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

Introduction. In Buenavista, Michoacan, Mexico, the area planted with papaya (Carica papaya L.) is of the Maradol Roja variety and most farmers use a conventional agricultural production model, where the productivity and profitability of the crop is not known with certainty. culture; therefore, it is important to know these two variables in order to obtain an efficient production that in the medium term allows them to improve the socio-economic environment of the farmers. Objective. Compare a sustainable agricultural production model against the conventional papaya production model, to identify agricultural production and the cost-benefit ratio. Materials and methods. The experiment was carried out in the municipality of Buenavista, Michoacan, Mexico during 2015. It was characterized by having two experimental units, one treatment per unit [sustainable and conventional] with a simple randomized sampling. Fruit weight, total soluble solids, and fruits per plant were evaluated. Statistical analysis included Levene’s test, Kolmogorov-Smirnov, and Lilliefors test, ANOVA and non-parametric Mann-Whitney U test. Economic analysis was carried out with the indicators: total investment cost, total income, cost-benefit ratio, profitability, and break-even point. Results. The sustainable model showed for fruit weight 1.71 kg, 38.06, fruits per plant, total investment cost of USD $ 8,736.83 ha-1, cost-benefit ratio of 2.24, and an equilibrium point of 38.47 %. The conventional model showed 2.20 kg in fruit weight, 53.72 fruits per plant, a total investment cost of USD $ 9,262.03 ha-1, cost-benefit ratio 1.08, and an equilibrium point of 90.11 %. Conclusion. The conventional model was economically unfavorable, so it is suggested to gradually improve it until it becomes profitable. The sustainable model proved to be very economically attractive and to have efficient use of local natural resources.  

Introduction. The genus Meloidogyne contains many species and their correct diagnosis of these must be based on the use of multiple tools, which in diagnostic laboratories allow a correct and reliable evaluation, specially for quarantine nematodes. The proper identification of a phytonematode is important not only to establish an appropriate control strategy, but also to avoid its spread to other areas where it could cause damage that would result in economic losses. Objective. To perform taxonomic and molecular studies to confirm the Meloidogyne species, associated to a coffee plantation located in Barva, Heredia. Materials and methods. Soil and root samples were collected in a coffee plantation located in Barva, Heredia, Costa Rica, which were processed in the Nematology laboratory of the School of Agricultural Sciences at the Universidad Nacional (UNA), using the centrifugation-flotation method in sugary solution and molecular techniques. Results. On average, 30 J2 100 cc-1 were counted in soil and 1000 J2 10 g-1 of roots of the root-knot nematode. Taxonomic and molecular techniques allowed to identify that the females and juveniles extracted from coffee roots corresponded to Meloidogyne exigua. Analysis of the sequences generated by PCR and the use of the DraI enzyme confirmed the identity of the species with 99 % similarity when compared to sequences from Costa Rica and Nicaragua, reported in the Genbank. Conclusion. Using different morphometric and molecular techniques, M. exigua associated with a coffee plantation was identified.

Introduction. In the wachado system, the soil used is continuously rotated with potatoes (one or two harvests) and pasture for dairy cattle (two to three years). Wachado is a pre-Columbian production system that only uses a manual tool, and is practiced and conserved by indigenous communities on Andean slopes of Colombia, Peru, and Ecuador. The system is relegated by the intensive mechanization systems in which research predominates, unlike the wachado research where it is scarce. Objective. To evaluate the effect of sowing in wachado on the state of some physical properties of the soil. Materials and methods. The work was carried out in three locations in the department of Nariño, Colombia, between January and March 2015. In each locality, soil samples were taken at different depths, and rain simulations were performed in triplicate to determine volumetric, water regulation, structural stability, and texture indicators in plots that were on pasture for three years. Results. After thirty years of use, the wachado soil retained a low apparent density (0.41 to 0.91 g cc-1), high total porosity (56 % to 70 %), high moisture content at low, and high suctions (75 % and 40 %). In addition, moderate structural stability (DPM greater than 1.5), 60 % microporosity, low infiltration (19 % to 33 %), and high runoff (66 % to 81 %) were found. Conclusion. After thirty years of potato cultivation under the wachado system, the values of the physical indicators of the soils showed that the minimum tillage and the potato/grass rotation, reduced soil degradation and regulated the hydric condition.

