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

The objective of this study is to describe and identify problems and potentials of the production and commercialization of pitahaya in the socio-economic context of the town of San Luis Atolotitlan, Caltepec, Puebla. A questionnaire was applied to 20 producers who are also marketers of the Rural Production Association of San Luis Atolotitlan, Caltepec between March and May 2020. The cultivation of pitahaya is part of a diversified system of crops in a social context of migration, under educational level and with extensive dependence on local buyers, however with minimal maintenance practices, use of organic fertilizers and average yields, which, if management is improved and, above all, marketing and transformation channels are identified and diversified, could be the system that stimulates the economy of the region. A potential for these actions are the young producers, with a higher degree of education and with an innovative attitude.

Goal. – Carry out the first molecular characterization of the Bardcoding COI region of S. frugiperda in Tabasco, as well as test whether it can reliably identify the race of S. frugiperda present. Design/methodology/approach. - Specimens of S. frugiperda were collected using four pheromone traps in maize plots. DNA extraction, PCR with LCOL/HCOL primers, and sequencing of six individuals captured in traps were performed. Results. - The sequences were aligned and a phylogenetic tree was built, which groups the S. frugiperda of this study in the rice race. Implications. - Identification of the race of S. frugiperda is necessary for management purposes, since each race may require a different control method. Findings/conclusions. - Our study revealed that the isolates from Chontalpa, Tabasco in Mexico correspond to races of fall armyworm reported in other latitudes belonging to the RS. This becomes the first report of this race of S. frugiperda in Tabasco, relevant since this species has the potential to become a serious pest in the sugarcane and rice areas of the state.

Objective: The objective of the present study was to evaluate the J-Synch protocol with two doses of eCG in beef heifers during the summer in Northeast Mexico. Design/methodology/approach: In this experiment, 218 heifers of the Mashona breed (109/treatment) with a live weight of 350 ±12.1 kg were used. On Day 0, all heifers received an intravaginal device (1.2 g P4) plus 2 mg, i.m., EB; On day 5, it was withdrawn and 0.15 mg of D-Cloprostenol was applied; where treatment 1 (T1) consisted of the application of 250 IU of eCG; in treatment 2 (T2), 300 IU of eCG was applied. Subsequently, the total number of heifers from both treatments were inseminated at a fixed time (FTAI) at 72 hours after the removal of the device with frozen bull semen; likewise, at the time of the FTAI, 10.5 µg of GnRH was applied to each heifer. Results: There were no significant differences (p > 0.05) in the percentage of estrus at the first service (T1 = 91%; T2 = 96%; as well as in the percentage of repeaters (T1 = 25.2% vs T2 = 19 .2%). For the inseminating technician and the color of the heifers' coat, there was an effect on the percentage of heifers repeating estrus. For the percentage of pregnancy at first service, it was 64.8% for T1 and 70.1 % for T2 (p > 0.05) There was only an effect of the inseminator technician in terms of pregnancy percentage, varying from 63.4% for the best-qualified technician vs. 48.6% for the one with the lowest percentage. Limitations on study/implications: At least in this study, the pregnancy rate in beef heifers will depend mainly on the experience and skill of the inseminator technician. Findings/conclusions: According to the present investigation, the indistinct application of 250 or 300 IU of eCG can be used with the same results of the presence of estrus and gestation during the summer season in beef heifers, however, the inseminator technician has an important role on pregnancy outcomes.

