ABSTRACT. Salt stress affects crop growth and productivity. In this study, we determined the growth, yield of photosystem II (PSII), and K + and Na + concentration in root, stem, old leaves, and young leaves of two Mexican varieties of rice, Tres Ríos and Cotaxtla. In addition, the K + /Na + ratio in stem and root of both varieties was determined. The experiment was conducted in a growth chamber under controlled conditions, under a completely randomized distribution, with a 2 x 2 (Variety x Salinity) factorial arrangement and 12 replications. Plants were grown in a hydroponic solution for 15 days and then some of them were treated with 100 mM NaCl; control plants (without NaCI treatment) were grown in parallel. Salt stress caused 20 and 15% reductions in stem and root length, respectively, in the variety Tres Ríos, while in the variety Cotaxtla no significant differences were observed in these variables compared to the control. Dry matter weight decreased by 24% in the variety Tres Ríos. The quantum yield of PSII decreased by 30% the third day of treatment application, in both varieties. Na + concentration was significantly (p ≤ 0.05) higher in NaCI-treated plants. In the variety Tres Ríos, the yield of PSII was completely eradicated six days after treatment implementation, while the K+ concentration in stem and older leaves also decreased and the lowest K + / Na + ratio in stem was recorded, which could indicate that it is more susceptible to salinity than the variety Cotaxtla.

El presente ensayo analiza el desafío mundial de la inseguridad alimentaria de aquí al año 2050, particularmente ante una población mundialmente urbanizada que se estima rebase los 9.1 mil millones de habitantes, en un contexto de cambio climático y alta competencia por recursos como agua y suelo. Se discuten algunas propuestas que podrían permitir afrontar la situación futura de inseguridad alimentaria y generar una cultura de consumo y nutrición saludable y sustentable. Se propone que la agricultura ecointensiva de alta tecnología puede ser una opción para superar las necesidades alimentarias basada en un manejo sustentable de alta tecnología (computadoras, sensores remotos, drones y manejo cibernético), donde prácticas agrícolas convencionales, agroecológicas y biotecnológicas podrían convivir en una relación armoniosa con fines de producir más y mejores alimentos con menor impacto ambiental. Se concluye que lograr la seguridad alimentaria al año 2050 debe ser un asunto de seguridad nacional, y para ello se requiere tener claro este reto y fomentar procesos de investigación, desarrollo tecnológico e innovación sobre seguridad alimentaria con un verdadero compromiso y visión de gran alcance.

Objective: To identify the most relevant aspects of global scientific research on biocharin terms of number of articles published, main authors and publishing countries, citation,subjects of scientific journals, funding institutions and general trends.Design/Methodology/Approach: A bibliometric study was carried out in the Scopusdatabase. The word "biochar" was used in the search engine. The search was limited to articles and reviews published from 2009 to March 2020. The VOS viewer software was used to identify the main thematic axes and to glimpse the knowledge gaps that exist to date.Results: A total of 11,444 documents were identified. The trend of work on biochar is onthe rise. China and the United States are the countries with the most publications onbiochar. Jefferson Lehman and Stephen Josephs are the most cited authors on thesubject. Global research on biochar focuses on the mitigating effect of climate changeand the properties that this material has to improve the physicochemical properties ofthe soil. Research on biochar in Mexico is scarce. Study Limitations/Implications: Biochar is a new technology that is not fullyunderstood.Findings/Conclusions: Interest in biochar as a multifaceted solution to agricultural andenvironmental problems is growing at a rapid rate both domestically and internationally.

El objetivo de la investigación fue identificar las interrelaciones entre el Modelo de Turismo Rural Comunitario (TRC) del Ministerio de Comercio Exterior y Turismo de Perú y el marco de bienes de capital rural, a partir de la capacidad de las comunidades para generar estrategias de desarrollo territorial. Se estudiaron nueve comunidades rurales que han desarrollado el modelo de TRC con éxito en tres regiones turísticas del sur del Perú: Cusco, Puno y Arequipa. Se aplicaron 45 entrevistas a personas dedicadas a labores de agricultura, artesanía, alojamiento, guías turísticos, gastronomía y promotores de difusión; así como a dueños de emprendimientos y autoridades municipales. Los resultados indican que cuatro comunidades han logrado generar las estrategias turísticas del modelo, dos comunidades han perdido la visión del tejido social y la cadena de valor de TRC, dos comunidades más tienen dificultad con la accesibilidad al lugar y falta de promoción turística; y una última comunidad comienza a desarrollar el TRC. Se concluye que la actividad socioeconómica del capital rural del modelo TRC permite el desarrollo local y el bienestar de las familias rurales en el Perú.

