Proyectos

Fires have historically played an important role in the composition and distribution of terrestrial ecosystems. However, these events have also represented an important pressure that have induced land degradation worldwide; especially in regions with Mediterranean climates with dry summers and elevated temperatures. In forests, fires not only exert an individual effect on each of their components; including vegetation, animals and other natural resources such as soil and water, among others, but also on the relationship among these constituents, which in turns, compromise the functionally of the whole ecosystem. Forest fires directly affect aboveground biomass production and other ecosystem services (i.e. benefits society directly or indirectly obtain from ecosystems). Land burning can also compromise belowground conditions that are essential to support aboveground life. Though soil biological processes are recognized as main drivers of ecosystem recovery following fires, the consequences of land burning on soil microorganisms are less understood than those on soil physicochemical properties. The present research aims precisely to elucidate what are the effects of fires on a particular group of soil microorganisms, crucial for maintenance of proper soil ecosystem services and natural resilience. The microbial specialist studied in this project would be microorganisms capable of nitrogen fixation (diazotrophs), particularly those living in non-mutualistic associations in soil environments (within the soil rhizosphere or as free-living organisms in bulk soils). It is known that land burning can negatively impact soil microorganisms directly by compromising diversity and altering their composition; moreover, these pressures can also indirectly affect soil microbiota by altering soil physicochemical properties. Recently, advanced on molecular biology and analytical techniques have allowed to incorporate the study of microbial interactions and adaptations following soil disturbances. Microbial co-occurrences network studies have shed lights on particular microbial taxa relationships (negative and positive) and adaptations to changes in soil abiotic factors following disturbances. Thus, these analyses can contribute to better understand the ecological significance of environmental pressures on proper soil ecosystem functioning considering the previous background, the present study aims to assess through ecological molecular analyses how non-mutualistic diazotrophic microorganisms interact with other members of the bacterial community and adapt to changes in soil physicochemical conditions in Mediterranean forest following fires. In the present work, it is hypothesized that ecological networks will reveal shifts in non-mutualistic diazotrophic population structure in Mediterranean forest after fires, due to changes in their interactions with other microorganisms and responses to modified physicochemical properties. To test this hypothesis, classical soil physicochemical analyses and cutting-edge, molecular based, microbial ecology analyses will be implemented in burned and unburned soils of two Mediterranean native forest in the Region of O’Higgins in central Chile. The strategy used for this study will consist of two types of studies: 1) at the field scale, and 2) at a field-laboratory scale. The field scale study will include burned areas and unburned areas for comparison. The field-laboratory scale experiment will consist of soil samples taken in the field, burned in the laboratory, and incubated at their original site for different periods of time. By accomplishing the proposed project, it is expected to identify what are the main biotic conditions (e.g. taxa positively or negatively interacting with diazotrophs) and the main abiotic parameters correlating with these interactions in burned and unburned soils. This knowledge would allow to better design and implement soil restoration initiatives in Mediterranean native forest, which will in turn contribute to the reestablishment of proper functionally of the whole forest ecosystem, contributing to sustain their ecosystem services and their natural resilience towards future environmental pressures.

In this project, the research hypothesis is that in a scenario of climate change (IPCC 2014), the increase of mean air temperature by 2 °C triggers flowering asynchrony between pollen donors and female cultivars on kiwifruit species (Actinidia spp.) Then, the general objective is to model the impact of temperature changes on interaction between pollen donors and the effective pollination period (EPP) of kiwifruit cultivars (Actinidia spp.). In detail, the specific objectives are: (1) to determine flowering phenology and the effective pollination period (EPP) on kiwifruit cultivars; (2) to evaluate the effect of temperature on sensitivity of pollen-pistil interplay; and (3) to develop a dynamic model of kiwifruit pollination on crop value under potential scenarios of temperature changes. The proposed methodology will be divided in three years. In the first year, flowering phenology of six pollen donors (male cultivars) and two female cultivars (one green-fleshed and other yellow-fleshed) will be characterized. Moreover, in female cultivars the length of time that female flowers can be successfully pollinated, commonly known as the effective pollination period (EPP), will be determined. The EPP may be restricted by limitations in three main events: stigmatic receptivity, pollen tube kinetics and ovule longevity, which will also be evaluated. On the other hand, a dynamic pollination model will be developed using the modeling software Stella®, based initially on literature review and grower information. In the second year, two experiments will be conducted to evaluate the effect of temperature on sensitivity of pollen-pistil interplay: in planta in the field and in vivo in controlled chambers under heat treatments. Consequently, results of all experiments will be integrated on the dynamic pollination model. Finally, in the third year, after the construction of the model, data of all inputs and outputs will be collected from several kiwifruit orchards of different regions and conditions. Part of these data will be used to find the model weaknesses and to determine how to improve it. The remaining data will be used on cross validation. The main expected result is to determine the vulnerability of interaction between pollen donors and female cultivars by the increase of temperature. The dynamic model of kiwifruit pollination will be permit to predict present and future problems, which will help growers to optimize pollination managements (bee hives and/or supplemental pollen applications) in the short term. Furthermore, this model can be complemented with other submodels, as thinning, pruning, etc, in order to study simulations of orchard managements. In the long term, these results of heat stress impact on kiwifruit cultivars will be used in further research for establishing new screening criteria of best-adapted genotypes (pollen donors, for example) to Chilean conditions.

