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

A research was carried out in Sarapiquí, Heredia, Costa Rica, between May and September, 1993. The objective was to determine the phases of susceptibility of native papaya to anthracnose produced by Colletotrichum sp., as well as to prove the presence of anthracnose-resistant genotypes. Results indicated that at all ages, fruits examined were susceptible to anthracnose, and that a combination of native papaya genotypes may either present a permanent resistance to the disease, or never show any signs at all. There was no evidence to prove that fruits might show a temporary resistance at certain development phases, which might be camouflaged by subsequent susceptible periods. Nor was there evidence to suggest phases of greater or lesser susceptibility to the disease. Some native papaya genotypes showed resistance through the period examined.

Field studies were carried out during 1994 and 1995, in order to determine the impact of applying commercial foliar fertilizers on the ‘Clemson Spineless 80” okra fruit variety (Abelmoschus esculentus). Carboxy and Foltron applied on folliage, and Profit-G applied on the soil, as well as their combinations applied on fertilized soil were evaluated in 1994. Carboxy, Foltron and Mora-Leaf fertilizers were applied to folliage in high dosages and on non-fertilized soil during 1995. All plants were sprayed five times in 7 to 10-day intervals starting the first week of harvest. When compared to control plants, treatments applied during 1994 did not have a significant effect on fruit weight, fruit commercial yield and plant height. Treatments applied during 1995 did not influence plant height or fruit yield. The study proved that foliar fertilization does not have an impact on okra fruit yield.

Native germplasm of a Panama common bean was evaluated in order to obtain its morphologic characteristics and compare them with a group of lines and varieties of CIAT’s breeding program. The purpose was to find a germplasm that could surpass native varieties in terms of its resistance to Web Blight, yield, growing habits, and grain color. A randomized complete block design was used. Five promising lines for commercial use were selected based on yield, resistance to Web Blight, growth pattern, and grain color criteria. Three bean lines are undergoing validation trials in farms.

This study was carried out in order to determine the efficiency of paraquat and glyphosate herbicides mixed with four coadjutants for post-emergent weed control, as compared to mechanical control, as well as their economic feasibility. The study took place in Sierra de Arteaga, Coahuila, México. Information was collected 3, 13, 17, 31, and 83 days after application. A randomized block design with four repetitions was used. Glyphosato combined with adherent controlled 80% of weeds 83 days after application; glyphosate combined with moisturizer, and glyphosate combined with humic acid yielded 78.6 and 77.1% control respectively. Parquat mixed with humic acid controlled 88.4% 31 days after application and parquat mixed with adherent showed 75.1% control after 31 days. Overall, glyphosato combined with coadjutants showed better weed control 83 days after application. The cost of such treatment was $346.3 (Mexican currency), while the cost for the mechanical method was $810.00 (Mexican currency). The chemical method proved to be the most cost-efficient.

The aim of this work was to analyze changes of physiological and metabolic parameters as indicators of heat stress of cows in pasture systems. The research was carried out from 2011 to 2012 at the Turipaná Agricultural Research Center of Corpoica located in the Caribbean region in Cereté–Colombia. Environmental temperature (T) and relative humidity (H) were determined, as well as and rectal temperature (RT), skin temperature (ST), respiratory frequency (RF) and the acid-basic status of animals. The variables were measured in the morning (6:00 h) and in the afternoon (13:00 h). Significant Statistical differences were observed (p<0.05) in environmental temperature treatments (T) with 7% and 6% less temperature in p-Arbus-Arbor y p-Arbor, respectively, compared with grass treatment. There was a significant hour effect on T and H (p<0.05) and a significant treatment-hour interaction on T (p<0.05). TP and FR showed a significant treatment-hour interaction per hour (6:00/13:00 h). The results show a positive effect of shadow from trees on the physiological variables. The negative effects observed on the physiological variables of unshaded treatments impacted in a minimal way the metabolic variables suggesting homeostatic responses in the animals under the evaluated stressful environmental conditions.

The aim of this study was to explore the extent of inter-regional genetic diversity present in the cattle of Costa Rica. 1498 DNA samples were collected (year 2013) from eight different regions within the country. Allelic frequencies and major population genetic parameters were determined for eighteen microsatellite markers. An analysis of molecular variance was also carried out and genetic distances were calculated between cattle from different regions. At the national level, a high allelic diversity was found, with an average of 14.6±1.01 observed alleles and 5.6+0.37 effective alleles per marker. Observed (Ho) and expected (He) heterozygosities were 0.76±0.01 and 0.81±01, respectively. Polymorphic Information Content (PIC) and Coefficient of Inbreeding (FIS) were 0.79±0.06 and 0.06±0.004, respectively. At the regional level, Ho ranged between 0.73±0.02 in the South Central region to 0.78±0.01 in the North Huetar region. The dendrogram showed three clearly distinct groups, Metropolitan Central and West Central regions in one group, Caribbean Huetar, South Central, Central Pacific and Chorotega regions in a second group; and North Huetar and Brunca regions in a third intermediate group. Estimates of genetic differentiation (RST) were significant between regions from different groups and non-significant for regions within the same group. Genetic differences between regions are related to differential proliferation of breed groups based on their adaptability to the agro-ecological conditions and production systems prevailing in each region.

