Abstract We evaluate how the concentrations of inorganic nutrients and chlorophyll a vary in a heterogeneous area (Equatorial SW Atlantic), covering a gradient from stations closer to the coast to others more distant associated or not with turbid-zone reefs. Vertical temperature (27.9 ± 0.10 °C; mean ± standard deviation) and salinity (36.2 ± 0.14) profles showed that the water column is well mixed (0-30 m depth). The oligotrophic condition was marked by low concentrations of phosphate (0.30 ± 0.22 µM) and dissolved inorganic nitrogen (0.64 ± 0.74 µM). Moreover, dissolved reactive silicon (DSi) was low in most samples (< 2.0 µM), but higher (>10 µM) in nearshore stations, probably related to continental runoff and/or resuspension of the bottom sediments. The pelagic phytoplankton biomass indicated that chlorophyll a (0.25 ± 0.08 µg L-1) was low, positively correlated with light and negatively correlated with nutrients, indicating possible phytoplankton uptake. Chlorophyll a concentrations were lower in stations closer to the coast and higher in some stations near the reefs, indicating that the latter could be more prone to phytoplankton development and depletion of nutrients, especially DSi. Therefore, although oligotrophy is present along this coast, we found some unexpected heterogeneity of nutrient and chlorophyll a distributions, which were probably infuenced by benthic-pelagic coupling due to the presence of extensive reefs, sponge gardens (18-30 m depth), and the proximity to the coast. These results highlight the importance of understanding the heterogeneity of ocean productivity, especially in lesser known low-latitude areas, which showed distinct nutrient and chlorophyll a levels related to the occurrence of tropical reefs that are capable of supporting important fsh stocks and unique biological communities.

RESUMEN Conocer la dinámica de pérdida de nutrientes debido a la severidad de las tormentas eólicas contribuiría a entender este proceso y a predecir el efecto de eventos extremos debido al calentamiento global. Es por ello que el objetivo del presente trabajo fue cuantificar la concentración de carbono orgánico (CO), nitrógeno total (NT) y fósforo total (PT) en el sedimento erosionado, sus relaciones de enriquecimiento y el cambio en la concentración de estas especies químicas en la superficie del suelo, luego de eventos simulados en un túnel de viento, utilizando velocidades y duraciones contrastantes. En un Haplustol éntico se simularon dos velocidades de viento: 10 y 20 m s-1 y dos duraciones: 1 y 3 min. Se analizó el flujo de masa horizontal, la concentración de NT, CO y PT en el sedimento erosionado, su relación de enriquecimiento (RE) y los cambios de concentración de estos elementos en la superficie del suelo antes y después de las simulaciones. Aumentó la concentración de NT con la velocidad de viento más baja, y la de PT con la velocidad de viento menor y de mayor duración. Sin embargo, el efecto de la velocidad y la duración de los eventos sobre la relación de enriquecimiento y la relación de concentración superficial, antes y después de las simulaciones, no determinaron una remoción selectiva de CO, NT y PT. A pesar que la relación de enriquecimiento de estas especies químicas fueron mayores a bajas velocidades, se pudo observar que a altas velocidades y cortas duraciones, el sedimento resultaba empobrecido en PT (RE<1), con mayores concentraciones en la superficie del suelo luego de dichos eventos.

ABSTRACT The knowledge of the dynamics of nutrient loss due to the severity of wind storms may contribute to understand their mechanisms and predict the effect of extreme events expected to increase due to global warming. So, our objective was to quantify the concentration of organic carbon (CO), total nitrogen (NT) and total phosphorus (PT) in the eroded sediment, their relative enrichment ratios and the change in the concentration of these chemical species on the soil surface after wind erosion simulations with a wind tunnel using contrasting speeds and durations. For this, in an Entic Haplustoll we simulated two wind speeds: 10 and 20 m s-1 and two durations: 1 and 3 min. We analysed the horizontal mass flow, the sediment concentration of NT, CO, and PT, the sediment enrichment ratios (RE), and surface concentration changes before and after the simulations. The sediments had a higher concentration of NT in the lowest velocity and of PT in the lowest velocity and longest duration. However, the effect of the speed and duration of the events on the enrichment ratios and the change in surface concentrations before and after the simulations, did not determine a selective removal of CO, NT and PT. Although the enrichment ratios of these chemical species were higher at low speeds, it was observed that at high speeds and short durations, the sediment is depleted in PT (RE<1), with higher concentrations in the soil surface after the events.

Resumen El hierro dúctil (DI) puede modificar sus propiedades con la adición de elementos aleantes y tratamientos térmicos adecuados. En este trabajo se estudiaron los efectos del vanadio y molibdeno en la microestructura y resistencia a la corrosión del DI y el hierro dúctil austemperizado (ADI). La resistencia a la corrosión fue evaluada por la técnica de polarización potencio-dinámica en 0.5 M H2SO4, 0.5 M NaCl y 0.5 M NaOH como electrólito. El ADI aleado con vanadio presenta ausferrita gruesa formada por agujas gruesas de ferrita, mientras que la combinación de vanadio y molibdeno permite obtener una microestructura fina compuesta de ausferrita y agujas delgadas de ferrita; esta microestructura mejora la resistencia a la corrosión en NaCl y NaOH. El DI presenta corrosión debido al par galvánico entre los nódulos de grafito y la ferrita; sin embargo, la presencia de una gran cantidad de carburos incrementa su resistencia a la corrosión en H2SO4.

