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Focusing on new food production methods and sustainable pillars’ accomplishments has changed the definition of sustainable pillars themselves. Moreover, some general characteristics of the main pillars can be redefined in separate dimensions to better explain their positive sustainable impacts. Therefore, the main objective of this research is to redefine the sustainable pillars linked to food production and review the most important cultural and technological sustainability impacts they have, in addition to the three classic pillars: economic, social, and environmental sustainability. Cultural and technological sustainability are increasingly important complements to the traditional sustainability concept. Furthermore, new food production technologies and systems are influenced by ancient production methods, as well as by profitable crop selection. Traditional agricultural and aquaculture production in relation to more recent aquaponic production concepts are still a major part of global food security, but the better usage of waste materials or residues generates a more favorable agroecological impact. In conclusion, constantly redefining the sustainable pillars in the context of sustainable food production methods and proving the viability of their general production impacts is important.

La agricultura es la base de la alimentación, se desarrolla en suelo e hidroponía. La hidroponía se explica cómo cultivos sin suelo, en soluciones nutritivas, para el caso del tomate y del pepino es en sustrato. Los sustratos han incrementado la productividad, con uso eficiente de agua y fertilizantes. Si la agricultura consume 70% de agua y en gasto 30% es fertilizantes, el objetivo de este trabajo fue utilizar hidrogel de acrilato de potasio por su capacidad de disminuir la pérdida de fertilizantes como ser reserva de agua, permitiendo mantener la producción de tomate y pepino. La investigación se realizó en Querétaro en 2017. Se evaluó diferentes capacidades de saturación del hidrogel para sus propiedades, la mezcla de sustrato y el rendimiento de tomate y pepino, encontrando diferencias significativas.

The immune response against pathogens, both in plants and animals, relies on a complex recognition system of danger signs. This system is based on the recognition of exogenous molecules termed Microbe- or Pathogen-Associated Molecular Patterns (MAMPs/PAMPs), and endogenous signals called “Damage-Associated Molecular Patterns” (DAMPs). This review will focus on DAMPs, which are molecules with a normal physiological state inside the cell, but at the time of damage or infection are usually released to the extracellular media, indicating cell damage. DAMPS are represented by a wide range of molecules consisting in small peptides, proteins, carbohydrates, cell wall fragments, extracellular ATP (eATP), extracellular DNA (eDNA) and volatile organic compounds (VOCs). Here we review plant DAMPs types and a new approach in eDNA use as biotechnological molecules for plant disease prevention. In particular, self-eDNA has gained importance due to its function of growth inhibition observed over a wide variety of organisms, this function is being studied as a new strategy for biological control to obtain highly pathogen-specific products, without wasting time and research resources. On the other hand, eDNA, as other DAMPs, could act as an immune response elicitor, which could conduce to a new approach for the protection of crops against pests.

A center of origin of cultivated species defined as the geographical area where a particular species originated or differentiated from another and began its domestication process. The interactions between the different factors (climate, soil, macro, and micro-organisms) present in the centers of origin have allowed the selection of specific phenotypic characteristics propitiating the adaptation of the species according to their hormetic potential. Most studies carried out in the centers of origin has been geared towards the genetic part, the search for accessions with resistance to pests and diseases, yield and agronomic attributes. New approaches such as the phytobiome study that considers the complex network of interactions inside and outside the plant combined with the use of accession search methods such as focused identification of germplasm strategy have demonstrated their potential in crop improvement. These approaches have allowed establishing relationships between the environment, specific geographic areas, and characteristics of resistance, particularly of native breeds and wild relatives of crop plants. The study of the biotic and abiotic factors present in these sites and their application to the management of hormesis will improve the agronomic characteristics of the species and their potential for xenohormesis. The objective of this work is to share some reflections about the potential that the xenohormetic vision of the centers of origin can provide in terms of the improvement of agronomic characteristics in general and the functional features of the food obtained from the crops.

