.copyrightStatement## The value chain of tree tomato (Solanum betaceum) network in Ecuador 2020-01-01T09:54:23-06:00 Carlos Moreno-Miranda José Isaac Molina Jacqueline Ortiz Carla Peñafiel Raúl Moreno <p><strong> <span class="CharOverride-2">Introduction. </span></strong>The fruit and vegetable sector in Ecuador has shown promising performance in domestic and international markets. Likewise, this sector has faced problems of a social, economic and productive nature in its structure and articulations, which until now require intervention.<strong> <span class="CharOverride-2">Objective. </span></strong>The objective of this study was to analyze in a descriptive way the structure of the tree tomato agro-food network.<strong> <span class="CharOverride-2">Materials and methods. </span></strong>This study was carried out in the provinces of Cotopaxi, Tungurahua, and Chimborazo, Ecuador, during the period between the second quarter of 2016 and the end of 2017. The study applied a systemic methodology aimed at the identification and characterization of stages, agents and activities (primary and support), and the analysis of network governance mechanisms.<strong> <span class="CharOverride-2">Results. </span></strong>The present study showed the main social and productive characteristics, horizontal and vertical sizing; and the proposal of strategies focused on improving their productive performance.<strong> <span class="CharOverride-2">Conclusions. </span></strong>The inclusion of women, the sense of associativity of processors and distributors, and the training of producers in topics related to post-harvest, and good agricultural practices, would significantly improve the economic performance of the network, and also encourage greater participation of the agents involved. The network requires increasing the area allocated to tree tomato cultivation, and the application of greenhouse production systems that increase yields.</p> 2020-01-01T00:00:00-06:00 ##submission.copyrightStatement## Genotype by environment interaction of nine cotton varieties for inter Andean Valleys in Colombia 2020-02-04T12:25:01-06:00 Julian Roberto Mejia-Salazar Carlos Hernando Galeano-Mendoza Esteban Burbano-Erazo Franco Alirio Vallejo-Cabrera Miguel Arango <p><strong><span class="CharOverride-2">Introduction. </span></strong>The use of stability estimators for agronomic characteristics of interest allows understanding the behavior of the genotype in relation to those environmental factors that influence its expression.<span class="CharOverride-2"><strong> Objective.</strong> </span>The objective of this study was to determine genotype by environment (GE) interaction to select cotton varieties with a high seed yield potential and fiber percentage. <span class="CharOverride-2"><strong>Materials and methods.</strong> </span>Nine varieties of transgenic cotton were evaluated in ten localities distributed in two geographically different ecoregions: geographical valleys of the Magdalena and Cauca rivers, by means of random complete block design, between the months of March and August in 2013.<strong><span class="CharOverride-2"> Results.</span> </strong>Cotton seed yield had significant GE interaction, where the three principal components (PC) of the Additive Main Effects and Multiplicative Interaction (AMMI) model were significant (p&lt;0.01), with contributions of 86.9, 6.4, and 3.3 %, respectively. The average yield for the two ecoregions were 3.3 t ha<span class="CharOverride-3">-1</span> (Magdalena river geographical valley) 4.5 t ha<span class="CharOverride-3">-1</span> (Cauca river geographical valley), and for all the evaluated localities in the ecoregions was 3.9 t ha<span class="CharOverride-3">-1</span>. Fiber percentage did not present significative GE interaction and had an average value of 43,34%. The V004 variety showed the best performance with an average yield of 4.9 t ha<span class="CharOverride-3">-1</span>. The varieties with greater adaptability were V001 and V002. A high correlation was observed between the most productive varieties and the most productive environments. <strong><span class="CharOverride-2">Conclusion. </span></strong>The differential behavior between varieties and localities for yield allowed to select varieties for specific environments, or with phenotypic plasticity for several environments.</p> 2020-01-01T00:00:00-06:00 ##submission.copyrightStatement## Productive performance of seven soybeans genotypes in acid soils of the Colombian Orinoquía 2020-01-01T09:54:27-06:00 Samuel Caicedo-Guerrero Yuli Stephani Tibocha-Ardila Luis Fernando Campuzano-Duque Deisy Lorena Flórez-Gómez Jorge Arguelles-Cardenas <p><strong><span class="CharOverride-2">Introduction.</span></strong> In Colombia, soy is one of the main raw materials for the production of feed for animals, demand that was only satisfied in 7% in 2007. In the country, this legume is only produced in the Orinoquía region, as part of the rice-corn-soybean rotation system, and its current commercial production is associated with the Soyica P-34 (Altillanura) and Corpoica Superior 6 (Piedemonte) varieties, which are susceptible to <span class="CharOverride-4">Cercospora sojina</span>, which compromise yield. <strong><span class="CharOverride-2">Objetive.</span> </strong>The objective of this work was to identify soy genotypes with specific adaptation for acid soils oxisoles (Altillanura) and inceptisoles (Piedemonte) with superior grain yield a lower affectation by <span class="CharOverride-4">Cercospora sojina </span>K. Hara.<span class="CharOverride-2"><strong> Materials and methods.</strong> </span>An agronomic evaluation test (PEA) consisting of seven genotypes and two commercial varieties was carried out as controls in six localities located in two sub-regions of the Orinoquía (Altillanura and Piedemonte) during 2011, in a randomized complete block design (DBCA) and four repetitions. The AMMI model and its biplot graph were used to determine the phenotypic stability with the variable grain yield.<strong> <span class="CharOverride-2">Results.</span></strong> The AMMI model explained 81.8% of the genotype x locality interaction with the first two main components, the biplot graph allowed to identify three soy genotypes candidates for variety, two with specific adaptation for the Altillanura (L-062 and L-103), and one for Piedemonte (L-189). These genotypes showed higher grain yields by 8% and a lower affectation by <span class="CharOverride-4">Cercospora sojina</span> in relation to commercial witnesses.<strong> <span class="CharOverride-2">Conclusion.</span></strong> The study allowed three soy genotypes to be selected and registered as commercial varieties in the National Cultivation System of the ICA as Corpoica Guayuriba (L-189), Corpoica Achagua (L-062) and Corpoica Iraca (L-103), according to their specific adaptation by sub-region.</p> 2020-01-01T00:00:00-06:00 ##submission.copyrightStatement## Chemical control of Pogonomyrmex barbatus with corn attractants, in Irapuato, Guanajuato, Mexico 2020-01-01T09:54:20-06:00 Manuel Darío Salas-Araiza Luis Gerardo Lara-´Álvarez Oscar Alejandro Martínez-Jaime José Antonio Díaz-García <p><strong><span class="CharOverride-2">Introduction. </span></strong>Granivorous ants have an economic and ecological impact because they are considered agricultural pests that transport seeds and defoliate cultivated plants.