Abstract Ductile iron (DI) can acquire various properties with the addition of alloying elements and through heat treatment. In this work, the effects of vanadium and molybdenum on the microstructure and corrosion resistance of DI and austempered ductile iron (ADI) were studied. Corrosion resistance was evaluated by potentiodynamic polarization techniques in 0.5 M H2SO4, 0.5 M NaCl, and 05 M NaOH as electrolyte. The ADI alloyed with vanadium presented an upper ausferritic microstructure consisting of broad ferrite needles, while the combination of vanadium and molybdenum allows obtaining a fine microstructure composed of ausferrite and thin needles of ferrite; this microstructure improves the corrosion resistance in NaCI and NaOH. The DI’s showed corrosion due to the galvanic pair between the graphite nodule and the ferrite; however, a high amount of carbide increases the corrosion resistance in H2SO4.

Abstract Knowledge of the genetic variability and yield heritability and its components within the plant breeding allows to optimize the selection process. The objective of the research was to determine the genetic variability of yield and its components, as well as their correlations to identify selection criteria for increased grain productivity. 19 genotypes, planted in the spring-summer cycle, were used in 7 locations of rainfed in Mexico’s High Valleys. The experimental design was Alpha lattice with two repetitions in each environment. The experimental unit was four grooves 3 m long with a separation of 30 cm. The variables evaluated were: days at maturity, plant height, grains per spigot, number of spikes of wheat and grains per square meter, as well as harvest index, weight of a thousand grains and grain yield. The highest coefficients of genetic variation 20.8 and 18.4 were for grain and grain yield per spigot, respectively. But the highest genetic variations and heritability are presented by the weight of a thousand grains and grains per spigot which facilitates the selection of these characters. The yield had significant correlations with number of grains per square meter, grains per spigot, number of spikes and harvest index with values of 0.92, 0.57, 0.54 and 0.54, respectively. So, they can be used as selection criteria to promote productivity. For this group of genotypes, it is necessary to increase the genetic variability for spigot per square meter and weight of a thousand grains. It is proposed to the genotypes Don Carlos M2015, 6, 11 and 8 as genetic sources to increase the weight of grain, number of grains per spike, greater number of spikes and grains per square meter to promote grain yield.

Resumen El conocimiento de la variabilidad genética y heredabilidad del rendimiento y sus componentes dentro del fito mejoramiento permite optimizar el proceso de selección. El objetivo de la investigación fue determinar la variabilidad genética del rendimiento y de los componentes, así como sus correlaciones para identificar criterios de selección para mayor productividad de grano en trigo harinero. Se utilizaron 19 genotipos, sembrados en el ciclo primavera-verano en siete localidades de temporal en los Valles Altos de México. El diseño experimental fue alfa látice con dos repeticiones en cada ambiente. La unidad experimental fue de cuatro surcos de 3 m de longitud con una separación de 30 cm. Las variables evaluadas fueron: días a madurez, altura de planta, granos por espiga, número de espigas y granos por metro cuadrado, así como índice de cosecha, peso de mil granos y rendimiento de grano. Los mayores coeficientes de variación genética 20.8 y 18.4 fueron para rendimiento de grano y granos por espiga, respectivamente. Pero las variaciones genéticas y herededabilidades más altas las presento el peso de mil granos y granos por espiga lo cual facilita la selección de estos caracteres. El rendimiento presentó correlaciones significativas con número de granos por metro cuadrado, granos por espiga, número de espigas e índice de cosecha con valores de 0.92, 0.57, 0.54 y 0.54, respectivamente, que se pueden utilizar como criterios de selección para la productividad. Para este grupo de genotipos es necesario incrementar la variabilidad genética para espigas por metro cuadrado y peso de mil granos. Se propone a Don Carlos M2015, 6, 11 y 8 como fuentes genéticas para incrementar el peso de grano, número de granos por espiga, mayor número de espigas y granos por metro cuadrado para el rendimiento.

Abstract Wheat production in Mexico depends on more than 90% of the irrigated areas, which are classified as having a high water shortage, so varieties that are efficient in the use of water must be planted. In such a way that the objective of the investigation was to evaluate the behavior of the yield and its components of genotypes in function of the decrease of irrigation sheets (LR). Eight varieties of bread wheat and four LR were used. Genotypes were established in a split-plot design with large plots arranged as a randomized full-block design, with two replications. LR reductions of 1 to 0.8, 0.6, and 0.4 m decreased grain yield by 14.4, 37.6, and 76.8%, respectively. In limiting humidity (0.4 m) the number of spikes and biological yield decreased 63.7 and 73.3%. Grain yield was correlated with the number of grains and spikes per square meter. When the LR decreased from 1 to 0.8 m, Rebeca F2000 and Temporalera M87 presented grain yields greater than 6.5 t ha-1 associated with high biological yields. While Temporalera M87, in the 0.4 m sheet, was the one with the highest biological yield, number of grains and grain yield with 2.4 t ha-1. Therefore, genotypes and yield components were identified to help in the selection process with higher yield potential in limiting humidity conditions.

