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

Introduction. Water is the most limiting factor in the production of extensive rainfed crops in the Pampas region of Argentina and in many parts of the world. Objective. To determine the water use efficiency, both in grain yield and in total biomass produced, for different crop sequences under different fallow managements. Materials and methods. The trial was carried out in the Experimental Station of the Facultad de Ciencias Agrarias y Forestales, J. Hirschhorn (34 ° 52´ LS, 57 ° 58´ LO), La Plata, Buenos Aires, Argentina, where since 2011 four crop sequences have been working and from 2015, in the period between summer crops, different treatments were implemented that included the use of cover crops with and without fertilization in the successor crop and the application of compost. During the period 2015 - 2018, total biomass produced, yield, and water use efficiency were determined. Results. The sequence oats (Avena sativa L.) / soybean (Glicine max L.) 2nd - corn (Zea mays L.) - sunflower (Helianthus annuus L.) - wheat (Triticum aestivum L.) was the most efficient in the use of water. In the last place, the sequence wheat / soybean 2nd-soybean-soybean-wheat was found, with the highest frequency of the soybean crop. The different types of fallows affected the water use efficiency, with less efficient values under the control treatment. Conclusion. The crop sequences analyzed showed differences in water use. The fallows with cover crops and compost were more efficient in water use by 10,85 % on average of grain, and in 3,64 % on average of biomass.

Introduction. In many countries, cow dairy products represent the majority of the alternatives; however, goat milk has nutraceutical properties that make it an option to be explored. Objective. To evaluate the physicochemical and sensory characteristics of chocolate bars made with different proportions of goat and bovine milk. Materials and methods. From January to December 2016, at the Food Technology School of the Universidad de Costa Rica, three experimental chocolates were made with different proportions of goat and cow milk (100 % bovine milk, 100 % goat milk, and a 50 % mixture of both). For three different batches of each formulation, moisture, fat, viscosity, color, texture, particle size, and overall liking were evaluated, the last one by means of a sensory panel. Results. The lowest percentage of moisture (1.81 %), the lowest average particle size (10 μm) (p≤0,05), and the highest percentage of fat (39.68 %) (p≤0,05) were obtained in goat milk chocolate. As the percentage of substitution of cow’s milk for goat’s milk increased, the viscosity and particle size decreased (p≤0,05). Regarding the color parameters, the cow’s milk chocolate was lighter (luminous). The most liked chocolate was from the bovine milk, but with positive results for all formulations. Conclusions. The substitution of bovine milk for goat milk generated products with appropriate physicochemical and sensory characteristics in all formulations.

Introduction. At present, the net blotch caused by Dreschlera teres in barley, does not have a visual scale to assess the severity of the disease in the field, therefore, the lack of a standard method for visual quantification of the disease can lead to imprecise estimates that induce to wrong conclusions. Objective. To develop a scale to assess the severity of net blotch in barley leaves. Materials and methods. One hundred leaves of different malting barley cultivars used in a trial at the experimental field of the Universidad Nacional del Noroeste de la Provincia de Buenos Aires, in the locality of Junin, Buenos Aires, Argentina, were collected in 2017, which presented different severity levels. The scale was determined with the following severity values: 1 %, 2.1 %, 4.5 %, 9.1 %, 17.8 %, 31.7 %, and 50 %. The validation of the proposed scale was carried out based on fifty barley leaves with different levels of net blotch severity, distributed to twenty evaluators without experience in estimating the damage from this disease. Validation was carried out by evaluating the severity of the leaves first without scale and then with the proposed scale. Statistical analyzes were performed using a t-test and simple linear regression. Results. The use of the scale improved the assessment of the severity in leaves with net blotch, because on average the slope of the regression of most of the evaluators increased by 15 % when they used the visual scale to evaluate the disease. Conclusion. The development of a scale to assess the severity of the net blotch in barley leaves was achieved.

