Agronomía Mesoamericana 2019-04-19T14:52:43-06:00 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 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> Mealybugs (Hemiptera: Pseudococcidae) and their impact on the Musaceae crop 2019-04-19T14:52:31-06:00 Melissa Palma-Jiménez Mónica Blanco-Meneses César Guillén-Sánchez <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> 2019-01-01T00:00:00-06:00 ##submission.copyrightStatement## Chlorogenic acids present in coffee: antioxidant and antimicrobial capacity 2019-04-19T14:52:28-06:00 Evelyn Carolina Chaves-Ulate Patricia Esquivel-Rodíguez <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> 2019-01-01T00:00:00-06:00 ##submission.copyrightStatement## Polyethylene glicol 8000 to identify corn tolerant to water stress during germination 2019-04-19T14:52:24-06:00 Maria Alma Rangel-Fajardo Noel Gómez-Montiel Jorge Ismael Tucuch-Haas Dianelly de la Cruz Basto-Barbudo Antonio Villalobos-González Johnny Abraham Buros-Díaz <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> 2019-01-01T00:00:00-06:00 ##submission.copyrightStatement## Genetic analysis of tropical Beauveria and Metarhizium associated with sugar cane insects 2019-04-19T14:52:35-06:00 Alejandro Vargas-Martínez José Daniel Salazar-Blanco Allan González-Herrera Ramón Molina Bravo <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> 2019-01-01T00:00:00-06:00 ##submission.copyrightStatement## Ecosystem-Based Adaptation Governance for coffee smallholders in Central America 2019-01-08T08:37:32-06:00 Raffaele Vignola Marco Otarola Francisco Alpizar Pavel Rivera <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> 2019-01-01T00:00:00-06:00 ##submission.copyrightStatement## Antibiosis of proteins and metabolites of three species of Trichoderma against paraguayan isolates of Macrophomina phaseolina 2019-04-19T14:52:22-06:00 Alberto Anastacio Cubilla-Ríos Dani Daniel Ruíz-Díaz-Mendoza María Cristina Romero-Rodríguez María Eugenia Flores-Giubi Javier Enrique Barúa-Chamorro <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> 2019-01-01T00:00:00-06:00 ##submission.copyrightStatement## Economic analysis of bean market grain in Mexico 2019-04-19T14:52:25-06:00 Eugenio Guzmán-Soria María Teresa de la Garza Carranza José Alberto García Salazar Samuel Rebollar Rebollar Juvencio Hernández Martínez <p><strong>Introduction. </strong>The grain bean is a traditional key agri-food product in the Mexican diet due to its, price and for being an important source of protein. <strong>Objective. </strong>The objective of this work was to determine and analyze econometrically the factors that affect the grain bean market; as well as measuring the effect that the different price levels have on this one in Mexico from 1980 to 2016. <strong>Materials and methods. </strong>In this work, a model of simultaneous equations was estimated with annual information from 1980 to 2016; composed of five regression equations and an identity. <strong>Results. </strong>The results indicated that in the short term the consumption and production of grain beans in Mexico, responded inelastically (-0,2996% and 0,4151%) with changes of 1% in the corresponding prices. The changes in the factors that most affected consumption are the national income available for per capita consumption, the price of the egg and the price of the corn tortilla, with price-cross elasticities of -0,8797, -0,8594 and -0,7101; and to the production are the price of rice, the price of corn and the price of fertilizer with price-cross elasticities of -0,7005, -0.5545 and -0,3474. The effect of the international price and the transport cost in Mexico, affected the wholesale price of beans at a level of 0,27 and 0,23%, for each unit percentage change in the first. <strong>Conclusion. </strong>Since the price elasticity of bean consumption in Mexico is more inelastic in absolute terms, compared to the corresponding production elasticity; It suggests that the consumer surplus is greater than that of the national producer when participating in the bean market and implies that a subsidy policy for this grain would encourage production.&nbsp;</p> 2019-01-01T00:00:00-06:00 ##submission.copyrightStatement## Genetic, chemical and agronomical characterization of husk tomato advanced lines 2019-04-19T14:52:23-06:00 Mario Martin González-Chavira Salvador Horacio Guzmán-Maldonado GUZMAN.HORACIO@INIFAP.GOB.MX José Luis Pons-Hernández PONS.JOSELUIS@INIFAP.GOB.MX Salvador Villalobos-Reyes VILLALOBOS.SALVADOR@INIFAP.GOB.MX Enrique Gónzalez-Pérez <p><span class="CharOverride-2"><strong>Introduction.</strong> </span>Knowledge about the genetic, chemical and morphological diversity that exists between individuals and populations is very useful in breeding programs, because it facilitates the organization of the material and the appropriate selection of superior genotypes for the development of an improved population. <strong><span class="CharOverride-2">Objective. </span></strong>The aim of this research was to make a genetic, chemical and agronomic characterization in twenty advanced husk tomato lines (<span class="CharOverride-3">Physalis ixocarpa</span> Brot.), belonging to the vegetable breeding program of the Campo Experimental Bajío (CE-Bajío), of the Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP), México. <span class="CharOverride-2"><strong>Materials and methods. </strong></span>During the spring-summer and autumn-winter 2017, the genetic variability was quantified with molecular markers of DNA, type AFLP (Amplified Fragment Length Polymorphisms), likewise, the phenolic and tomatidine compounds in the fruit were determined, and agronomic traits like germination percentage, number of fruits per plant, weight of the fruit, equatorial and polar diameter per fruit, and fruit yield were determined. A general average of similarity between the genotypes of 0.86 was obtained. <span class="CharOverride-2"><strong>Results.