O Background: The implementation of polyphytic pastures composed of grasses and legumes is an important component of agricultural systems in temperate zones, since grazing pastures which can reduce feed costs— are a viable option for small-scale dairy systems (SSDS). Objective: To evaluate the continuous grazing of dairy cows in Festulolium pastures associated with annual and perennial ryegrass and with clover in two farmrs. Methodology: Two experiments were carried out. The first experiment was established in the municipality of Almoloya of Juárez using eight cows that were divided into two groups of four; the cows grazed on two pastures with Festulolium associated with annual ryegrass and they were fed with 3.6 kg DM/cow/day of commercial concentrate, for 16 weeks. The second experiment was carried out in the Northwest of State of Mexico; six multiparous cows grazed on two pastures, under a cross over design arrangement; one pasture features Festulolium cv Spring Green and the other, annual ryegrass. Milk and body condition ere measured every 3 and 12 d, respectively. Variables from both experiments were analyzed using a split-plot experimental design. Results: Neither experiment recorded significant differences for the net accumulation of forage, the height of the pastures, and their chemical composition (P>0.05). No significant differences between treatments (P>0.05) were recorded regarding the yields and chemical composition of the milk. Study Limitations/Implications: The study of mixed pastures can be an alternative for feeding grazing cows, helping to reduce costs in SSDS. Findings/Conclusions: Festulolium/annual ryegrass pastures with white clover are a viable forage alternative for small-scale dairy systems.

Objective: The objective of the research was to compare the diversity of winged aphids in papaya cultivation and determine the population fluctuation of vector species of ringspot. Design/methodology/approach: The capture of winged aphids was carried out by placing eight Moerick-type water traps, four green and four yellow. Weekly samplings were carried out to locate the plants with symptoms of the disease and to record the abundance of the vector species of PRSV, as well as the progress of the disease. Results: A total of 694 individuals belonging to 20 species were collected, of which seven species were captured with green traps and 19 species with yellow traps. The highest diversity value was recorded in the green traps; however, the yellow traps captured the highest richness. Of the captured aphids, six are reported as transmitters of PRSV. When analyzing the population fluctuation of the vector species, it was determined that A. spiraecola presented two population spikes during the study, the first was at week three capturing 93 individuals and the highest peak at week ten with 316. The presence of PRSV was recorded in the seventh week of sampling with nine diseased plants, reaching 100% contagion in week 44. Limitations on study/implications: The correct choice of methods for the capture and monitoring of insect populations in agricultural crops is of vital importance, since the development of prevention and control strategies for pest species and disease vectors depends on this. Findings/conclusions: It can be inferred that the vector species perform small migrations within the plantation, which can be supported by the increase in the number of diseased plants. Keywords: Aphids, cultivation, disease, insects, virus.

ABSTRACT Objective: To evaluate the fertilization with vermicompost and NPK mineral fertilizer in Young lemon Persian lemon tree. Design/methodology/approach: To develop the experiment, a random block design with eight treatments and four repetitions was established. The treatments were the following: T1: 0 kg/tree, T2: 90-22.5-22.5 N-P-K kg/ha, T3: 2 kg/vermicompost tree, T4: 3 kg/vermicompost tree, T5: 4 kg/vermicompost tree, T6: 90-22.5-22.5 N-P-K kg/ha + 2 kg/vermicompost tree, T7: 90-22.5-22.5 N-P-K kg/ha + 3 kg/vermicompost tree; T8: 90-22.5-22.5 N-P-K kg/ha + 4 kg/vermicompost tree. The study variables were: tree height, stem thickness, Crown diameter from North to South (N-S) and East to West (E-W), soil pH and soil moisture (%). The data were analyzed statistically by applying the MINITAB v. 17 statistics through an ANOVA (P≤0.05), was used to compare means, multivariate analysis. Results: Persian lemon trees treated with 4kg/tree of vermicompost (T5) were different in the following variables: tree height and crown diameter. Vermicompost treatments combined with NPK mineral fertilizer showed a similar development in the tree canopy compared to T5. Limitations on study/implications: Conventional lemon production uses synthetic fertilizers indiscriminately, causing the contamination of natural resources. A nutritional alternative for the lemon tree is the use of organic fertilizers. Findings/conclusions: Vermicompost treatment is efficient in maintaining adequate soil moisture content in the dry season allowing better growth better growth and development Persian lemon tree.