<strong> <span class="CharOverride-2">Objective. </span></strong>The objective of this work was to evaluate the effectiveness of the insecticides Imidacloprid and Novaluron in mixture with three cornflour-based attractants for the control of <span class="CharOverride-11">Pogonomyrmex barbatus</span> in field trials in Irapuato, Guanajuato, Mexico. <strong><span class="CharOverride-2">Materials and methods. </span></strong>This research was conducted from August to November 2014, six tratments were considered, the first three consisted of the mixture of Imidacloprid with cornflour (in finely milled pellet, in milled pellet and without pelletizing), the fourth was Novaluron combined with cornflour in milled pellet, and the last two consisted only of cornflour (in finely milled pellet and without pelletizing), in addition to an absolute control. Individuals counts per minute were performed before (reading at 0 h), and after the application of the treatments (readings at 1, 24, 72, 144, and 240 h) on the outside of three anthills previously selected for this purpose. The analysis of variance of the design was completely randomized according to sub-subdivided stripes with three repetitions, and three factors that were the following: six treatments and the absolute control, six readings over time including the count prior to the application of the treatments and the three anthills. <span class="CharOverride-2"><strong>Results.</strong> </span>There were highly significant statistical differences for the factors: treatments and readings, as well as for the interaction between both. <strong><span class="CharOverride-2">Conclusion</span>.</strong> The treatments with insecticide showed their maximum control at 72 h of its application, the best were the Imidacloprid combined with cornflour in two presentations (in milled pellet and without pelletizing), showing greater effectiveness after 24 h of its application.</p> 2020-01-01T00:00:00-06:00 ##submission.copyrightStatement## Leaf litter and Mycena citricolor inoculum on the American leaf spot epidemic 2020-01-22T11:49:02-06:00 María del Milagro Granados-Montero Jacques Avelino Felipe Arauz-Cavallini Sebastián Castro-Tanzi Natalia Ureña <p><span class="CharOverride-4"><strong>Introduction.</strong> </span>The American leaf spot caused by <span class="CharOverride-5">Mycena citricolor</span> is among the main coffee diseases in Costa Rica. Cyclic attacks occur approximately every fourteen years, related to increased rainfall and inoculum. <strong><span class="CharOverride-4">Objective. </span></strong>Determine the impact of litterfall and primary inoculum on the epidemiology of this disease. <strong><span class="CharOverride-4">Materials and methods. </span></strong>In coffee plantations located in the coffee region of Tarrazú, Costa Rica, the effect of the manual elimination of diseased leaves attached to the plant and the layer of fallen leaves on the American leaf spot epidemic in 2013 and 2014 was assessed. 1200 branches were evaluated in an experiment of divided plots, where the four treatments were obtained by combining the “with and without” levels for each factor. The disease was described by quantifying the number of diseased leaves, lesions, and geminifers. The disease development curves were constructed and the area under the curve was calculated for each variable. The growth and defoliation of coffee plants was calculated.<strong><span class="CharOverride-4"> Results. </span></strong>Based on the disease incidence curve for each treatment in each year, it was determined that the logistic growth of epidemics is the best fit model. The rates of apparent infection (<span class="CharOverride-5">r</span>) were close to 0.04 units per day in 2013 and there was no significant statistical difference in the developed epidemics; but for 2014, where they varied between 0.03 and 0.05. A main effect of the initial inoculum factor was observed on the presence or absence of litterfall. <span class="CharOverride-4"><strong>Conclusion.</strong> </span>Litterfall had no significant effect on the development of the American leaf spot epidemic. This is the first investigation that determines the impact of possible sources of inoculum other than the lesions present in coffee leaves.</p> 2020-01-01T00:00:00-06:00 ##submission.copyrightStatement## Effect of doses of nitrogen in the agronomy and physiology of yellow passion fruit 2020-01-01T09:54:24-06:00 Gustavo Adolfo Rodríguez-Yzquierdo Héctor Eduardo Pradenas-Aguila Carmen Amalia Basso-de-Figuera Marta Barrios-García Rommel Igor León-Pacheco Mercedes Pérez-Macias <p><strong><span class="CharOverride-2">Introduction.</span></strong> The passion fruit plant is important as fresh fruit and in the agroindustry, since its rich in minerals and vitamins and also has potential for domestic consumption and exportation. It has been shown that nitrogen (N) has an influence on fruit yield but there is no information on the optimal N range for maximum production. <strong><span class="CharOverride-2">Objective. </span></strong>Determine the agronomic, physiological, and phenological response, yield and quality of fruit in the cultivation of parchita passion fruit against different doses of nitrogen. <strong><span class="CharOverride-2">Materials and methods. </span></strong>At the Universidad Central de Venezuela, Maracay, Venezuela from April 2014 to march 2015, passion fruit plants were planted in a completely randomized design, six replicates, and six plants per experimental unit, a control (8 g N plant<span class="CharOverride-3">-1</span> (T1)) was evaluated and three doses of N (100 (T2), 200 (T3) and 300 (T4) g plant<span class="CharOverride-3">-1</span>), an a dose of 50 and 300 g plant<span class="CharOverride-3">-1</span> of P<span class="CharOverride-4">2</span>O<span class="CharOverride-4">5</span> and K<span class="CharOverride-4">2</span>O, respectively were evaluated. The evaluated variables were: plant height, number of leaves, photosynthesis rate (A), transpiration (E), stomach conductance (Gs), chlorophyll index (CI), total leaf N content in doses at flowering and fruiting, yield, and fruit quality. <strong><span class="CharOverride-2">Results.</span></strong> Higher doses of N obtained higher values in height, number of leaves, plant precocity, chlorophyll index, net photosynthesis, and foliar N content and lower values in T1. The variables Gs, A and E, did not show significant differences between the treatments. A 55 % yield reduction was obtained in the control treatment compared to the 200 g N plant<span class="CharOverride-3">-1</span> treatment which obtained the highest yield. The average fruit weight was significantly higher in T3. <strong><span class="CharOverride-2">Conclusion.</span></strong> The best nitrogen dose in passion fruit plants was 200 g N plant<span class="CharOverride-3">-1</span>.