</strong> </span>A general similitude mean between genotypes of 0.86 was obteined. According to the genetic relationships, a geographic pattern was identified and genotypes 4 and 70 were detected as possible progenitors of improved hybrids. Chemical diversity indicated that the fruits flavonoids content in L-86 was the highest (51.1mg EAG/100g), phenols (396.8 mg EAG/100 g) and anthocyanin’s (7.22 mg EAG/100g) for L-182 and tannins (188.4 mg EAG/100 g) for L-97, while tomatidine (2.23-3.81 mg EAG/100 g) was higher in green fruits than purple fruits. The agronomic results indicate that the lines fruit yield ranged from 11.4 to 47.6 t/ha, the 20% of the lines has a superior yield than the national mean yield (40 t/ha), The L-37 was noticeable, since it has the highest fruit yield with 47.6 t/ha, and has the highest number of fruits number per plant, equatorial and polar diameters, and germination rate (93.3%). <strong><span class="CharOverride-2">Conclusion.</span></strong> Based on the results the lines 37, 25, 27 and 167 are positioned as lines with potential for commercial use and as parental lines.</p> 2019-01-01T00:00:00-06:00 ##submission.copyrightStatement## Adaptation of ten cultivars of Lolium sp. in the high tropic of Nariño, Colombia 2019-04-19T14:52:25-06:00 Máryory Maricela Cadena-Guerrero Mario Augusto García-Dávila Diego Hernán Meneses-Buitrago Sonia Patricia Morales-Montero Edwin Castro-Rincón <p><strong>Introduction. </strong>Dairy systems at the Nariño department in Colombia, are characterized by the presence of kikuyo grass (<em>Cenchrus clandestinus</em>), which is susceptible to frost, pests,&nbsp;and pathogens reducing biomass productivity.&nbsp;<strong>Objective. </strong>The objective of this research was to evaluate the adaptation of ten genotypes of ryegrass in three localities at the high lands (2905 – 3157 masl) and to determine the behavior in dry and rainy season. <strong>Materials and methods. </strong>The study was carried out from February 2016 to February 2017. A complete randomized block design with four repetitions was used with a multifactorial arrange including genotypes (ten), locality, season (dry or rainy) and time of harvesting (25, 30, 35 and 40 days). Plant height, coverage, the severity of diseases and yield of dry matter were measured. <strong>Results.&nbsp;</strong>There was a response of genotypes to dry and rainy season, improving height, cover,&nbsp;and yield of dry matter in the&nbsp;rainy season. The genotypes with highest values for plant height, cover percentage, yield of dry matter and the lowest severity of disease at Pasto locality in rainy season were Conquistador (46,33 cm), Aubade (99,67 %), Tetralite II, Best for Plus, Aubade and Boxer (2,22-2,09 t/ha/cut), and Samson (1,14). In the same order of variables in rainy season at Cumbal locality, were genotypes Best fort (32,60 cm), Aubade (90,62%), Best for and Tetralite II (1,60t/ha/cut), and genotype Boxer (1,06); and for Sapuyes locality were Best for (25,33 cm), Boxer (98,53%), Best for and Tetralite II (0,66 y 0,65 t/ha/cut), and Samson, Conquistador and Angus genotypes (1,0) with the lowest severity of diseases. <strong>Conclusion. </strong>The rainy season affected the response of the genotypes, with a higher yield of dry matter, plant height, and cover. The response of the genotypes was affected by the dry and rainy seasons, the yield of the dry matter, the plant height and coverage were affected. The genotypes with good agronomic behavior are suggested for commercial validation to diversify the forage supply in the localities studied.&nbsp;</p> 2019-01-01T00:00:00-06:00 ##submission.copyrightStatement## Heat treatment of colostrum increases immunoglobulin absorption in Holstein heifer calves 2019-04-19T14:52:34-06:00 Ericka Salazar-Acosta Jorge Alberto Elizondo-Salazar <p><span class="CharOverride-4"><strong>Introduction.</strong> </span>The best line of defense against invading pathogens in the newborn dairy calf is the immunoglobulins from colostrum that are absorbed in the small intestine. <strong><span class="CharOverride-4">Objective. </span></strong>The objective of this work was to determine the efficiency of absorption of inmunoglobulins G (IgG) in Holstein heifer calves by supplying low and good quality heat-treated calostrum. <strong><span class="CharOverride-4">Materials and methods.</span></strong> The study was carried out from August 2016 to August 2017 in a commercial dairy farm in Las Nubes de Coronado, San José, Costa Rica. First milking colostrum was collected from fifty Holstein cows, placed into plastic containers and separated into two categories (low&lt;50 and high≥50 g of immunoglobulin/l). Colostrum within each category was pooled and mixed to create two unique uniform batches, half of each batch (35 l) was transferred into containers properly identified and frozen until required for feeding (colostrum without heat treatment). The remaining half of each colostrum half was heated to 60 °C and maintained for 30 min in a commercial pasteurizer. The different colostra were analyzed for total coliforms, fecal coliforms and E. coli, fat, crude protein, lactose, total solids and total IgG concentration. Blood samples were obtained from 36 calves and were analyzed for total serum protein, IgG and ºBrix. <span class="CharOverride-4"><strong>Results.