Influence of new integrated pest management strategies on aphidophagous predators in horticultural crops

El 1 de enero de 2014 entró en vigor la Directiva Europea 2009/128/CE sobre uso sostenible de plaguicidas y el Real Decreto 1311/2012 por el cual se traspone dicha normativa comunitaria al ámbito nacional. Estos reglamentos establecen el marco legal por el que las explotaciones agrícolas deben cumplir los principios generales de la Gestión Integrada de Plagas (GIP). Los principios de la GIP dan preferencia a aquellos métodos de control que sean sostenibles y respetuosos con el medio ambiente, dando prioridad al control biológico, al físico y a otros de carácter no químico. Sin embargo, el uso de insecticidas selectivos con los enemigos naturales es necesario en ocasiones para el adecuado manejo de las plagas en cultivos hortícolas. Por ello, el objetivo general de esta Tesis ha sido aportar conocimientos para la mejora del control de plagas en cultivos hortícolas, mediante la integración de estrategias de lucha biológica, física y química. La primera de las líneas de investigación de esta Tesis se centró en el estudio del efecto de la presencia dos depredadores, larvas Chrysoperla carnea y adultos de Adalia bipunctata, en la dispersión del virus de transmisión no persistente Cucumber mosaic virus (CMV) y del virus de transmisión persistente Cucurbit aphid-borne yellows virus (CABYV), transmitidos por el pulgón Aphis gosypii en cultivo de pepino. La tasa de transmisión de CMV fue baja para los dos tiempos de evaluación ensayados (1 y 5 días), debido al limitado movimiento de su vector A. gossypii. Las plantas que resultaron infectadas se localizaron próximas a la fuente de inóculo central y la presencia de ambos enemigos naturales no incrementó significativamente el porcentaje de plantas ocupadas por pulgones ni la tasa de transmisión de CMV. Los patrones de distribución de A. gossypii y de CMV tan solo fueron coincidentes en las proximidades de la planta central infectada en la que se liberaron los insectos. En los ensayos con CABYV, la presencia de C. carnea y de A. bipunctata respectivamente provocó un incremento significativo de la dispersión de A. gossypii tras 14 días, pero no tras 7 días desde la liberación de los insectos. La reducción en el número inicial de pulgones en la planta central infectada con CABYV fue siempre mayor tras la liberación de C. carnea en comparación con A. bipunctata. Sin embargo, la tasa de transmisión de CABYV y su distribución espacial no se vieron significativamente modificadas por la presencia de ninguno de los depredadores, ni tras 7 días ni tras 14 días desde el inicio de los ensayos. Al igual que se estudió el efecto de la presencia de enemigos naturales en el comportamiento de las plagas y en la epidemiología de las virosis que transmiten, en una segunda línea de investigación se evaluó el posible efecto del consumo de pulgones portadores de virus por parte de los enemigos naturales. Este trabajo se llevó a cabo en el Laboratorio de Ecotoxicología del Departamento de Entomología de la Universidade Federal de Lavras (UFLA) (Brasil). En él se evaluó la influencia en los parámetros biológicos del enemigo natural Chrysoperla externa al alimentarse de Myzus persicae contaminados con el virus de transmisión persistente Potato leafroll virus (PLRV). El consumo de M. persicae contaminados con PLRV incrementó significativamente la duración de la fase larvaria, reduciendo también la supervivencia en comparación a otras dos dietas a base de M. persicae no contaminados con el virus y huevos del lepidóptero Ephestia kuehniella. La duración de la fase de pupa de C. externa no difirió significativamente entre las dietas a base de pulgones contaminados con PLRV y pulgones no contaminados, pero ambas fueron menores que con la dieta con huevos de E. kuehniella. Sin embargo, ni la supervivencia en la fase de pupa ni los parámetros reproductivos de los adultos emergidos mostraron diferencias significativas entre las dietas evaluadas. Por el contrario, la supervivencia de los adultos durante los 30 primeros días desde su emergencia sí se vio significativamente afectada por la dieta, siendo al término de este periodo del 54% para aquellos adultos de C. externa que durante su fase larvaria consumieron pulgones con PLRV. Dentro de la GIP, una de las estrategias de carácter físico que se emplean para el control de plagas y enfermedades en cultivos hortícolas protegidos es el uso de plásticos con propiedades fotoselectivas de absorción de la radiación ultravioleta (UV). Por ello, la tercera línea de investigación de la Tesis se centró en el estudio de los efectos directos e indirectos (mediados por la planta) de condiciones especiales de baja radiación UV sobre el crecimiento poblacional del pulgón A. gossypii y los parámetros biológicos del enemigo natural C. carnea, así como sobre las plantas de pepino en las que se liberaron los insectos. Los ensayos se realizaron en jaulones dentro de invernadero, utilizándose en el primero de ellos plantas de pepino sanas, mientras que en el segundo las plantas de pepino fueron previamente infectadas con CABYV para estudiar de qué manera afectaba la incidencia del virus en las mismas condiciones. Las condiciones de baja radiación UV (bajo plástico Térmico Antivirus®) ejercieron un efecto directo en las fases iniciales del cultivo de pepino, promoviendo su crecimiento, mientras que en fases más avanzadas del cultivo indujeron un aumento en el contenido en nitrógeno de las plantas. Las plantas de pepino que fueron sometidas a mayor intensidad de radiación UV (bajo plástico Térmico Blanco®) al inicio del cultivo mostraron un engrosamiento significativo de las paredes de las células epidérmicas del haz de las hojas, así como de la cutícula. El uso del plástico Térmico Antivirus®, utilizado como barrera fotoselectiva para crear condiciones de baja radiación UV, no alteró con respecto al plástico Térmico Blanco® (utilizado como control) el desarrollo poblacional del pulgón A. gossypii ni los parámetros biológicos evaluados en el depredador C. carnea. En el segundo experimento, realizado con plantas infectadas con CABYV, la incidencia de la virosis enmascaró las diferencias encontradas en experimento con plantas sanas, reduciendo aparentemente la influencia de las distintas condiciones de radiación UV. Por último, para el desarrollo de las estrategias de GIP es importante estudiar los posibles efectos secundarios que los plaguicidas pueden tener en los enemigos naturales de las plagas. Es por ello que en la Tesis se evaluaron la toxicidad y los efectos subletales (fecundidad y fertilidad) de flonicamida, flubendiamida, metaflumizona, spirotetramat, sulfoxaflor y deltametrina en los enemigos naturales C. carnea y A. bipunctata. Los efectos secundarios fueron evaluados por contacto residual tanto para larvas como para adultos de ambos enemigos naturales en condiciones de laboratorio. Flonicamida, flubendiamida, metaflumizona y spirotetramat fueron inocuos para larvas de último estadio y adultos de C. carnea y A. bipunctata. Por este motivo, estos insecticidas se presentan como buenos candidatos para ser incorporados dentro de programas de GIP en combinación con estos enemigos naturales para el control de plagas de cultivos hortícolas. Sulfoxaflor fue ligeramente tóxico para adultos de C. carnea y altamente tóxico para larvas de último