Blackberry fruits are appreciated as a source of nutrients and compounds related to benefit human health. However, they are highly perishable and very susceptible to decay factors. Current methods to improve and maintain blackberry quality are limited in use because of the fruit's fragile physical properties. Regarding these properties, it has been reported that the activities of certain enzymes are linked to senescence and fruit softening processes. This study was aimed to assess the effect of salicylic acid (SA) and chitosan (COS) as preharvest treatments on the physiology related to improving fruit conservation and preserving the marketability index of blackberry fruit. The preharvest treatments were foliar sprayed on blackberry plants at different concentrations. The activities of enzymes superoxide dismutase (SOD), catalase (CAT), phenylalanine ammonia-lyase (PAL), and polygalacturonase (PG) were measured. Total soluble solids (TSS), titratable acidity (TA), TSS/TA ratio, and marketability index (MI) were analyzed after 144 h of storage. The application of 3 mM of SA and 0.25% of COS treatments preserved the MI of blackberries by reducing leakage, red drupelet reversion (RDR), and mycelium presence in the fruit. SA application increased SOD, CAT, and PAL activities. Our results also showed that SA and COS preharvest treatments modified the activity of the cell wall degrading enzyme PG, which might play a role in improving the shelf life and resistance to decay factors of blackberry fruit without any significant effects on physicochemical properties like TSS, TA, and the TSS/TA ratio.

The stocking density of the freshwater prawn native to the Mexican Pacific coast, Macrobrachium tenellum, has not been evaluated in a recirculating aquaculture system. M. tenellum prawns with an average wet weight of 1.71 ± 0.11 g were reared for 60 days at three stocking densities (T1 = 10 ind m−2; T2 = 15 ind m−2; T3 = 20 ind m−2), in nine (1 m2) tanks connected to a recirculating aquaculture system inside a greenhouse. Average individual weight gain (AIWG), biomass weight gain (BWG), specific growth rate (SGR), food conversion ratio (FCR) and survival rate (SR) were determined. Stocking density affected the BWG and SR. The lowest BWG was observed at the highest density (T1, 20.70 ± 4.75 g m−2; T2, 20.75 ± 4.72 g m−2; T3, 11.31 ± 3.65 g m−2), although weight per area unit increased with densities. SR decreased with increasing density (T1, 77.77 ± 9.62%; T2, 59.25 ± 12.83%; T3, 44.44 ± 4.81%). Other parameters did not show a difference between densities, with a maximum average individual weight at T2 (5.41 ± 1.14 g). The overall results suggested that stocking density affected the productivity and survival but not the individual growth of juvenile M. tenellum prawns cultured in a recirculating aquaculture system.

The need to produce food in a sustainable way to counteract the effects of excessive use of agrochemicals opens the door to the generation of new technologies that are not based on fossil fuels and are less toxic to ecosystems. Plant growth-promoting bacteria (PGPB) could represent an alternative to chemical biofertilizers and pesticides offering protection for biotic and abiotic stresses. In this work, a bacterial isolate from roots of castor bean (Ricinus communis) was identified and named as Bacillus cereus strain “Amazcala” (B.c-A). This isolate displayed the ability to solubilize inorganic phosphate and produce gibberellic acid (GA3). Moreover, this bacterium provided significant increases in height, stem width, dry weight, and total chlorophyll content in tomato plants. Interestingly, B.c-A also significantly decreased the severity of bacterial canker disease on tomato caused by Clavibacter michiganensis (Cmm) in preventive disease assays under greenhouse conditions. Based on our results, B.c-A can be considered as PGPB and a useful tool in Cmm disease control on tomato plant under greenhouse conditions.

In Mexico, the accelerated and unplanned growth of population causes the increment in informal facilities, complicating access to essential services such as adequate sanitation and organic waste management, where the most affected are usually the vulnerable population. The Mexican government has implemented programs and support to encourage the use of ecotechnologies and thus provide alternatives to improve their living conditions by taking advantage of local resources and waste. However, these programs and supports lack planning, creating little interest from users. This research proposes an acceptance strategy for the integration of ecotechnologies that adapt to the lifestyle of populations that need an alternative for their method of sanitation and organic waste management. The strategy is mainly based on a course of action that operates with four main lines of intervention. It was executed as a practical exercise with biodigesters, in the Mexican community of La Trinidad, in the municipality of Tequisquiapan, Querétaro. With the help of the strategy, important factors for the end-user were identified that must be considered when integrating one ecotechnology into the population. In general terms, the strategy showed an improvement in sanitation and organic waste management and a greater acceptance of biodigesters as an alternative of use.