</strong> </span>Heat treatment significantly reduced bacterial population and maintained IgG concentration. Heat treatment significantly increased (P&lt;0.001) total serum IgG concentration regardless of colostrum quality. IgG concentration increased from 15.9 to 23.8 and 3.9 to 8.1 % for the high and low quality group, respectively. Heat treatment also increased apparent efficiency of absorption; there was an increase from 16.0 to 31.1% for the group of calves consuming high quality colostrum and from 12.7 to 32.7% for the group consuming low quality colostrum. <strong><span class="CharOverride-4">Conclusion.</span> </strong>Feeding heat-treated colostrum to new born Holstein heifer calves significantly increased apparent efficiency of absorption, therefore, IgG concentration in animals’ blood serum.</p> 2019-01-01T00:00:00-06:00 ##submission.copyrightStatement## Factors that affect the production in first lactation of dairy cattle of Costa Rica 2019-04-19T14:52:27-06:00 Gloriana Castillo-Badilla Bernardo Vargas-Leitón Frank Hueckmann-Voss Juan José Romero-Zúñiga <p><strong>Introduction.&nbsp;</strong>The young calf rearing method, determines the dairy cow of the future. Therefore, health, feeding and housing techniques, influence the start and performance of the productive life of a dairy cow. <strong><span class="CharOverride-2">Objective. </span></strong>The aim of this work was to determine the effect of animal and environmental factors, modifiable and non-modifiable on the first lactation milk yield (FLM) in specialized dairy farms from Costa Rica. <strong><span class="CharOverride-2">Materials and methods. </span></strong>A cohort retrospective study was conducted. A total of 2747 Jersey and Holstein cows, with age at first calving (AFC) between the years 2013 and 2015, belonging to twenty-two specialized dairy herds located in different ecological zones of Costa Rica, with data in the Bovine VAMPP program, were included in the study. All data in the present research was analyzed by descriptive analysis and a generalized linear model. <strong><span class="CharOverride-2">Results. </span></strong>The average FLM at 305 days was 5485.8 kg (±1547.8). Non-modifiable variables, like breed, had significant effects over FLM, with 5360.1 kg (CI95%: 5158.2-5562.1) and 4694.1 (CI95%: 4578.5-4809.7; P&lt;0.001) for Holstein and Jersey breeds respectively. AFC, had a significant effect over FLM, were a tendency to increased milk production with higher AFC was found until twenty-six month of AFC, after that milk yield remain stable (P&lt;0.001). Furthermore, the results showed a significant effect of management as a modifiable variable (P&lt;0.0001) revealing that farms with high quality calf rearing protocols produced 213.9 kg (FML: 5809.0; CI95%: 5570.6-6047.7) more milk in their first lactation than heifers raised under medium quality rearing and 1133.7 kg more milk than animals from low quality rearing programs (FML: 4676.3; CI95%: 4158.3-5194.3). <strong><span class="CharOverride-2">Conclusion.</span></strong>These results show that rearing factors affect the productive life time of dairy cows in tropical operations. Tropical environmental conditions, including temperature, humidity and precipitation, significantly affect the productive behavior of dairy cows.</p> 2019-01-01T00:00:00-06:00 ##submission.copyrightStatement## Organic selenium supplementation in layer hens and its transfer to the egg 2019-04-19T14:52:36-06:00 Marisol Rodríguez-Alfaro Catalina Salas-Durán Carlos Orozco-Vidaorreta <p><span class="CharOverride-2"><strong>Introduction.</strong> </span>Selenium is an essential trace mineral for human and animal health, is part of the selenoproteins, that have an antioxidant function, and also prevent and reduce the damage caused by free radicals in the organism. <strong><span class="CharOverride-2">Objective.</span></strong> The objective was to evaluate the effect of the dietary supplementation with organic selenium in layer hens on the productive performance, egg quality and its transfer to the egg for human consumption. <strong><span class="CharOverride-2">Materials and methods. </span></strong>Two trials were performed with flocks of 33 000 ISA Brown hens (of 32 and 40 weeks of age), in Alajuela province, Costa Rica, during the first semester of 2013. After a control period (four weeks), the diet was supplemented with 0.4 ppm of organic selenium (three weeks for adaptation and three weeks for enrichment), with a withdraw period (three weeks). Laying percentage, accumulated eggs, mortality, feed intake, egg weight and mass and feed conversion were monitored weekly; a sample of fifty birds per flock was used to evaluate body weight. Haugh units, shell thickness and yolk color were determined weekly in fifteen fresh eggs, fifteen seven days-old-eggs and fifteen fourteen-days-old eggs. The selenium concentration in eggs was measured in the three periods (six eggs per period). <strong><span class="CharOverride-2">Results.</span> </strong>No variations were observed on production performance parameters that can be attributable to the addition of the selenium. The dietary supplementation with organic selenium increased the egg content of this mineral, which varied from not being detected during the control period on both trials, to 0.14 µg/g and 0.39 µg/g during the supplementation period, respectively. The egg storage affected significantly (p&lt;0.05) Haugh units and yolk color in both trials, and in trial 1 also affected egg weight and mass. <span class="CharOverride-2"><strong>Conclusion.