estadio de A. bipunctata. Para A. bipunctata, sulfoxaflor y deltametrina fueron los compuestos más dañinos. Deltametrina fue también el compuesto más tóxico para larvas y adultos de C. carnea. Por tanto, el uso de deltametrina y sulfoxaflor en programas de GIP debería tomarse en consideración cuando se liberasen cualquiera de estos dos enemigos naturales debido al comportamiento tóxico que mostraron en condiciones de laboratorio. ABSTRACT On 1 January 2014 came into effect the Directive 2009/128/EC of the European Parliament about sustainable use of pesticides and the Royal Decree 1311/2012 that transposes the regulation to the Spanish level. These regulations establish the legal framework that agricultural holdings must adhere to in order to accomplish the general principles of Integrated Pest Management (IPM). The guidelines of IPM give priority to sustainable and eco-friendly pest control techniques, such as biological and physical measures. Nevertheless, the use of pesticides that are selective to natural enemies is sometimes a necessary strategy to implement accurate pest management programs in horticultural protected crops. Therefore, the general objective of this Thesis was to contribute to the improvement of pest management strategies in horticultural crops, by means of the integration of biological, physical and chemical techniques. The first research line of this Thesis was focused on the evaluation of the effects of two aphidophagous predators, Chrysoperla carnea larvae and Adalia bipunctata adults, on the spread of the non-persistently transmitted Cucumber mosaic virus (CMV, Cucumovirus) and the persistently transmitted Cucurbit aphid-borne yellows virus (CABYV, Polerovirus), by the aphid vector Aphis gossypii in a cucumber crop under greenhouse conditions. The CMV transmission rate was generally low, both after 1 and 5 days, due to the limited movement of its aphid vector A. gossypii. Infected plants were mainly located around the central virusinfected source plant, and the percentage of aphid occupation and CMV-infected plants did not differ significantly in absence and presence of natural enemies. The distribution patterns of A. gossypii and CMV were only coincident close to the central plant where insects were released. In the CABYV experiments, the presence of C. carnea larvae and A. bipunctata adults induced significant A. gossypii dispersal after 14 days but not after 7 days. The reduction in the initial aphid population established in the central plant was always higher for C. carnea than for A. bipunctata. Nevertheless, CABYV spread was not significantly modified by the presence of each predator either in the short term (7 days) or in the long term (14 days). Furthermore, the percentage of CABYV-infected plants did not significantly differ when each natural enemy was present in any evaluation period. It is important to evaluate the influence that natural enemies have on pest dynamics and on the spread of viral diseases, but it should be also taken into account the possible effect on the performance of natural enemies when they feed on preys that act as vectors of viruses. Thus, in a second research line developed in the Laboratory of Ecotoxicology, Department of Entomology, of the Universidade Federal de Lavras (UFLA) (Brazil), it was evaluated the performance of Chrysoperla externa under the condition of consuming Myzus persicae acting as vector of Potato leafroll virus (PLRV). The diet composed of PLRV-infected M. persicae significantly increased the length and reduced the survival rate, of the larval period in regard to the other two diets, composed of non-infected M. persicae and Ephestia kuehniella eggs. The lengths of the pupal stage were not significantly different between the aphid diets, but both were significantly shorter than that of E. kuehniella eggs. Neither pupal survival nor reproductive parameters revealed significant differences among the diets. Nevertheless, the adult survival curves during the first 30 days after emergence showed significant differences, reaching at the end of this interval a value of 54% for those C. externa adults fed on PLRVinfected aphids during their larval period. According to the IPM guidelines, one of the physical strategies for the control of pests and diseases in horticultural protected crops is the use of plastic films with photoselective properties that act as ultraviolet (UV) radiation blocking barriers. In this sense, the third research line of the Thesis dealt with the study of the direct and plant-mediated influence of low UV radiation conditions on the performance of the aphid A. gossypii and on the biological parameters of the natural enemy C. carnea, as well as on the cucumber plants where insects were released. The experiments were conducted inside cages under greenhouse conditions, using for the first one healthy cucumber plants, while for the second experiment the cucumber plants were previously infected with CABYV in order to assess the influence of the virus in the same conditions. The low UV radiation conditions (under Térmico Antivirus® plastic film) seemed to exert a direct effect in the early stages of cucumber plants, enhancing their growth, and in an increasing nitrogen content at further developmental stages. The higher UV radiation exposure (under Térmico Blanco® plastic film) in the early stages of the cucumber crop induced the thickening of the adaxial epidermal cell walls and the cuticle of leaves. The use of Térmico Antivirus® plastic film as a photoselective barrier to induce low UV radiation conditions did not modify, in regard to Térmico Blanco® plastic film (used as control), neither the population development of A. gossypii nor the studied biological parameters of the predator C. carnea. In the second experiment, done with CABYV-infected cucumber plants, the incidence of the virus seemed to mask the direct and plant-mediated influence of the different UV radiation conditions. In last term, for the development of IPM strategies it is important to study the potential side effects that pesticides might have on natural enemies. For this reason, in the Thesis were tested the toxicity and sublethal effects (fecundity and fertility) of flonicamid, flubendiamide, metaflumizone, spirotetramat, sulfoxaflor and deltamethrin on the natural enemies C. carnea and A. bipunctata. The side effects of the active ingredients of the insecticides were evaluated with residual contact tests for the larvae and adults of these predators under laboratory conditions. Flonicamid, flubendiamide, metaflumizone and spirotetramat were innocuous to last instar larvae and adults of C. carnea and A. bipunctata. Therefore, these pesticides are promising candidates for being incorporated into IPM programs in combination with these natural enemies for the control of particular greenhouse pests. In contrast, sulfoxaflor was slightly toxic to adults of C. carnea and was highly toxic to last instar larvae of A. bipunctata. For A. bipunctata, sulfoxaflor and deltamethrin were the most damaging compounds. Deltamethrin was also the most toxic compound to larvae and adults of C. carnea. In accordance with this fact, the use of sulfoxaflor and deltamethrin in IPM strategies should be taken into consideration when releasing either of these biological control agents, due to the toxic behavior observed under laboratory conditions.