Chili pepper (Capsicum spp.) is one of the most economically important horticultural crops in the world, its production for the food and pharmaceutical industries has been increasing worldwide. The economic importance of this crop is due, in part, to the nutraceutical properties derived from its secondary metabolism. Drought is the main environmental factor that affects crop production. Nevertheless, studies involving water deficit have considered short-term responses to sharp water deficit rather than long-term acclimation processes through moderate and gradually increasing water deficits, which omitted the dynamics and profile of the secondary metabolism that are part of the plant&rsquo, s defence system against this stress factor. The present study aimed to identify the different mechanisms that chili pepper plants use to cope with drought stress using a progressive decrease and increase of water availability, conditions that commonly occur for crops in open fields. Four treatments were applied as follows: gradual water deficit (GWD), initial waterlogging with gradual water deficit (IWGD), sudden water deficit with gradual recovery (SWDR), and no deficit of water (NDW). These conditions should represent a more real situation similar to that faced by plants in the agricultural environment. In order to evaluate the response mechanisms associated with these water deficits, changes in phenological variables, proline accumulation, and the gene expression of phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), peroxidase (POD), and superoxide dismutase (SOD) were measured in chili pepper plants growing on land under different irrigation regimes in two contrasting soil types in areas where chili pepper plants are cultivated in central Mexico. The variables evaluated showed a differentiated response of the mechanisms in plants growing under different levels of water deficit. Given the differential response observed for the gene expression and morphological and biochemical variables studied in chili pepper plants against different water regimes, in this work, this may have implications for more efficient use of water in crops with high nutraceutical content, in addition to prospects for using products derived from secondary metabolism in the pharmaceutical industry.

Dentro de la teoría de identificación de sistemas, los modelos de redes neuronales artificiales (ANN) artificial neural networks por sus siglas en inglés, han mostrado gran capacidad para encontrar patrones de relación entre variables de procesos altamente no lineales, así como resolver la limitante de la regresión no lineal, donde no es posible usar variables correlacionadas como entradas. El objetivo de la presente investigación fue modelar la tasa de fotosíntesis foliar de plantas de jitomate, cultivadas bajo invernadero, mediante redes neuronales artificiales, empleando como variables de entrada: temperatura, humedad relativa, déficit de presión de vapor y concentración de dióxido de carbono (CO2) del aire, así como radiación fotosintéticamente activa. El experimento se desarrolló durante 2009 en un invernadero experimental de la Universidad Autónoma de Querétaro, México. Se usó el equipo de fitomonitoreo PTM-48M (Daletown Company, Ltd), para registrar el intercambio de CO2 de las hojas, así como las variables meteorológicas. Para eliminar ruidos de los sensores en las mediciones se aplicó el filtro Savitzky-Golay. Se evaluaron diferentes configuraciones para redes de retropropagación, siendo la de 4 capas con 10 neuronas en la primera capa oculta, 15 en la segunda y 10 más en la tercera, la que generó los mejores índices estadísticos sobre datos de prueba: coeficiente de determinación, R2= 0.9756 y cuadrado medio del error, CME= 0.8532. Tomando las predicciones de la mejor ANN, se realizó una optimización estática, relacionando dos variables climáticas con la tasa de fotosíntesis, mediante gráficas en tercera dimensión, a fin de mostrar estrategias para maximizar la tasa de fotosíntesis.

RESUMEN. El efecto de la densidad y el consumo de oxigeno sobre el crecimiento de la tilapia (Oreochromis niloticus) fueron analizados. Alevines con un peso humedo promedio de 1,57 ± 0,14 g se colocaron en estanques rectangulares de plastico de 972 L, dentro de un invernadero de polietileno con un area de 504 m2, las densidades utilizadas fueron 90 (T1), 180 (T2), and 270 (T3 ind m-3 (con una biomasa promedio total por tanque de 0,14, 0,28 y 0,42 kg m-3). Para la alimentacion se utilizo alimento comercial (Api-Tilapia 1, MaltaCleyton® con 50% proteina y 12% de lipidos), que se suministro hasta la aparente saciedad tres veces al dia durante un periodo de 60 dias. Al finalizar este periodo se seleccionaron aleatoriamente individuos de cada tratamiento para determinar el metabolismo aerobio, que se determino por el metodo de camaras semicerradas mantenidas a temperatura constante y volumen conocido (1 L). Se determino que la tasa de crecimiento de T1 (0,38 g dia-1; 4,65% dia-1) y T2 (0,21 g dia-1; 3,68% dia-1) fue significativamente mas alta que T3 (0,11 g d-1; 2,67% dia-1). El consumo de oxigeno en el ciclo de 24 h mostro diferencias significativas entre los tratamientos T1 = 350 ± 170, T2 = 260 ± 170, and T3 = 200 ± 130 (mgO2 kg-1 h-1). De acuerdo con los resultados obtenidos, el cultivo de tilapia bajo condiciones de invernadero a una densidad de 90 ind m-3 puede ser utilizado para incrementar la productividad de O. niloticus.