</strong> </span>Dietary supplementation of laying hens with organic selenium can lead to the production of added-value eggs.</p> 2019-01-01T00:00:00-06:00 ##submission.copyrightStatement## Effect of different media and rooting substrates on the hardening-off process of transgenic rose 2019-04-19T14:52:39-06:00 Adrián Héctor Palacios-Arriaga Nutan Prasad Rout <p><strong>Introduction. </strong><em>In vitro </em>culture allows the genetic improvement of rose (<em>Rosa hybrida</em>), however, the acclimatization of plantlets in solid sustrate is a difficult process, it leads to malfuntion of stomata in the plants and consequently low carbon dioxide assimilation. <strong>Objective. </strong>The objective of this research was to evaluate three <em>in vitro </em>rooting media and different substrates for <em>ex vitro </em>acclimatization through solid and liquid media of transgenic rose. <strong>Materials and methods. </strong>transgenic rose (<em>Rosa hybrida </em>L.) cv. Classy plants were obtained from somatic embryo that&nbsp;were cultured <em>in vitro </em>for two years and were subjected rooting <em>in vitro </em>and <em>ex vitro </em>followed by acclimation. For in vitro rooting three different medium and for the ex vitro experiments, seven different combination of substrate were used. The study was carried out between August 2012 to January 2013 in Centro de Investigación y Asistencia de Tecnología y Diseño del Estado Jalisco, A.C. <strong>Results. </strong>The results from the <em>in vitro </em>and <em>ex vitro </em>experiments showed that the best <em>in vitro </em>rooting medium was the MS medium with the addition of 30 g/l sucrose and 0.5 g/l activated charcoal. The substrate composed of 70% peat moss and 30% pearlite was found to be the best for <em>ex vitro </em>conditions obtaining 20% of rooting. The substrate with 25% humus produced the highest chlorophyll content, however, there was no rooting. Solid treatments produced a higher percentage of seedling survival, high average number of leaves per plant, high chlorophyll content and a better sprout quality than hydroponics. However, the survival rate was 40% in the absence of aeration and 0% with aeration after sixteen days of the experiment. Treatment without aeration did not show any rooting. Higher contents of organic matter in the rooting substrate and the presence of aeration in a hydroponic solution did not guarantee a greater survival during acclimatization. <strong>Conclusion. </strong>Higher contents of organic matter in the rooting substrate and the presence of aeration in a hydroponic solution may not guarantee a greater survival during acclimatization. The results represent an optimization in the acclimatization of plants and the establishment of hydroponic culture of rose.</p> 2019-01-01T00:00:00-06:00 ##submission.copyrightStatement## Relationship between growth traits and yield formation in Indica-type rice crop 2019-04-19T14:52:38-06:00 Lazaro Alberto Maqueira López <p><strong>Introduction. </strong>Climatic variation is one of the causes for the decrease in yield and its variability in Indica-type rice (<em>Oryza sativa </em>L.). This evidences the necessity of the study of the interaction of meteorological variables with the behavior of rice cultivars, to establish the base of management of the harvest and increase of the yield. <strong>Objective. </strong>The objective of the present study was to relate the yield of rice with variables of plant growth. <strong>Materials and methods. </strong>Four rice cultivars were planted in the “dry” season of December 2004, February 2005 and January 2006, and in the rainy season of March 2006, April 2008 and 2009, in Los Palacios, Pinar del Río province, Cuba. The yield and its components, the dynamics of plant growth (LAI and dry matter), the variation of the dry matter of the internodes, peduncle, flag leaf, leaf and leaf sheath during the grain filling phase were evaluated the panicle growth in addition to the meteorological data. A multivariate analysis was used to relate the performance to the characteristics of the plants evaluated. <strong>Results. </strong>The yield was higher in the “dry” season and to obtain higher yields, the growth dynamics of the plant and the variation of the dry matter of the third internode during the grain filling were important. In both seasons, different source-sink relationships were established and these situations depended mainly on the temperature regime at which the plants were subjected. <strong>Conclusion. </strong>Breeders, in order to increase potencial yields, may fows their atttention in grow traits during vegetative stages.</p> 2019-01-01T00:00:00-06:00 ##submission.copyrightStatement## Effect of crossbreeding on growth characteristics in zebu cattle of Chorotega region 2019-04-19T14:52:29-06:00 Mónica Madrigal-Valverde Jorge Camacho-Sandoval Catalina Salas-Durán <p><span class="CharOverride-2"><strong>Introduction.</strong> </span>There is little research about the effect of crossbred between <span class="CharOverride-3">Bos indicus</span> * <span class="CharOverride-3">Bos indicus </span>breeding, however, crossbreeding is an important optimization’s tool used by the livestock producers. <strong><span class="CharOverride-2">Objective. </span></strong>The objective of this study was to determine the behavior of growth characteristics on different proportions of<span class="CharOverride-3"> Bos indicus </span>breed crosses.