3.18 Tesis de magíster

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    Caracterización agronómica de preselecciones de cerezos (Prunus avium L.) obtenidas por el programa de mejoramiento genético de cerezos perteneciente al Consorcio Tecnologico de la Fruta
    (2024) Silva Lorca, Carlos Esteban; Ayala Zapata, Marlene; Pontificia Universidad Católica de Chile. Facultad de Agronomía y Sistemas Naturales
    The agronomic characterization of the 23 preselections obtained from the cherry tree genetic improvement program allows for efficient segregation and selection of individuals with ideal qualities to become a new Chilean variety. Initially, a productive characterization of the preselections was conducted, quantifying the number of spurs per linear meter of main branch, the average number of floral buds per spur, the average number of flowers per spur, the number of fruit sets between 5-10 millimeters, the harvested fruits, and their size. Phenology was recorded weekly from the swollen bud stage until harvest, with emphasis on the beginning of bloom, full bloom, fruit set, and harvest date. Additionally, in August, 1% hydrogenated cyanamide was applied to an individual to analyze its response to the endodormancy realese traitment. The Association of Fruit Exporters of Chile S.A (ASOEX S.A) collaborated with the exporter Ranco Cherries to assist in the harvest and post-harvest evaluation of the fruit, measuring quality components such as size, firmness, soluble solids, and their response to postharvest storage. In the postharvest laboratory of the Pontificia Universidad Católica de Chile, certain preselections were tested, based on fruit availability, for induced pitting susceptibility. The productivity components showed significant differences in their means for the six variables studied. Phenology and harvest data were recorded from week 46 to week 50 of the fruit calendar. Additionally, the chilling requirement to reach the first swollen bud stage, the degree days accumulated in the main phenological stages until harvest, the cycle length of the preselections, and the fruit growth curves were plotted. Finally, pitting susceptibilities, fruit quality parameters, and postharvest performance were documented.
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    Comparación de dos métodos agronómicos y uno geofísico para la determinación del estatus hídrico de suelo y planta en condiciones naturales y de cultivos frutales
    (2023) Schmidt Kamp, José Andrés; Gil Montenegro, Pilar Macarena; Pontificia Universidad Católica de Chile. Facultad de Agronomía e Ingeniería Forestal
    The current mega drought in Chile represents a major problem for fruit crops of the central regions and its native vegetation, the sclerophyll forest. The traditional methods to determine soil water status used in agriculture fail to deliver data that is representative of the soil profile in which roots from vegetation are distributed, due to non-uniformity in the soil texture. Electric Resistivity Tomography method (ERT) solves this problem by measuring the soil profile entirely at several depths. In this study, measurements of soil moisture were carried out in fruit orchards (apples and almonds), and in three locations with native vegetation, during a whole season following the same transect. Measurements include: Soil moisture by Frequency domain Reflectometry (FDR) and gravimetric method, soil apparent resistivity by ERT; and four physiological parameters taken in adjacent plants: stomatal conductance (gs), midday stem water potential (ψMD), maximum yield of PSII (Fv/Fm) and chlorophyl concentration. Both FDR and gravimetric methods had difficulties to explain the behavior of vegetation because they assume a point based humidity data as representative of the entire soil profile. The best method to predict the ecophysiological behavior in apple and in natural conditions was ERT.
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    Diversidad biológica y genética de microartrópodos edáficos asociados a cultivos de vid en Chile Central
    (2021) Carpio Mamani, Milena; Arellano, Eduardo; Pontificia Universidad Católica de Chile. Facultad de Agronomía e Ingeniería Forestal
    Agricultural management causes effects on agroecosystems, altering the characteristics of the soil. Our objective was to determine the biological diversity and genetic diversity of microarthropods associated with organic and conventional vineyards, to establish whether organic management favors the biodiversity of soils and molecular identification of oribatid mites. The extraction of the individuals was realized through the medium of a modified Berlese-Tullgren method and amplified environmental DNA (eDNA). The abundance and richness of taxa had significant differences in vineyards with organic management compared to conventional ones. Furthermore, the relationship between the main groups of Acari and Collembola indicated that both systems are healthy. However, for this study, only agricultural practices did not explain these variations between these systems. Oribatid genetic diversity was high in all systems. Bayesian and Median-Joining Network analysis suggest that the 14 haplotypes identified belonged to the genera of Oppiella, Protoribates, Chamobates, Epilohmannia, Rhysotritia and haplotypes of the family Lohmanniida, which belongs to the suborder Brachypylina and Mixonomata, all appear on the order oribatida, however specific haplotypes were not defined for each manner of handling. Therefore, the biological and genetic diversity of the populations of microarthropods (Oribatida), can be good indicators of the changes that occur in different ecosystems, specifically the genetic diversity can be considered as an indicator of soil alteration, allowing us to determine its level of productivity, making them sustainable over time, helping to maintain biodiversity in these systems.
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    Evaluación de pruebas de vigor en semillas de quínoa (Chenopodium quinoa Willd.) y su correlación con pruebas de emergencia
    (2023) Sánchez Cabeza, Carla; Contreras E., Samuel; Pontificia Universidad Católica de Chile. Facultad de Agronomía e Ingeniería Forestal
    El cultivo de quinoa (Chenopodium quinoa Willd.) tiene un alto potencial de desarrollo, sin embargo, existe poco conocimiento acerca de cómo evaluar su calidad de semilla. El objetivo de este estudio fue encontrar una prueba de laboratorio que evalúe de mejor forma el vigor de semilla en quínoa. Para lograr esto se evaluaron distintas pruebas de vigor en nueve lotes de semilla de quínoa y sus resultados se correlacionaron con los resultados de pruebas de emergencia de plántula en invernadero. Las pruebas de envejecimiento acelerado no tuvieron un buen desempeño prediciendo el comportamiento de los lotes en invernadero debido a diferencias en la longevidad entre genotipos. Ninguna prueba realizada en laboratorio obtuvo correlaciones significativas con todas las pruebas realizadas en invernadero producto de la presencia de dormancia en la semilla de quínoa, que generó diferencias en clasificaciones de calidad de los lotes dependiendo de si la prueba evaluaba velocidad de germinación o no, ya que la dormancia se presentó como una disminución en la velocidad de germinación sin afectar el porcentaje final. La prueba de germinación estándar no fue superada por ninguna otra prueba en su correlación con el comportamiento de los lotes de quínoa en invernadero.