Escuela de Ciencias Agrarias

URI permanente para esta comunidadhttp://10.0.96.45:4000/handle/11056/14688

La Escuela de Ciencias Agrarias (ECA) de la Universidad Nacional, genera conocimientos y capacidades por medio de la docencia, investigación, extensión y servicios, que contribuyen al desarrollo de la agricultura sostenible, los agronegocios y la competitividad, y de los espacios rurales y territoriales, para mejorar el desarrollo humano sostenible y equitativo de la sociedad.

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Mostrando 1 - 9 de 9

A new dagger nematode, Xiphinema poasense N.Sp. (Nematoda: Longidoridae), from Costa Rica
(Universidad Nacional, Costa Rica, 2018) Varela-Benavides, Ingrid; Peraza-Padilla, Walter; Cantalapiedra-Navarrete, Carolina; Palomares-Rius, Juan; Castillo, Pablo; Archidona-Yuste, Antonio
A new dagger nematode, Xiphinema poasense N.Sp., is described and illustrated from three populations extracted from soil associated with a combined plantation of Eucalyptus sp., Cupressus sp. and Pennisetum sp. and wild plants from a tropical pre-montane forest in Costa Rica. The new dagger nematode is characterised by a moderate body size 2612 (2416-3042) μm long, a rounded lip region 15.0 (13.5-16.5) μm broad, separated from the body contour by a shallow depression, amphidial fovea large, stirrup-shaped, a very long odontostyle (175 (164-188) μm), stylet guiding ring located 167 (136-181) μm from anterior end, vulva situated anterior to mid-body (36-40%), anterior genital branch complete but strongly reduced, without uterine differentiation, female tail short, hemispherical to convex-conoid with a c′ ratio = 0.7 (0.6-0.8) and bearing two pairs of caudal pores, and male absent. Integrative diagnosis was completed with molecular data using D2-D3 expansion segments of 28S rRNA, ITS1 region, partial 18S-rRNA and the partial mitochondrial gene cytochrome c oxidase subunit 1 (coxI). The phylogenetic relationships based on D2-D3 segments of this species with other Xiphinema spp. of the X. non-americanum group indicated that X. poasense N.Sp. clustered with other species with a reduced anterior genital branch from the morphospecies Group 2, viz., X. costaricense and X. krugi. However, the phylogeny of coxI and partial 18S rRNA gene revealed that the new species did not cluster with Xiphinema species having the anterior genital branch absent or reduced (i.e., morphospecies Groups 1 and 2, respectively). © 2018 Copyright 2018 by Koninklijke Brill NV, Leiden, The Netherlands.
Applying a ribosomal DNA sequence "barcode" to assess nematode biodiversity in a Costa Rican rainforest preserve.
(Universidad Nacional, Costa Rica, 2009) Esquivel Hernández, Alejandro; POWERS, T. O.; NEHER, D. A.; MULLIN, P.; GIBLIN-DAVIS, R. M.; KANZAKI, N.; STOCK, S. P.; MORA, M. M.; URIBE LORIO, L
Comparisons of nematode communities among ecosystems have indicated that, unlike many organisms, nematode communities have less diversity in the tropics than in temperate ecosystems. There are, however, few studies of tropical nematode diversity on which to base conclusions of global patterns of diversity. This study reports an attempt to estimate nematode diversity in the lowland tropical rainforest of La Selva Biological Research Station in Costa Rica. We suggest one reason that previous estimates of tropical nematode diversity were low is because habitats above the mineral soil are seldom sampled. As much as 62% of the overall genetic diversity, measured by an 18S ribosomal barcode, existed in litter and understorey habitats and not in soil. A maximum-likelihood tree of arcodes from 360 indi vidual nematodes indicated most major terrestrial nematode lineages were represented in the samples. Estimated ‘species’ richness ranged from 464 to 502 within the four 40 × 40 m plots. Directed sampling of insects and their associated nematodes produced a second set of barcodes that were not recovered by habitat sampling, yet may constitute a major class of tropical nematode diversity. While the generation of novel nematode barcodes proved relatively easy, their identity remains obscure due to deficiencies in existing taxonomic databases. Specimens of Criconematina, a monophyletic group of soil-dwelling plant parasitic nematodes were examined in detail to assess the steps necessary for associating barcodes with nominal species. Our results highlight the difficulties associated with studying poorly understood organisms in an understudied ecosystem using a destructive (i.e. barcode) sampling method.
Changes in food behavior during the first lockdown of COVID-19 pandemic: a multi-country study about changes in eating habits, motivations, and food-related behaviors
