Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Characterization studies contribute to establishing better bases for the design of strategies for exploitation, conservation and genetic improvement. In this context, the morphological variation of a collection of native maize (Zea mays L.) populations from central Chiapas, México, was characterized. Twenty-five (25) populations were evaluated under a design of complete random blocks in three contrasting environments. Fourteen (14) morphological variables were found and combined variance analysis, correlation analysis and biplot graphing were applied based on the first two principal components. Significant differences were detected between populations for all the variables, something considered as an indicator of diversity. The accessions were grouped into four groups, named: Olotillo complex, which gathered the populations of greater plant height (245 to 295 cm), late flowering (63 to 68 days), and low number of lines (8 to 9); Tuxpeño, whose populations presented greater height than the mean (244 to 272 cm), masculine flowering representative of the warm climate (60 to 65 days) and intermediate value of lines (10 to 12); Zapalote Grande, which was populations of precocious cycle (51-55 DFM) and lower plant height (212 to 227 cm); and finally, Tuxpeño that included populations with a higher number of lines (12.8 to 13.3) with intermediate values in the characters measured. The variation identified can be the basis for genetic improvement and different conservation strategies.

The Thermal Constant (TC) is the units of accumulated heat that a plant needs to complete its cycle, since temperature is one of the most decisive climate elements in plant development. This research was done with the purpose of defining the TC of Hylocereus undatus, unknown value for this species. The reproductive phenology of three selections of dragon fruit (‘Ana’, ‘Juana’ and ‘Carlos’) was studied in the 2013 and 2014 cycles, established on the INIFAP Campo Cotaxtla field in Medellín, Veracruz, México. The register dates of the phenological phases were determined: flower budbreak, anthesis, fruit set, and fruit maturity, as well as the duration in days of the phenological stages (budbreak-anthesis, anthesis-fruit maturity, and complete period). The TC was calculated in degrees-day-development (DDD), using the residual method. The reproductive period of the dragon fruit began after the maximum temperature values were found (<34 °C). The TC in each phenological stage did not vary statistically among fluxes, cycles, or among selections. For the stage of budbreak-anthesis, the TC was 360 DDD, for anthesis-fruit maturity the TC was 537 DDD, therefore, to complete the budbreak-fruit maturity period, the dragon fruit took 897 DDD.

The study was carried out in the Biotechnology Laboratory of the Agricultural Sciences School Campus IV (UNACH) with the objective of determining the effect of two traditional growth regulators and one homobrassinolide (brassinosteroid) added in two concentrations to the MS medium for the in vitro growth of Gran Enano banana (Musa sp.). It was established on two growth media based on modified Murashige and Skoog (MS) (1962), and three growth regulators, BAP, AIA and Br in two concentrations of 2 mg L-1 and 4 mg L-1, at pH of 5.6. The explants were incubated at 26±1 °C, 60% H.R., I.L: 45 mE.m-2 s-1 and a light period of 16 hours light and 8 darkness; in total, 14 treatments with 10 repetitions in a completely random design. The number of buds, leaves, roots and height were measured. The results indicated differential effect between growth media and concentrations of growth regulators. In the radical induction, the MS medium at 50 % in interaction with AIA and brassinosteroid increased the number of roots in the explants, while the number of leaves increased with BAP and brassinosteroid and decreased with AIA.

This article is a philosophical elucidation about the concept of nature in relation to man. The question is not idle: is there something such as nature, or is it only a way of stringing together everything that is not man-made? Given that the ethical, political and instrumental dimension that will be adopted depends on the way in which this concept is constructed. The concept of life is also analyzed. It is concluded that the solutions for biosphere sustainability must be radical and that there is no need to depend on the ghost of our disappearance as a species to make definitive and long-term decisions.

The accessions from a germplasm bank of “siete caldos” peppers (Capsicum annuum) from the Escuela de Estudios Agropecuarios de Mezcalapa, Chiapas, México, were evaluated, grown under shade house and outdoor conditions. The fruits harvested from different tonalities were analyzed with food science techniques. The results showed that 86 % of the moisture content of green fruits harvested outdoor do not present significant statistical differences against shade house pepper fruits. Of the protein content, 21 % is the highest value reported for purple color fruits under the two cultivation conditions, and the red fruits presented values of 8.00% and 7.34%, for outdoor and shade house, respectively. The fruits in tonalities of red-green and red-dark-green color showed the highest values of raw fiber (16.10% y 16.50%, respectively) outdoor and ash (9.0%).