</p> 2020-01-01T00:00:00-06:00 ##submission.copyrightStatement## Pea production and commercialization in the department of Nariño-Colombia 2020-01-01T09:54:24-06:00 Francisco Javier Torres-Martínez Carlos Nelson Rivadeneira-Miranda Álvaro José Castillo-Marín <p class="Resumen"><strong><span class="CharOverride-2">Introduction.</span> </strong>Traditional agricultural production systems prevail in the southern region of Nariño, however, the area harvested from transitory potato, corn and beans crops has been decreased. To address this problem, pea planting has been strengthened, which is marketed in local and regional markets. The department of Nariño is the first pea producer in Colombia, and in 2018, 9425 ha were reported, with an average yield of 1.19 t ha<span class="CharOverride-3">-1</span>. The farmers in the study area are traditional and show technical limitations of production and commercialization.&nbsp;<strong><span class="CharOverride-2">Objective.</span></strong> The objective of the investigation was to analyze the production and commercialization of peas in the department of Nariño. <strong><span class="CharOverride-2">Materials and methods. </span></strong>The research was descriptive and allowed to establish costs, production volumes, planting times, product characteristics, prices, and marketing during 2012. The target population included producers, municipal intermediaries, wholesalers and retailers, and association leaders located in the pea-producing municipalities. <strong><span class="CharOverride-2">Results. </span></strong>The Andean variety was the most sown, the post-harvest losses were 52 %, the prices vary due to the seasonality of production, and the greater volume of production was channeled through intermediaries. <span class="CharOverride-2"><strong>Conclusions.</strong> </span>The production and commercialization of peas in Nariño presents difficulties that requiere sowing planning to balance production volumes, access development credit, train and organize farmers, and foster strategic alliances to guarantee conditions in the value chain.</p> <p>Keywords: productivity, competitiveness, value generation, production flow.</p> 2020-01-01T00:00:00-06:00 ##submission.copyrightStatement## Herd management information systems to support cattle population research: the VAMPP® case 2020-01-01T09:54:22-06:00 Z. Sánchez-Hernández C. S. Galina-Hidalgo B. Vargas-Leitón J. Rojas-Campos S. Estrada-König <p><strong><span class="CharOverride-2">Introduction. </span></strong>Livestock information systems, besides being indispensable for the daily management of the herd, can serve as a basis for research at the population level.<strong><span class="CharOverride-2"> Objective.</span></strong>The objective of the study was to analyze the role of the VAMPP® system as a source of information for cattle population research over 32 years of evolution in Costa Rica. <strong><span class="CharOverride-2">Materials and methods. </span></strong>A statistical analysis of the system database (VAMPP®) covering the period between 1987 and 2018 was carried out. Trends in the dissemination and adoption of the system were evaluated according to period, area, production system, and herd size. The use of information for the exploration of trends by breed and area was exemplified. The contribution of the system at the academy level and production of scientific literature was quantified.<strong> <span class="CharOverride-2">Results. </span></strong>2285 herds (88.8 % specialized dairy and 11.2 % dual purpose) were counted with an average of 9.4±7.9 years of follow-up in the VAMPP® system. The areas with greater diffusion were the very humid premontane forest (29 %) and very humid tropical forest (25 %). The average size of the herd was 124±255 adult cows. The system contains records on 404 316 cows, mostly of Holstein (36.3 %), Jersey (24.6 %), and Holstein×Jersey (20.9 %) breeds. The database includes information on 1,249,557 calvings, 16,223,260 records of daily milk production, and 443,108 health events, predominantly related to mastitis (35.6 %) and laminitis (14.1 %). The system has been used for the elaboration of at least 74 investigations leading to academic degrees and the production of 71 scientific articles, mainly related to health and genetic issues. <strong><span class="CharOverride-2">Conclusion. </span></strong>The information obtained from the VAMPP® system has allowed a detailed characterization of the productive performance of local dairy cattle.</p> 2020-01-01T00:00:00-06:00 ##submission.copyrightStatement## Productive characteristics of forage crops for supplementation in milk production systems, Nariño, Colombia 2020-01-01T09:54:27-06:00 David Felipe Nieto-Sierra Diego Hernán Meneses-Buitrago Sonia Patricia Morales-Montero Filadelfo Hernández-Oviedo Edwin Castro-Rincón <p class="Resumen"><strong><span class="CharOverride-2">Introduction.</span> </strong>Grass is the main source of feed for ruminants, however, it is not able to provide the nutrients required for its maintenance and productivity, added to this, in the high tropics is very noticeable the seasonality of fodder production, so it is very important to know other feeding alternatives. <strong><span class="CharOverride-2">Objective. </span></strong>Characterize and evaluate ten forage crops as alternative sources of supplementation in milk production systems in the high tropic of Nariño. <strong><span class="CharOverride-2">Materials and methods. </span></strong>The study was carried out in three localities (L1, L2 and L3) representative of the milk basin of the department of Nariño between november 2016 and september 2017. A Random Complete Blocks (BCA) design was used with ten treatments <span class="CharOverride-8">Vicia faba</span> (espadrille), <span class="CharOverride-8">Vicia faba</span> (red), <span class="CharOverride-8">Vicia faba</span> (common), <span class="CharOverride-8">Zea mayz</span> var. ICA V-305, <span class="CharOverride-8">Raphanus sativus</span> L., <span class="CharOverride-8">Beta vulgaris</span>, <span class="CharOverride-8">Avena sativa</span> var. Cayuse, <span class="CharOverride-8">Phalaris</span> sp., <span class="CharOverride-8">Medicago sativa</span> L. var. moapa, <span class="CharOverride-8">Medicago sativa</span> L. var. 10 10, three repetitions and comparison of averages to 0.05. A the time of harvest it was estimated: green forage yield and dry matter, crude protein (PC), neutral detergent fibre (FDN)), acid detergent fibre (FDA), lignin, hemicellulose, dry matter digestibility, and net lactation energy (ENL).<strong><span class="CharOverride-2"> Results.</span></strong> The outstanding species were the bean (the three varieties) and fodder beet for its yield and nutritional quality, which presented values between 7.48 and 20.24 % for PC and 1.14 and 1.49 Mcal kg<span class="CharOverride-5">-1 </span>for ENL. Differences between treatments were presented for each locality, both in productive and nutritional variables. <strong><span class="CharOverride-2">Conclusion.</span> </strong>The forage species with the highest productive yield and nutritional quality were the three bean varieties (red, common, and espadrille) and beet.