(ELSEVIER, 2022-02-10) Lamy, Elsa; Villalobos, Keylor; Viegas, Claudia; Rocha, Ada; Lucas, María Raquel; Tavares, Sofía; Capela e Silva, Fernando; Guedes, David; Laureati, Mónica; Zian, Zeineb; Salles Machado, Alessandra; Ellssel, Pierre; Freyer, Bernhard; González Rodrigo, Elena; Calzadilla, Jesús; Majewski, Edward; Prazeres, Ibrahim; Silva, Vlademir; Juračak, Josip; Platilová Vorlíčková, Lenka; Kamutali, Antonino; Tschá, Elizabeth Regina; Želvytė, Rasa; Monkeviciene, Ingrida; Elati, Jalila; De Souza Pinto, Ana María; Midori Castelo, Paula; Anzman-Frasca, Stephanie
The COVID-19 pandemic resulted in severe, unprecedented changes affecting the world population. Restrictions in mobility, social distancing measures, and the persistent social alarm, during the first period of pandemic, resulted in dramatic lifestyle changes and affected physical and psychological wellbeing on a global scale. An international research team was constituted to develop a study involving different countries about eating motivations, dietary habits and behaviors related with food intake, acquisition, and preparation. This study presents results of an online survey, carried out during the first lockdown, in 2020, assessing food-related behavior and how people perceived them to change, comparatively to the period preceding the COVID-19 outbreak. A total of 3332 responses, collected from 16 countries, were considered for analysis [72.8% in Europe, 12.8% in Africa, 2.2% in North America (USA) and 12.2% in South America]. Results suggest that the main motivations perceived to drive food intake were familiarity and liking. Two clusters were identified, based on food intake frequency, which were classified as “healthier” and “unhealthier”. The former was constituted by individuals with higher scholarity level, to whom intake was more motivated by health, natural concerns, and weight control, and less by liking, pleasure or affect regulation. The second cluster was constituted by individuals with a higher proportion of male and intake more influenced by affect-related motivations. During this period, a generalized lower concern with the convenience attributes of foods was noted (namely, choice of processed products and fast-food meals), alongside an increase in time and efforts dedicated to home cooking. Understanding the main changes and their underlying motivations in a time of unprecedented crisis is of major importance, as it provides the scientific support that allows one to anticipate the implications for the future of the global food and nutrition system and, consequently, to take the appropriate action.
Establecimientos de un programa de producción de esquejes de Aglaonema Commutatum bajo invernadero en la empresa Orocosta Agroindustrial S.A., Horquetas de Sarapiquí, Heredia Costa Rica.
(Universidad Nacional, Costa Rica, 2026-01-28) Jiménez Araya, Pablo Antonio; Arboleda Julio , Esteban
This study aimed to establish a production program for Aglaonema commutatum cuttings under greenhouse conditions as an alternative to diversify the income sources of Orocosta Agroindustrial S.A. The research was conducted in Horquetas de Sarapiquí, Heredia, Costa Rica, from January to May 2024. Included the development of an initial inventory of mother plants, nutritional and substrate analyses, determination of average cutting production per variety, and evaluation of plant recovery time after harvest. Technical management practices were also implemented to ensure quality, plant health, and production efficiency. The results allowed the establishment of key production parameters and the estimation of the number of mother plants required to meet market demand. It is concluded that the production of aglaonema cuttings is technically and economically viable, representing a growth opportunity in the ornamental plant market.
Evaluation of the viability of microencapsulated Trichoderma longibrachiatum conidia as a strategy to prolong the shelf life of the fungus as a biological control agent
(PubMed Central (PMC), 2025-01-15) Arias-Chavarría, Luis Diego; Batista-Menezes, Diego; Orozco-Cayasso, Steffany; Vargas-Martínez, Alejandro; Vega-Baudrit, José Roberto; Montes de Oca-Vásquez, Gabriela
Trichoderma is an antagonistic fungus used commercially; however, the viability of these formulations is affected by biotic and abiotic factors. In this research, microcapsules of sodium alginate reinforced with nanocellulose and/or chitosan were developed to encapsulate T. longibrachiatum conidia and characterized by SEM, FTIR, and TGA. The viability of the microencapsulated conidia was evaluated through different temperatures (room temperature, 5°C and 37°C), as well as their in vitro antagonistic potential against Fusarium oxysporum. The formulations evaluated had encapsulation efficiencies above 92% and the microcapsules with alginate, chitosan, and nanocellulose maintained 100% viability at 37°C for 2 months. In addition, all formulations evaluated retained antagonistic ability against F. oxysporum. These findings support the use of alginate, nanocellulose and chitosan for the formulation of microcapsules to maintain the viability of T. longibrachiatum conidia over time and at different temperature conditions.
