Memoria para optar al Título Profesional de Ingeniero Agrónomo Mención: Fruticultura / En la Zona Sur de Chile los cerezos han ido desplazando cultivos tradicionales con variedades de maduración tardía, de las cuales ‘Kordia’ y ‘Regina’ son las variedades autoincompatibles más importantes y de mayor interés comercial, tanto por su tolerancia a la partidura, buena firmeza y calidad organoléptica, como por su cosecha tardía, alcanzando los mejores precios en los mercados internacionales. En el Sur de Chile y en particular en la localidad de Angol estas variedades han presentado bajos rendimientos, esto debido, en parte, a la falta de polinizantes que coincidan en las floraciones y que sean compatibles. Debido a la falta de información de estas variedades en el país se hace necesario determinar polinizantes apropiados para incluirlos en los huertos comerciales y en los diseños de nuevas plantaciones con el fin de aumentar los rendimientos. El objetivo de este estudio fue determinar la intensidad del cuajado de frutos de ‘Kordia’ y ‘Regina’, polinizadas con distintas variedades compatibles en la localidad de Angol (IX Región). Se realizaron tres ensayos, uno para ‘Kordia’ y dos para ‘Regina’ donde se utilizaron como polinizantes las variedades Sam, Staccato, Summit, Sunburst, Schneider y además Kordia y Regina entre sí, donde se evaluó la intensidad del cuaje, la concordancia de los estados fenológicos y la viabilidad del polen utilizado. ‘Sunburst’ se comportó como un buen polinizante de ‘Kordia’ con un 37% de cuaje y con una coincidencia completa en la floración, presentando diferencias significativas con ‘Sam’ (4,9% de cuaje). Otras variedades tuvieron coincidencias completa y parciales en la floración, pero con bajo porcentaje de cuaje. En ‘Regina’, las variedades utilizadas presentaron una coincidencia parcial con la floración y un cuaje bajo a muy bajo, no presentando diferencias significativas entre los tratamientos.

To advance crop monitoring techniques in horticultural tree crops, earlier research has examined the relationship between crop vigor (height, canopy den- sity, health) as assessed by remote sensing technologies and aspects such as fruit quality and yield requirements. In recent years, structure-from-motion image pro- cessing techniques have been widely used to generate orthomosaics and 3D point clouds from RGB and multispectral (MS) imagery acquired by unmanned aerial vehicles. However, this process requires a lot of computing power and can be expensive, especially for large commercial orchards. However, studies have been scarce comparing the accuracy of different remote sensing technologies in deter- mining tree height and plant area index. Light detection and ranging (LiDAR) is an alternative method to generate 3D point clouds that requires less compu- tational power. This study assessed the accuracy, processing parameters, and limitations of UAV-based RGB, MS, and LiDAR data for measuring cherry trees’ height and plant area index in a high-density orchard in Malauc`ene, southeastern France. Furthermore, the plant area index changes of 5 different cherry culti- vars were assessed during the growth cycle. Overall, the LIDAR data provided the highest accuracy for tree height measurements around harvest (R² = 0.923, RMSE = 0.215 m) and the beginning of leaf senescence (R² = 0.863, RMSE = 0.218 m). LiDAR-derived plant area index also produced the best accuracy at May (R² = 0.48 and RMSE = 0.42) and October (R² = 0.45 and RMSE = 0.59). Our findings demonstrate that UAV-based LiDAR data provide an effective and rapid means for measuring cherry tree height and plant area index over time. Such information can serve as a general indicator of tree health and aid growers in making informed agricultural crop monitoring and management decisions.