<strong><span class="CharOverride-2"> Materials and methods. </span></strong>The analysis was made based on production records of a selected cattle farm with Brahman, Nelore and commercial stock located in the North Pacific region, Costa Rica. The records of 4.294 animals, collected during the 2002-2012 period in the farm, were used; the breed groups included in the study were: Brahman, Nelore, Guzerat, ½ Brahman ½ Nelore, ½ Brahman ½ Guzerat, ¼ Brahman ¾ Nelore, and ¼ Nelore ¾ Brahman. Birth weight, weaning weight, weaning daily weight gain, year old weight, year old daily weight gain, 18 months weight, and 18 months daily weight gain were analyzed according to the breed group of the offspring and the parents. In addition, the non-additive effects (sex, season of birth and year of birth) and their influence on the characteristics were analyzed. <strong><span class="CharOverride-2">Results. </span></strong>It was found that the Brahman, Nelore and ¼ Nelore ¾ Brahman breed groups had the highest weights at all ages, male animals presented higher weights for most of the analyzed characteristics (P &lt;0.05); the animals born in the rainy season presented the highest weights for all the characteristics, in relation to the dry season, while the year of birth did not present trends. The study concluded that the breed group of the mother influenced the early ages of the offspring and the breed group of the father caused differences after one year of age. Likewise, the study concluded that the variables sex and season of birth presented defined behaviors, while the year of birth have fluctuating results.<strong> <span class="CharOverride-2">Conclusion.</span></strong> In crossbreds <span class="CharOverride-3">Bos indicus</span>, the breed group of the progenitors have influences in the growth characteristics of progeny.</p> 2019-01-01T00:00:00-06:00 ##submission.copyrightStatement## Sustitution of Megathyrsus maximus grass by square guineo and urea in silage mixtures 2019-04-19T14:52:32-06:00 Michael Jesús López-Herrera Augusto Rojas-Bourrillon Ernesto Briceño-Arguedas <p><strong><span class="CharOverride-6">Introduction. </span></strong>Tropical pastures have higher fiber content in proportion to other nutrients, this limits the dry matter intake by ruminants. Usage of additives in silage can improve nutritive content in forages that can be preserved to use in moments of lower forage availability. <strong>Objective.</strong> The objective of this research was to evaluate the effect of substituting <span class="CharOverride-5">Megathyrsus maximus</span> cv Mombaza grass for immature square bananas (<span class="CharOverride-5">Musa</span> ABB) and urea in silages. <strong><span class="CharOverride-6">Materials and methods</span>.</strong> The experiment was carried out between August and December 2016. A factorial design with eight treatments was used. The forage mixtures were stored for sixty days in bags of 5.0 kg bags. <strong><span class="CharOverride-6">Results. </span></strong>Usage of square banana fruit produced an increase in pH, ammonia nitrogen, and urea. The fruit also increased the concentration of dry matter and non-fibrous carbohydrates, this improved the relative value of the forage and the energy content. On the other hand, urea improved the crude protein content by 10 percentage units, due to its contribution as non-proteic nitrogen. The energy content of the treatments fluctuated between 59.5 and 63.6% TND, in the treatments with greater use of square banana fruit. <strong><span class="CharOverride-6">Conclusion.</span></strong> Silage with 30% of substitution by square banana fruit and 0.5 - 1.0% urea are considered an alternative for feeding ruminants, as a complement to a balanced diet.</p> 2019-01-01T00:00:00-06:00 ##submission.copyrightStatement## Assessing gene action for hypoxia tolerance in cotton (Gossypium hirsutum L.) 2019-04-19T14:52:37-06:00 Altaf Hussain Zafar Ullah Zafar Habib-Ur-Rehman Athar Jehanzeb Farooq Saghir Ahmad Wajad Nazeer <p><strong>Introduction. </strong>The inheritance studies on hypoxia tolerance in cotton are very scanty. <strong>Objective. </strong>The objective of this work was to study the inheritance pattern of seed cotton yield, ginning out-turn, and fiber length under normal and hypoxia conditions. <strong>Materials and Methods. </strong>An 8•8 diallel mating system was employed in F1 generation of cotton. The experiment was conducted during the years 2011-2012 at Cotton Research Institute, Multan, Pakistan. <strong>Results. </strong>Analysis of variance revealed significant variation (P&lt;0.01) for all the traits under both non-stress and flooding stress conditions. The value of regression coefficient b deviated significantly from zero but not from unity for all the traits which enabled further analysis of the data. The additive component (D) was significant for all the traits and this has more values than the values of dominance components H1 and H2, which clearly indicates the preponderance of additive genetic effects. Under normal and hypoxia conditions the estimates of narrow sense heritability were higher. <strong>Conclusion. </strong>Predominance of additive genetic effects, high heritability along with partial dominance under both conditions suggested that selection for these traits under hypoxic environment at early generation will be useful.