</p> 2020-01-01T00:00:00-06:00 ##submission.copyrightStatement## Production and quality of Tithonia diversifolia and Sambucus nigra high andean colombian tropic 2020-01-01T09:54:25-06:00 Carolina Guatusmal-Gelpud Laura Dayana Escobar-Pachajoa Diego Hernán Meneses-Buitrago Juan Leonardo Cardona-Iglesias Edwin Castro-Rincón <p><strong><span class="CharOverride-7">Introduction.</span></strong> Among the limitations of the livestock systems of the Colombian high tropic is fodder seasonality. The use of silvopastoral systems could be a strategy to maximize food production and guarantee a supply of nutrients throughout the year. <strong><span class="CharOverride-7">Objective.</span></strong>&nbsp;The objective was to evaluate in <span class="CharOverride-8">Tithonia diversifolia </span>and <span class="CharOverride-8">Sambucus nigra</span> established in a silvopastoral system, the effect of two ages and cutting heights on morphometric, production, and nutritional quality variables. <strong><span class="CharOverride-7">Materials and methods. </span></strong>The study was conducted at the Obonuco Research Center of the Corporacion Colombiana de Investigacion Agropecuaria (AGROSAVIA) (Pasto, Colombia) between January and November 2018. A random block design was established in factorial arrangement with four treatments (two ages and two cutting heights) for each species (T1:60 days*20 cm, T2:60 days*50 cm, T3:80 days*20 cm, T4:80 days*50 cm for <span class="CharOverride-8">T. diversifolia</span> and T1:60 days*30 cm, T2:60 days*50 cm, T3:90 days*30cm, T4:90 days*50 cm for <span class="CharOverride-8">S. nigra</span>). <span class="CharOverride-7"><strong>Results.</strong> </span>The productive variables showed significance in <span class="CharOverride-8">T. diversifolia</span> with higher dry matter (DM kg/bush) at 80 days (30.6 ton ha<span class="CharOverride-5">-1 </span>year<span class="CharOverride-5">-1</span>) and<span class="CharOverride-8"> S. nigra</span> at 90 days (14.4 ton ha<span class="CharOverride-5">-1 </span>year<span class="CharOverride-5">-1</span>); the number of branches and shoots showed higher values in T4 for <span class="CharOverride-8">T. diversifolia </span>(127.10 branches/bush and 819.65 shoots/bush). The nutritional quality of <span class="CharOverride-8">T. diversifolia</span> and <span class="CharOverride-8">S. nigra</span> was significantly higher at 60 days; with 26.73 % and 26.25% crude protein, digestibility of 75.45 %, and 76.28 %, and net lactation energy of 1.58 and 1.60 Mcal kg<span class="CharOverride-5">-1</span> DM, respectively. <strong><span class="CharOverride-7">Conclusion. </span></strong>Biomass production (DM) and resurgence capacity increased when harvested at 80 days in <span class="CharOverride-8">T. diversifolia </span>and 90 days in <span class="CharOverride-8">S. nigra</span>; however, a better nutritional quality was presented at cutting ages of 60 days in the high tropic of Nariño, which evidenced its productive potential for cattle feeding.</p> <p>&nbsp;</p> 2020-01-01T00:00:00-06:00 ##submission.copyrightStatement## Detection of viruses in sweet potato (Ipomoea batatas L.) using qPCR 2020-01-01T09:54:18-06:00 Ingrid Varela-Benavides Carla Trejos-Araya <p><strong><span class="CharOverride-2">Introduction. </span></strong>Sweet potato (<span class="CharOverride-9">Ipomoea batatas</span>) is a root crop very susceptible to viral diseases, which have been associated with crop yield reductions of over 50 %. In the Costa Rican sweet potato plantations the presence of feathery mottle virus (SPFMV), chlorotic stunt virus (SPCSV), and leaf curl virus (SPLCV) have been reported, for the development of adequate control programs, early detection and identification is necessary through the use of sensitive and efficient techniques. <strong><span class="CharOverride-2">Objective.</span> </strong>The objective of this research was to estimate the incidence of SPFMV, SPCSV, and SPLCV in sweet potato plantations using qPCR. <strong><span class="CharOverride-2">Materials and methods. </span></strong>In 2018 foliar tissue samples were collected from eighty plants showing viral symptoms from twenty-five sweet potato plantations distributed in four provinces in Costa Rica. The detection of the three viruses was performed by qPCR with the use of primers and specific hydrolysis probes.<strong><span class="CharOverride-2"> Results. </span></strong>In 92 % of the plantations studied, the presence of virosis was found. The Sweet potato virus disease (SPVD) defined as the combined infection of SPFMV and SPCSV, was the most common viral disease found in all plantations. The plantations located in Sabanilla, El Cacao, and La Guacima were the only ones to present the three viruses studied. The SPLCV virus was only detected in the Limón and Alajuela provinces. <strong><span class="CharOverride-2">Conclusion.</span></strong> It is possible to make an early detection of three of the most frequent sweet potato viruses with the use of qPCR which would contribute to certified seed production programs.</p> <p>&nbsp;</p> 2020-01-01T00:00:00-06:00 ##submission.copyrightStatement## Owner perceptions and management of stereotypic behaviors in four horse breeds in Costa Rica 2020-01-01T09:54:17-06:00 Ana Margarita Arias-Esquivel Carissa L. Wickens Luis A. Villalobos-Villalobos <p><span class="CharOverride-5"><strong>Introduction.</strong> </span>There is little information about stereotypic behaviors in stock-type sport horses and paso horses in Costa Rica. The lack of knowledge regarding stereotypic behaviors, such as cribbing, weaving, and stall walking in horses, affects their welfare. <span class="CharOverride-5"><strong>Objective.</strong> </span>The objective of this study was to monitor the status of stereotypic behaviors and the management reported by owners of horses registered in ACRICAMDE and ASCACOPA in Costa Rica.&nbsp;<strong><span class="CharOverride-5">Materials and methods.</span></strong> A cross-sectional survey was conducted from June through September 2018 in Costa Rica to gather information on horse behavior and current management practices of 552 horses of the breeds Quarter Mille, Appaloosa, American Paint Horses and Costa Rica Paso. The database collected was analyzed using descriptive statistics. <span class="CharOverride-5"><strong>Results.</strong> </span>Almost half of the horse owners (48.4 %) reported stereotypic behaviors, being cribbing the most observed (86.2 %), followed by stall walking (24.1 %) and weaving (13.8 %). Most owners and managers (89.7 %) have tried to stop horses from performing stereotypic behaviors with anti-cribbing collars and by increasing social contact with other horses as the most common approaches. Fewer hours of grazing were reported (2 or less, or none) while there were horses without access to pasture (35.7 %). <strong><span class="CharOverride-5">Conclusion. </span></strong>Horse owners of the breeds included in this study lacked knowledge of stereotypic behaviors. In order to improve management of these behaviors, more training is required to avoid further complexities under the current conditions.