The objective of this research was to evaluate and select Creole maize (Zea mays L.) varieties for tolerance to germination and other morphological characteristics of the seedlings under water deficit. Forty-two (42) varieties collected in areas with recurring drought in Chiapas, México, were evaluated. The study was carried out in the Plant Physiology lab of INIFAP’s Central Chiapas Experimental Field. The water deficit was induced with polyethylene glycol PM 8000 (SIGMA) at a concentration of 12.5 g in 100 ml of water, originating a water deficit of -5 baryes. A completely random experimental design with four repetitions was used. The variance analysis detected significant statistical differences between Creole varieties for percentage of germination, length of the coleoptile, length of the mesocotyl, and total dry weight of the seedling, under water deficit, indicating great genetic variability between them. The following Creole varieties were selected: Olotillo, Azul, Amarillo, Tuxpeño, Jarocho and Rocamex, because of their higher tolerance to germination and morphological characteristics under water deficit, which should be used in the programs for genetic improvement for drought tolerance in the subhumid warm region of Chiapas and other regions with similar climate.

The objective of this study was to evaluate the relationship between the body weight (BW) and the hip width (HW) in replacement heifers bred in the humid tropics. The BW and HW were determined in 200 crossbred heifers. The relationship between the BW and the HW was estimated through regression models. The correlation coefficient between the BW and the HW was 0.97 and the regression equations had a coefficient of determination of 0.95. In this study, the exponential model was the one that presented the best adjustment. The equation was BW (kg)=0.33xHW1.83 (P=0.0001, r2=0.95, MES=369.29, SRD=19.21 and n=200). The mean error square (MES) varied from 369.29 to 424.14 with standard residual deviations (SRD) (SRD, kg) of 19.21 to 20.59, representing 6.8 % to 7.3 % of the average BW. The HW allows predicting with precision the BW of crossbred heifers kept under conditions of the humid tropics, the prediction error corresponded to 6.8 % of the average BW.

Rambutan (Nephelium lapacceum) is an exotic fruit with increasing demand, whose presence in México has scarcely been attempted to be explained based on some approaches to reality. In this study an ordered recounting of facts related to the introduction of rambutan in México is presented, by doing interviews with people who were part of this history in Soconusco, Chiapas, and complemented with bibliographical information. The presence of this species in México is consequence of a series of isolated events that took place during a period of almost 60 years, since the first attempt to introduce it in 1959. In this lapse of time rambutan was introduced into México at least five times, primarily in the region of Soconusco, Chiapas, which explains the high genetic diversity of the fruit produced in México. The technique of graft propagation and the search for commercialization paths were defining factors for the establishment and dissemination of this crop, with great economic potential for México.

The main objective of this investigation was to study the receptivity, application and usefulness of small farmers in the framework of the project Establishment and Management of Integrated Farms. The project started in 2014 and finished in December 2016; it was conducted in the ecosystem of Mata Redonda wetland, Rosario de Nicoya, Costa Rica.The project was born thanks to the results of the relation between the sustainable agricultural production and the conservation of wetlands, which were identified in the execution of the Plan General de Manejo Refugio Nacional de Vida Silvestre Mata Redonda (General Plan for Management of Mata Redonda National Wildlife Refuge) by the Centro Mesoamericano de Desarrollo Sostenible del Trópico Seco (Mesoamerican Center for Sustainable Development of the Dry Tropics- CEMEDE) in 2013. This paper analyzes the interest expressed by the community during the implementation of the project. It also analyzes the farmers’ experience when implementing alternative, sustainable, agricultural technologies as measures for adaptation to the climate change in their farms, as well as the difficulties and achievements these producers faced. The project consisted of a participatory work between the academy, the community and the administration of the Área de Conservación Tempisque (ACT-Tempisque Conservation Area), which promoted the implementation of sustainable technologies for the conservation of the wetland ecosystems.

This paper mainly aims to determine the contributions to human development (HD) and the expansion of university extension capabilities the National University of Costa Rica is currently making. The paper analyzes the coherence between the university extension and the values of human development approach welfare, participation, equity and sustainability (Boni and Gasper, 2011). It also seeks to contribute to human development in terms of the capabilities generated in the beneficiary population of three university projects; this contribution would be through the evaluations made by local people and the staff responsible for the projects. We have achieved an approach to the Latin American and Costa Rican extensionist tradition through the programs, projects and extension activities of the National University. In this paper, we present the human development and capabilities approach from the perspectives of Sen and Nussbaum, and the views of some authors on the contribution of this approach to university quality. The case study was implemented as a method of analysis; qualitative techniques were used to deepen the evaluations of people, such as semi-structured interviews, participant observation, and document review. We managed to analyze and discuss the evidence found in relation to the theoretical framework: the presence of the values of human development in philosophy and extension activities; a list of expanded capabilities through university policies; and the fact of highlighting that conversion factors (such as personal characteristics, environmental characteristics of the locations, and the presence of institutions) are crucial to the expansion of freedoms. Despite some weaknesses and challenges, we consider as highly important that Latin American universities keep the accompaniment to the local population as a determining factor for the human development of depressed communities.