Fruit Characterization of Cocos Nucifera L. (ARECACEAE) Cultivars From the Pacific Coast of Costa Rica and the Philippines
(Kluwer Academic Publishers, 2000-10-01) Vargas, Alfonso; Blanco, Fabio A.
Tall coconut cultivars from the Pacific coast of Costa Rica and the Philippines (San Ramón, Tagnanán, and Laguna), were evaluated for fruit characteristics. Most of the introduced cultivars showed extremely large heterogeneity. A cluster analysis, based on the Ward method, classified the palms into four groups with high internal homogeneity. Some of the evaluated coconut palms from the Costa Rican Pacific area had nut characteristics similar to the San Ramon and Tagnanan palm groups but not to the Laguna group. At the association level used (semipartial R2 = 0.10), another group which included the remaining palms sampled from the Costa Rican Pacific coast was constituted.
Insights into the Consumption of Edible Flowers in Costa Rica
(Nova Science Publishers, Inc., 2021) Guiné, Raquel; Correia, Paula; Florença, Sofía; Moya, Keylor; Anjos, Ofélia
Edible flowers (EF) have been used since ancient times in some parts of the world, either for culinary purposes or as a traditional medicine. Their use in modern times is supported by high reputed chefs, who use and promote them in their gourmet preparations as highly valuable assets, having a great potential for decoration, flavour and aroma, besides their nutritional value. Moreover, they are very rich in some phenolic compounds, such as anthocyanins, responsible for the colours and which have a proven antioxidant capacity, so exerting a beneficial effect on the human body against oxidation and cellular stress. This study describes how the people in Costa Rica perceive edible flowers, if and how they consume them, how they buy them and how much they are acquainted with possible health risks associated with their consumption. It comprised a questionnaire survey undertaken on a sample of 130 participants from Costa Rica, carried out through the internet. The results obtained indicated that the great majority of the participants know what EF are, but they recognize that there is not enough information about this topic. Only about 30% of the participants are aware that consuming EF can bear some risks, which are associated with toxicity and possible presence of pesticides. About half of the participants have already consumed EF, particularly in salads, and for decoration and confection of dishes. The most consumed flowers are rose, camomile and pumpkin flower. The most relevant motivations to consume EF are their taste and aroma, aswell as being a novelty and useful for decoration. These results allow us to understand some eating habits, knowledge and consciousness of people from Costa Rica towards EF.
Mudanças e reconfigurações da Agroindústria Sucroenergética Brasileira a partir da década de 1990: uma retrospectiva
(Universidade Federal Rural do Rio de Janeiro, (UFRRJ), 2023-05-31) Cerdas Vega, Gerardo
O artigo apresenta o processo de mudanças institucionais, organizacionais e políticas experimentado pelo complexo agroindustrial canavieiro no Brasil, em particular pelos grupos de maior poder econômico, concentrados no estado de São Paulo, a partir da década de 1990 até o ano de 2014. Esses grupos, denominados no contexto da pesquisa como Agroindústria Sucroenergética Brasileira (ASB), passaram de um modelo de organização setorial de corte burocrático e estado-cêntrico, para um de caráter mais aberto, flexível e diversificado no tocante aos atores participantes, mas no qual a presença e a participação do Estado brasileiro continuou como parte essencial das relações entre o poder estatal e a grande agricultura patronal canavieira.
Selection Response of Growth Rate in Rabbits for Meat Production
(International Academic Publisher Sciences, 1992-09-21) Estany, J.; Camacho, J.; Baselga, M.; Blasco, A.
Genetic and environmental trends in 2 lines of rabbit (B and R) selected on individual weight gain (WG) from weaning (4 wk) to slaughter (11 wk) were estimated using mixed model methodology. Line B was derived from the California breed and line R was a synthetic of stock of different origin. The data were collected from a single herd and comprised 7 718 individuals in line B and 9 391 in line R, the lines having 12 and 9 generations of selection respectively. Realized responses in the 2 lines were 2.7% and 2.2% of the initial mean per year respectively and showed that selection on WG was effective but was less than expected. Selection on slaughter weight (SW) and effects of selection on other economic traits are discussed. It is concluded that selection on either WG or SW is a simple method for improving growth rate in rabbit sire line stocks.

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