</p> 2020-01-01T00:00:00-06:00 ##submission.copyrightStatement## Purines discharge capacity of a liquid manure spreading tank 2020-01-01T09:54:28-06:00 Carlos Boschin-Figueroa Claudio Fabián Vargas-Rodríguez <p><strong><span class="CharOverride-6">Introduction.</span></strong> Liquid manure can improve soil structure and crop productivity, but calibrated equipment is needed to achieve uniform distribution. <strong><span class="CharOverride-6">Objective. </span></strong>The objective of this work was to determine at the field level, the appropriate combinations of operation of a liquid manure distribution tank and a tractor that commands it to achieve a uniform distribution of slurry and diluted manure. <strong><span class="CharOverride-6">Materials and methods.</span> </strong>The experiment was carried out during July 2016 at the Experimental Station “Alfredo Volio Mata” of the Universidad de Costa Rica, in Ochomogo of Cartago, Costa Rica. A plowed and harrowed plot of 5000 m<span class="CharOverride-5">2</span> was used where twenty plastic containers were placed, arranged in two rows separated, 4 m between and within rows. A manure tank coupled to a tractor was used and the treatments were four travel speeds (four low gears of the tractor) and a fixed degree of acceleration (442 rpm). The measured variables were the capacity and volume of discharge per unit area, and the covered area. <span class="CharOverride-6"><strong>Results.</strong> </span>The discharge and dispersion of liquid manure in the different gears was highly significant (p&lt;0.01), being the discharge per unit of area greater in the low gears. The relative discharge between the different working speeds was quantified, and the highest discharge gear (Gear I) equivalent to 52 m<span class="CharOverride-5">3</span> ha<span class="CharOverride-5">-1</span>, was set as 100 %, in gear II the relative discharge was 65 % compared to the first. In gears III and IV, the volumes were 24 and 17 m<span class="CharOverride-5">3</span> ha<span class="CharOverride-5">-1</span> respectively. <strong><span class="CharOverride-6">Conclusion. </span></strong>The low gears distributed more material per m<span class="CharOverride-5">2</span> favorable in more demanding crops, while with higher marches more area can be covered with less material.</p> 2020-01-01T00:00:00-06:00 ##submission.copyrightStatement## Fusarium wilt by tropical race 4: Current status and presence in the American continent 2020-01-01T09:54:29-06:00 Gustavo Enrique Martínez-Solórzano Juan C. Rey-Brina Rafael E. Pargas-Pichardo Edwuar Enrique Manzanilla <p class="Resumen"><strong><span class="CharOverride-2">Introduction.</span> </strong>Fusarium wilt, caused by the fungus <span class="CharOverride-6">Fusarium oxysporum</span> f. sp. <span class="CharOverride-6">cubense</span>, tropical race 4, is considered the most lethal disease of the musaceae because it can survive on the ground for more than twenty years, without effective control. <strong><span class="CharOverride-2">Objective. </span></strong>Review the current status and significant features of this disease and indicate the potential impact risk in Latin America and the Caribbean countries in the face of its recent report in Colombia. <strong><span class="CharOverride-2">Developing.</span></strong> It has several races: race 1 attacks clones of the Silk (<span class="CharOverride-6">Musa</span> AAB) and Gros Michel (<span class="CharOverride-6">Musa</span> AAA) subgroups and was responsible for the loss of the world banana market in 1958, dominated by the latter, being replaced by Cavendish clones (<span class="CharOverride-6">Musa</span> AAA). Race 2 attacks clones of the Bluggoe subgroup (<span class="CharOverride-6">Musa</span> ABB); and race 4, through its tropical and subtropical variants, attacks all Cavendish clones, and those susceptible to race 1 and race 2. There are no natural clones that can replace the current ones. Tropical race 4 (R4T), has spread in different continents, causing multimillion dollar losses, with extreme limitations for its eradication, and recently is a cause for concern in Latin American and Caribbean (LAC) countries, due to its recent report in the Colombian Guajira. <strong><span class="CharOverride-2">Conclusion. </span></strong>The deficient control, and ignorance of thr traits of the pathogen and the disease, make necessary the development of research for its early diagnosis, management strategies, education measures, and / or promotion of contingency plans. Recently it was detected in Colombia, which implies high risk for the rest of the countries of the LAC region (with emphasis on Ecuador, Panama, and Venezuela), due to the constant flow of people (including tourists) and commercial transactions, being necessary in a way it is imperative to review the risk analysis in this new scenario.</p> 2019-12-11T00:00:00-06:00 ##submission.copyrightStatement## Climatic conditions and jersey cattle dairy production on two altitudinal levels 2020-01-01T09:54:29-06:00 Juan Federico Conejo-Morales Rodolfo WingChing-Jones <p class="Resumen"><strong><span class="CharOverride-2">Introduction.</span></strong> Precipitation, temperature, radiation, and relative humidity vary according to height, this causes the presence of microclimates that affect the productivity of the animals.<strong><span class="CharOverride-2"> Objective. </span></strong>Associate the climatic conditions present in the productive systems with dairy production of a pure Jersey herd in two altitudinal floors of the province of Cartago, Costa Rica. <strong><span class="CharOverride-2">Materials and methods. </span></strong>In retrospect, during the year 2016, the productive information of two dairy farms, located at 660 and 1800 m.a.s.l. was evaluated. From the first farm, the records of 61 animals in a twelve-year period (12,083 data) were analyzed; while in the second, the lactations of 387 animals in a five-year period (13,820 records) were analyzed. Observations included: identification of the cow, day of generation of the record, month, year, daily milk production, lactation days, calving number, animal age, temperature, precipitation, solar radiation and average relative humidity. <strong><span class="CharOverride-2">Results.</span></strong> The lactation days, the lactation number (3-5), the age of the animal (3.7 to 5.8 years), and the calving number affected the daily milk production on both farms (p&lt;0.001). At 1800 m, when the precipitation was greater than 5 but less than or equal to 10 mm day<span class="CharOverride-3">-1 </span>and the relative humidity greater than 80 but less than 90 % day<span class="CharOverride-3">-1</span> (p&lt;0.001), milk production decreased. On the other hand, at 660 m the effect came from relative humidity less than or equal to 70 %. The environmental temperature had a significant effect in both altitudes. <strong><span class="CharOverride-2">Conclusion.</span></strong> The conditions of temperature, humidity, precipitation, and radiation in each ecosystem, generated differences in the productivity of the animals, related to the type of forages and the thermal sensation to which the cattle was exposed, which caused heat or cold stress.