Viruses are estimated to be responsible for approximately 50% of the emerging plant diseases, which are difficult to control, and in some cases, there is no cure. It is essential to develop therapy practices to strengthen the management of these diseases caused by viruses in economically important crops. Metal nanoparticles (MeNPs) possess diverse physicochemical properties that allow for them to have a wide range of applications in industry, including nanomedicine and nano-agriculture. Currently, there are reports of favorable effects of the use of nanoparticles, such as antibacterial, antifungal, and antiviral effects, in animals and plants. The potential antiviral property of MeNPs makes them a powerful option for controlling these histological agents. It is crucial to determine the dosage of NPs, the application intervals, their effect as a biostimulant, and the clarification of the mechanisms of action, which are not fully understood. Therefore, this review focuses on discussing the ability of metal nanoparticles and metal oxides to control viruses that affect agriculture through an exhaustive analysis of the characteristics of the particles and their interaction processes for a possibly beneficial effect on plants.

The efficiency of water use in intensive greenhouse production can mean reduction in fertilization costs and less environmental pollution, mainly salinization of soils. This efficiency depends on the type of control in the irrigation system, either periods, solar radiation, ambient temperature, water availability in the substrate or by algorithms that combine some of the variables mentioned. However, all these variables are exogenous to the crop and it is the crop which presents water demand and the need for nutrients; therefore, phytomonitoring systems measuring the variables of the crop should be used to control irrigation in greenhouses. This research studies the foliar temperature as a parameter that contributes to the control of an irrigation system. A husk tomato (Physalis ixocarpa Brot.) crop, grown on pumice stone, was subjected to different periods without irrigation 0, 24, 48 and 72 hours. Foliar temperature was measured using an infrared sensor. Thermal gradients between treatments were detected, indicating that foliar temperature of the crop can be used as extra variable for irrigation control. The correlation coefficient (R2) between foliar temperature and greenhouse climate variables (relative humidity, solar radiation and ambient temperature) was calculated; for the first two R2 was less than 0.47 and R2 for air temperature values were between 0.65 and 0.75.

Over time plants developed complex mechanisms in order to adapt themselves to the environment. Plant innate immunity is one of the most important mechanisms for the environmental adaptation. A myriad of secondary metabolites with nutraceutical features are produced by the plant immune system in order to get adaptation to new environments that provoke stress (stressors). Hormesis is a phenomenon by which a stressor (i.e., toxins, herbicides, etc.) stimulates the cellular stress response, including secondary metabolites production, in order to help organisms to establish adaptive responses. Hormetins of biotic origin (i.e., biostimulants or biological control compounds), in certain doses might enhance plant performance, however, in excessive doses they are commonly deleterious. Biostimulants or biological control compounds of biotic origin are called "elicitors" that have widely been studied as inducers of plant tolerance to biotic and abiotic stresses. The plant response toward elicitors is reminiscent of hormetic responses toward toxins in several organisms. Thus, controlled management of hormetic responses in plants using these types of compounds is expected to be an important tool to increase nutraceutical quality of plant food and trying to minimize negative effects on yields. The aim of this review is to analyze the potential for agriculture that the use of biostimulants and biological control compounds of biotic origin could have in the management of the plant hormesis. The use of homolog DNA as biostimulant or biological control compound in crop production is also discussed.

The study of the rhizosphere with conventional methods can lead to errors in the analysis of the soil-root interface. The aim of this work is to design and carry out a versatile Rhizobox system that allows the study of different crops and types of research. For this purpose, a model that allows different adjustments in the support and development compartments of the rhizosphere and an array of access points in the lower compartment to easy aquare samples in situ were designed. The above, aims to generate an information platform that basis to generate strategies for performance of crops.