El aumento en las condiciones de sequía experimentadas en el centro de Chile durante el último siglo ha sido poco estudiado en términos de sus posibles impactos en la dinámica forestal de los bosques mediterráneos de Chile central. Se ha observado una disminución del crecimiento y una pobre regeneración por semilla, que se asociaría con los cambios en los patrones climáticos. El presente proyecto busca evaluar desde una perspectiva histórica la respuesta de los árboles mediterráneos de Chile frente al cambio global reciente, utilizando especies perennes (bosques esclerófilos) y caducifolios (bosques de Nothofagus) en un gradiente altitudinal y latitudinal (30°-35° S), complementando con estudios retrospectivos (análisis dendrocronológico e isotópico) y estudios prospectivos (análisis en cámaras de crecimiento controlado). Los resultados proporcionarán información valiosa para comprender la resiliencia ecológica de los ecosistemas mediterráneos de América del Sur y, por lo tanto, serán útiles para futuros programas de conservación y restauración ecológica.

Chile is one of the principal producer and exporter country of fruit and vegetable crops in the southern hemisphere. In both fruit and vegetable crops there are an increasing concern about agriculture sustainability that includes the evaluation and implementation of practices with lower environmental impact. In this context, and considering the modern vegetable crop production, the use of rootstocks is being considered an essential component due to their ability to adapt a particular cultivar to diverse environmental conditions and/or cultural practices. In agriculture, rootstocks have been used since over 2000 years ago. Specifically, in cucurbits, the most grafted vegetable crops are watermelon, melon and cucumber. For watermelon, Lagenaria siceraria (bottle gourd) has been used in different countries as one of the main rootstocks. Considering the recent agricultural scenario, in which drought represent the major risk that impacts negatively the production of major and minor crops, the rootstocks development and the understanding of the role of key root traits would help to assist breeders for drought tolerance landraces selection. In fact, the effects of water regime or deficit on root system development of bottle gourd is not well understood, in addition, the underlying phenotypic and genotypic variability of bottle gourd with respect to root system architecture parameters has not been welldocumented. A crucial component of roots is their architecture, which refers to the spatial-temporal extension of the entire root system in the soil, the root system architecture (RSA). RSA traits, or phenes, has been shown to be important in agricultural systems, in fact, it is considered relevant for improve selection in fruit and vegetable rootstocks breeding programs. Understanding the contribution of specific RSA traits to root system function is critical, and plays a pivotal role in crop performance because it allows the identification of keys traits that contribute in desired functions, and consequently could be considered for developing crops with more efficient roots. In this proposal it is hypothesized that, landraces of Lagenaria siceraria shows high phenotypic and genotypic variation for RSA traits like Root Growth Angle (RGA) and Roots System Depth (RSD). In turn, these phenes are positively correlated with drought tolerance and therefore useful to develop rootstocks with this characteristic in Lagenaria siceraria. In addition, it is also hypothesized that selected L. siceraria rootstocks are able to confer to grafted varieties of watermelon (Citrullus lanatus) an enhanced tolerance to drought. For that, the main goal is to evaluate the root system architecture as parameter of selection for drought tolerance in different Lagenaria siceraria landraces and in grafted plants of watermelon (Citrullus lanatus). The specific goals are: 1. To assess the phenotypic and genotypic variation of Lagenaria siceraria landraces by using root system architecture parameters and genotyping-by-sequencing through SNP markers; 2. To determine the root system architecture parameters that help into the selection of Lagenaria siceraria under drought stress condition; 3. To characterize the response to drought stress of watermelon grafted onto Lagenaria siceraria landraces under field conditions after the selection through the root system architecture parameters. To reach this goals it is proposing the phenotypic characterization of root traits (phenes) in Lagenaria siceraria landraces in a greenhouse under drought stress condition. The genotypic variation of bottle gourd will be studied by using Genotyping-by-sequencing, principal component analysis and genetic relatedness (identityby-state). A multivariate statistical analysis will be implemented to select key root phenes which will be used to evaluate the selection of L. siceraria in a rootstock breeding program. These root phenes will be characterized in grafted plants of watermelon into L. siceraria under field conditions by using the shovelomics phenotyping method. This proposal expects to contribute with the knowledge of genotypic and phenotypic variation in bottle gourd for root system architecture traits, and to identify the possibilities that offers the key root phenes to screen rootstocks for drought tolerance. These results would be relevant for the selection and breeding of cucurbits rootstock with better tolerance to drought. It is also expected that some of these Lagenaria siceraria landraces will be important rootstock for watermelon under semi-arid conditions of Chile.