Control of insect vectors and plant viruses in protected crops by novel pyrethroid-treated nets

Long-lasting insecticide-treated nets (LLITNs) constitute a novel alternative that combines physical and chemical tactics to prevent insect access and the spread of insect-transmitted plant viruses in protected enclosures. This approach is based on a slow-release insecticide-treated net with large hole sizes that allow improved ventilation of greenhouses. The efficacy of a wide range of LLITNs was tested under laboratory conditions against Myzus persicae, Aphis gossypii and Bemisia tabaci. Two nets were selected for field tests under a high insect infestation pressure in the presence of plants infected with Cucumber mosaic virus and Cucurbit aphid-borne yellows virus. The efficacy of Aphidius colemani, a parasitoid commonly used for biological control of aphids, was studied in parallel field experiments.

Selecting crop models for decision making in wheat insurance

In crop insurance, the accuracy with which the insurer quantifies the actual risk is highly dependent on the availability on actual yield data. Crop models might be valuable tools to generate data on expected yields for risk assessment when no historical records are available. However, selecting a crop model for a specific objective, location and implementation scale is a difficult task. A look inside the different crop and soil modules to understand how outputs are obtained might facilitate model choice. The objectives of this paper were (i) to assess the usefulness of crop models to be used within a crop insurance analysis and design and (ii) to select the most suitable crop model for drought risk assessment in semi-arid regions in Spain. For that purpose first, a pre-selection of crop models simulating wheat yield under rainfed growing conditions at the field scale was made, and second, four selected models (Aquacrop, CERES- Wheat, CropSyst and WOFOST) were compared in terms of modelling approaches, process descriptions and model outputs. Outputs of the four models for the simulation of winter wheat growth are comparable when water is not limiting, but differences are larger when simulating yields under rainfed conditions. These differences in rainfed yields are mainly related to the dissimilar simulated soil water availability and the assumed linkages with dry matter formation. We concluded that for the simulation of winter wheat growth at field scale in such semi-arid conditions, CERES-Wheat and CropSyst are preferred. WOFOST is a satisfactory compromise between data availability and complexity when detail data on soil is limited. Aquacrop integrates physiological processes in some representative parameters, thus diminishing the number of input parameters, what is seen as an advantage when observed data is scarce. However, the high sensitivity of this model to low water availability limits its use in the region considered. Contrary to the use of ensembles of crop models, we endorse that efforts be concentrated on selecting or rebuilding a model that includes approaches that better describe the agronomic conditions of the regions in which they will be applied. The use of such complex methodologies as crop models is associated with numerous sources of uncertainty, although these models are the best tools available to get insight in these complex agronomic systems.

Selection, training and validation process of a sensory panel for bread analysis: Influence of cultivar on the quality of breads made from common wheat and spelta wheat

A protocol of selection, training and validation of the members of the panel for bread sensory analysis is proposed to assess the influence of wheat cultivar on the sensory quality of bread. Three cultivars of bread wheat and two cultivars of spelt wheat organically-grown under the same edaphoclimatic conditions were milled and baked using the same milling and baking procedure. Through the use of triangle tests, differences were identified between the five breads. Significant differences were found between the spelt breads and those made with bread wheat for the attributes ?crumb cell homogeneity? and ?crumb elasticity?. Significant differences were also found for the odor and flavor attributes, with the bread made with ?Espelta Navarra? being the most complex, from a sensory point of view. Based on the results of this study, we propose that sensory properties should be considered as breeding criteria for future work on genetic improvement.

Wind pumps for irrigating greenhouse crops: comparison in different socio-economical frameworks

Wind power can play an interesting role in irrigation projects in different areas. A methodology can determine the feasibility of the technology and the levels of daily irrigation demand satisfied by windmills at different levels of risk, using tomato (Lycopersicon esculentum Mill) as greenhouse crop. The present work compared the feasibility of the technology and the critical factors involved in three different countries: Cuba, Spain and Pakistan. The study considered as factors the wind speed level, the energy cost, the tomato prices, the reliability and distance to the electrical grid, and the crop development dates, determining the economic feasibility for each combination of factors in each country.

Economics of Wheat in Egypt

Este estudio pretende estimar la eficiencia y la productividad de las principales provincias de la producción de trigo en Egipto. Los datos utilizados en este estudio son datos de panel a nivel de provincias del período 1990-2012, obtenidos del Ministerio de Agricultura y Recuperación Tierras, y de la Agencia Central de Movilización Pública y Estadística, Egipto. Se aplica el enfoque de fronteras estocásticas para medir la eficiencia (función de producción de Cobb-Douglas) y se emplean las especificaciones de Battese y Coelli (1992) y (1995). También se utiliza el índice de Malmquist como una aproximación no paramétrica (Análisis de Envolvente de Datos) para descomponer la productividad total de los factores de las principales provincias productoras de trigo en Egipto en cambio técnico y cambio de eficiencia. El coeficiente de tierra es positivo y significativo en los dos especificaciones Battese y Coelli (1992) y (1995), lo que implica que aumentar la tierra para este cultivo aumentaría significativamente la producción de trigo. El coeficiente de trabajo es positivo y significativo en la especificación de Battese y Coelli (1992), mientras que es positivo y no significativo en la especificación de Battese y Coelli (1995). El coeficiente de la maquinaria es negativo y no significativo en las dos especificaciones de Battese y Coelli (1992) y (1995). El coeficiente de cambio técnico es positivo y no significativo en la especificación de Battese y Coelli (1992), mientras que es positiva y significativo en la especificación de Battese y Coelli (1995). Las variables de efectos del modelo de ineficiencia Battese y Coelli (1995) indican que no existe impacto de las diferentes provincias en la producción de trigo en Egipto; la ineficiencia técnica de la producción de trigo tendió a disminuir durante el período de estudio; y no hay ningún impacto de género en la producción de trigo en Egipto. Los niveles de eficiencia técnica varían entre las diferentes provincias para las especificaciones de Battese y Coelli (1992) y (1995); el nivel mínimo medio de eficiencia técnica es 91.61% en la provincia de Fayoum, mientras que el nivel máximo medio de la eficiencia técnica es 98.69% en la provincia de Dakahlia. La eficiencia técnica toma un valor medio de 95.37%, lo que implica poco potencial para mejorar la eficiencia de uso de recursos en la producción de trigo. La TFPCH de la producción de trigo en Egipto durante el período 1990-2012 tiene un valor menor que uno y muestra un declive. Esta disminución es debida más al componente de cambio técnico que al componente de cambio de eficiencia. La disminución de TFPCH mejora con el tiempo. La provincia de Menoufia tiene la menor disminución en TFPCH, 6.5%, mientras que dos provincias, Sharkia y Dakahlia, son las que más disminuyen en TFPCH, 13.1%, en cada uno de ellas. Menos disminución en TFPCH ocurre en el período 2009-2010, 0.3%, mientras que más disminución se produce en TFPCH en el período 1990-1991, 38.9%. La disminución de la PTF de la producción de trigo en Egipto se atribuye principalmente a la mala aplicación de la tecnología. ABSTRACT The objectives of this study are to estimate the efficiency and productivity of the main governorates of wheat production in Egypt. The data used in this study is a panel data at the governorates level, it represents the time period 1990-2012 and taken from the Ministry of Agriculture and Land Reclamation, and the Central Agency for Public Mobilization and Statistics, Egypt. We apply the stochastic frontier approach for efficiency measurement (Cobb-Douglas production function) and the specifications of Battese and Coelli (1992) and (1995) are employed. Also we use Malmquist TFP index as a non-parametric approach (DEA) to decompose total factor productivity of the main governorates of wheat production in Egypt into technical change and efficiency change. The coefficient of land is positive and significant at Battese and Coelli (1992) and (1995) specifications, implying that increasing the wheat area could significantly enhance the production of wheat. The coefficient of labor is positive and significant at Battese and Coelli (1992) specification, while it is positive and insignificant at Battese and Coelli (1995) specification. The coefficient of machinery is negative and insignificant at the specifications of Battese and Coelli (1992) and (1995). The technical change coefficient is positive and insignificant at Battese and Coelli (1992) specification, while it is positive and significant at Battese and Coelli (1995) specification. The variables of the inefficiency effect model indicate that there is no impact from the location of the different governorates on wheat production in Egypt, the technical inefficiency of wheat production tended to decrease through the period of study, and there is no impact from the gender on wheat production in Egypt. The levels of technical efficiency vary among the different governorates for the specifications of Battese and Coelli (1992) and (1995); the minimum mean level of technical efficiency is 91.61% at Fayoum governorate, while the maximum mean level of technical efficiency is 98.69% at Dakahlia governorate. The technical efficiency takes an average value of 95.37%, this implying that little potential exists to improve resource use efficiency in wheat production. The TFPCH of wheat production in Egypt during the time period 1990-2012 has a value less than one and shows a decline; this decline is due mainly to the technical change component than the efficiency change component. The decline in TFPCH is generally improves over time. Menoufia governorate has the least declining in TFPCH by 6.5%, while two governorates, Sharkia and Dakahlia have the most declining in TFPCH by 13.1% for each of them. The least declining in TFPCH occurred at the period 2009- 2010 by 0.3%, while the most declining in TFPCH occurred at the period 1990-1991 by 38.9%. The declining in TFP of wheat production in Egypt is attributed mainly to poor application of technology.