In recent years has been suggested that foliar application of H 2 O 2 alleviate symptoms of drought in several crops. The aim of this work was to assess the effect of exogenous H 2 O 2 application on Capsicum annuum L. crop as a protective treatment to further water deprivation. DNA methylation (5-methylcytosine percentage), stomatal density, number of leaves and photosynthetic activity were the variables evaluated.

Resumen. La ventilacion natural en invernaderos produce altas tasas de intercambio de aire; sin embargo, este comportamiento se producen cerca de las ventanas, lo que ocasiona un bajo intercambio de aire en la zona central del invernadero, debido a un efecto de estancamiento que reduce la distribucion del viento en todo el invernadero. La prediccion de los gradientes en un invernadero con ventilacion natural es dificil de lograr, debido a la naturaleza inherentemente estocastica del flujo de aire. Las Redes bayesianas son tecnicas numericas de incertidumbre que se pueden utilizar para estudiar este problema. Se obtuvo un conjunto de datos experimentales: temperatura del aire, humedad del aire, velocidad del viento, y concentracion de CO2 a uno y tres metros sobre el suelo, en el espacio de cultivo. El conjunto de datos fue discretizado y utilizado para desarrollar un modelo de Red Bayesiana que describe las relaciones entre las variables estudiadas. El modelo muestra las diferencias que nos permitan identificar el grado de dependencia de las variables, asi como cuantificar su inferencia.

This study was aimed at evaluating the different concentrations of nitrogen for tomato seedling production (Lycopersicon esculentum Mill.), hybrid Loreto. Five concentrations of nitrogen were analyzed: 0, 4, 8, 12 and 16 mEq / L, using as a basis the Steiner nutrient solution. A pilot randomized block design was used with six replications and five treatments. Thirty-five days after sowing, the following variables were analyzed: seedling height, stem diameter, fresh stem weight, fresh leaf weight, leaf area, dry steam weight, dry leaf weight, dry root weight and total nitrogen content. An ANOVA analysis (p

Stevia rebaudiana (Bertoni) is a perennial shrub native from Paraguay whose leaves accumulate steviol glycosides. Plants increase the production of phytochemicals as a response to stress factors to cope with possible damage. Elicitors are biological stress factors that can induce plant response to stress. Steviol glycosides are the phytochemicals responsible of the sweetener power of stevia (Stevia rebaudiana Bertoni cv. Morita II), which is up to 300-fold stronger than sucrose. Elicitors might affect Steviol glycosides content and gene expression-associated to their biosynthesis. The aim of this research was to evaluate the effect of controlled elicitation using salicylic acid, chitosan and hydrogen peroxide on plant performance, steviol glycosides contents and gene expression-associated to steviol glycosides biosynthesis (SrKA13H, SrUGT85C2, SrUGT74G1 and SrUGT76G1) in stevia cultivated under greenhouse conditions. Weekly applications of elicitors were foliarly sprayed during four weeks, morphological measurements were made and samples were lyophilized and processed to evaluate SGs content. Gene expression-associated was analyzed by Ultra-Performance Liquid Chromatography coupled to a Quadrupole-Time of Flight. Results showed that all the evaluated elicitors (especially salicylic acid 0.1 mM) enhanced steviol glycosides content, which correlated with inducement of gene expression-associated to the biosynthesis of these compounds and increase in leaf number in stevia. Thus, controlled elicitation of stevia cultivation might be used to improve the yield of steviol glycosides for industrial purposes.