</p> 2019-12-05T00:00:00-06:00 ##submission.copyrightStatement## Increase okra production with the addition of nitrogen 2020-01-01T09:54:30-06:00 Valdilene Coutinho-Miranda Irais Dolores Pascual-Reyes Aline Torquato-Tavares João Victor Gonçalves-Carline Kássio Abel Silva-Sousa Ildon Rodrigues-do-Nascimento <p><strong><span class="CharOverride-2">Introduction.</span> </strong>The growth, production, and quality of the okra (<span class="CharOverride-4">Abelmoschus esculentus</span> (L.) Moench) are related to the application of fertilizers with nitrogen (N) being the most prominent, due to the direct relationship with photosynthesis and vegetative growth of the plant.<strong> <span class="CharOverride-2">Objective. </span></strong>The objective was to evaluate the agronomic and productivity characteristics of the okra based on the dose of N. <strong><span class="CharOverride-2">Materials and methods.</span> </strong>The study was carried out in the experimental area Campus Gurupi, of the Universidad Federal de Tocantins (UFT), in two planting periods (autumn/winter and spring/summer). The experimental design used was randomized blocks (DBC) with six treatments (0, 50, 100, 150, 200, and 250 kg N ha<span class="CharOverride-3">-1</span>) and four repetitions. Urea was used as a source of N. The characteristics evaluated were: productivity, average fruit mass, height and chlorophyll index of the plant. <span class="CharOverride-2"><strong>Results.</strong> </span>The productivity and height of the plant were higher in the autumn/winter crop. The average mass and chlorophyll index were not influenced by the sowing period. For productivity a linear response was obtained, increasing the dose up to the limit of the dose of N used (250 kg ha<span class="CharOverride-3">-1</span>), with an average value higher than 14 t of fruit. The mean mass and plant height responded linearly to the increase in the dose of N. Nitrogen affected the chlorophyll index, with maximum values of 45.96 and 47.19, observed in the two evaluation periods. <strong><span class="CharOverride-2">Conclusion.</span></strong> The sowing season and the N content in the soil interacted with the height of the plant, being favorable in the period when there was no precipitation. N influenced all characteristics, demonstrating the importance of nitrogen fertilization development okra plants.</p> 2019-12-02T00:00:00-06:00 ##submission.copyrightStatement## Environmental stratification of rice by genotype x environment interaction analysis using five methods 2020-01-01T09:54:31-06:00 Marco Antonio Acevedo-Barona Rubén Silva-Diaz Rosa Álvarez-Parra Orlando Torres-Angarita Edicta Reyes-Ramone <p><span class="CharOverride-4"><strong>Introduction.</strong> </span>Venezuela has more than two million hectares suitable for rice production, of which about the 25% are exploited, under the production system with flood irrigation with various agronomic management technologies and environments that could affect the phenotypic expression of the genetic materials.<strong><span class="CharOverride-4"> Objective. </span></strong>The objective of this work was to quantify the magnitude of the environmental genotype interaction (IGA) to stratify the irrigated rice environments through five analytical methods and determine their association. <strong><span class="CharOverride-4">Materials and methods.</span></strong> Eight rice genotypes were evaluated in twelve environments resulting from the combination of localities and planting seasons in the regions of the Central and Western Plains of Venezuela, during the years 2012-2013. The stratification of environments was made based on five methods: traditional Lin (TL), Euclidean distance (ED), simple percentage of IGA (% SP), Pearson correlation (r<span class="CharOverride-5">xy</span>), and factor analysis (AF). The randomized complete block statistical design was used with three repetitions in 20 m<span class="CharOverride-3">2</span> plots. <strong><span class="CharOverride-4">Results.</span></strong> ANOVA detected significant IGA, explaining 35% of the total variation. Favorable environments for rice represented 33%. The methods used TL, ED, % SP, rxy, and AF grouped the twelve irrigated rice environments into 10, 5, 8, 10, and 3 groups respectively; they were not efficient in identifying different environments when different planting seasons were used in the same locality. <span class="CharOverride-4"><strong>Conclusions.</strong> </span>The factor analysis method was more efficient in identifying homogeneous environments, complemented with % SP and TL methods that presented moderate association. The Bancos of San Pedro and Asoportuguesa environments were more informative and indicated for the evaluation of rice genotypes. The opposite occurred with the Araure, Algodonal, and Torunos localities.</p> 2019-11-25T00:00:00-06:00 ##submission.copyrightStatement## Effect of nitrogen and phosphate fertilization on perennial ryegrasses and red clovers 2020-02-25T10:07:30-06:00 Andrea Milena Sierra-Alarcón Yesenia Moreno-Oviedo Edgar Augusto Mancipe-Muñoz Yesid Avellaneda-Avellaneda Juan de Jesús Vargas-Martínez <p><strong><span class="CharOverride-2">Introduction. </span></strong>Specialized dairy systems are forage based, which makes necessary to generate recommendations that promote the efficient and sustainable use of this resource. <strong><span class="CharOverride-2">Objective. </span></strong>The objective of this work was to evaluate increasing levels of nitrogen and phosphate fertilization on forage yield and compositional quality of ryegrass (<span class="CharOverride-3">Lolium perenne</span>) and red clovers (<span class="CharOverride-3">Trifolium repens</span>). <span class="CharOverride-2"><strong>Materials and methods.</strong> </span>In September 2016, two perennial ryegrasses plots and two red clovers were established in two Colombian departments (Boyacá and Cundinamarca), in 4 m<span class="CharOverride-1">2</span>. The first one received 0, 50, 100 or 150 kg N ha<span class="CharOverride-1">-1</span>; and 0, 25 or 50 kg P<span class="CharOverride-4">2</span>O<span class="CharOverride-4">5</span> ha<span class="CharOverride-1">-1</span>; and the second one received 0, 12.5, 25 or 37.5 P<span class="CharOverride-4">2</span>O<span class="CharOverride-4">5</span> ha<span class="CharOverride-1">-1</span>. After the establishment period (120 days) and a uniform cut, forages were harvested at 21, 35 and 49 regrowth days, during two evaluation periods (April-May and June-July 2017). The variables were evaluated through a split-plot design with repeated measures. <strong><span class="CharOverride-2">Results.</span> </strong>Nitrogen fertilization increased (p&lt;0.05) dry matter yield, chlorophyll and crude protein concentration; and decreased neutral detergent fiber. Phosphatic fertilization did not modify (p&gt;0.05) ryegrass and clover yield and composition. Furthermore, the extension in the age of regrowth increased (p&lt;0.05) the concentration of components less soluble in clovers and ryegrass, which are related to the lower nutritional value. <span class="CharOverride-2"><strong>Conclusion.