</p> 2019-01-01T00:00:00-06:00 ##submission.copyrightStatement## Use of Ecosystem-based Adaptation practices by smallholder coffee farmers in Central America 2019-04-19T14:52:30-06:00 Adina Chain-Guadarrama Ruth M. Martínez-Rodríguez José Mario Cárdenas Sergio Vílchez Mendoza Celia A Harvey <p><strong><span class="CharOverride-3">Introduction.</span> </strong>In Central America, smallholder coffee farmers are threatened by rising temperatures and changes in rainfall patterns. One strategy that could help support smallholder farmer communities adapt to climate change is the use of Ecosystem based Adaptation (EbA) practices, which are based on the conservation, restoration and sustainable management of ecosystems and biodiversity. However, little information exists on how farmers use these practices.<strong><span class="CharOverride-3"> Objective.</span></strong> The objective of this work was to describe the use of eleven EbA practices by smallholder coffee farmers in five landscapes in Costa Rica, Honduras and Guatemala, and compare whether the biophysical characteristics and implementation of these practices differed between landscapes.<strong><span class="CharOverride-3"> Materials and methods.</span></strong> The characterization of EbA practices in the field was done using participatory mapping, surveys, area and measurements of vegetation composition and structure, from July 2014 to June 2015. Comparisons between landscapes were made using analysis of variance. <strong><span class="CharOverride-3">Results.</span> </strong>The study suggests that most farmers are already actively using EbA practices, especially shade trees in coffee plots, contour planting, home gardens and live fences. However, there were important differences across landscapes in the prevalence and characteristics of the EbA practices implemented. <span class="CharOverride-3"><strong>Conclusion.</strong> </span>These differences suggest that smallholder farmers adapt the use of these practices in response to their social and biophysical contexts and that there is value in organizing exchanges among farmers from different regions to share their knowledge of these practices.</p> 2019-01-01T00:00:00-06:00 ##submission.copyrightStatement## Chemical composition and antimicrobial activity of the essential oil of Psidium guajava and Cymbopogon citratus 2019-04-19T14:52:26-06:00 María José Bermúdez-Vásquez Fabio Granados-Chinchilla Andrea Molina <p><span class="CharOverride-4"><strong>Introduction.</strong> </span>The resistance of microorganisms to antibiotics is a public health problem that can affect livestock producers by having fewer options to treat animals in the event of a infection. Extracts of some plants with antimicrobial activity may represent an alternative to the use of antibiotics in livestock production. <strong><span class="CharOverride-4">Objective. </span></strong>The objective of this work was to analyze the chemical composition and antimicrobial activity of the essential oils of guava leaves (<span class="CharOverride-5">Psidium guajava</span> L.) and lemon grass (<span class="CharOverride-5">Cymbopogon citratus</span> (DC.) Stapf) grown in Costa Rica and evaluate antimicrobial activity of<span class="CharOverride-5"> P. guajava</span> L. in meat and bone meal. <strong><span class="CharOverride-4">Materials and methods. </span></strong>This research was developed at the Animal Nutrition Research Center (CINA) of the University of Costa Rica between March and October 2016. <span class="CharOverride-5">P. guajava </span>leaves were collected from two different locations (San Pedro and Escazú) and those from<span class="CharOverride-5"> C. citratus</span> from the areas of Sarapiquí and Escazú. The extraction of the oils was done by hydrodistillation. The chemical composition was analyzed by gas chromatography and mass spectrometry. The antimicrobial capacity of the essential oils was evaluated by the disk diffusion test and the 96-well plate microdilution procedure. <strong><span class="CharOverride-4">Results.</span> </strong>The essential oils of <span class="CharOverride-5">C. citratus</span> and <span class="CharOverride-5">P. guajava </span>presented antimicrobial activity against the ten bacterial strains tested, being the gram positive bacteria the most sensitive to them. <span class="CharOverride-5">P. guajava</span> oil from Escazú showed higher antimicrobial activity <span class="CharOverride-5">in vitro </span>with respect to <span class="CharOverride-5">P. guajava</span> oil from San Pedro and <span class="CharOverride-5">C. citratus</span> oil. The oil of <span class="CharOverride-5">P. guajava</span> had the ability to eliminate <span class="CharOverride-5">Escherichia coli</span> that had previously been added to a matrix of meat and bone meal, but not to prevent colonization of it. <span class="CharOverride-4"><strong>Conclusion.</strong> </span>According to the results of this research, the essential oils of lemon grass and guava leaf grown in Costa Rica, have an antimicrobial effect against bacteria relevant for feed safety and feed shelf life, future research is required to evaluate its applicability in animal feed.