The Capsium genus comprises one of the most economically important and gastronomic plant groups in the world. In Mexico, C. annuum one of the five species was domesticated. Guajillo chili belongs to this species; whose main use is dry. In this type of chili, little is known about its genetic parameters. The objective was to identify populations with better plant characteristics and high yield in order to obtain information on his heterotic patterns. For this study, nine populations of Guajillo chili from different entities of Mexico were used, which by means of a partial dialectic design, originated 36 crosses. The analysis of variance showed highly significant effects (P ≤ 0.001) in the general combining ability (GCA) in the parents, as well as for the specific combining ability (SCA) in their crosses mainly in the performance variables. In the variable number of fruit per plant (NFP), a higher GCA was observed, as well as in the cross P1 x P9 that showed higher value of heterosis and heterobeltiosis. The fresh fruit yield, the positive heterotic value, was observed in the crosses P2 x P5, P3 x P4, P3 x P5, P4 x P9 and P7 x P9. While the yield of dried fruit showed the positive and highly significant heterotic and heterobeltiosis value, at the P1 x P9 and P2 x P6 crosses. While the cross P3 x P9 only shows a significant positive value of heterosis.

<p><strong>Background. </strong>Even though many studies have been done in agronomic characters, there is no knowledge about studies that address the genetic effects on the physical and physiological quality of seeds in native populations of Guajillo chile (<em>Capsicum annuum</em> L.). <strong>Objective.</strong> The objective of this research was to identify the effects of general combining ability (GCA), and specific (SCA) on seed quality variables, as well as to determine the type of gene action in them. <strong>Methodology.</strong> F₁ and F2 seeds were analyzed from native populations of chili Guajillo through the accelerated aging test and digitization of seed images. <strong>Results. </strong>The results obtained show that: 1) all the variables were significant for the GCA and SCA, which indicates that the additive and non-additive effects are involved in the genetic control of these characters; 2) In the crosses with the highest average, at least one progenitor with a high GCA effect participated; 3) The effects of GCA were more important than the effects of SCA for the physical quality of seed, length and fresh seedling biomass; 4) In general, heritability in the narrow sense varied from low to moderate (0.00-0.30). <strong>Implications.</strong> The information generated about the non-additive genetic effect on the quality of Guajillo seed, can be used in breeding programs applying the hybridization technique. <strong>Conclusions. </strong>There is no relationship between the best crosses and parents with the effects of GCA high. The parents used in this research have acceptable GCA for most traits, crosses with higher SCA values do not necessarily derive from parents with acceptable GCA values.</p>

Sugarcane (Saccharum spp. hybrids) is moderately sensitive to salinity and the effects on plant performance vary according to stress level and genotype. This study aimed to evaluate the effect of salt stress induced by application of different NaCl levels in the irrigation solution on plant height, indirect index of chlorophylls (SPAD), and macronutrients concentration (N, P, K, Ca, Mg and S) and Na in leaves of two sugarcane varieties: CP 72-2086 and Mex 69-290. The experiment was set in a completely randomized design with a 2×5 factorial arrangement. The study factors were sugarcane variety (CP 72-2086 and Mex 69-290) and NaCl concentration (0.0, 71.8, 143.6, 215.4 and  282.7 mM NaCl). Salinity as a single factor negatively affected plant height, SPAD units and N and P concentration in leaves; Ca concentrations increased, while K, Mg and S remained unaffected by the tested NaCl levels. Mex 69-290 grew higher and concentrated greater levels of N and K. Interactions of factors showed that salinity reduced growth in both varieties, but this reduction was more pronounced in CP 72-2086. SPAD units were also significantly reduced by salinity in both varieties. Concentrations of N and P in leaves decreased in both varieties in response to NaCl, while those of K and Ca increased in Mex 69-290. Concentration of Na was higher in Mex 69-290 which exhibited better performance than CP 72-2086. Sodium concentrations in leaves increased in direct relation to the tested NaCl concentrations. Mex 69-290 reached higher concentrations of Na in leave tissues but displayed better health than CP 72-2086. Thus, the variety Mex 69-290 showed more efficient Na-tolerance mechanisms related to Ca and K concentrations, and an indirect chlorophyll index better than CP 72-2086.

Esta investigación tuvo como objetivos determinar el crecimiento de la concha de abanico, Argopecten purpuratus sometida a experimentación; determinar la diversidad de los epibiontes de la especie; determinar la mortalidad de la concha de abanico experimental; identificar la concentración de salinidad y tiempo de tratamiento adecuados para reducir los epibiontes con la menor mortalidad de los organismos cultivados. Se realizó un experimento factorial con tres concentraciones de salinidad aplicadas como baños por 5, 10 y 15 minutos para controlar los epibiontes. El crecimiento en peso de A. purpuratus varió entre 11,19 g, como mínimo y 20,55 g como máximo. El crecimiento en altura valvar fluctuó entre 8.15 mm como mínimo y 11,9 mm como máximo. La composición de epibiontes de la concha de abanico estuvo dada por un reducido número de especies: Hydroides sp, Balanus, Semimitylus algosus, Aglaophenia sp. y Ciona intestinales, predominando Hydroides sp y Mitylus. La menor mortalidad de la concha de abanico se obtuvo a la salinidad de 20%º y la biomasa menor de epibiontes con el baño de 5 minutos. Se considera adecuado para reducir los epibiontes el tratamiento con 20%º de salinidad y aplicado por 5 minutos.