Resumen La producción de trigo en México depende en más de 90% de las zonas de riego las cuales están clasificadas con escasez alta de agua por lo que se deben sembrar variedades eficientes en el uso de agua. De tal manera que el objetivo de la investigación fue evaluar el comportamiento del rendimiento y sus componentes de genotipos en función de la disminución de láminas de riego (LR). Se utilizaron ocho variedades de trigo harinero y cuatro LR. Los genotipos se establecieron en un diseño de parcelas divididas con parcelas grandes arregladas como un diseño de bloques completos al azar, con dos repeticiones. Las reducciones en LR de 1 a 0.8, 0.6 y 0.4 m disminuyó el rendimiento de grano en 14.4, 37.6 y 76.8%, respectivamente. En humedad limitante (0.4 m) el número de espigas y rendimiento biológico disminuyeron 63.7 y 73.3%. El rendimiento de grano se correlacinó con el numero de granos y espigas por metro cuadrado. Al disminuir la LR de 1 a 0.8 m Rebeca F2000 y Temporalera M87 presentaron rendimientos de grano superiores a 6.5 t ha-1 asociados a altos rendimientos biológicos. Mientras Temporalera M87, en la lámina de 0.4 m, fue la de mayor rendimiento biológico, número granos y rendimiento de grano con 2.4 t ha-1. Por lo que se identificaron genotipos y componentes de rendimiento para ayudar en el proceso de selección con mayor potencial de rendimiento en condiciones limitantes de humedad.

Abstract: Background: Cozumel island, Mexico has one of the best preserved and threatened coastal vegetation in the Mexican Caribbean. Increasing the ecological knowledge about these communities can help to establish conservation priorities. Question: How are the structure and composition of well-preserved coastal vegetation communities in the Island of Cozumel? Study site and dates: The study was conducted in the northeastern coast of the island of Cozumel, at the Municipality of Cozumel, Quintana Roo, Mexico, from July 2014 to November 2014. Methods: Five interception lines of 80 m were randomly established along environmental gradient, perpendicular to the coastal line, in each three different environments: rocky beaches, sandy beaches, and coastal dunes. Species richness, diversity, and importance value index of the species in the community were computed, and floristic composition recorded. Results: We recorded 23 families, 35 genera and 37 species. The most representative families are Poaceae with four species, Rubiaceae and Asteraceae with three species each; Sideroxylon and Euphorbia were the richest genera, with two species each. The three coastal environments presented no statistical differences in its relative density, coverage and diversity, but differed in species composition and richness (higher in rocky beaches and coastal dunes). Conclusions: Two dissimilar coastal plant communities can be recognized into the halophilous vegetation type, which are established in sandy and rocky environments respectively. The floristic composition and the species association of the rocky beaches reveal the relationship between the Island of Cozumel coastal vegetation and plant communities in other Caribbean islands.

Resumen: Antecedentes: Cozumel tiene una de las vegetaciones costeras más conservadas y amenazadas en el Caribe mexicano. El incremento del conocimiento de estas comunidades puede ayudar a establecer prioridades de conservación. Pregunta: ¿Cómo es la estructura y composición de la vegetación costera en la isla de Cozumel? Lugar y fechas del estudio: El estudio se realizó en la costa noreste de la isla de Cozumel, Municipio de Cozumel, Quintana Roo, México, desde julio de 2014 hasta noviembre de 2014. Método: Se establecieron aleatoriamente cinco líneas de intercepción de 80 m en un gradiente ambiental, perpendicular a la costa, en tres entornos diferentes: playa rocosa, playa arenosa y duna costera. Se calculó la riqueza, la diversidad y el índice de valor de importancia de las especies, y se registró la composición florística. Resultados: Registramos 23 familias, 35 géneros y 37 especies. Las familias más representativas son Poaceae con cuatro especies, Rubiaceae y Asteraceae con tres cada una; Sideroxylon y Euphorbia fueron los géneros con mayor riqueza, dos especies cada uno. Los tres ambientes no presentaron diferencias en su densidad relativa, cobertura y diversidad, pero sí en la composición y riqueza (mayor en playa rocosa y duna costera). Conclusiones: Se reconocen dos comunidades de vegetales de tipo de vegetación halófila, las de ambientes arenosos y rocoso respectivamente. La composición florística y la asociación de especies de la playa rocosa revelan la relación entre la vegetación costera de Cozumel y las comunidades de plantas en otras islas del Caribe.

Abstract In 2013 wheat production in México depended on 4% of irrigation water; however, there is less availability of this resource. As a result, genetic improvement programs in irrigation areas usually evaluate grain yield and water use, but the effect of this factor on industrial quality is missing. Therefore, the objective of this research was to evaluate the industrial quality of wheat flour according to the number of irrigations. Ten commercial varieties were used and irrigations were applied at 0-35, 0-35-70, 0-35-70-105 and 0-35-70-105-125 days. The experimental design was of complete random blocks with two replicates with treatment arrangement in split plots. The experimental unit was four furrows of 3 m and a separation of 30 cm. The evaluated variables were hectoliter weight, grain hardness, protein content in flour, kneading time, mass strength, tenacity/ extensibility ratio and bread volume. By means of three irrigations the highest protein content in flour, strength of the dough and bread volume were obtained and decreased with four and five. Generally, by two, three and four irrigations the genotypes presented bread volumes greater than 800 mL, due to their mass strength greater than 350*10-4 J and tenacity/extensibility values lower than 1.2, while with five irrigations the majority of the genotypes showed bread volumes lower than 800 mL due to their lower protein content and mass strength. The above indicates that by managing the number of irrigations, the date of application and varieties it is possible to modify the industrial quality of wheat flour.