Memoria para optar al titulo profesional de: Ingeniera Agrónoma / Las cerezas frescas actualmente enfrentan un mercado altamente competitivo. Entre los mayores productores de cerezas dulces se encuentran Estados Unidos, Turquía e Irán. Chile es el tercer exportador a nivel mundial y el primero del Hemisferio Sur. Tal relevancia a nivel mundial hace necesario evaluar la competitividad que el país tiene en el negocio. El objetivo principal de este estudio fue analizar la competitividad de las cerezas frescas chilenas de exportación en el mercado internacional y como objetivos específicos el análisis de los factores determinantes de la competitividad, caracterizar las brechas logísticas del transporte de exportación, proponer orientaciones para contrarrestar las amenazas del negocio de cerezas frescas. Se realizaron entrevistas a informantes calificados, los cuales entregaron sus apreciaciones respecto a la competitividad de las cerezas frescas chilenas de exportación. Esta información fue fundamental para llevar a cabo el modelo de cinco fuerzas de Porter para este producto. El análisis se acompañó también de indicadores de competitividad, como la balanza comercial relativa, transabilidad, grado de apertura exportadora, grado de penetración de las importaciones e indicador de especialización. Todos los datos fueron extraídos del período comprendido entre los años 2006-2011. Finalmente con estos indicadores se elaboró un ranking para determinar los países más competitivos. Chile, resultó ser bastante competitivo en el negocio de cerezas frescas de exportación. Además, posee un consumo interno marginal, coincidiendo con la condición de exportador neto y abastecedor propio. Así mismo presenta ventajas de producción primaria y arancelaria que le permiten posicionarse como un actor importante a nivel mundial. / At present, fresh cherries face a very competitive market. The largest producers are The United States, Turkey and Iran. Chile is the third exporter in the world and first in the South Hemisphere. Such world level relevance makes it necessary to evaluate the country’s competitiveness in the market. The main objective of this project was to analyze the competitiveness of Chilean export fresh cherries in the international market and the specific objectives : analysis of the determinants of competitiveness gaps characterize export transport logistics, propose guidelines to counter threats of fresh cherries business Qualified specialists were interviewed to obtain important tips respecting the competitiveness of fresh cherries export. This information was very important to elaborate Porter's five forces model regarding Chilean cherries. The analysis was also accompanied with indicators of competitiveness, like the relative trade balance, tradability, exporting openness rate, degree of import penetration and indicator of specialization. All the data were collected in the period between 2006 and 2011. Finally with this information a ranking to determine the competitiveness of cherry exporting countries was built. Chile turned out to be one of the best evaluated countries, having a low internal consumption, one of the main characteristics of the net exporter and self sufficient country. Besides, it shows important advantages in primary production and low departure taxes allowing for its placing among one of the most important actors of the market.

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<p> This thesis describes the isolation and structural determination of flavonoids from the heart wood of Prunus avium as well as synthesis of polyhydroxy pyrrolidine derivatives and aniline core structures as potential antibacterial agents. Nitrogen-synthons containing saturated heterocyclic systems and aniline core structures are important synthons in organic chemistry because of their presence in many biologically-active natural products. Mycobacterial viability is dependent upon the ability of the organism to produce an intact cell wall. Therefore, compounds that interfere with the biosynthesis of the cell wall complex glycons have the potential to become new drugs for the treatment of mycobacterial infections. The oligosaccharide galactan is one of the major structural components of the outer wall of the micro-organism. Galactofuranose is essential for cell growth and survival and therefore, its biosynthesis constitutes a new drug target. The biosynthetic process involves several enzymes having Uridine-diphosphogalacto furanose (UDP-Galf) as the substrate; uridine 5^1 -diphosphogalacto pyranose mutase which catalyzes the interconversion of UDP galacatopyranose to UDP-galactofuranose as well as Galf-transferase. We are seeking and designing molecules that could be mechanistic probes and/or inhibitors of efflux pumps to potentially combat multidrug resistance.</p> <p> The isolation and structure-determination of six naturally occurring Flavan-type Natural products was performed. Such derivatives are known to reverse multiple-drug-resistance (MDR) in persistent microbial infections. The synthesis of pyrrolidine-based antibacterial agents was attempted using two different approaches from tartaric acid. These derivatives were designed as potential transition-state mimics of a carbohydrate processing enzyme specific to TB. A synthetic approach to the aromatic core structure of the antibacterial agent Platensimycin was also investigated. The synergistic use of cytotoxic agents in conjunction with efflux-pump modulators is an emerging area of research in the MDR field; our efforts to make available materials for high-throughput screening in this area will be described.</p> / Thesis / Master of Science (MSc)