Objective: To photodegrade Diuron with TiO2-Al2O3 nanomaterials supported on graphene nanoplatelets (GnPs) Design/methodology/approach: The synthesis of the materials was carried out by the sol-gel method under mild conditions. Subsequently, the obtained materials were subjected to thermal processing for structural stabilization and pulverized. Synthesized nanomaterials were then characterized by nitrogen adsorption/desorption, X-ray diffraction, scanning electron microscopy, and Uv-Vis spectroscopy. Results: The adsorption/desorption results indicated that the ternary TiO2-Al2O3/GnPs nanomaterials were found to have complex porosity, which suggested that TiO2-Al2O3 was formed on agglomerated GnPs. X-ray diffraction data revealed that the anatase phase of TiO2 and the g-Al2O3 phase coexist with the crystalline phase of graphene. The morphology of the materials indicates that the nanoplatelets were randomly dispersed in a continuous mixed oxide phase. About the UV analysis, the presence of GnPs at 1 wt % concentration reduces the band gap by 6%. Limitations on study/implications: The physical and chemical properties of GnPs make the material an excellent candidate for the degradation of pollutants by photocatalysis. Findings/conclusions: The addition of GnPs improved the Diuron degradation, probably by forming a nanostructured interface or heterojunction.  

Abstract Objective: Tobacco production experienced a gradual growth during the first half of the 20th century, but its increase has been truncated in the last four decades. The objective of the study is to analyze the productivity of tobacco in Mexico in order to certify its importance in Mexican society and to measure its productivity. Design/methodology/approach: The article presents an analysis of tobacco’s productivity in Mexico in the 1980-2020 period, through the KLEMS methodology. Analysis of census samples from the period studied has confirmed the decrease experienced by this agricultural production. Results: The importance of production has been visibly decreased within macroeconomic factors such as the Gross Domestic Product (GDP), which leads to a loss of participation of this agricultural product both in the national and international context. This has resulted in the contraction, in addition, ostensibly, of the number of jobs that are directly related to this agricultural activity and the ulterior consequences that come up for the family economy. Limitations on study/implications: The statistical records from the period 1980 to 2020 were taken into account, since there were no records available before 1980. Findings/conclusions: Through the research results, the decrease experienced by the tobacco industry from 1980 to 2020 was confirmed, and also that production will disappear at the industrial level.

Objective: To estimate the indicator of the risk of the future price of yellow corn #2 of the Chicago Futures Exchange in the United States to the spot price of white corn in the main white corn producing regions of Mexico through the financial volatility indicator. Methodology: The research used the returns of the monthly time series for the period January 1998 to December 2020 corresponding to the spot price of white corn for five producer-consumer regions of Mexico and the futures price of yellow corn #2 listed on the Chicago Stock Exchange. To quantify volatility, the generalized autoregressive conditional heteroskedasticity model of order (1,1) was estimated. Results: The volatility indicator for yellow corn turned out to be 0.9870 for the futures price of quality 2 yellow corn. In the case of the spot price of white corn in Mexico, the volatility was 0.0.7977 for the national price; 0.3385 for the central region; 0.3206 for the western region and 0.0078 for the southeastern region, respectively. Implications: The high volatility of yellow corn #, close to unity, shows that the international market for this commodity is riskier than the national market or the regional markets in Mexico. Conclusions: The national white corn market showed to be more risky than the western, central and southeastern regional markets, showing a higher volatility indicator.

Objective: Analyze social interactions and business portfolio of vegetable producers in Central Mexico. Design/methodology/approach: we worked with 16 small vegetable producers. Semi-structured questionnaires and periodic monitoring were used in field to collect data. A Social Network analysis was carried out to know social interactions between producers, and the Boston Consulting Group (BCG) and Ansoff matrix for the business portfolio. Results: We found that the products with potential in the market were lettuce and nopal. Broccoli and squash represent low sales and low utility. Producers with a higher degree of centrality grow lettuce, broccoli and squash, so we suggested to develop strategies for introducing nopal. Limitations on study/implications: It was necessary to deep in market and consumers analysis.