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

In this paper we describe in detail an algorithm for the efficient computational implementation of the finite difference method (FDM) in the two-dimensional time-dependent heat equation with non-homogeneous Dirichlet boundary conditions. The MATLAB® software was used to validate the method mentioned here; however, the processes are presented independently from the programming language. Finally, numerical results are presented to validate the proposed algorithm.

After harvesting, barley grains (Hordeum vulgare L.) can show dormancy and water sensitivity, which delays industrial use. Both effects depend on the barley genotype and environmental conditions during grain maturation. In order to analyze the effect of the average temperature and the total rainfall accumulated during and in the final third of the grain filling, on the dormancy and water sensitivity and the relationship between them, three cultivars of barley were sownin four dates in 2009 and two in 2011. Temperature and daily rainfall were recorded from anthesis to physiological maturity. The dormancy was evaluated as germination at 12 days post physiological maturity and the water sensitivity as germination in water excess conditions at 100 days post physiological maturity. The variables that presented a higher correlation with germination and water sensitivity were average temperature and accumulated rainfall during grain maturity. Environments with average high temperature during grain filling, reduced dormancy, but on water sensitivity decrease was cultivar dependent. The increase of rainfall during grain filling, decreased dormancy, but increased water sensitivity in all three cultivars.

This study aimed at evaluating, during storage, the yield components and germination of the soybean crop based on seeds industrially treated with mineral- biological fertilizer containing amino acids. To achieve this, the experiment was carried out by using a completely randomized experimental design with the treatments arranged in subdivided plots, with four replications. The plots included the industrial seed treatments (IST), while the storage periods (0 and 45 days) were allocated to the subplots. The following characteristics were assessed: germination, initial stand, number of pods per plant, number of seeds per pods, number of lateral branches per plant, thousand-seed mass and yield. Under the conditions tested, the storage period contributed to a reduction in the agronomic parameters herein assessed, especially considering the control. However, compared to the seeds submitted only to the standard IST and, especially in relation to the untreated seeds (control), the use of biostimulant fertilizer in the industrial treatment enabled an increase in the agronomic characteristics during storage.

his study was carried out in order to compare different methodologies to select a representative core collection from an initial collection of Cynara cardunculus L. species, using both morphological and molecular markers. The combination of two stratification criteria with three sampling strategies allowed the establishment of six different core collections. The Maximization strategy was applied in order to obtain the seventh one. All the obtained collections were validated through phenotypic and molecular parameters, establishing as an initial criterion that the core collection should include, at most, 35-40 % of the accessions belonging to the original collection. All collections passed molecular validation; nevertheless morphological validation determined that the Proportional sampling strategy is the best to keep the initial variability while retaining the least number of accessions, especially when combined with the first stratification criterion. Although Maximization strategy allowed to preserve the original variability, it retained the largest number of accessions. In conclusion, the combination PrS1 (proportional sampling and first stratification criterion) is the best strategy to perform a representative core collection from a Cynara cardunculus L. initial collection, using both morphological and molecular data.

The food industry aims at offering food that provides not only nutritional but also functional properties. Celery has been used for a long time, but its bioactive compounds have remained unknown. The objective of this research is to measure the changes in the physical and chemical characteristics, total polyphenols (TP) and antioxidant activity (AA) after applying hot air dehydration (DA) and lyophilization (LF) with two different cut types: rod-shaped (R) and sliced (S). It was found that dehydration treatments can enhance some characteristics in celery. When comparing the results, the treatment of (LF-S) presented the best characteristics with less water activity, 46 % of total dietary fiber constituted by 41 % of insoluble fiber and 5 % soluble fiber, 377.69 mg GAE/100g in total polyphenol content and an antioxidant activity of 82.17 μmol TE/100g. These results allow to conclude that celery is a raw material with functional attributes and that it can be industrialized with dehydration technologies, which will enable a long useful life for its bioactive compounds.  

The objective of this research was to identify alternatives for the agroecological management of shrub species in livestock agroecosystems in the northwest of Córdoba, Argentina. Participatory techniques were used to determine the dominance of shrubs, the importance of the impact attributed to them, the feasibility of conventional control treatments and the prefeasibility of the alternatives for their agroecological management. The most dominant species were Vachellia caven, Celtis chichape, Senegalia gilliesii, Vachellia astringens, Geoffroea decorticans and Larrea divaricata. Management, profitability, colonization and accessibility was the most important negative impacts for 'productive' actors, while protection, diversity and feeding was the most relevant positive impacts according to 'conservationists'. The feasibility of the control treatments ranged between 0.3 and 0.6, with higher values for rolling, harrowing and the combination of both. 83.3 % of the agro-ecological management alternatives obtained more than 50 % of the maximum possible value. The existence of multiples beneficial attributes in these species facilitates the implementation of management strategies and the productive use in agroforestal systems. The payment for environmental services, the pruning of the cup elevation, the rotational sequential grazing of cattle and goats, and the commercialization of the products derived from these plants, are the most promising alternatives.