Resumen En 2013 la producción del trigo en México dependió 4% del agua de riego; sin embargo, existe menor disponibilidad de éste recurso. Por lo que usualmente los programas de mejoramiento genético en las zonas de riego evalúan el rendimiento de grano y el uso del agua, pero falta conocer el efecto de este factor sobre la calidad industrial. Por lo que el objetivo de esta investigación fue evaluar la calidad industrial del trigo harinero en función del número de riegos. Se utilizaron diez variedades comerciales y se aplicaron riegos a los 0-35, 0-35-70, 0-35-70-105 y 0-35-70-105-125 días. El diseño experimental fue de bloques completos al azar con dos repeticiones con arreglo en parcelas divididas. La unidad experimental fue de cuatro surcos de 3 m y una separación de 30 cm. Las variables evaluadas fueron peso hectolítrico, dureza del grano, contenido de proteína en harina, tiempo de amasado, fuerza de la masa, relación tenacidad/ extensibilidad y volumen de pan. Mediante tres riegos se obtuvieron los mayores contenidos de proteína en harina, fuerza de la masa y volumen de pan y disminuyeron con cuatro y cinco. De manera general mediante dos, tres y cuatro riegos los genotipos presentaron volúmenes de pan mayores a 800 mL, por su fuerza de la masa superior a 350*10-4 J y valores de tenacidad/extensibilidad menores a 1.2, mientras con cinco riegos la mayoría de los genotipos mostraron volúmenes de pan menores a 800 mL debido al menor contenido de proteína y fuerza de la masa. Lo anterior indica que, mediante el número de riegos, la fecha de aplicación y variedades es posible modificar la calidad industrial del trigo harinero.

La identificación de los estadios del cultivo de fréjol (Phaseolus vulgaris L.) en los que la deficiencia de agua que disminuye la fijación biológica de nitrógeno FBN, se realizó en ensayos de campo en un suelo Typic Haplustoll, franco arenoso del Centro Experimental La Tola, Pichincha, Ecuador. La temperatura media anual de la localidad es de 15 ºC y la humedad relativa de 74%, a una altitud de 2465 metros sobre el nivel del mar (msnm). Se registraron 123 mm de precipitación durante el período del experimento (julio y noviembre de 1995). Los tratamientos consistieron en 6 regímenes de humedad S1= Riego normal durante todo el ciclo, S2= Riego deficitario durante todo el ciclo, S3= Stress hídrico durante la fase de crecimiento vegetativo (20-50 días después de la siembra dds), S4= Stress hídrico durante la floración (53-81 dds), S5= Stress hídrico durante el llenado de la vaina (82-110 dds) y S6= Stress hídrico durante la maduración (111-130 dds). La humedad del suelo fue medida con una Sonda de neutrones hasta 0.40 m de profundidad, 24 h antes y después del riego. La FBN fue estimada con la metodología de N-15. Los resultados indican que el Stress hídrico durante todo el ciclo del cultivo (S2), durante la floración (S4) y durante el llenado de vainas (S5) afectó significativamente la fijación biológica del nitrógeno en el cultivo de fréjol. La restricción de riego durante la fase de crecimiento vegetativo (S3) y la maduración del grano (S6) no redujeron significativamente la fijación biológica de nitrógeno, alcanzando valores del 38%, estadísticamente similares al cultivo con un régimen de riego normal durante todo el ciclo (S1).

The identification of the stages of the cultivation of beans (Phaseolus vulgaris L.), in which water deficiency reduces the biological fixation of nitrogen BNF, took place in field trials in a soil Typic Haplustoll, loamy sand of La Tola Experimental Center, Pichincha, Ecuador. The average annual temperature in the location is 15 ºC with a relative humidity of 74%, at an altitude of 2465 meters above the sea level. 123 mm of rainfall were recorded during the period of the experiment (July at November 1995). The moisture regime treatments were as follows: S1 = normal irrigation throughout the cycle, S2 = deficit irrigation throughout the cycle, S3 = water stress during vegetative growth (20-50 days after planting dap), S4 = water stress during flowering (53-81 dap), S5 = water stress during pod filling (82-110 dds), and S6 = water Stress during ripening (111-130 dap). The soil moisture was measured with a neutron probe up to 0.40 m depth, 24 h before and after watering. The BNF was estimated with the methodology of N-15. The results indicate that the water stress during the entire cultivation (S2), during flowering (S4) and during the filling of pods (S5) significantly affected the biological nitrogen fixation in the cultivation of beans. The restriction of watering during the vegetative growth (S3) and the maturation of grain (S6) not significantly reduced biological nitrogen fixation, reaching values of 38%, statistically similar to the cultivation with a normal irrigation throughout the cycle (S1) regime.

Wind erosion (WE) is an irreversible soil degradation process of arid and semiarid regions. With portable wind tunnels it is possible to simulate WE controlling critical variables such as wind speed and direction, duration of erosive events; and soil surface parameters under natural conditions as moisture, roughness and cover level. The objectives of this study were: 1) to describe the main aspects of the design and operation of a portable wind tunnel to study WE, and 2) to calibrate the wind tunnel to fit the aerodynamics criterions related to the development of a vertical wind profile and an eroded material distribution similar to natural conditions. The main components of wind tunnel are chassis, engine, wind fan, s-shaped section, honeycomb diffusor, the stabilization section and the working sections. These sections have 2 m length; 0.5 m width and 1 m height. The wind tunnel was calibrated in an Entic Haplustoll in a bare and flat surface. The maximum measured velocity reached at 0.6 m was 22.5 m s-1, implying that the wind tunnel allows simulating field erosive wind velocities. The vertical wind profile and eroded material distribution are similar to those produced under natural field conditions. The use of this wind tunnel will improve the study of basic processes and technology for wind erosion control of soils of Argentina, also it will serve as a guide for future wind tunnel developments to study wind erosion.