Studies on the biological aspects of fish typically focus on species that currently have commercial value, causing species that lack such market value to be ignored. This is the case of several freshwater fish, specifically of several members of the Goodeidae family. In the State of Querétaro there are several species of this family characterized for being viviparous and having distinctive sexual dimorphism that may have commercial potential. The subject of this study is Girardinichthys multiradiatus, a viviparous fish endemic to the upper-half of the Lerma River basin. The lack of knowledge regarding its biology and ecology has prevented the development of guidelines to manage its habitat and to preserve its population. The objective was to determine the ecophysiological responses of G. multiradiatus to its environmental management. From the sampling (24 hours every two months) population structure and dynamics were analyzed throughout a hydrological cycle using meristic data (standard length). Trophic and ecophysiological responses to fluctuations in environmental factors were also identified. Although the mexcalpique is a polytrophic species, results show that it prefers feeding on Diptera or Cladocera, while detritus is the third substance frequently found in their stomachs. Environmentally, the water regime is responsible for fluctuations in the population dynamics of the species, while temperature changes are the most influence its energy balance. These results can guide efforts to conserve this species and its habitat. Los estudios sobre aspectos biológicos de los peces se centran, generalmente, en especies que actualmente tienen interés comercial, lo que ocasiona que las especies que carecen de tal valor en el mercado estén prácticamente olvidadas; tal es el caso de varios peces de agua dulce y más específicamente de algunos integrantes de la familia Godeidae. En el estado de Querétaro se encuentran varias especies pertenecientes a esta familia que se caracterizan por ser vivíparas y presentar un marcado dimorfismo sexual, aspectos que pudieran definir un potencial comercial. El pez objeto de este estudio es Girardinichthys multiradiatus, especie endémica de la parte alta-media de la cuenca del río Lerma; los lugares donde habita presentan procesos de degradación, fragmentación del hábitat y extracción de agua, que ponen en riesgo su existencia. Además, la falta de conocimiento sobre su biología y ecología, no permiten que se elaboren pautas de gestión de sus poblaciones o hábitats con fines de conservación y preservación de la especie o de los procesos ecológicos que mantienen la estabilidad del ecosistema que ocupa. En el presente trabajo se estudió la población de G. multiradiatus localizada en el bordo de San Martín, Amealco. El objetivo del presente trabajo fue determinar las respuestas ecofisológicas de G. multiradiatus debido al manejo de su ambiente. Se hicieron ciclos de 24 horas en muestreos bimensuales a lo largo de un ciclo hidrológico en el que se analizaron la estructura y dinámica de la población; asimismo, se determinaron las respuestas tróficas y ecofisiológicas de la población ante las fluctuaciones de los factores ambientales de su entorno. Los resultados muestran que aunque el mexcalpique es polítrofo, prefiere dípteros, cladóceros y detritus, habiendo diferencias alimentarias entre las clases de edades. G. multiradiatus presenta 12 clases de talla que van de 8 a 48 mm de longitud patrón. En el medio ambiente, el régimen de agua es responsable de las fluctuaciones en la dinámica poblacional de las especies, mientras que el cambio de temperatura es el factor de mayor influencia sobre su balance energético. Estos resultados pueden guiar los esfuerzos para conservar esta especie y su hábitat.

Native species, in comparison to exotic species in aquaculture, such as tilapias, are an alternative with a lower risk to regional biodiversity, due to competition for resources caused by introduced species. Productivity, length-weight relationship and relative condition factor of a native cichlid Herichthys cyanoguttatus were investigated in comparison to tilapia Oreochromis niloticus . Fish with a wet weight of 0.54 ± 0.07 g were placed in 100 L tanks inside a polyethylene greenhouse during 84 days. Wet weight (g) was obtained each week and standard length once per month. Both species had a high survival rate with a relative condition factor close to 1, showing a length-weight relationship with an isometric growth, meaning that they were in good condition. A significant difference was found in growth (P < 0.05) from the second week, with a specific growth rate of 2.28 ± 0.07% day -1 for tilapia and 1.35 ± 0.02% day -1 for the native cichlid, tilapia reached twice the total weight gain than the native cichlid (31.26 ± 0.95 g; 83.70 ± 4.54 g). Food conversion rate was higher in tilapia than in H. cyanoguttatus . The survival rate of H. cyanoguttatus , as well as the relationship of isometric growth and condition factor of both species, suggests that H. cyanoguttatus has the ability to grow in aquaculture systems. Normal 0 false false false ES-MX JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; mso-bidi-font-size:10.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-ansi-language:ES-MX; mso-fareast-language:JA;}

A thermosolar nursery development for rural producers was built and tested in three different operational conditions. The system consisted of a solar collector connected to a coiled heat exchanger inside a fish culture tank. A pump activated by two thermostats was used to circulate water throughout the heating circuit. A short-term pilot test was performed to probe the maximum heating of the system. Two more tests (Tests A and B) were carried out to evaluate the effect of heat insulation covering on the thermosolar fish tank. A student´s t-test was performed to assess the statistical difference in temperature and fish growth between the thermosolar tank and the control tank (which lacked thermal heating). The maximum temperature achieved by the system was 37.94°C. In Test A, the mean temperature of the thermosolar and control tanks after 49 days were 27.50 and 25.02°C, respectively. In Test B, the mean temperature after 38 days was 25.84 and 20.06°C, respectively. Differences in the weight and length of the fish were found. On test B, daily growth rate, survival and total biomass were higher in the thermosolar system than in control. The results suggest that the system can improve the growth performance and survival of the fingerlings. Key words: Active thermosolar systems, tilapia fingerlings, aquaculture, solar panel.