</strong> </span>The application of increasing levels of nitrogen, but not phosphorus, elevated the production and quality of ryegrasses. Phosphorus application did not modify clovers yield nor composition.</p> 2019-09-01T00:00:00-06:00 ##submission.copyrightStatement## Emission of greenhouse gases in the soil under the green manure effect 2020-02-25T10:07:25-06:00 Breno Augusto Sosa-Rodrigues Yuly Samantha García-Vivas <p><span class="CharOverride-4">Introduction. </span>Soil management practices in agroecosystems, such as the use of green manures (GM), positively affect greenhouse gas (GHG) emissions.<span class="CharOverride-4"><strong> Objective.</strong> </span>The objective of the research was to evaluate CO<span class="CharOverride-5">2</span>,CH<span class="CharOverride-5">4</span>, and N<span class="CharOverride-5">2</span>O emission of a soil cultivated with corn and soybean under the use of green fertilizers, fallow (B), and nitrogen fertilization. <span class="CharOverride-4"><strong>Materials and methods.</strong> </span>Between July 2011 and June 2012, in a Typic Haplustert located in Valle del Cauca, Colombia, corn and soybeans were planted in a intervleaved manner, and the monocultures of corn and soybeans were managed in a conventional manner. The association between<span class="CharOverride-6"> Mucuna pruriens</span> var. <span class="CharOverride-6">utilis</span> and maize was established as GM, ninety days after sowing, the total residues were incorporated as GM or disposed on the soil surface as organic mulch (AO). Eleven treatments were used under the design of randomized complete blocks, with 3<span class="CharOverride-2">2</span> + 2 factorial arrangement, with three repetitions. The main plots were GM, AO and B. Each was divided into sub-plots corresponding to compost fertilization, industrial chemical synthesis fertilizer and no additions. In the flowering and grain filling stage of the crops, variables such as N<span class="CharOverride-5">2</span>O, CH<span class="CharOverride-5">4</span>, CO<span class="CharOverride-5">2</span> and total water-filled porosity were analyzed. <span class="CharOverride-4"><strong>Results</strong>. </span>CO<span class="CharOverride-5">2</span> flow was higher in the intercrops added with GM/AO compared to monocultures. In the main plots, the use of industrial chemical synthesis fertilizers significantly stimulated N<span class="CharOverride-5">2</span>O and CH<span class="CharOverride-5">4</span> fluxes. <span class="CharOverride-4"><strong>Conclusion.</strong> </span>The use of high quality organic materials such as GM/AO did not ensure GHG sink soils in the short-term, since soil conditions and nitrogen fertilization significantly influenced emissions.</p> 2019-09-01T00:00:00-06:00 ##submission.copyrightStatement## Evaluation of arboreal and shrub strata in a silvopastoral system in Colombian high Andean tropics 2020-02-25T10:07:29-06:00 Laura Dayana Escobar-Pachajoa Carolina Guatusmal-Gelpud Diego Hernán Meneses-Buitrago Juan Leonardo Cardona-Iglesias Edwin Castro-Rincón <p class="Resumen"><strong><span class="CharOverride-4">Introduction.</span> </strong>Silvopastoral systems are presented as an alternative for the sustainable use of natural resources, so there is a need to identify potential species for their establishment in the high tropics. <span class="CharOverride-4"><strong>Objective.</strong> </span>The objective was to evaluate the initial growth of eight woody species in a silvopastoral design for water source protection. <strong><span class="CharOverride-4">Materials and methods. </span></strong>The study was carried out in the Obonuco research center of Corporacion Colombiana de Investigacion Agropecuaria (Pasto, Colombia) between September 2017 and June 2018. A randomized block design was developed in a factorial arrangement, where tree/bush species differentiated by their growth habit interacted (high stratum: <span class="CharOverride-5">Cedrela montana</span>, <span class="CharOverride-5">Quercus humboldtii</span>, <span class="CharOverride-5">Ficus andicola</span>; middle stratum: <span class="CharOverride-5">Salix babylonica</span>, <span class="CharOverride-5">Alnus acuminata</span>, <span class="CharOverride-5">Smallanthus pyramidalis</span>; lower stratum: <span class="CharOverride-5">Morella pubescens </span>and <span class="CharOverride-5">Sambucus nigra</span>) and altitude (2750, 2770 and 2800 masl) with four repetitions to evaluate morphometric variables and seedling quality.<strong> <span class="CharOverride-4">Results. </span></strong>In the variable height the best behavior was presented in <span class="CharOverride-5">Ficus andicola </span>at 2750 masl with 191.37 cm and <span class="CharOverride-5">Alnus acuminata </span>at 2800 masl with 181.83 cm. In stem diameter <span class="CharOverride-5">Ficus andicola</span> stood out at 2750 masl with 42.98 mm, <span class="CharOverride-5">Smallanthus pyramidalis </span>at 2800 masl with 37.24 mm, and <span class="CharOverride-5">Sambucus nigra</span> at 2800 masl with 8.16 mm. The number of regrowths did not show a significant effect of the interaction, and as seedlings, <span class="CharOverride-5">Quercus humboldtii </span>at 2750 and 2700 masl and <span class="CharOverride-5">Ficus andicola</span> at 2750 masl showed the best quality of individuals; while <span class="CharOverride-5">Cedrela montana</span> showed mortality at the three altitudes evaluated. <span class="CharOverride-4"><strong>Conclusions.</strong> </span>Native species stood out for their adaptibility, reflected in fast and optimal growth and development, which evidences its great potential to be evaluated in silvopastoral systems in an associated way to decide its multiple benefits and potential contribution to the sustainable development of the livestock in the region.</p> 2019-09-01T00:00:00-06:00 ##submission.copyrightStatement## Ex-ante impact evaluation of the L23 rice genotype on the colombian Altillanura plains 2020-02-25T10:07:26-06:00 Diego Armando Marín-Salazar Robert Santiago Andrade-López Ricardo Antonio Labarta-Chaverri Ángela Rocío Vásquez-Urriago Samuel Caicedo Guerrero <p class="Resumen"><strong><span class="CharOverride-2">Introduction.&nbsp;</span></strong>The Colombian Altillanura is going through a process of transformation, marked by the expansion of its agricultural border. In the region, it is being implemented a research agenda that seeks to develop and validate promising technologies for the improvement of productivity and sustainability of agricultural production systems. Economic evaluation plays an important role in prioritizing activities, allocating resources, and guiding agricultural research towards rural development objectives.<strong>&nbsp;</strong><span class="CharOverride-2"><strong>Objective.</strong>&nbsp;</span>The objective of this work was to implement an ex-ante economic evaluation to estimate the results and potential impacts of the new promising L23 rice line improved for the Colombian Altillanura.&nbsp;<strong><span class="CharOverride-2">Materials and methods.