The objective was to characterize the stomata of five species of vanilla. Throughout 2012, leaf samples of V. planifolia G. Jackson, V. pompona Schiede, V. indora Schiede, V. insignis Ames and V. odorota Presl were taken from the vanilla germplasm bank at the Benemérita Universidad Autónoma de Puebla. The stomata size was obtained considering their length and width, as well as the index and stomata number of the abaxial and adaxial leaf surfaces in a randomized complete block design with three replications. V. pompona Schiede and V. inodora Schiede showed the highest stomatal index with 8713 and 8246 stomata per mm2, respectively, followed by V. odorata Presl with 4412 stomata per mm2. V. insignis Ames and V. planifolia G. Jackson showed the lowest stomata index with 2968 and 1378 stomata per mm2, respectively, in the abaxial leaf surface, these differences were statistically significant (P≤0.05). According to the position of the leaf stomata, V. planifolia G. Jackson and V. inodora Schiede can be considered to be hypostomatics since they showed stomata only in the abaxial leaf surface. V. insignis Ames, V. inodora Schiede and V. odorata Presl. can be considered to be anfiestomatic because they showed stomata in both the abaxial and adaxial leaf surfaces. V. inodora Schiede had smaller stomata compared with the other species.That is an important feature to be included in the genetic improvement of the genus Vanilla, because due to climate change, temperature will increase and precipitation will decrease, so Vainilla will require more efficient genotypes for water use.

The aim of this study was to characterize and group agroecosystems with sheep production in the eastearn side of Yucatan, Mexico. This study was held from August 2012 to April 2013. A semi-structured questionnaire was applied while interviewing 93% of producers from seven municipalities that have sheep within their agroecosystems. Random sampling, cluster analysis, ANOVA using GLM and comparison of means by Tukey (P>0.05) were performed. Four different groups of agroecosystems with sheep production were obtained: GA (elderly people in charge, middle schooling, and high amount of land, large herds or more years practicing sheep farming), GB middle age people in charge, higher schooling, intermediate amount of land, and intermediate herd size), GC (elderly people in charge, less schooling, low amount of land and reduced herd size), and GD (younger people in charge, high schooling, low amount of land, small herd size and less time performing the activity). Sheep farming was the first, second, and third productive option for 12%, 75% and 11,8% of producers. In some cases, sheep production in the region has been practiced for over 15 years; however it is the economic priority only of a small group of producers. Access to resources determined their level of development and lack of organization among sheep producers is evident.

The objective of this study was to identify nematodes species of the genus Meloidogyne associated with upland ornamental plants. We sampled ten ornamental species in a commercial nursery in San Isidro, Heredia, Costa Rica between 2011-2012. Morphometric measurements of the stylet length, the tail length, and the hyaline region of J2s, as well as perineal patterns of egg-carrying females were used for identification, Genomic DNA was extracted from single J2s and molecular analyses were performed by amplifying the intergenic region between cytochrome oxidase subunit II of the COII and the long subunit of the ARN ribosomal genes by PCR-RFLP. Combining these methods allowed identification of five species of nematodes of the genus Meloidogyne (M. arenaria, M. hapla, M. hispanica, M. incognita and M. javanica), and new restriction enzyme patterns were reported for M. hapla and M. javanica using AluI. Additionally, a preliminary report of M. hispanica was described by sequencing the 28S and 18S regions.

  The objective of this study was to evaluate in vitro the endophytic bacteria resistance to different lead concentrations. The sampling was undertaken in the first half of 2013, when tissue samples of commercial varieties of rice at tillering stage were collected in Montería, Cordoba, Colombia. Each tissue was subjected to surface cleaning. Endophytic bacteria in agar R2A medium were isolated. Population density (CFU/g tissue) was determined from each tissue, by direct counting of R2A medium surface. morphotypes were classified by shape, color, size, and appearance. A total of 168 morphotypes were isolated from root, tillers, and leaf of different commercial varieties of rice. The lead resistance test was performed in vitro, to do that, suspensions of endophytic bacteria in log phase were prepared and inoculated in minimal medium with five concentrations of lead as Pb(NO3)2. The experiment was incubated at 32 °C and agitated at 150 rpm, for five days. Every hour afterstarting the test, turbidimetry measuring at 600 nm was conducted. Results showed the ability of endophytic bacteria to grow at concentrations of 100% of Pb as Pb(NO3)2. The results of the identification with kit API20E confirmed the presence of Burkholderia cepacia and Pseudomonas putida, which showed resistance to different lead concentrations.