The objective of this study was to characterize and compare the protein composition of half-sib families of opaque-2 maize from Argentina through progeny testing. Grain hardness, protein fractions, amino acid content and in vitro protein digestibility (PD) of whole grain flour were determined. Non-opaque genotypes were used as control. Total protein content of o2 genotypes correlated negatively with the grain hardness (r=-42 in 2012 and r=-0.32 in 2013) and did not show significant differences in relation to non-opaque genotypes; however, o2 genotypes showed significantly higher PD, lower zein proportion, and higher albumin, globulin and glutelin contents. The o2progenies showed significantly higher lysine content and higher levels of other essential amino acids, such as isoleucine and threonine compared to white corn. Lysine content, protein fraction contents and PD showed a higher contribution of genetic variance to the total variability, despite the high contribution of crop year variance obtained by total protein content. The differences shown by progeny protein profiles would enable the identification of o2 genotypes with lower zein level and higher lysine content; this allows us to continue the selection and improvement to obtain open-pollination varieties enhanced in terms of protein quality.

The yield gap (BR) in late corn (December) was evaluated in the central region of Córdoba, Argentina, comparing planting densities (DS) of 6 and 8 pl m-2 using the AquaCrop model. Running the model between 1960 and 2017 required analyzing the consistency of the Penman-Monteith method (PM) to estimate the daily rate of reference evapotranspiration (ETo) using only maximum and minimum temperature records (ETo_PMTxTn), instead of the complete set of 4 fundamental variables. The ETo_PMTxTn values explain approximately 80 % of the variability of those obtained with the complete set of variables. AquaCrop was calibrated by using crop coverage samples, aerial biomass and soil water that were collected in a plot of late corn during the crop season 2015-2016. Three sowing dates were evaluated, 3 fixed and 3 variables, with no significant differences in BR for both DS. A small advance or delay in planting does not represent a decision affecting climate risk condition. While the increase of DS to 8 pl m-2 produced a significant increase in BR, it also presented average effective yields (RR) that are higher than those obtained with 6 pl m-2 for 47 of the 57 crop cycles analyzed.

Assimilate partitioning into reproductive structures is a relevant physiological feature in increasing peanut yield, and its analysis through the source-sink relationship is an important contribution to genetic improvement and crop management. The objective was to analyze the source-sink relationship of runner-type cultivars grown in Argentina. Two field experiments were performed, Exp1 consisted in the analysis of the cultivar Granoleico in three sowing dates during 2009-2010 and 2010-2011. In Exp2, six runner-type cultivars (Florunner, Florman, Manigran, Asem-485, Pepe-Asem and Granoleico) were sown during 2011-2012. The source-sink relationship was analyzed using two methodologies: total biomass assigned to each pod during pod filling period (g pod-1) in relation to its final weight, and analysis of the trade-off between pod number and pod weight at harvest. The lack of trade-off between pod number and weight showed that the peanut plant has conditions to fill a wide number of pods (20-57 pods plant-1) in the same way. Also, the average pod weight (1.05 g) was lower than the total plant biomass assigned to that pod during its formation (2.63 g). A marked limitation by sinks was determined, indicating the possibility of to increase the peanut yield by means of improvements in sinks size.

The effect of differents compost, obtained through the same composting methodology, was evaluated on the soil after two years of application. On a Typic Haplustoll, 40 Mg ha-1 of each compost was applied to the soil, forming the following treatments: CBIO with addition of biosolids compost, CF with addition of cattle-manure compost, CG with addition of poultry-manure compost, CROU with addition of organic urban waste compost. One treatment with inorganic fertilizer (FI) and an untreated or control soil (C0) was also included. Soil pH was slightly affected by compost addition according to compost characteristics. CROU and CBIO increasing and decreasing the pH, respectively (R2= 0.98). Soil organic matter of CG treatment showed changes in content of carbon fractions, without increment in total organic carbon (COT). The Cfracción>53?m increased in 85 % and alcali-extractable C increased in 24 % in CG respect to C0. Finally, concentration of CuM and ZnM increased in CROU. Our results show that a single incorporation of compost can modify soil properties due to the multiple materials composted. It should be done a monitoring to soil conditions to identify early trends and avoid negative environmental effects.