&nbsp;</span></strong>The impact was measured on the L23 rice genotype, which was developed as a collaboration between the Colombian Corporation of Agricultural Research (AGROSAVIA) and the International Center for Tropical Agriculture (CIAT), for the Colombian Altillanura. The ex-ante evaluation combined a partial budgets analysis with information from experimental tests and economic surpluses model.&nbsp;<strong><span class="CharOverride-2">Results.&nbsp;</span></strong>The two methodological approaches were consistent and showed that with the adoption of the L23 genotype at least 29.7%, a probability of 17.1 % could be achieved for rice producers in the Altillanura due to the expected increase in crop yield. However, a sensitivity analysis of the assumptions warns that a low potential level of adoption along with non-significant changes in yield would make the research and development of the new genotype economically unfeasible.&nbsp;<strong><span class="CharOverride-2">Conclusion.</span></strong>&nbsp;For the research, development and, introduction of the L23 rice genotype to be profitable, it is required a diffusion process that allows the reproduction of the seed and facilitates the access to producers, so that they can reach higher levels of adoption.</p> 2019-09-01T00:00:00-06:00 ##submission.copyrightStatement## Pathogenicity and autodissemination of promising entomopathogenic fungi strains on Rhynchophorus palmarum L. (Coleoptera: Dryophthoridae) 2020-02-25T10:07:24-06:00 Guillermo Adolfo León-Martínez Juan Carlos Campos-Pinzón Jorge Humberto Arguelles-Cárdenas <p><strong><span class="CharOverride-4">Introduction.</span>&nbsp;</strong>In Latin America, the weevil (<span class="CharOverride-5">Rhynchophorus palmarum</span>&nbsp;L.) is an important pest of oil palm and coconut palm because it is associated with the transmission of red ring (RRD) and bud rot (BR); diseases that cause high management costs and mortality of plantations; the entomopathogens&nbsp;<span class="CharOverride-5">Metarhizium anisopliae</span>&nbsp;and&nbsp;<span class="CharOverride-5">Beauveria bassiana</span>&nbsp;(Hypocreales: Clavicipitaceae) represent an microbiological control alternative.&nbsp;<span class="CharOverride-4">Objective.&nbsp;</span>The objective of this work was to determine the pathogenicity of promising strains of&nbsp;<span class="CharOverride-5">M. anisopliae&nbsp;</span>and&nbsp;<span class="CharOverride-5">B. bassiana</span>&nbsp;on adults of&nbsp;<span class="CharOverride-5">R. palmarum</span>&nbsp;and to evaluate the spread of the best strains, from inoculated weevil male adults to not-inoculated females.<span class="CharOverride-4">&nbsp;<strong>Materials and methods.&nbsp;</strong></span>The study was carried out in two phases in the La Libertad Research Center of the Corporación Colombiana de Investigación Agropecuaria (AGROSAVIA), Department of Meta, Colombia through factorial arrangements in completely random designs; in the first one, four strains of<span class="CharOverride-5">&nbsp;M. anisopliae</span>, one of&nbsp;<span class="CharOverride-5">B. bassiana</span>, and one commercial product based on&nbsp;<span class="CharOverride-5">M. anisopliae</span>&nbsp;were evaluated; in the second one, to determine the self-dissemination of the entomopathogen, the two highest effectiveness strains from the first experiment (CPMa1104 and Mt008) were evaluated by two methods of application to males (immersion and powder).&nbsp;<strong><span class="CharOverride-4">Results.&nbsp;</span></strong>The CPMa1104 strain showed the highest efficacy (1x10<span class="CharOverride-3">4</span>&nbsp;and 1x10<span class="CharOverride-3">8</span>&nbsp;conidia ml<span class="CharOverride-3">-1</span>), followed by Mt008 (1x10<span class="CharOverride-3">8</span>&nbsp;conidia ml<span class="CharOverride-3">-1</span>) with mortalities of 78.6 % and 67.9 %, respectively. Contact dissemination capacity of&nbsp;<span class="CharOverride-5">M. anisopliae</span>&nbsp;strains CPMa1104 and Mt008 was observed from inoculated male adults to non-inoculate females. Female mortality reached 100 % when the males were inoculated with powdered CPMa1104.&nbsp;<strong><span class="CharOverride-4">Conclusion.&nbsp;</span></strong>The dissemination of CPMa1104 and Mt008 strains of&nbsp;<span class="CharOverride-5">M. anisopliae</span>&nbsp;by inoculated males to non-inoculated females was tested, which makes the use of this entomopathogen a promising control alternative.</p> 2019-09-01T00:00:00-06:00 ##submission.copyrightStatement## Beauveria bassiana with flupyradifurone for the control of Trialeurodes vaporariorum Vuill in French beans crop 2020-02-25T10:07:22-06:00 Claudia Elizabeth Toledo-Perdomo <p class="Resumen"><strong><span class="CharOverride-4">Introduction</span>.&nbsp;</strong><span class="CharOverride-3">Trialeurodes vaporariorum&nbsp;</span>(Westwood) is one of the main pests of the French bean (<span class="CharOverride-3">Phaseolus vulgaris</span>&nbsp;L.), legume for consumption in inmature pods, and is a vector of the golden mosaic virus, which affects the quality and yield of the crop reaching losses of up to 100%, being difficult to control because many chemicals no longer control the pest. The French bean within the non-traditional products in Guatemala, occupies the second place in the export. Ensuring a good phytosanitary management with low chemical load by pesticides are important factors to be able to export it.<span class="CharOverride-4">&nbsp;<strong>Objective.</strong>&nbsp;</span>The objective of the investigation was to determine the effectiveness of the combination between Flupyradifurone and&nbsp;<span class="CharOverride-3">Beauveria bassiana</span>&nbsp;for the control of whitefly in French bean cultivation.&nbsp;<strong><span class="CharOverride-4">Materials and methods.</span>&nbsp;</strong>The study was conducted from February to December 2018 in Parramos, Chimaltenango, Guatemala. Seven plots of 100 m² were established corresponding to each treatment. Weekly, whiteflies were sampled during two cultivation cycles, and natural enemies of these were also collected on each plot. Three applications of each treatment were made in each crop cycle, and the plants were sampled divided into three strata (high, medium, low).&nbsp;<strong><span class="CharOverride-4">Results.</span>&nbsp;</strong>The treatments that showed the best control of the whitefly population (nymphs and adults) when performing the Tukey test (0,05), were flupyradifurone (1 l ha<span class="CharOverride-2">-1</span>) +&nbsp;<span class="CharOverride-3">B. bassiana</span>, and flupyradifurone (0.75 l ha<span class="CharOverride-2">-1</span>) +&nbsp;<span class="CharOverride-3">B. bassiana</span>. The largest distribution of whitefly populations was found in the upper and middle strata.&nbsp;<span class="CharOverride-4"><strong>Conclusion.</strong>&nbsp;</span>The combination of flupyradifurone (0,05) with&nbsp;<span class="CharOverride-3">B. bassiana</span>&nbsp;can be used within an integrated pest management, and is presented as an alternative control of whiteflies, which has acquired resistance to some agrochemicals.</p> 2019-09-01T00:00:00-06:00 ##submission.copyrightStatement##