Metodología de integración de actividades de adaptación al cambio climático en proyectos de desarrollo rural

Hoy en día, ya no se puede pasar por alto la necesidad de una agricultura climáticamente más inteligente para los 500 millones de pequeños agricultores del mundo (Wheeler, 2013). Estos representan aproximadamente el 60 % de la agricultura mundial y proporcionan hasta el 80 % de los alimentos en los países en vías de desarrollo, los pequeños agricultores gestionan vastas extensiones de tierra y lamentablemente incluyen los grupos con mayor proporción de personas en estado de inseguridad alimentaria. El cambio climático está transformando el contexto para la agricultura en pequeña escala. Durante siglos, los pequeños agricultores desarrollaron la capacidad de adaptarse a los cambios ambientales y la variabilidad del clima, pero la velocidad y la intensidad del cambio climático está superando su capacidad de respuesta. Si no se cambia la manera que tenemos de lidiar con el cambio climático, tanto en acciones locales como globales, es muy probable que las personas rurales de entornos vulnerables tengan que adaptarse a un calentamiento global promedio de 4 °C por encima de los niveles preindustriales para el año 2100. Esta alza de las temperaturas aumentará aún más la incertidumbre y provocará desastres naturales como las sequías, la erosión del suelo, la pérdida de biodiversidad y la escasez agua sean mucho más frecuentes. Uno de los factores más importantes para los pequeños agricultores es que ya no pueden depender de los promedios históricos, por lo que es más difícil para ellos para planificar y gestionar la producción debido a los cambios en los patrones climáticos. Algunos de los principales cultivos de cereales (trigo, arroz, maíz, etc.) han alcanzado su umbral de tolerancia al calor y un aumento de la temperatura en torno a 1,5-2 °C podría ser muy perjudicial. Estos efectos a corto plazo podrían ser agravados por otros a medio y largo plazo, los que se refieren al impacto socioeconómico en términos de oportunidades y estabilidad política. El cambio climático está haciendo que el desarrollo de la pequeña agricultura resulte mucho más caro. A nivel de proyectos, los programas resistentes al clima tienen, normalmente, unos costos iniciales más altos, tanto de diseño como de implementación. Por ejemplo, es necesario incluir gastos adicionales en infraestructura, operación y mantenimiento; desarrollo de nuevas capacidades y el intercambio de conocimientos en torno al cambio climático. También se necesita mayor inversión para fortalecer las instituciones frente a los nuevos retos que propone el cambio climático, o generar información que pueda ser de escala reducida y con enfoques que beneficien a la comunidad, el cambio climático es global pero los efectos son locales. Es, por tanto, el momento de redefinir la relación entre agricultura y medio ambiente, ya que se hace cada vez más necesario buscar mejores y más eficientes maneras para responder al cambio climático. Es importante señalar que la respuesta al cambio climático no significa reinventar todo lo que se ha aprendido sobre el desarrollo, significa aplicar un esfuerzo renovado para hacer frente a los cambios en el trabajo de cooperación al desarrollo de una manera más sistemática y más amplia. Una respuesta coherente al cambio climático requiere que la comunidad internacional reconozca la necesidad de aumentar el apoyo financiero para la adaptación así como un mayor énfasis en proporcionar soluciones diseñadas para aumentar la resiliencia1 de los pequeños agricultores a las crisis relacionadas con el clima. Con el fin de responder a algunos de los desafíos mencionados anteriormente, esta investigación pretende contribuir a fortalecer las capacidades de los pequeños productores, aquellos que actualmente están la primera línea frente a los desafíos del cambio climático, promoviendo un desarrollo que tenga un impacto positivo en sus medios de vida. La tesis se compone de cuatro capítulos. El primero define y analiza el marco teórico de las interacciones entre el cambio climático y el impacto en los proyectos de desarrollo rural, especialmente los que tienen por objetivo mejorar la seguridad alimentaria de los pequeños productores. En ese mismo capítulo, se presenta una revisión global de la financiación climática, incluyendo la necesidad de asignar suficientes recursos para la adaptación. Con el fin de lograr una mayor eficacia e impacto en los proyectos de desarrollo, la investigación desarrolla una metodología para integrar actividades de adaptación al cambio climático, presentada en el segundo capítulo. Esta metodología fue implementada y validada durante el periodo 2012-14, trabajando directamente con diferentes equipos gubernamentales en diez proyectos del Fondo Internacional de Desarrollo Agrícola ). El tercero presenta, de manera detallada, la aplicación de la metodología a los estudios de caso de Bolivia y Nicaragua, así como un resumen de las principales conclusiones en la aplicación de los ocho países restantes. Finalmente, en el último capítulo se presentan las conclusiones y un esbozo de futuras líneas de investigación. Actualmente, el tema de la sostenibilidad ambiental y el cambio climático está ganando terreno en la agenda de desarrollo. Es por ello que se alumbra esta investigación, para que a través de los resultados obtenidos y la implementación de la metodología propuesta, sirva como herramienta estratégica para la planificación y la gestión operativa a la hora de integrar iniciativas de adaptación en los proyectos de desarrollo rural. ABSTRACT The need for climate-smart agriculture for the world’s 500 million smallholder farms cannot be overlooked: they account for 60 per cent of global agriculture, provide up to 80 per cent of food in developing countries, manage vast areas of land and make up the largest share of the developing world’s undernourished. Climate change is transforming the context for smallholder agriculture. Over centuries smallholders have developed the capacity to adapt to environmental change and climate variability, but the speed and intensity of climate change is outpacing the speed of historically autonomous actions. In the absence of a profound step-change in local and global action on climate change, it is Increasingly likely that poor rural people would need to contend with an average global warming of 4 degrees above pre-industrial levels by 2100, if not sooner. Such substantial climatic change will further increase uncertainty and exacerbate weather –related disasters, droughts, biodiversity loss, and land and water scarcity. Perhaps most significantly for smallholder farmers, they can no longer rely on historical averages, making it harder for them to plan and manage production when planting seasons and weather patterns are shifting. The major cereal crops (wheat, rice, maize, etc.) are at their heat tolerance threshold and with a 1.5-2°C temperature increase could collapse. These “first-round” effects will be compounded by second-round socio-economic impacts in terms of economic opportunities and political stability. Climate change is making the development of smallholder agriculture more expensive. At project level, climate-resilient programmes typically have higher up-front design and implementation costs – e.g. infrastructure costs and initially increased asset management, operation and maintenance, more capacity-building and knowledge sharing, strengthening institutions, greater project development costs (downscaled data generation and community-based approaches), and greater costs from enhancing cross sectorial and stakeholders collaboration. Consequently it’s time to redefine the relationship between agriculture and environment as we need to look better and more efficient ways to respond to climate change. It is important to note that responding to climate change does not mean to throwing out or reinventing everything that has been learnt about development. It means a renewed effort to tackle wider and well-known development changes in a more systematic way. A coherent response to climate change requires acknowledge of the need to increase the financial support for adaptation and a continued emphasis on provided solutions designed to increase the resilience of smallholders and poor communities to shocks, which are weather related. In order to respond to some of the challenges mentioned before, this research aims to contribute to strengthen the capacities of the smallholders and to promote a development that will positively impact in the rural livelihoods of the most vulnerable smallholders farmers; those who currently are in the first line facing the challenges of climate change. The thesis has four chapters. Chapter one describes and analyses the theoretical framework of the interactions between climate change and the impact on rural development projects, especially those aimed at improving the food security of smallholders producers. In this chapter a comprehensive review of climate financing is presented, including the need to allocate sufficient resources for adaptation. In order to achieve greater effectiveness and impact on development projects, the research develops in the second chapter a methodology to integrate adaptation activities for climate change. This methodology was implemented and validated during the 2012-14 period, working directly with various government teams in ten projects of the International Fund for Agricultural Development (IFAD). The third chapter presents in detail the application of the methodology to the case studies of Bolivia and Nicaragua, as well as a summary of the main conclusions of its implementation in the remaining eight countries. The final chapter exposes the main conclusions and future research topics. At a time when environmental sustainability and climate change issues are gaining more attention, the research and obtained results through the implementation of the model methodology proposed, can be considered a strategic tool for planning and operational management to integrate adaptation initiatives in rural development projects. The use of the proposed methodology will boost incentives to scale up climate resilience programmes and integrate adaptation to climate change into wider smallholder development programmes.