Introduction. The rice cultivar INCA LP-7 is one of the eleven principal cultivars in Cuba due to their high yield potential, salinity tolerance, and pathogens resistance. However, there are not reports about the isolation, identification, and characterization of bacteria associated to this cultivar that promote its growth. Objective. To select promising bacteria from the rhizosphere of the INCA LP-7 rice cultivar to promote the crop growth. Materials and methods. The investigation was carried out in 2015 and 2016 at the Instituto Nacional de Ciencias Agropecuarias, Cuba and Instituto de Investigaciones Biologicas Clemente Estable, Uruguay. The 16SrNA gene of bacteria associated with the INCA LP-7 rice cultivar was isolated and identified by sequencing. Characterization was performed as plant growth promoting bacteria and the effect of bacterial inoculation on rice growth was studied. Results. Eleven rizopheric bacteria were isolated from rice plants of the INCA LP-7cultivar. A phylogenetic analysis showed that for the first time in Cuba Pantoea, Acinetobacter, and Mitsuaria genera were reported associated with rice. Rhizobium and Enterobacter genera were also informed as rhizospheric bacteria of INCA LP-7 rice cultivar. Some isolates solubilize inorganic phosphates and potassium, produce siderophores and indolic compound, had exo-celulase and protease activity and formed biofilm. The inoculation of isolates belonging to Pantoea genus produced an increase in height, root length, and biomass of rice plants under greenhouse conditions. Conclusions. Pantoea sp. GG1 and Pantoea sp. GG2 were the most promising strains for the inoculation of the INCA LP-7 rice cultivar. This is the first report in Cuba that focuses on the characterization of the bacterial microbiota part associated to Cuban rice cultivar INCA LP-7 and reports bacteria of the Pantoea genus as crop growth promoters.

Introduction. The study of the sperm morphometry of the white-tailed deer (Odocoileus virginianus peruvianus) allows to characterize the sperm cells of this species for conservation purposes. Objective. To determine the sperm subpopulations according to the morphometry of the epididymal spermatozoa of the white-tailed deer, using a CASA-Morph system. Materials and methods. The study was carried out in the second semester 2016, at the Universidad Nacional San Antonio Abad del Cusco, Peru. In semen samples obtained from the caudal end of the epididymis of two deer (two and four teeth), it was determined based on the CASA-Morph system, Integrated Semen Analysis System (ISAS®v1): the length, width, area, perimeter, ellipticity, elongation, regularity, and roughness of the sperm head were determined, also, the width, area, distance, and midpiece insertion angle of the sperm. Principal components analysis (PCA) was performed and the non-hierarchical k-means model was applied to determine the optimal number of clusters. Results. The morphometric variables were distributed in five PCAs: ellipticity, size, circularity, midpiece insertion angle, which explained 81.24 % of the total variance. The Cluster analysis determined four subpopulations (SP), SP1 grouped large, elongated cells with high elongation and ellipticity (21.76 %), SP2 composed of small and thin spermatozoa both in the head and in the midpiece (37.7 %). The SP3 was related to the presence of elongated cells with high values of midpiece width, ellipticity, and elongation (17.7 %), and SP4 grouped spermatozoa with intermediate size of the head and the midpiece (22.84 %). Conclusion. The determination of four sperm subpopulations in white-tailed deer semen can be the basis of assisted reproduction programs for this species.

Introduction. The characterization and diversification of goat dairy products is very important to strengthen this incipient productive sector. Objective. To compare the physicochemical and sensory characteristics of whole, skimmed and lactose-free cow and goat milks, as well as their combinations. Materials and methods. In San Jose, Costa Rica, between January and December of 2015, the contents of fat (F), non-fatty solids (NFS), acidity, protein, density, pH, viscosity, and color of the types of milk mentioned were evaluated. Also, a generic descriptive sensory analysis and a general liking test were carried out. Results. Whole goat milk presented higher values of NFS, density and acidity, and lower pH, being whiter than bovine milk, with a similar viscosity. The removal of lactose did not affect viscosity; this factor interacted with the type of milk, but did not affect the fat and protein contents. There was an interaction between the type of milk and the modifications made for the color parameters. The panelists detected significant differences for all the attributes in the products except for the acid aroma. The presence of three clusters was established for the liking test, composed by 37.4 %, 28.8 %, and 34.5 % of the judges. The first and second showed a preference for whole and whole lactose-free cow’s milk and the third for whole and whole-lactose-free cow’s and goat’s milk. The lowest overall liking was for both skimmed and lactose-free bovine and goat samples. Conclusions. The skimming and lactose removal process modified the milk at the physicochemical level, the goat milks with the highest liking were whole and whole lactose-free; the lowest overall liking was for those skimmed-lactose-free in both species.

Introduction. The use of remote sensing to identify the different plant health conditions, and its relationship with crop yield, constitutes a very important tool in the implementation of Precision Agriculture. Objective. To relate the phytosanitary status, obtained by experts through visual assessment, of oil palm (Elaeis guineensis Jacq.) plants affected by bud rot (BR), with the vegetation indices calculated with multispectral images obtained with an unmanned aerial vehicle (UAV). Materials and methods. The study was conducted in a four-hectare plantation with oil palm three-year-old, owned by CoopeCalifornia R.L., located in Parrita, Costa Rica. Four visual assessments of the BR state were conducted from December 2014 to February 2017. With these assessments, the spatial-temporal evaluation of the incidence of BR during 26 months was obtained. In the last evaluation, a flight was performed with a UAV carrying a Parrot Sequoia multispectral camera, with which vegetation indexes were calculated and then related to the BR status of the oil palm plants. Results. A high spatial and temporal variability of BR was found during all visual evaluations performed. A strong relationship was also found between data from field assessments and data generated from remote sensing. The Simple Ratio (SR) vegetation index showed significant differences between plants classified as healthy and plants classified with BR, with degrees 2 and 3 of severity. Conclusions. Field data, obtained through expert judgment, can be linked to high spatial resolution multispectral information to identify BR in commercial oil palm plantations.