Introduction. The evaluation and selection of new fodder species with appropriate production and quality attributes is a safe and effective strategy to improve the efficiency of milk production systems in Colombia. Objective. To describe the development process and the main characteristics of Altoandina, a new variety of fodder oats. Materials and methods. During the second half of 2016, an agronomic assessment test (PEA) was carried out in four locations in the Altiplano Cundiboyacense subregion and in four locations in the Altiplano of Nariño subregion, in a randomized complete block design, with two genotypes of fodder oats AV25-S and AV25-T and three varieties (Avenar, Cajica, Cayuse). Results. AV25-S and AV25-T showed: tolerance to overturn unlike the three controls that showed a overturn of more than 30%, resistance to leaf and stem rust, and green forage performance of 64.6 and 65.3 t ha-1, respectively, higher than that obtained in Avenar (55.5), Cajica (43.7) and Cayuse (59.1). Conclusion. AV25-T for its tolerance to overturning, resistance to leaf and stem rust and green fodder yield superior to commercial varieties, was registered in the national cultivar system as a new fodder variety called Altoandina, with recommendation for the Cundiboyacense Altiplano and Nariño Altiplano.

Introduction. There is not much information on pure cattle with a genealogical certificate in Costa Rica. It is necessary to know the status of this population to direct efforts towards the productive improvement of the Zebu cattle breeds. Objective. To update the database of the Costa Rican Cebu Cattle Breeders Association (ASOCEBÚ), characterize this population and analyze the use of males of the gray Brahman breed in the country. Materials and methods. An inventory was done in 121 herds to update the Association’s database to 2018. The information was sorted by breed, sex, age, total animals, breeders, socio-economic region, province, and canton. The frequency of use of gray Brahman breeders was determined. Results. A total of 10 995 pure animals were counted, distributed in six breeds (gray Brahman, red Brahman, Nelore, Gyr, Guzerat, and Indubrasil). The gray Brahman breed predominated with 74.5 % of the population and 76.8 % of the total of breeders. The Chorotega region had the highest registered population (49.5 %) and the highest number of breeders (37.2 %). 55.8 % of the total population came from ten breeders, however, the largest number of herds corresponds to farms with few animals. In the gray Brahman breed, 60.8 % of the population comes from domestic bulls, and 39.2 % from other countries. Conclusion. Registered pure zebu cattle are distributed throughout the whole country. Attention should be put to genetic management to minimize inbreeding. Census and survey managers are encouraged to include the purebred populations in their assessments.

Introduction. The fall armyworm, Spodoptera frugiperda, is one of the world’s most devastating pests. Although originally from the Americas, this insect has become a global food security threat. The reason is that its polyphagia and adaptability combine with the effects of climate change. In Costa Rica, the species of the Spodoptera order, are considered minor pests in sugarcane production. Nevertheless, there is a knowledge gap in population dynamics of the moths of this genus. Objective. Monitor the populations of S. frugiperda, S. sunia, and S. exigua species in a sugarcane field. Materials and methods. The study was conducted in a sugarcane plantation of the variety CC 01-1940, located in Guanacaste, Costa Rica between February 2018 and May 2019. Sexual pheromone-baited traps formulated for S. frugiperda, S. sunia, and S. exigua were used, each pheromone corresponded to a treatment and ten replicates of each one were established. The abundance of each species was compared and correlated with several climatological variables. Results. The highest percentage of catches corresponded to S. frugiperda, followed by S. sunia, while the captures of S. exigua were marginal. For both S. frugiperda and S. sunia, the dry season months favored larger populations, so factors such as higher average temperature, thermal amplitude, and lower relative humidity were associated with higher captures in the traps. Conclusions. Increases in the average temperature and decrease in rainfall periods could increase the incidence of Spodoptera genus as pests in sugarcane production.

Introduction. Jatropha curcas L., is a species with high oil content suitable for biofuel; however, due to its wild condition, the yield of fruit and oil is low; therefore, it warrants genetic improvement. Objective. To know the productive performance of J. curcas in three ecoregions of Colombia. Materials and methods. The work was carried out from 2012 to 2014. A randomized complete block design with fifteen genotypes in three ecoregions (dry Caribbean, Inter-Andean Valley and Orinoquia) was established. The AMMI model and its biplot graph were used to determine phenotypic stability of the fruit yield and with the oil yield the net benefit and the benefit-cost ratio were determined. Results. In two of the three ecoregions used; dry Caribbean and Inter-Andean Valley, J. curcas presented an accumulated fruit yield of 3.6 t ha-1 and 6.7 t ha-1, respectively; in the Orinoquia region the yield was less than 0.1 t ha-1. The cost of a liter of J. curcas oil was US$1.07 for Albania (dry Caribbean) and US$1.24 for Espinal (Inter-Andean Valley), higher than that of African palm oil (Elaeis guineensis) of US$0.89. Conclusion. The fifteen J. curcas genotypes used in this study showed the best productive performance in Albania (dry Caribbean) and Espinal (Inter-Andean Valley), and the CJC3 genotype was the one with the best fruits and oil production.