The effects were examined of plant-response signaling compounds, salicylic acid (SA) and methyl jasmonate (MeJA), on resistance to pill-bugs (Armadillidium vulgare) attack in lettuce plants. Foliar SA and MeJA applications were made at weekly intervals from the emergence of the plant until one week before harvesting. SA and MeJA induced detectable levels of hydrogen peroxide (H2O2) at least during 5 days post-application in these plants throughout their cultivation. On the whole, SA and MeJA in the concentrations and application scheme evaluated in this research did not significantly influence the dry and fresh weight matter of plants, or the chlorophyll and nitrate contents. In addition, both signal elicitors significantly diminished lettuce mortality due to pill-bugs, which was positively correlated with phenolics and flavonoids contents. Our results suggest that SA and MeJA, especially in low concentrations, should be further evaluated in lettuce production and priming resistance.

In high-fish-density aquaculture systems, tilapia producers are compelled to provide 100% of food required to obtain profitable growth rates. It is well known that fish have a low food conversion rate and feeding represents the most important expenditure, approximately 40% of total production cost. Therefore, precise quantities of food should be provided to avoid water pollution and economic losses due to food waste when water conditions are inadequate for fish feeding. A way to control food provisions in this work was determined by the conditions of temperature, dissolved oxygen, fish age, and body weight, since these variables have a direct effect on fish metabolism and growth. Thus, a change in metabolism is reflected in a modification of energy requirements and, as a consequence, in variations of food consumption. In this work, a new feeder with fuzzy-logic control algorithms is proposed for fish feeding; this technique allows farmer knowledge to be taken into account in a series of if–then-type rules. To define these rules the temperature and dissolve oxygen were considered in order to provide precise food quantities. The results show minimal differences in growth (P > 0.05) between treatments, important food saving of 29.12% (equivalent to 105.3 kg), and lower water pollution (reduced water dissolved solids and ammonium components) compared with timed feeders. This system provides an important contribution to sustainability of intensive aquaculture systems, increasing productivity and profitability, and optimizing water use.

Success in greenhouse production is due, in part, to the use of a well-characterized substrate and a suitable fertigation schedule, among others. The behavior of several mixtures of stone substrate (tezontle, pumice) with improvers (potassium acrylate copolymer and agave fiber) was evaluated in this research. The physical properties of the resultant mixtures, such as water- and air-retention, drainage and apparent density. Were measured and then, the energetic state of the mixture (Field Capacity (FC)) was calculated in laboratory. Afterwards, the mixtures were exposed to irrigation in greenhouse conditions; the FC and drainage were measured. T-3 (pumice with 8g of potassium acrylate copolymers) and T-6 (pumice agave fiber) were distinguished by having a favorable moisture retention, T-1 (pumice) was selected as control. These treatments were carried in a greenhouse cucumber crop cycle.

El movimiento de aire causado por la ventilacion en los invernaderos es un factor importante que afecta la uniformidad de sus condiciones climaticas y consecuentemente la uniformidad y calidad del crecimiento de las plantas. La prediccion de las condiciones climaticas de los invernaderos es realmente importante para tomar las acciones apropiadas para controlar el clima interno. En este trabajo se compararon un modelo mecanicista y otro basado en la dinamica de fluidos computarizada para determinar su precision para predecir las temperaturas internas de los invernaderos en las condiciones climaticas mexicanas. Los resultados muestran que el modelo mecanicista tiene un mejor ajuste a las temperaturas internas (R2 = 0.97) que el basado en la dinamica de fluidos computarizada (R2 = 0.94). Sin embargo, ambos modelos pueden ser usados como herramientas ingenieriles para el diseno de invernaderos.