Generalización de variables medioambientales mediante interpolación GIS

La investigación de esta tesis se centra en el estudio de técnicas geoestadísticas y su contribución a una mayor caracterización del binomio factores climáticos-rendimiento de un cultivo agrícola. El inexorable vínculo entre la variabilidad climática y la producción agrícola cobra especial relevancia en estudios sobre el cambio climático o en la modelización de cultivos para dar respuesta a escenarios futuros de producción mundial. Es información especialmente valiosa en sistemas operacionales de monitoreo y predicción de rendimientos de cultivos Los cuales son actualmente uno de los pilares operacionales en los que se sustenta la agricultura y seguridad alimentaria mundial; ya que su objetivo final es el de proporcionar información imparcial y fiable para la regularización de mercados. Es en este contexto, donde se quiso dar un enfoque alternativo a estudios, que con distintos planteamientos, analizan la relación inter-anual clima vs producción. Así, se sustituyó la dimensión tiempo por la espacio, re-orientando el análisis estadístico de correlación interanual entre rendimiento y factores climáticos, por el estudio de la correlación inter-regional entre ambas variables. Se utilizó para ello una técnica estadística relativamente nueva y no muy aplicada en investigaciones similares, llamada regresión ponderada geográficamente (GWR, siglas en inglés de “Geographically weighted regression”). Se obtuvieron superficies continuas de las variables climáticas acumuladas en determinados periodos fenológicos, que fueron seleccionados por ser factores clave en el desarrollo vegetativo de un cultivo. Por ello, la primera parte de la tesis, consistió en un análisis exploratorio sobre comparación de Métodos de Interpolación Espacial (MIE). Partiendo de la hipótesis de que existe la variabilidad espacial de la relación entre factores climáticos y rendimiento, el objetivo principal de esta tesis, fue el de establecer en qué medida los MIE y otros métodos geoestadísticos de regresión local, pueden ayudar por un lado, a alcanzar un mayor entendimiento del binomio clima-rendimiento del trigo blando (Triticum aestivum L.) al incorporar en dicha relación el componente espacial; y por otro, a caracterizar la variación de los principales factores climáticos limitantes en el crecimiento del trigo blando, acumulados éstos en cuatro periodos fenológicos. Para lleva a cabo esto, una gran carga operacional en la investigación de la tesis consistió en homogeneizar y hacer los datos fenológicos, climáticos y estadísticas agrícolas comparables tanto a escala espacial como a escala temporal. Para España y los Bálticos se recolectaron y calcularon datos diarios de precipitación, temperatura máxima y mínima, evapotranspiración y radiación solar en las estaciones meteorológicas disponibles. Se dispuso de una serie temporal que coincidía con los mismos años recolectados en las estadísticas agrícolas, es decir, 14 años contados desde 2000 a 2013 (hasta 2011 en los Bálticos). Se superpuso la malla de información fenológica de cuadrícula 25 km con la ubicación de las estaciones meteorológicas con el fin de conocer los valores fenológicos en cada una de las estaciones disponibles. Hecho esto, para cada año de la serie temporal disponible se calcularon los valores climáticos diarios acumulados en cada uno de los cuatro periodos fenológicos seleccionados P1 (ciclo completo), P2 (emergencia-madurez), P3 (floración) y P4 (floraciónmadurez). Se calculó la superficie interpolada por el conjunto de métodos seleccionados en la comparación: técnicas deterministas convencionales, kriging ordinario y cokriging ordinario ponderado por la altitud. Seleccionados los métodos más eficaces, se calculó a nivel de provincias las variables climatológicas interpoladas. Y se realizaron las regresiones locales GWR para cuantificar, explorar y modelar las relaciones espaciales entre el rendimiento del trigo y las variables climáticas acumuladas en los cuatro periodos fenológicos. Al comparar la eficiencia de los MIE no destaca una técnica por encima del resto como la que proporcione el menor error en su predicción. Ahora bien, considerando los tres indicadores de calidad de los MIE estudiados se han identificado los métodos más efectivos. En el caso de la precipitación, es la técnica geoestadística cokriging la más idónea en la mayoría de los casos. De manera unánime, la interpolación determinista en función radial (spline regularizado) fue la técnica que mejor describía la superficie de precipitación acumulada en los cuatro periodos fenológicos. Los resultados son más heterogéneos para la evapotranspiración y radiación. Los métodos idóneos para estas se reparten entre el Inverse Distance Weighting (IDW), IDW ponderado por la altitud y el Ordinary Kriging (OK). También, se identificó que para la mayoría de los casos en que el error del Ordinary CoKriging (COK) era mayor que el del OK su eficacia es comparable a la del OK en términos de error y el requerimiento computacional de este último es mucho menor. Se pudo confirmar que existe la variabilidad espacial inter-regional entre factores climáticos y el rendimiento del trigo blando tanto en España como en los Bálticos. La herramienta estadística GWR fue capaz de reproducir esta variabilidad con un rendimiento lo suficientemente significativo como para considerarla una herramienta válida en futuros estudios. No obstante, se identificaron ciertas limitaciones en la misma respecto a la información que devuelve el programa a nivel local y que no permite desgranar todo el detalle sobre la ejecución del mismo. Los indicadores y periodos fenológicos que mejor pudieron reproducir la variabilidad espacial del rendimiento en España y Bálticos, arrojaron aún, una mayor credibilidad a los resultados obtenidos y a la eficacia del GWR, ya que estaban en línea con el conocimiento agronómico sobre el cultivo del trigo blando en sistemas agrícolas mediterráneos y norteuropeos. Así, en España, el indicador más robusto fue el balance climático hídrico Climatic Water Balance) acumulado éste, durante el periodo de crecimiento (entre la emergencia y madurez). Aunque se identificó la etapa clave de la floración como el periodo en el que las variables climáticas acumuladas proporcionaban un mayor poder explicativo del modelo GWR. Sin embargo, en los Bálticos, países donde el principal factor limitante en su agricultura es el bajo número de días de crecimiento efectivo, el indicador más efectivo fue la radiación acumulada a lo largo de todo el ciclo de crecimiento (entre la emergencia y madurez). Para el trigo en regadío no existe ninguna combinación que pueda explicar más allá del 30% de la variación del rendimiento en España. Poder demostrar que existe un comportamiento heterogéneo en la relación inter-regional entre el rendimiento y principales variables climáticas, podría contribuir a uno de los mayores desafíos a los que se enfrentan, a día de hoy, los sistemas operacionales de monitoreo y predicción de rendimientos de cultivos, y éste es el de poder reducir la escala espacial de predicción, de un nivel nacional a otro regional. ABSTRACT This thesis