Chez les espèces fruitières, la dormance est une période clé qui influencera la floraison et la fructification. La dormance est finement régulée par de nombreux facteurs génétiques et environnementaux. Elle est composée de deux phases principales, l’endodormance (ou dormance « vraie ») et l’écodormance (ou dormance « environnementale »). L’endodormance est caractérisée par une incapacité totale des bourgeons à débourrer, même dans des conditions normalement propices à la croissance. C’est le froid hivernal qui permet la sortie de l’endodormance, nécessaire à la floraison puis la fructification. Les besoins en froid, quantité nécessaire de froid pour accéder à la levée de l’endodormance, sont génétiquement déterminés, et sont relativement élevés chez la plupart des variétés de cerisier doux (Prunus avium L.) comparativement à d’autres espèces. Dans un contexte de réchauffement climatique, les besoins en froid pourraient ne plus être satisfaits et conduire à des pertes économiques.. L’objectif de cette thèse est donc d’approfondir les connaissances sur les voies impliquées dans la levée d’endordormance. L’étude porte sur un panel de variétés contrastées pour leurs besoins en froid, depuis des variétés très précoces comme ‘Cristobalina’ jusqu’à des variétés très tardives comme ‘Fertard’. Des approches métabolomiques, moléculaires et d’apport exogène de molécules ont été utilisées. Les résultats montrent que les voies 1) hormonales, 2) du stress oxydatif et 3) des sucres, ont un rôle différent. La voie des sucres donne un aperçu de l’activité métabolique ainsi que des marqueurs des différentes phases de la dormance. La voie hormonale est un système permettant de contrôler la croissance sans lien causal sur la dormance. La voie du stress oxydatif indique que les variétés précoces sont dans un état globalement plus oxydé que les variétés tardives lors de cette période. Les données de RNA-seq permettent l’identification de gènes ayant un rôle majeur dans la dormance et de confirmer les hypothèses des mécanismes impliqués. Ces résultats seront déterminants pour la création de variétés adaptées aux conditions climatiques futures. / Among fruit tree species, dormancy is a key period determining the success of flowering and fruit producing. Dormancy is tightly regulated by numerous genetic and environmental factors. It can be divided in two main phases: endodormancy (“true dormancy”) and ecodormancy (“environmental dormancy”). Endodormancy is characterized by a total incapacity of buds to burst, even in conditions proper to growth. Winter chilling enables the end of endodormancy, necessary for flowering and fruit production. Chilling requirements, necessary amount of chill for endodormancy release, are genetically fixed and relatively elevated in sweet cherry (Prunus avium L.) varieties compared to other species. In a climate change context, chilling requirements may not be entirely fulfilled and lead to drastic economic losses. The objective of this work is to increase the knowledge on the pathways involved in endodormancy release. The study relies on a panel of varieties contrasted for their chilling requirements, varying from a very low chill cultivar ‘Cristobalina’ to a high chill cultivar ‘Fertard’. Metabolomics and molecular studies, and exogenous molecules supply were used for dormancy deciphering. Hormonal pathway, oxidative stress and sugar pathway seem to have different roles. Sugar pathway enables to have an overview of the metabolic activity, and may be used as molecular markers to identify dormancy phases. Hormonal pathway has a role on growth control but no causal link with dormancy release was assessed. Major results concern the role of oxidative stress, with low chill cultivars in a more oxidized status than high chill cultivars. Moreover, RNAseq data enable the identification of key genes controlling dormancy and confirms the hypothesis on mechanisms involved. These results will be crucial for breeding new verities well adapted to future climatic conditions.