Introduction. 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 Cercospora sojina, which compromise yield. Objetive. 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 Cercospora sojina K. Hara. Materials and methods. 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. Results. 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 Cercospora sojina in relation to commercial witnesses. Conclusion. 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.

Introduction. The rapid growth of private investment in the maize seed sector poses challenges for public breeding organizations and smaller seed companies that have increasingly less access to technologies and markets. The International Maize Improvement Consortium (IMIC-LA) created in Mexico in 2011, seeks to increase the size and competitiveness of the seed sector through access to germplasm and breeding tools. However, there are no recent basic data and measures of the sector structure that allow evaluating this and other sector initiatives. Objective. To update and analyze the structure indicators of total seed sales, participation in sales by categories of companies and type of seed varieties, and coverage with improved seeds in Mexico. Materials and methods. Maize seed sales data from interviews and surveys with seed companies and official seed production statistics from the Servicio Nacional de Inspeccion y Certificacion de Semillas (SNICS) from 2011 to 2016 were used. Results. The results showed a larger and more competitive seed sector after twenty-five years of opening, especially in the most recent years in which the rapid increase in volume and the share of sales of the national business subsector stands out. Conclusion. The broad participation of seed companies as members of the consortium and the development and commercialization of new seed varieties suggest a positive impact and a role of the consortium in the growth and competitiveness of the national subsector.  

Cretaceous porphyry copper deposits of northern Chile (28º-29º30’ S) are genetically related with dacitic to dioritic porphyries and they represent a still poorly-explored target for Cu resources. The porphyries correspond to stocks distributed into two separated discontinuous NS trending belts of different age. The location of these porphyries is generally adjacent to orogen-parallel major fault systems that extend along the studied segment and also have a marked temporal relationship with deformation events registered along these structures. A first episode of Cu-bearing porphyry emplacement took place between 116 and 104 Ma (Mina Unión or Frontera, Cachiyuyo, Punta Colorada, Dos Amigos, Tricolor porphyries). These Early Cretaceous dacite to diorite porphyries are spatially associated with the eastern segments of the Atacama Fault System, which records sinistral transpression that started at 121 Ma producing ground uplift, consequent denudation and exhumation of the Early Cretaceous magmatic arc. This resulted in a change from marine to continental deposition with an angular unconformity in the site of the back-arc basin after of eastward migration of the deformation around 112-110 Ma. At the scale of the continental margin, this deformation is correlated with early stage of the Mochica Orogenic event described in Perú. A second episode of Cu-bearing porphyry emplacement occurred between 92 and 87 Ma (Elisa, Johana, Las Campanas and La Verde deposits), which are spatially and temporally associated with the regional-scale Las Cañas-El Torito reverse fault, active between 89 and 84 Ma, during the Peruvian Orogenic Phase. This fault up thrust to the west part of the Chañarcillo Group rocks (Lower Cretaceous) over the younger upper levels of the Cerrillos Formation (Upper Cretaceous). The integrated geological mapping and geochemical data of the Early to Late Cretaceous volcanic rocks indicates that both Early Cretaceous sinistral transpression and Late Cretaceous east-west compression were not significant in promote changes in magma genesis, except for slight changes in trace element ratios (increase in Th/Ta, Nb/Ta and La/Yb) suggesting that the Late Cretaceous deformation event produced only slightly increase in crustal thickness (>40 km), but far from being comparable to major Cenozoic orogenic phases, at least along the magmatic arc to back-arc domains in the study area. Finally, our study give insights about regional geological parameters that can be used as a first order guide for exploration of Cu resources along Cretaceous magmatic belts of northern Chile, where both Early and Late Cretaceous Cu-bearing porphyry intrusions are restricted to a large structural block bounded to the west and east by Cretaceous fault systems.