</p> 2019-01-01T00:00:00-06:00 ##submission.copyrightStatement## Disinfection effect of nodal segments from Vanilla planifolia Andrews on the morphogenetic response of in vitro plants 2019-04-19T14:52:33-06:00 José Bernal Azofeifa Bolaños German Rivera-Coto Amelia Paniagua-Vásquez Roberto Cordero-Solórzano Eduardo Salas-Alvarado <p><strong>Introduction. </strong>The aseptic establishment in laboratory conditions of wild type <em>Vanilla planifolia </em>has not been documented in any sterilization and regeneration protocols, nor has been evaluated the importance of disinfection to enhance the plant vigor. <strong>Objective. </strong>The aim of this experiment was to evaluate the effect of a double disinfection process (greenhouse and laboratory) on the morphogenetic response of nodal segments of vanilla during the establishment and <em>in vitro </em>multiplication. <strong>Materials and methods. </strong>Laboratory experiments were conducted during 2015 and 2016 at “Instituto de Investigación y Servicios Forestales (INISEFOR) de la Universidad Nacional (UNA)”, Heredia, Costa Rica. The culture medium used was Murashige and Skoog (MS). Six treatments were evaluated: 1) alcohol 70%/NaClO 0.35%; 2) kilol/NaClO 0.35%; 3) control/NaClO 0.35%; 4) alcohol 70%/HgCl2 0.2%; 5) kilol/ HgCl2 0.2% and 6) control/HgCl2 0.2%. Growth variables evaluated were: percentage of total, bacterial and fungal contamination; length, weight, and diameter of the shoot; number, length and weight of the roots. <strong>Results. </strong>The main genera of bacteria and fungi were <em>Pantoea </em>sp. (33%) and <em>Fusarium </em>sp. (12%). The best disinfection treatment was obtained with the use of kilol in the nursery and HgCl2 in the laboratory, where 100% pathogen-free explants were obtained. For this treatment, a significant increase of length and weight of the shoot, number and weight of the roots were achieved during the establishment. In the multiplication stage, the experimental groups in the aseptic condition showed significant higher values for the variables length and weight compared to the morphogenic response obtained for the green and vigourous <em>in vitro </em>plants in the condition of contamination. <strong>Conclusion. </strong>The disinfection treatments sequence represents the base line to the optimization of <em>in vitro </em>culture protocols of wild type relatives of <em>V. planifolia</em>, this constitutes a contribution for the <em>ex situ </em>conservation of unique materials and increases promising genetic material.</p> 2019-01-01T00:00:00-06:00 ##submission.copyrightStatement## Carlos Salas Fonseca 1924-2017. Honorary member of the PCCMCA 2019-01-08T14:40:55-06:00 Rodolfo Araya Villalobos 2018-10-17T00:00:00-06:00 ##submission.copyrightStatement## Gardenia: characteristics, uses, pests and diseases and basic aspects of its cultivation 2019-04-19T14:52:39-06:00 Yanelis Castilla-Valdés <span>The gardenia (</span><span class="CharOverride-3">Gardenia jasminoides</span><span> Ellis) is a plant that is very appreciated in gardening for the beauty and fragrance of its flowers, attractive size and the intense green color of the foliage. In contrast to its ornamental qualities, it is not one of the most used plants in Cuba and other countries, so it is necessary to promote its cultivation. The present review objective was deepening and integrating information regarding the characteristics, utility, main pests and diseases and methods of propagation of the gardenia. The sunny and warm conditions during the day and fresh at night, relative humidity upper than 60% and acid soil, rich in iron, are favorable for this species development. Between the lesser known properties of gardenia, there are the medicinal ones because its extracts have diverse pharmacological effects. Its most common diseases are of fungal origin and provoke the rot roots and foliar spots. Among the pests that have the greatest incidence stand out the insects (aphids, citrus whitefly, coccids, and thrips). Gardenia plants can be propagated by different traditional methods (seeds, air layering, cuttings, and grafting), but the application of</span><span class="CharOverride-3"> in vitro</span><span> cultivation techniques are an efficient way to achieve this purpose, since it allows accelerated multiplication and production of healthy plants, also, it constitutes an alternative for obtaining secondary metabolites with pharmaceutical properties.</span> 2018-09-01T14:40:32-06:00 ##submission.copyrightStatement## Green legume fertilizers: integration in agricultural and livestock systems in the tropics 2019-04-19T14:52:40-06:00 Edwin Castro-Rincón José Edwin Mojica-Rodríguez Juan Evangelista Corulla-Fornaguera Carlos Eduardo Lascano-Aguilar <span>In dry areas dominated by dual purpose cattle systems, the production of milk decreases significantly in the dry season. An alternative to maintaining production in the dry season is through the use of annual crops (corn and sorghum) to silage. The objective of this literature review was to compile information on aspects associated with the technology of green legume fertilizers and how they could be integrated into different agricultural and livestock production systems in tropical zones. Whether for crop production, animal feed or for use as hay directly. The use of forage crops to be sustainable requires the application of N since it is one of the most limiting elements to produce forage biomass. The use of synthetic nitrogen fertilizers is limited by high costs, and they also have adverse effects, such as production and leaching of nitrates that contaminate groundwater with negative effects on human health and production of nitrous oxide, which is a potent greenhouse gas which has negative effects on global warming. An alternative to the use of chemical nitrogen is the use of N-fixing forage legumes as green fertilizers to supply the N required by forage crops, but the adoption of green manures in livestock systems is very low, possibly since the benefits obtained with their use are not reflected directly in milk production at critical times of the year, which is important for producers. It is necessary to select N-fixing legumes with high biomass production and drought tolerance and demonstrate that these legumes have positive effects directly in the dry season.