La erosión eólica (EE) es un proceso de degradación irreversible de suelos de regiones áridas y semiáridas. Con el uso de túneles de viento portátiles es posible simular la EE controlando variables críticas como la velocidad y dirección del viento, la duración de los eventos erosivos; además de parámetros del suelo en condiciones naturales como los niveles de humedad, rugosidad y cobertura. Los objetivos de este trabajo fueron: 1) describir los principales aspectos del diseño y la operación de un túnel de viento portátil para estudios de erosión eólica, y 2) Calibrar el túnel para cumplir con los criterios aerodinámicos relacionados con el desarrollo de un perfil vertical de viento y de distribución de material erosionado similares a las condiciones naturales. Los principales componentes del túnel son: chasis, motor, hélice, sección curva, placa cribada y las secciones del túnel propiamente dicho. Cada una de estas secciones tiene 2 m de largo; 0,5 m de ancho y 1 m de alto. El túnel fue calibrado en un Haplustol Éntico con una superficie lisa y sin cobertura vegetal. La velocidad máxima alcanzada medida a 0,6 m fue de 22,5 m s-1. Esto significa que el túnel permite simular velocidades consideradas erosivas a campo. El perfil vertical de viento y la distribución de material erosionado son similares a los producidos en condiciones naturales. El túnel de viento desarrollado cumple con las condiciones de diseño para la simulación de eventos de erosión eólica a campo. El uso del mismo mejorará el estudio de procesos básicos y el desarrollo de tecnología para el control de la erosión eólica en suelos de Argentina, además de ser una fuente de consulta para la construcción de futuros túneles de viento para el estudio de la erosión eólica.

Abstract Wheat diseases cause up to 70 % of the yield losses and affect industrial grain quality. The aim of this study was to evaluate the performance of agronomic variables and industrial quality by controlling diseases in susceptible and resistant genotypes of flour wheat. Nine genotypes were planted under rainfed conditions at four locations: Bellavista (state of Morelos); Chapingo, Juchitepec and Coatepec (Estado de Mexico). Folicur® and Sportak® were used as fungicides. The experimental design was of randomized blocks with two replications in a split land plot array of treatments, in which the largest plots were the treatments with and without fungicide and the small land plots were the varieties. The experimental unit was of four rows of 3 m length, separated 30 cm apart from each other. An ANOVA was carried out with the data and treatments means were compared with the Tukey test (p≤0.05). There were significant differences between locations, genotypes and in the location-genotype and genotype-fungicide interactions in most of the analyzed variables. Foliar diseases caused between 7.3 % and 28.6 % yield loss, which depended on each genotype tolerance to foliar disease complex and their yield potential. Rebeca F2000, Juchi F2000 and Tlaxcala F2000 varieties showed minor losses in leaf area and grain yield, but Pavon F76 and Galvez M87 presented an opposite behavior. Chemical control of disease increased hectolitre weight but decreased protein content, and with it, dough strength and bread volume in some genotypes. Therefore, the use of disease tolerant varieties or fungicides application will allow higher yield, appropriate hectolitre weight for the milling industry, and strong-balanced or extensible dough that favor bread volume.

Resumen Las enfermedades en trigo causan hasta 70 % de pérdidas en rendimiento y afectan la calidad industrial del grano. El objetivo de este estudio fue evaluar el comportamiento de variables agronómicas y calidad industrial al controlar las enfermedades en genotipos susceptibles y resistentes de trigo harinero. Nueve genotipos se sembraron en cuatro localidades en condiciones de secano, en Bellavista, Morelos, y en Chapingo, Coatepec y Juchitepec, Estado de México. Los fungicidas fueron Folicur® y Sportak®. El diseño experimental fue de bloques al azar con dos repeticiones en un arreglo de tratamientos de parcelas divididas, en el cual la parcela grande fue los tratamientos con y sin fungicida y las parcelas chicas fueron las variedades; la unidad experimental fueron cuatro surcos de 3 m de longitud con 30 cm de separación. Con los resultados se realizó un ANDEVA y las medias se compararon con la prueba de Tukey (p≤0.05). Hubo diferencias significativas entre localidades, genotipos y para las interacciones localidad por genotipo y genotipo por fungicida para la mayoría de las variables analizadas. Las enfermedades foliares provocaron pérdidas de 7.3 % a 28.6 % en rendimiento, lo cual dependió de la tolerancia de cada genotipo al complejo de enfermedades foliares y de su potencial de rendimiento. Rebeca F2000, Juchi F2000 y Tlaxcala F2000 mostraron las pérdidas menores en área foliar y rendimiento, pero Pavón F76 y Gálvez M87 presentaron un comportamiento contrario. El control químico de las enfermedades aumentó el peso hectolítrico pero disminuyó el contenido de proteína y, por tanto, la fuerza de la masa y volumen de pan en algunos genotipos. Entonces, el uso de variedades tolerantes a las enfermedades o la aplicación de fungicidas permitiría rendimiento alto, peso hectolítrico adecuado para la industria molinera, y masa fuerte-balanceada o extensible que favorezca el volumen de pan.