explores geostatistical techniques and their contribution to a better characterization of the relationship between climate factors and agricultural crop yields. The crucial link between climate variability and crop production plays a key role in climate change research as well as in crops modelling towards the future global production scenarios. This information is particularly important for monitoring and forecasting operational crop systems. These geostatistical techniques are currently one of the most fundamental operational systems on which global agriculture and food security rely on; with the final aim of providing neutral and reliable information for food market controls, thus avoiding financial speculation of nourishments of primary necessity. Within this context the present thesis aims to provide an alternative approach to the existing body of research examining the relationship between inter-annual climate and production. Therefore, the temporal dimension was replaced for the spatial dimension, re-orienting the statistical analysis of the inter-annual relationship between crops yields and climate factors to an inter-regional correlation between these two variables. Geographically weighted regression, which is a relatively new statistical technique and which has rarely been used in previous research on this topic was used in the current study. Continuous surface values of the climate accumulated variables in specific phenological periods were obtained. These specific periods were selected because they are key factors in the development of vegetative crop. Therefore, the first part of this thesis presents an exploratory analysis regarding the comparability of spatial interpolation methods (SIM) among diverse SIMs and alternative geostatistical methodologies. Given the premise that spatial variability of the relationship between climate factors and crop production exists, the primary aim of this thesis was to examine the extent to which the SIM and other geostatistical methods of local regression (which are integrated tools of the GIS software) are useful in relating crop production and climate variables. The usefulness of these methods was examined in two ways; on one hand the way this information could help to achieve higher production of the white wheat binomial (Triticum aestivum L.) by incorporating the spatial component in the examination of the above-mentioned relationship. On the other hand, the way it helps with the characterization of the key limiting climate factors of soft wheat growth which were analysed in four phenological periods. To achieve this aim, an important operational workload of this thesis consisted in the homogenization and obtention of comparable phenological and climate data, as well as agricultural statistics, which made heavy operational demands. For Spain and the Baltic countries, data on precipitation, maximum and minimum temperature, evapotranspiration and solar radiation from the available meteorological stations were gathered and calculated. A temporal serial approach was taken. These temporal series aligned with the years that agriculture statistics had previously gathered, these being 14 years from 2000 to 2013 (until 2011 for the Baltic countries). This temporal series was mapped with a phenological 25 km grid that had the location of the meteorological stations with the objective of obtaining the phenological values in each of the available stations. Following this procedure, the daily accumulated climate values for each of the four selected phenological periods were calculated; namely P1 (complete cycle), P2 (emergency-maturity), P3 (flowering) and P4 (flowering- maturity). The interpolated surface was then calculated using the set of selected methodologies for the comparison: deterministic conventional techniques, ordinary kriging and ordinary cokriging weighted by height. Once the most effective methods had been selected, the level of the interpolated climate variables was calculated. Local GWR regressions were calculated to quantify, examine and model the spatial relationships between soft wheat production and the accumulated variables in each of the four selected phenological periods. Results from the comparison among the SIMs revealed that no particular technique seems more favourable in terms of accuracy of prediction. However, when the three quality indicators of the compared SIMs are considered, some methodologies appeared to be more efficient than others. Regarding precipitation results, cokriging was the most accurate geostatistical technique for the majority of the cases. Deterministic interpolation in its radial function (controlled spline) was the most accurate technique for describing the accumulated precipitation surface in all phenological periods. However, results are more heterogeneous for the evapotranspiration and radiation methodologies. The most appropriate technique for these forecasts are the Inverse Distance Weighting (IDW), weighted IDW by height and the Ordinary Kriging (OK). Furthermore, it was found that for the majority of the cases where the Ordinary CoKriging (COK) error was larger than that of the OK, its efficacy was comparable to that of the OK in terms of error while the computational demands of the latter was much lower. The existing spatial inter-regional variability between climate factors and soft wheat production was confirmed for both Spain and the Baltic countries. The GWR statistic tool reproduced this variability with an outcome significative enough as to be considered a valid tool for future studies. Nevertheless, this tool also had some limitations with regards to the information delivered by the programme because it did not allow for a detailed break-down of its procedure. The indicators and phenological periods that best reproduced the spatial variability of yields in Spain and the Baltic countries made the results and the efficiency of the GWR statistical tool even more reliable, despite the fact that these were already aligned with the agricultural knowledge about soft wheat crop under mediterranean and northeuropean agricultural systems. Thus, for Spain, the most robust indicator was the Climatic Water Balance outcome accumulated throughout the growing period (between emergency and maturity). Although the flowering period was the phase that best explained the accumulated climate variables in the GWR model. For the Baltic countries where the main limiting agricultural factor is the number of days of effective growth, the most effective indicator was the accumulated radiation throughout the entire growing cycle (between emergency and maturity). For the irrigated soft wheat there was no combination capable of explaining above the 30% of variation of the production in Spain. The fact that the pattern of the inter-regional relationship between the crop production and key climate variables is heterogeneous within a country could contribute to one is one of the greatest challenges that the monitoring and forecasting operational systems for crop production face nowadays. The present findings suggest that the solution may lay in downscaling the spatial target scale from a national to a regional level.