Este proyecto forma parte del Programa Tecnológico para la Fruticultura de Exportación Zona Centro-Sur 16PTECFS-6641 Especie Kiwi, Coejecutores: Consorcio de la Fruta - Pontificia Universidad Católica El objetivo general es identificar, evaluar y desarrollar una metodología que permita determinar la distribución de calibre en kiwi, variedad Hayward.

El objetivo general es desarrollar una propuesta de estrategia de marketing y modelo de negocio de producto de la variedad de ciruela japonesa “Sweet Pekeetah”, destacando su alta calidad sensorial y su potencial de poscosecha, a través del diseño de un protocolo de manejo agronómico y almacenamiento. Los objetivos específicos, corresponden a: 1. Desarrollar un protocolo de producción y de almacenamiento para la ciruela “Sweet Pekeetah” que permita optimizar la productividad y mantener los atributos organolépticos destacados de la variedad por periodos de conservación prolongados. 2. Realizar un análisis del potencial de lanzamiento comercial de la variedad “Sweet Pekeetah” entre intermediarios (exportadores y distribuidores), examinando los elementos críticos que se requieren para su estrategia de distribución y de marca. 3. Evaluar la recepción de los consumidores finales de la nueva variedad de ciruela “Sweet Pekeetah”, particularmente estableciendo sus diferencias perceptuales con la oferta presente en el mercado. 4. Establecer una denominación (marca) para la variedad “Sweet Pekeetah” y determinar el valor agregado que entrega este elemento sobre la fruta en el mercado. Dentro de los resultados esperados: 1. Paquete tecnológico con énfasis en la polinización, carga frutal, índices de cosecha y postcosecha para obtener un producto de óptima calidad sensorial en mercados distantes. 2. Informe de la evaluación de la percepción de consumidores europeos, norteamericanos y chinos sobre el grado de aceptabilidad de la variedad “Sweet Pekeetah”. 3. Informe de la evaluación del efecto de una marca e imagen asociada a la variedad “Sweet Pekeetah” sobre la disposición a pago de consumidores en diferentes mercados. 4. Modelo de negocios para desarrollar la variedad “Sweet Pekeetah” en un formato de club exclusivo que asegure su sustentación en el largo plazo. 5. Patentamiento de la variedad “Sweet Pekeetah” en países del hemisferio norte, para su desarrollo comercial posterior.

Chile es uno de los líderes mundiales en exportación de fruta de palta, con aumentos de exportaciones cada vez mayores para mercados internacionales durante los últimos años. A pesar de los crecientes aumentos en las exportaciones de frutos, uno de los problemas en palta es conocido como mancha negra “Black spot”. La mancha negra se evidencia solo después del almacenamiento postcosecha prolongado, con la aparición de manchas oscuras circulares sobre el exocarpo del fruto y es detectado sólo tardíamente en los mercados de exportación provocando así el rechazo de la fruta. El presente proyecto tiene como objetivo entender las causas que originan la aparición de Black spot en frutos de palta var. Hass usando un enfoque integral de metabolómica y evaluaciones de calidad poscosecha. Hasta el momento, fueron cosechados frutos de 8 huertos (Ensenada, Pililén, Los Angeles, Resguardo, Inversiones, El Rancho, Quilhuica y Los Lilenes) correspondiente a cosecha temprana y 4 huertos (Resguardo, Pililén, Quilhuica y Los angeles) para cosecha tardía. Los frutos fueron evaluados a cosecha, a la salida de cámara de frio y en madurez de consumo. Los atributos evaluados correspondieron a: peso, color, presencia de daño lenticular, daño de pulpa, daño vascular, firmeza y materia seca. También se hicieron muestreos de epidermis de 5 frutos a la cosecha y cada 10 días de almacenamiento (0, 10, 20, 30 y 40 d) para analizar el sistema enzimático y no-enzimático de defensa y un análisis metabólico integral. Los resultados obtenidos hasta la fecha muestran que hay una disminución de firmeza y peso de frutos almacenados, con disminución más rápida a la salida de cámara hasta madurez de consumo. De todos huertos estudiados hasta la fecha no fue observado presencia de Black spot en los diferentes huertos. Muchos frutos estudiados presentaron presencia de lenticelosis, russet en la piel, picoteo y algunos con antracnosis. Frutos de Ensenada, Resguardo y Quilhuica almacenados por 25 días en aire regular presentaron alto porcentaje de lenticelosis. Frutos almacenados por 40 días presentaron un patrón similar, con alto porcentaje de lenticelosis para frutos provenientes del Resguardo, Ensenada y Los Angeles, y presencia de frutos con russet para Resguardo y Pililén. Frutos almacenados por 25 días de Ensenada maduraron en promedio en 8 días, Los Angeles entre 8 y 10 días, Pililén en 10 días, Quilhuica y Resguardo en 6 días. Cuando los frutos fueron almacenados por 40 días, frutos de Ensenada y Pililén maduraron en 5 días y aquellos de Los Angeles, Quilhuica y Resguardo maduraron en 3 días. La materia seca de los frutos de Ensenada (cosecha temprana) y Quilhuica (cosecha tardía) estuvo por debajo del mínimo de 23% y 27% respectivamente.