RESUMO A cultura da seringueira (Hevea brasiliensis) pode acumular quantidades significativas de carbono, seja na biomassa ou no solo. No entanto, ainda se está longe de uma compreensão abrangente sobre o potencial de estoque de C entre os diferentes clones de seringueira, em razão de esses serem tipicamente formados para exibir outras características, como aumento de produtividade e maior tolerância às doenças. Assim, este estudo teve como objetivo abordar as diferenças entre plantios clonais de seringueira, buscando preencher a lacuna decorrente da seguinte indagação: A hipótese do estudo foi que os diferentes clones de seringueira, desenvolvidos para serem adaptados a distintas condições ambientais e biológicas, divergem em termos de estoque de C no solo e na biomassa. Foram comparados os estoques de C no solo em quatro profundidades e profundidade total (0,00-0,05; 0,05-0,10; 0,10-0,20; 0,20-0,40; e 0,00-0,40 m) e nos diferentes compartimentos da biomassa arbórea. Foram comparados cinco diferentes clones de seringueira com sete anos de idade (FX 3864, FDR 5788, PMB 1, MDX 624 e CDC 312), que foram implantados em um delineamento em blocos casualizados, no campo experimental da Empresa de Pesquisa Agropecuária do Estado do Rio de Janeiro. Não foi observada diferença entre os plantios clonais de seringueira quanto aos estoques de C no solo, mesmo considerando o estoque total de 0,00-0,40 m. Diferentemente do que ocorreu no estoque de C no solo, os plantios clonais divergiram em termos de C na biomassa arbórea, com a fração tronco contribuindo majoritariamente para o total do C da biomassa. Foi verificado que a biomassa arbórea e o solo contribuem diferentemente para o estoque de C total, 36,2 e 63,8 %, respectivamente. Os padrões observados indicaram que, independentemente das diferenças entre clones, o cultivo de seringueira em si pode ser interessante para elevar o estoque de C do solo.

ABSTRACT Rubber tree (Hevea brasiliensis) crop may accumulate significant amounts of carbon either in biomass or in the soil. However, a comprehensive understanding of the potential of the C stock among different rubber tree clones is still distant, since clones are typically developed to exhibit other traits, such as better yield and disease tolerance. Thus, the aim of this study was to address differences among different areas planted to rubber clones. We hypothesized that different rubber tree clones, developed to adapt to different environmental and biological constrains, diverge in terms of soil and plant biomass C stocks. Clones were compared in respect to soil C stocks at four soil depths and the total depth (0.00-0.05, 0.05-0.10, 0.10-0.20, 0.20-0.40, and 0.00-0.40 m), and in the different compartments of the tree biomass. Five different plantings of rubber clones (FX3864, FDR 5788, PMB 1, MDX 624, and CDC 312) of seven years of age were compared, which were established in a randomized block design in the experimental field in Rio de Janeiro State. No difference was observed among plantings of rubber tree clones in regard to soil C stocks, even considering the total stock from 0.00-0.40 m depth. However, the rubber tree clones were different from each other in terms of total plant C stocks, and this contrast was predominately due to only one component of the total C stock, tree biomass. For biomass C stock, the MDX 624 rubber tree clone was superior to other clones, and the stem was the biomass component which most accounted for total C biomass. The contrast among rubber clones in terms of C stock is mainly due to the biomass C stock; the aboveground (tree biomass) and the belowground (soil) compartments contributed differently to the total C stock, 36.2 and 63.8 %, respectively. Rubber trees did not differ in relation to C stocks in the soil, but the right choice of a rubber clone is a reliable approach for sequestering C from the air in the biomass of trees.

The presence of low temperatures during the initial stages of grain filling in wheat flour produced in foster in the region of the high valleys of central Mexico, is atypical. So the aim of this research was to analyse the effect of frost on industrial quality bread wheat varieties recommended for rainfed. The genotypes were planted under an experimental design of randomized complete block with two replications in the towns of Jilotepec frost presence and Chapingo absence of frost in the spring-summer cycle 2011. The experimental plot consisted of four rows 3 m in length. Field was measured in days to flowering, while industrial quality was evaluated based on: test weight, grain hardness, protein in flour, kneading time, stability kneading bread volume and crumb colour. Due to the presence of frost during the stage of milky and doughy-soft grain, late genotypes hecolítrico reduced their weight and protein content, and increased grain hardness, time and stability to kneading, which was reflected low volume of bread. Such behaviour could be due to coincidence frost began with the accumulation of protein and starch in the grain. Furthermore the genotype that was in doughy-hard grain maintained its industrial quality at both locations. The presence of frost in the early stages of grain filling of wheat discourages physical grain quality of the dough and baked.

La presencia de bajas temperaturas durante las etapas iniciales del llenado de grano en trigo harinero, producido bajo temporal en la región de los Valles Altos del centro de México, es atípica. Por lo que el objetivo de la presente investigación fue analizar el efecto de la helada sobre la calidad industrial de variedades de trigo harinero recomendadas para secano. Los genotipos se sembraron bajo un diseño experimental de bloques completos al azar con dos repeticiones en las localidades de Jilotepec, presencia helada y Chapingo, ausencia de helada, en el ciclo primavera- verano 2011. La parcela experimental consistió de 4 surcos de 3 m de longitud. En campo se midió los días a floración, mientras que la calidad industrial se evaluó con base en: peso hectolítrico, dureza de grano, proteína en harina, tiempo de amasado, estabilidad al amasado, volumen de pan y color de la miga. Debido a la presencia de la helada, durante la etapa de grano lechoso y masoso-suave, los genotipos tardíos redujeron su peso hecolítrico y el contenido de proteína, e incrementaron la dureza del grano, el tiempo y estabilidad al amasado, lo anterior se reflejó en bajos volúmenes de pan. Dicho comportamiento pudo deberse a la coincidencia de la helada con el inició de la acumulación de proteína y almidón en el grano. Por otro lado el genotipo que se encontraba en grano masoso-duro mantuvo su calidad industrial en ambas localidades. La presencia de heladas en las etapas iniciales de llenado del grano del trigo desfavorece la calidad física del grano, de la masa y de panadería.