Mealiness Detection in Agricultural Crops: Destructive and Nondestructive Tests: A Review

Mealiness is known as an important internal quality attribute of fruits/vegetables, which has significant influence on consumer purchasing decisions. Mealiness has been a topic of research interest over the past several decades. A number of destructive and nondestructive techniques are introduced for mealiness detection. Nondestructive methods are more interesting because they are rapid, noninvasive, and suitable for real-time purposes. In this review, the concept of mealiness is presented for potato, apple, and peach, followed by an in-depth discussion about applications of destructive and nondestructive techniques developed for mealiness detection. The results suggest the potential of electromagnetic-based techniques for nondestructive mealiness evaluation. Further investigations are in progress to find more appropriate nondestructive techniques as well as cost and performance.

Wheat allergy in celiac children

Gluten is the main structural protein complex of wheat with equivalent toxic proteins found in other cereals (rye, barley, and oats) which are responsible for different immunologic responses with different clinical expressions of disease. The spectrum of gluten-related disorders has been classified according to pathogenic, clinical, and epidemiological differences in three main forms: (i) wheat allergy (WA), an IgE-mediated disease; (ii) autoimmune disease, including celiac disease (CD), dermatitis herpetiformis, and gluten ataxia; and (iii) possibly immune-mediated, gluten sensitivity [1]. WA is an immunologic Th2 response with typical manifestations which can vary from dermatological, respiratory, and/or intestinal to anaphylactic reactions. In contrast, CD is an autoimmune disorder, a gliadin-specific T-cell response which is enhanced by the action of intestinal tissue transglutaminase (tTG), with a wide clinical spectrum including symptomatic cases with either intestinal (e.g., chronic diarrhea, weight loss) or extraintestinal features (e.g., anemia, osteoporosis, neurologic disturbances) and silent forms that are occasionally discovered as a result of serological screening [1]. We studied wheat allergy in two children with early diagnosis of CD, who developed immediate allergic symptoms after eating small amounts of wheat flour.