Introduction. The world demand for cashew (Anacardium occidentale L.) nuts has increased at more than 7 % per year, while production keeps on a rate of 6 % per year. This global market status makes the cashew nuts and its derivatives, as a promising agricultural alternative in Colombia, where about 270 t of kernels are imported per year. Objective. To present the basic aspects of cashew crop, and to show the current technological development and future prospects in Colombia. Development. Approximately 60 % of the area cultivated with cashew in Colombia presents average yields lower than 100 kg ha-1 of walnut, considered low compared to 1000 kg ha-1 or even higher that can be obtained with a technician management of the crop, a situation due to the lack of knowledge and scarce application of technologies for intensive production by producers. However, there is currently a technological offer of cashew clones with outstanding productive and quality characteristics, as well as technical recommendations for agronomic management of the cultivation and post-harvest of the walnut, which can be disseminated and implemented to address the main limitations of the crop, to improve cashew production in a profitable and environmentally sustainable way. Conclusions. The sustainability of current commercial cashew plantations and the increase of planting areas in Colombia require the validation and adoption of innovative technologies in integrated crop and postharvest management that could have an impact on the cashew crop in the country, by presenting alternatives to improve its productive behavior, as well as profitability for producers.

Introduction. The blackberry (Rubus glaucus) is a fruit very susceptible to contamination by pesticide residues during its production stage. For this reason, the analysis of pesticide residues in this fruit is important to promote processes that contribute to ensure its quality and safety. Objective. To analyze the pesticide residues in blackberry (Rubus glaucus) fruits obtained from production areas and wholesale markets in Valle del Cauca. Materials and methods. During the second semester of 2020 and the first semester of 2021, fifteen samples from two wholesale markets and fifteen samples of three production areas of Valle del Cauca were analyzed through a multi-residue analysis of pesticides by gas chromatography coupled with a mass selective detector (GC - MSD) and liquid chromatography with mass-to-mass spectrometry (LC-MS / MS). For this, the QuEChERS method was used and, in addition, an analysis of total dithiocarbamates by carbon disulfide (CS2) generation was performed. Results. Eight active ingredients were found in the production areas, of which four of them exceeded the maximum residue limits: chlorpyrifos, carbendazim, mandipropamid, and difenoconazole. In the market places, fourteen active ingredients were determined, which five exceeded the maximum residue limits: carbendazim, iprodione, tebuconazole, dimethomorph, and difenoconazole. Conclusion. These findings reflect the high residual pesticide residues in ready-to-eat blackberries and suggest the need for follow-up processes to help ensure the safety of the fruit throughout the production chain.

Introduction. Corn (Zea mays L.) is a highly-consumed cereal in the world, which requires adequate fertilization to cover its nutritional requirements. Quitomax® is a biostimulant that has been successfully used to stimulate the yield of different crops. Objective. To evaluate the effectiveness of the application of Quitomax® on the growth of the improved Francisco variety corn crop. Materials and methods. The study was carried out in experimental areas of the National Institute of Agricultural Sciences (INCA) during 2018 and 2019, on a typical Ferralitic Red Leached eutric soil, with a randomized block experimental design with seven treatments and four replications. The Quitomax® treatments applied were: imbibition of the seeds for one hour at the concentrations of 0, 5 and 1 g L-1, foliar spray at the concentrations of 0, 5 and 1 g L-1, combination of both forms of application and concentrations, and a control. Yield and some of its components were evaluated. Results. The best results were obtained in the treatment that combined seed imbibition and foliar spraying (1 g L-1) (T6) of Quitomax®, with a yield of 12 t ha-1, plant height (A.P) of 2.12 m, mean diameter of the ear (DMM), and diameter of the stem (D. T) of 50.74 mm and 30.62 mm, respectively, height of the upper ear (AMS) of 1.13 cm, number of grains per row (NGH) and per ear (NGM) of 32.27 and 455.33, respectively, 17.53 cm ear length (LM), one hundred grain mass (M100S) of 38.90 g and 175.46 g total grain mass (MTSM). This treatment improved the benefit/cost ratio, and showed higher profits, although it was the most expensive. Conclusions. Seed and foliar application of Quitomax® was effective in increasing the yield and its components in corn.