The first record of Cuvieronius hyodon is reported in the Isthmus of Tehuantepec, southeastern Oaxaca, Mexico. It consists of a mandible fragment with an m3 collected from Pleistocene alluvium. The analysis of metrical data of 36 m3 of Cuvieronius and 25 m3 of Rhynchotherium from North American and South American localities revealed that the length of Cuvieronius m3 is larger in almost 75% of the analyzed data, whereas they are wider in slightly more than 50% of the studied specimens. A Welch t-test showed that m3 width index is significantly different between both genera. The 52 Pliocene-Pleistocene (Blancan-Rancholabrean) geographic records of Cuvieronius from Mexico are mainly in the central and southern part of the country; their wide altitudinal range suggests that Cuvieronius inhabited places a few meters above sea level as in the Isthmus of Tehuantepec, to others located more than 2500 m a.s.l. as in the State of Mexico. Its geographic distribution in Mexico suggests that Cuvieronius hyodon moved across temperate and tropical corridors.

Se reporta por primera vez Cuvieronius hyodon en el Istmo de Tehuantepec, sureste de Oaxaca, México, el cual está representado por un fragmento mandibular con un m3 procedente de sedimentos aluviales pleistocénicos. El análisis de los datos métricos de 36 m3 de Cuvieronius y de 25 m3 de Rhynchotherium de localidades norteamericanas y sudamericanas reflejó que la longitud de los m3 de Cuvieronius es mayor que la de Rhynchotherium en casi un 75% de los datos analizados, mientras que su anchura es mayor en poco más del 50% de los ejemplares estudiados. Adicionalmente, la prueba t de Welch aplicada al índice de anchura de los m3 indicó diferencias estadísticamente significativas entre ambos géneros. Los 52 registros de Cuvieronius pliocénicos-pleistocénicos (Blancano-Rancholabreano) de la República Mexicana se ubican principalmente en el centro y sureste del país; su amplio rango altitudinal sugiere que Cuvieronius habitó lugares que van desde el nivel del mar en el Istmo de Tehuantepec y la Planicie Costera del Golfo hasta más de 2500 m s.n.m. en el Estado de México. Adicionalmente, la distribución geográfica observada sugiere que Cuvieronius se desplazó a través de corredores templados y tropicales en el país.

Este trabalho resume os dados de florística e fitossociologia de 11, das 14 parcelas de 1 ha, alocadas ao longo do gradiente altitudinal da Serra do Mar, São Paulo, Brasil. As parcelas começam na cota 10 m (Floresta de Restinga da Praia da Fazenda, município de Ubatuba) e estão distribuídas até a cota 1100 m (Floresta Ombrófila Densa Montana da Trilha do rio Itamambuca, município de São Luis do Paraitinga) abrangendo os Núcleos Picinguaba e Santa Virgínia do Parque Estadual da Serra do Mar. Na Restinga o solo é Neossolo Quartzarênico francamente arenoso, enquanto que na encosta o solo é um Cambisolo Háplico Distrófico argilo-arenoso, sendo que todas as parcelas apresentaram solo ácido (pH 3 - 4) com alta diluição de nutrientes e alta saturação de alumínio. Na Restinga e no sopé da encosta o clima é Tropical/Subtropical Úmido (Af/Cfa), sem estação seca, com precipitação média anual superior a 2.200 mm e temperatura média anual de 22 ºC. Subindo a encosta mantêm-se a média de precipitação, mas há um gradativo resfriamento, de forma que a 1.100 m o clima é Subtropical Úmido (Cfa/Cfb), sem estação seca, com temperatura média anual de 17 ºC. Destaca-se ainda que, quase diariamente, a parte superior da encosta, geralmente acima de 400 m, é coberta por uma densa neblina. Nas 14 parcelas foram marcados, medidos e amostrados 21.733 indivíduos com DAP > 4,8 cm, incluindo árvores, palmeiras e fetos arborescentes. O número médio de indivíduos amostrados nas 14 parcelas foi de 1.264 ind.ha-1 (± 218 EP de 95%). Dentro dos parâmetros considerados predominaram as árvores (71% FOD Montana a 90% na Restinga), seguidas de palmeiras (10% na Restinga a 25% na FOD Montana) e fetos arborescentes (0% na Restinga a 4% na FOD Montana). Neste aspecto destaca-se a FOD Terras Baixas Exploradas com apenas 1,8% de palmeiras e surpreendentes 10% de fetos arborescentes. O dossel é irregular, com altura variando de 7 a 9 m, raramente as árvores emergentes chegam a 18 m, e a irregularidade do dossel permite a entrada de luz suficiente para o desenvolvimento de centenas de espécies epífitas. Com exceção da FOD Montana, onde o número de mortos foi superior a 5% dos indivíduos amostrados, nas demais fitofisionomias este valor ficou abaixo de 2,5%. Nas 11 parcelas onde foi realizado o estudo florístico foram encontradas 562 espécies distribuídas em 195 gêneros e 68 famílias. Apenas sete espécies - Euterpe edulis Mart. (Arecaceae), Calyptranthes lucida Mart. ex DC. e Marlierea tomentosa Cambess (ambas Myrtaceae), Guapira opposita (Vell.) Reitz (Nyctaginaceae), Cupania oblongifolia Mart. (Sapindaceae) e as Urticaceae Cecropia glaziovii Snethl. e Coussapoa microcarpa (Schott) Rizzini - ocorreram da Floresta de Restinga à FOD Montana, enquanto outras 12 espécies só não ocorreram na Floresta de Restinga. As famílias com o maior número de espécies são Myrtaceae (133 spp), Fabaceae (47 spp), Rubiaceae (49) e Lauraceae (49) ao longo de todo gradiente da FOD e Monimiaceae (21) especificamente nas parcelas da FOD Montana. Em termos de número de indivíduos as famílias mais importantes foram Arecaceae, Rubiaceae, Myrtaceae, Sapotaceae, Lauraceae e na FOD Montana, Monimiaceae. Somente na parcela F, onde ocorreu exploração de madeira entre 1960 e 1985, a abundância de palmeiras foi substituída pelas Cyatheaceae. O gradiente estudado apresenta um pico da diversidade e riqueza nas altitudes intermediárias (300 a 400 m) ao longo da encosta (índice de Shannon-Weiner - H' - variando de 3,96 a 4,48 nats.indivíduo -1). Diversas explicações para este resultado são apresentadas neste trabalho, incluindo o fato dessas altitudes estarem nos limites das expansões e retrações das diferentes fitofisionomias da FOD Atlântica durante as flutuações climáticas do Pleistoceno. Os dados aqui apresentados demonstram a extraordinária riqueza de espécies arbóreas da Floresta Ombrófila Densa Atlântica dos Núcleos Picinguaba e Santa Virgínia do Parque Estadual da Serra do Mar, reforçando a importância de sua conservação ao longo de todo o gradiente altitudinal. A diversidade desta floresta justifica também o investimento de longo prazo, através de parcelas permanentes, para compreender sua dinâmica e funcionamento, bem como monitorar o impacto das mudanças climáticas nessa vegetação.