Occupational allergic multiorgan disease induced by wheat flour

Bakers are repeatedly exposed to wheat flour (WF) and may develop sensitization and occupational rhinoconjunctivitis and/or asthma to WF allergens.1 Several wheat proteins have been identified as causative allergens of occupational respiratory allergy in bakery workers.1 Testing of IgE reactivity in patients with different clinical profiles of wheat allergy (food allergy, wheat-dependent exercise-induced anaphylaxis, and baker's asthma) to salt-soluble and salt-insoluble protein fractions from WF revealed a high degree of heterogeneity in the recognized allergens. However, mainly salt-soluble proteins (albumins, globulins) seem to be associated with baker's asthma, and prolamins (gliadins, glutenins) with wheat-dependent exercise-induced anaphylaxis, whereas both protein fractions reacted to IgE from food-allergic patients.1 Notwithstanding, gliadins have also been incriminated as causative allergens in baker's asthma.2 We report on a 31-year-old woman who had been exposed to WF practically since birth because her family owned a bakery housed in the same home where they lived. She moved from this house when she was 25 years, but she continued working every day in the family bakery. In the last 8 years she had suffered from work-related nasal and ocular symptoms such as itching, watery eyes, sneezing, nasal stuffiness, and rhinorrhea. These symptoms markedly improved when away from work and worsened at work. In the last 5 years, she had also experienced dysphagia with frequent choking, especially when ingesting meats or cephalopods, which had partially improved with omeprazole therapy. Two years before referral to our clinic, she began to have dry cough and breathlessness, which she also attributed to her work environment. Upper and lower respiratory tract symptoms increased when sifting the WF and making the dough. The patient did not experience gastrointestinal symptoms with ingestion of cereal products. Skin prick test results were positive to grass (mean wheal, 6 mm), cypress (5 mm) and Russian thistle pollen (4 mm), WF (4 mm), and peach lipid transfer protein (6 mm) and were negative to rice flour, corn flour, profilin, mites, molds, and animal dander. Skin prick test with a homemade WF extract (10% wt/vol) was strongly positive (15 mm). Serologic tests yielded the following results: eosinophil cationic protein, 47 ?g/L; total serum IgE, 74 kU/L; specific IgE (ImmunoCAP; ThermoFisher, Uppsala, Sweden) to WF, 7.4 kU/L; barley flour, 1.24 kU/L; and corn, gluten, alpha-amylase, peach, and apple, less than 0.35 kU/L. Specific IgE binding to microarrayed purified WF allergens (WDAI-0.19, WDAI-0.53, WTAI-CM1, WTAI-CM2, WTAI-CM3, WTAI-CM16, WTAI-CM17, Tri a 14, profilin, ?-5-gliadin, Tri a Bd 36 and Tri a TLP, and gliadin and glutamine fractions) was assessed as described elsewhere.3 The patient's serum specifically recognized ?-5-gliadin and the gliadin fraction, and no IgE reactivity was observed to other wheat allergens. Spirometry revealed a forced vital capacity of 3.88 L (88%), an FEV1 of 3.04 L (87%), and FEV1/forced vital capacity of 83%. A methacholine inhalation test was performed following an abbreviated protocol,4 and the results were expressed as PD20 in cumulative dose (mg) of methacholine. Methacholine inhalation challenge test result was positive (0.24 mg cumulative dose) when she was working, and after a 3-month period away from work and with no visits to the bakery house, it gave a negative result. A chest x-ray was normal. Specific inhalation challenge test was carried out in the hospital laboratory by tipping WF from one tray to another for 15 minutes. Spirometry was performed at baseline and at 2, 5, 10, 15, 20, 30, 45, and 60 minutes after the challenge with WF. Peak expiratory flow was measured at baseline and then hourly over 24 hours (respecting sleeping time). A 12% fall in FEV1 was observed at 20 minutes and a 26% drop in peak expiratory flow at 9 hours after exposure to WF,

Influence of allelic prolamin variation and localities on durum wheat quality

Thirty-seven varieties of a Mediterranean durum wheat collection grown in Tunisia and Spain were analysed for their allelic composition in prolamins, as well as their protein concentration, sodium dodecyl sulphate sedimentation (SDSS) test and mixograph parameters. Genotype was a greater source of variation in all measurements than locality. Uncommon high and low molecular glutenin subunits (HMW-GS and LMW-GS) were found (V and 2? subunits at Glu-A1, 13 þ 16 at Glu-B1, 5* subunit and ax allele at Glu-A3). The rare combinations 2 þ 4þ14 þ 18 and 8 þ 9þ13 þ 16þ18 subunits at the Glu-B3 locus were found. Glu-A3ax had a positive influence on SDSS and mixograph parameters. Of all the prolamins, those that have the B-LMW-GS composition aaa (for Glu-A3, Glu-B3 and Glu-B2 loci, respectively), when associated with the Glu-A1c and Glu-B1d gave the best semolina quality. By contrast, semolina quality is poor when this same composition is associated with the Glu-A1c and Glu-B1e and even poorer when associated with the Glu-A1c and Glu-B1f. In addition, the cultivars with B-LMW-GS allelic composition aab (for Glu-A3, Glu-B3 and Glu-B2 loci, respectively), when associated with the Glu- A1c and Glu-B1d, gave high quality, whereas when associated with the Glu-A1c and Glu-B1e or with Glu- A1o and Glu-B1f, the quality was very poor.

Clinical presentation, allergens, and management of wheat allergy

IgE-mediated allergy to wheat proteins can be caused by exposure through ingestion, inhalation, or skin/mucosal contact, and can affect various populations and age groups. Respiratory allergy to wheat proteins is commonly observed in adult patients occupationally exposed to flour, whereas wheat food allergy is more common in children. Wheat allergy is of growing importance for patients with recurrent anaphylaxis, especially when exercise related. The diagnosis of wheat allergy relies on a consistent clinical history, skin prick testing with well-characterized extracts and specific IgE tests. The accuracy of wheat allergy diagnosis may be improved by measuring IgE responses to several wheat components. However, a high degree of heterogeneity has been found in the recognition pattern of allergens among patient groups with different clinical profiles, as well as within each group. Thus, oral provocation with wheat or the implicated cereal is the reference test for the definitive diagnosis of ingested wheat/cereal allergy.

Temperature and precipitation effects on wheat yield across a European transect: a crop model ensemble analysis using impact response surfaces

This study explored the utility of the impact response surface (IRS) approach for investigating model ensemble crop yield responses under a large range of changes in climate. IRSs of spring and winter wheat Triticum aestivum yields were constructed from a 26-member ensemble of process-based crop simulation models for sites in Finland, Germany and Spain across a latitudinal transect. The sensitivity of modelled yield to systematic increments of changes in temperature (-2 to +9°C) and precipitation (-50 to +50%) was tested by modifying values of baseline (1981 to 2010) daily weather, with CO2 concentration fixed at 360 ppm. The IRS approach offers an effective method of portraying model behaviour under changing climate as well as advantages for analysing, comparing and presenting results from multi-model ensemble simulations. Though individual model behaviour occasionally departed markedly from the average, ensemble median responses across sites and crop varieties indicated that yields decline with higher temperatures and decreased precipitation and increase with higher precipitation. Across the uncertainty ranges defined for the IRSs, yields were more sensitive to temperature than precipitation changes at the Finnish site while sensitivities were mixed at the German and Spanish sites. Precipitation effects diminished under higher temperature changes. While the bivariate and multi-model characteristics of the analysis impose some limits to interpretation, the IRS approach nonetheless provides additional insights into sensitivities to inter-model and inter-annual variability. Taken together, these sensitivities may help to pinpoint processes such as heat stress, vernalisation or drought effects requiring refinement in future model development.

Improvement of root architecture under abiotic stress through control of auxin homeostasis in Arabidopsis and Brassica crops

Auxin plays an important role in many aspects of plant development including stress responses. Here we briefly summarize how auxin is involved in salt stress, drought (i.e. mostly osmotic stress), waterlogging and nutrient deficiency in Brassica plants. In addition, some mechanisms to control auxin levels and signaling in relation to root formation (under stress) will be reviewed. Molecular studies are mainly described for the model plant Arabidopsis thaliana, but we also like to demonstrate how this knowledge can be transferred to agriculturally important Brassica species, such as Brassica rapa, Brassica napus and Brassica campestris. Moreover, beneficial fungi could play a role in the adaptation response of Brassica roots to abiotic stresses. Therefore, the possible influence of Piriformospora indica will also be covered since the growth promoting response of plants colonized by P. indica is also linked to plant hormones, among them auxin.