Germin-like proteins (GLPs) are encoded by a family of genes found in all plants, and in terms of function, the GLPs are implicated in the response of plants to biotic and abiotic stresses. CchGLP is a gene encoding a GLP identified in a geminivirus-resistant Capsicum chinense Jacq accession named BG-3821, and it is important in geminivirus resistance when transferred to susceptible tobacco in transgenic experiments. To characterize the role of this GLP in geminivirus resistance in the original accession from which this gene was identified, this work aimed at demonstrating the possible role of CchGLP in resistance to geminiviruses in Capsicum chinense Jacq. BG-3821. Virus-induced gene silencing studies using a geminiviral vector based in PHYVV component A, displaying that silencing of CchGLP in accession BG-3821, increased susceptibility to geminivirus single and mixed infections. These results suggested that CchGLP is an important factor for geminivirus resistance in C. chinense BG-3821 accession.

Aquaponics is the combined production of aquaculture and hydroponics, connected by a water recirculation system. In this productive system, the microbial community is responsible for carrying out the nutrient dynamics between the components. The nutrimental transformations mainly consist in the transformation of chemical species from toxic compounds into available nutrients. In this particular field, the microbial research, the “Omic” technologies will allow a broader scope of studies about a current microbial profile inside aquaponics community, even in those species that currently are unculturable. This approach can also be useful to understand complex interactions of living components in the system. Until now, the analog studies were made to set up the microbial characterization on recirculation aquaculture systems (RAS). However, microbial community composition of aquaponics is still unknown. “Omic” technologies like metagenomic can help to reveal taxonomic diversity. The perspectives are also to begin the first attempts to sketch the functional diversity inside aquaponic systems and its ecological relationships. The knowledge of the emergent properties inside the microbial community, as well as the understanding of the biosynthesis pathways, can derive in future biotechnological applications. Thus, the aim of this review is to show potential applications of current “Omic” tools to characterize the microbial community in aquaponic systems.

The effects of climate change on plant diseases have been the subject of intense debate in the last decade; research in this sense has been carry out, however, more information is needed. Elevated temperatures and carbon dioxide concentrations associated with climate change will have a substantial impact on plant-disease interactions. Changes in temperature affect both the host and the pathogen; thus, risk analyses must be conducted for each pathosystem to determine the effects of climate change. Studies have been performed under controlled conditions, and the effects of high CO2 levels have been identified; however, field responses such as the adaptation of pathogens over time may be different. The climate influences the incidence as well as temporal and spatial distribution of plant diseases. The most likely effect of climate change in poleward modifies agroclimates zones, this causing a shift in the geographical distribution of host pathogens. Considering this climate change could profoundly affect the status of agricultural diseases, the focus of thisstudy was to review studies related to the effects of climate change on plant diseases. Taking into account the work done, this review addresses the impact of climate change on plant diseases, considering the effect on crop grown, development and the impact on crop production. Key words: CO2, global warming, temperature effect on diseases.

The study of the environmental conditions in the biological process is complicated, as in many cases it is necessary to use models based on energy transfer. Mathematical models based on mass and energy balances assume a homogeneous environment. These models generate a set of nonlinear ordinary differential equations without an analytical solution. However, a more detailed monitoring of the environment inside these processes reflects a two-dimensional and three-dimensional variability of environment variables.

Plants are fundamental elements of the human diet, either as direct sources of nutrients or indirectly as feed for animals. During the past years, the main goal of agriculture has been to increase yield in order to provide the food that is needed by a growing world population. However, as important as yield, but commonly forgotten in conventional agriculture, is to retain and, if possible, to increase the phytochemical content due to their health implications. By 2025, the global population will exceed 7 billion. In the short term, per capita availability of arable land and irrigation water will decrease from year to year while biotic and abiotic stresses expand. Food security, defined as economic, physical, and social access to a balanced diet and harmless drinking water will be a compromise, with a holistic approach to nutritional and non-nutritional factors needed to achieve success in the eradication of hunger. Science and technology will play a very important role in stimulating and sustaining agriculture leading to long-term increases in productivity without linked ecological harm.

Computational fluid dynamics is a tool that has been used in recent years to develop numerical models that improve our understanding of the interaction of variables that make up the climate inside greenhouses. In the past five years, more realistic studies have appeared due mainly to the development of more powerful software and hardware. However, it is necessary to perform an analysis to show us the trends, strengths and weaknesses in the use of this tool. In this study, we reviewed the state of the art of CFD in studies of airflow and climate inside greenhouses, analyzing the most important issues that help us understand how it has evolved, as well as trends and limitations on their use. Key words: Airflow, CFD, greenhouse, turbulence, porous media.