This paper summarizes floristic and phytossociology data of 11, out of 14 plots of 1 ha, allocated along an altitudinal gradient in the Serra do Mar, São Paulo, Brazil. The study was conducted at Serra do Mar State Park and the plots start at the sea level (10 m - plot of Restinga Forest that occurs at Praia da Fazenda, Picinguaba, municipality of Ubatuba) up to 1100 m above sea level (the Montane Ombrophilous Dense occurs alongside the Itamambuca Trail, municipality of São Luis do Paraitinga). The Restinga Forest occurs in Pleistocenic Coastal Plain where the soil is classified as a sandy Quartzipsamment (Quartzenic Neosol), while along the slopes of the Serra do Mar, the Ombrophylus Dense Forest grows on the top of a pre-Cambrian crystalline basement with granitic rocks, where the soil is a sandy-loam Dystrophic Inceptisol (Cambisol/Latosol). In all 14 plots soils are acidic (pH 3 - 4), chemically poor, with high dilution of nutrients and high saturation of aluminum. In the Restinga and at the foot of the slope the climate is Tropical/Subtropical Humid (Af/Cfa), with no dry season, an average annual rainfall over 2,200 mm and an average annual temperature of 22 ºC. Towards the top of the Serra do Mar there is a gradual cooling along the slope, but there is no reduction in rainfall, so at 1,100 m above sea level the climate is classified as Humid Subtropical (Cfa/Cfb), with no dry season and an average annual temperature of 17 ºC. It is important to remark that, almost daily, from 400 m above sea level up to the top of slopes the mountains are covered by a dense fog. In the 14 plots 21,733 individuals with DBH > 4.8 cm, including trees, palms and ferns, were marked, measured and sampled. The average number of individuals sampled in each plot was 1264 ind.ha-1(± 218 SE 95%). Within the parameters considered trees prevailed (71% in the Montane ODF to 90% in the Restinga Forest), followed by palms (10% in the RF and 25% in the Montane Ombrophilous Dense Forest/ODF) and ferns (0% % in the RF and 4% in the Montane ODF). Regarding these proportions the Exploited Lowlands ODF differs from the others with only 1.8% of palm trees and striking 10% of ferns. The forest canopy is irregular with heights ranging from 7 to 9 m, rarely emergent trees reach 18 m, and due to this irregularity of the canopy the amount of light that gets through sets conditions for the development of hundreds of epiphytic species. Aside from Montana ODF, where the number of dead trees was more than 5% of individuals sampled, in the other phytophysiognomies this value was below 2.5%. In the 11 plots where the floristic study was conducted we found 562 species in 195 genera and 68 families. Only seven species - Euterpe edulis Mart. (Arecaceae), Calyptranthes lucida Mart. ex DC. and Marlierea tomentosa Cambess (both Myrtaceae), Guapira opposita (Vell.) Reitz (Nyctaginaceae), Cupania oblongifolia Mart. (Sapindaceae), Cecropia glaziovii Snethl. and Coussapoa microcarpa (Schott) Rizzini (both Urticaceae) - occurred from Restinga to Montane ODF, while 12 other species did not occur only in the Restinga Forest. Families with the greatest number of species are Myrtaceae (133 spp), Fabaceae (47 spp), Rubiaceae (49) and Lauraceae (49) throughout the gradient and Monimiaceae (21) specifically in portions Montane ODF. Only in the F plot, where logging has occurred between 1950 and 1985, the abundance of palm trees has been replaced by Cyatheaceae. The study shows a peak of diversity and richness, Shannon-Weiner index (H') ranging from 3.96 to 4.48 nats.ind-1, in the intermediate altitudes (300 to 400 m) along the slope. Several explanations for this result are raised here, including the fact that these elevations are within the limits expansions and retractions of the different phytophysiognomies of the Atlantic ODF due to climate fluctuations during the Pleistocene. The results presented in this paper demonstrate the extraordinary richness of tree species of the Atlantic Rainforest from the northeastern coast of the State of Sao Paulo, reinforcing the importance of its conservation throughout the altitudinal gradient. The richness of this forest justifies a long term commitment to study its dynamics and functioning through permanent plots, and monitor the impacts of climate change in this vegetation.