</span> 2018-09-01T14:40:31-06:00 ##submission.copyrightStatement## Impacts of drought in the primary sector of the Central American Dry Corridor 2019-04-19T14:52:41-06:00 Oscar David Calvo-Solano Luis Eduardo Quesada-Hernández Hugo Hidalgo Yosef Gotlieb <p class="Texto ParaOverride-2">Central America has suffered the impact of several extreme hydrometeorological events, among which drought stands out. This has had adverse effects of different kinds in the region known as the Central American Dry Corridor (CSC, in Spanish). The objective of this work was to describe the impacts that agriculture, livestock and economy of the CSC countries have suffered due to droughts: agricultural, hydrological and socioeconomic. A review of primary and secondary sources was carried out, such as scientific articles, press reports and studies reports from national and international institutions. The most recurrent impacts are at the level of basic grains and cattle, also due in part to the ENSO (El Niño-Southern Oscillation) phenomenon. Because the CSC is a region with high vulnerability to drought and other extreme hydrometeorological events, it is necessary to carry out an adequate characterization of the CSC taking as a baseline similar studies like this one, that orginate a discussion process for the design and implementation of strategies and anticipated public policies of adaptation and mitigation of the drought in the CSC and therefore, lead to improve the quality of life of its population.</p> 2018-09-01T14:40:30-06:00 ##submission.copyrightStatement## Compilation of primers for the detection and classification of phytoplasmas 2019-04-19T14:52:42-06:00 Karina Araujo-Ruiz José Manuel Cambrón-Crisantos José Luis Cruz-Jaramillo Liliana Elizabeth Ronces-Frutos José Abel López-Buenfil José Gustavo Torres-Martínez <p class="Texto ParaOverride-1">Phytoplasmas are phytopathogenic prokaryotes of great importance because they have been linked to numerous diseases around the world. The aim of these research was to present the general characteristics, the size and composition of the genome and the genes and/or regions used as molecular markers for the identification and characterization of phytoplasmas. Among its main hosts are fruit and wood trees, vegetables, cut flowers and weeds, which generate alterations in the hormonal balance producing symptoms such as philodias and virescence. Because its isolation<span class="CharOverride-3"> in vitro</span> has not been possible, the detection and characterization has been carried out, mainly, with molecular techniques. In addition, the use of New Generation Sequencing (NGS) has allowed to know the complete genome of some phytoplasmas, as well as the regions and genes that constitute it. In the present bibliographic review, the information generated from the molecular techniques and NGS sequencing is compiled, as well as the primers reported to identify some groups of phytoplasmas.</p> 2018-09-01T14:40:29-06:00 ##submission.copyrightStatement## Chemical characterization of new varieties of drought tolerant Cenchrus purpureus 2019-04-19T14:52:43-06:00 José Leonardo Ledea-Rodríguez Dani Verdecia-Acosta Orestes La-O-León Jorge Valentín Ray-Ramírez Juan José Reyes-Pérez Bernardo Murillo-Amador <p class="Texto ParaOverride-1">Climate change has modified the behavior of climate variables, for this reason, pastures manifest a seasonal productive behavior, where the deposition of structural carbohydrates is modified and in some cases the absorption of minerals. The objective of this study was to characterize, in varieties of <span class="CharOverride-4">Cenchrus purpureus</span> tolerant to drought, the chemical composition of leaves and stems at different ages of regrowth in conditions of intense seasonal drought. The experimental period covered the years 2013 to 2015, in the Experimental Station of Pastures and Forages of the Institute of Agricultural Research “Jorge Dimitrov”. In a completely randomized design with the factorial arrangement was used, and the dynamics of the chemical composition of leaves and stems of new varieties of <span class="CharOverride-4">C. purpureus </span>were characterized, in different ages of regrowth and different climatic periods (rainy and not very rainy), and their combination (4 x 3 x 2). The interaction age of regrowth with climatic station affected the chemical composition of the leaves (p≤0.001), altering the content of cellulose (Cel), hemicellulose (Hcel), neutral detergent fiber (NDF), acid detergent fiber (ADF), cellular content (CC), calcium (Ca) and silica (Si), while in the stems this interaction only affected the concentration of ADF. The isolated effect of the climatic season modified in leaves (p≤0.01) the content of phosphorus (P) and lignin (Lig), it stems the P content (p≤0.001). When the regrowth age varied, there was a modification of the chemical composition of the leaves (crude protein and Lig) and stems (crude protein). The new varieties of <span class="CharOverride-4">C. purpureus</span> under conditions of degradation and intense seasonal drought showed a pattern of chemical behavior similar to that of tropical grasses, but with low contents of protein and phosphorus.</p> 2018-09-01T14:40:28-06:00 ##submission.copyrightStatement##