Chez les espèces fruitières, la floraison est un évènement majeur qui influencera fortement la fructification. Ce processus, finement régulé par de nombreux facteurs génétiques et environnementaux, est encore peu connu. Chez le cerisier doux (Prunus avium), les fleurs ne s’épanouissent qu’après avoir satisfait des besoins en froid et en chaud. Les effets du changement climatique sur la floraison sont déjà notables et pourraient induire d’importantes pertes économiques. La compréhension des déterminants génétiques et moléculaires impliqués dans la floraison permettra l’amélioration des programmes de sélection variétale visant l’obtention d’arbres adaptés aux futures conditions climatiques. L’objectif de cette thèse est d’accroître les connaissances sur ces déterminants et d’identifier les gènes contrôlant la floraison chez le cerisier. En étudiant les deux familles intra spécifiques ‘Regina’ × ‘Lapins’ et ‘Regina’ × ‘Garnet’, la détection de nombreux quantitative trait loci (QTL) sur l’ensemble des groupes de liaisons (GL) a permis de confirmer la forte implication des besoins en froid dans la floraison ainsi que la complexité de ces caractères. Un QTL à effet majeur a été localisé sur le GL4. Dans les régions couvertes par les QTL contrôlant la date de floraison, une centaine de gènes candidats (GC) pour ce caractère a été identifiée. Un sous ensemble de ces GC a ensuite été étudié pour leur expression au cours du développement des bourgeons par PCR quantitative (qPCR). A terme, ces travaux serviront de bases pour l’identification et la sélection de gènes qui permettront l’obtention de génotypes adaptés aux futures conditions climatiques. / In fruit species, the flowering is a major event which strongly influences fructification. This process tiny controlled by many genetic and environmental factors is still little known. In sweet cherry (Prunus avium), flowers open out only after having satisfied chill and heat requirements. The effects of climate change on the flowering are already notable and could induce important economic losses. Identification of genetic and molecular determinants involved in the flowering will allow the improvement of varietal selection programs to obtain trees adapted to future climate conditions. Objective of this thesis is to increase the knowledge of these determinants and identify genes involved in flowering in sweet cherry. By studying two intraspecific progenies ‘Regina’ × ‘Lapins’ and ‘Regina’ × ‘Garnet’, detection of many quantitative trait loci (QTL) on all linkage groups (LG) has enabled us to confirm the strong involvement of chill requirements in the flowering as well as the complexity of these traits. QTL with major effect was localized on the LG4. In regions covered by all the QTLs controlling flowering date, a hundred candidate genes (CG) for this trait was identified. A subset of these GC was then studied for their expression during development of buds by quantitative PCR (qPCR). In the long term, this work will serve as a basis for the identification and selection of genes that allow obtaining genotypes adapted to future climate conditions.

Tesis para optar al Título Profesional de Ingeniero Agrónomo y al Grado de Magíster en Ciencias Agropecuarias, Mención Producción Frutícola / Chile es uno de los principales productores de cerezas a nivel mundial, encontrándose en una posición privilegiada como abastecedor de cerezas para los mercados del Hemisferio Norte, cuando estos se encuentran sin producción, lo que permite a los productores alcanzar mayores precios (Muñoz, 2015). Se estima que la industria exportadora factura por sobre USD 400 millones, lo que podría ubicar a las exportaciones de cerezas como el tercer mayor generador de valor exportado frutícola (Bravo, 2013); esto conlleva una mayor generación de empleos en el sector, en especial en los momentos de cosecha del producto, aumentando el ingreso a las personas, socialmente, más vulnerables.

Thesis (MscAgric (Horticulture))--University of Stellenbosch, 2008. / Commercial production of sweet cherries has recently increased in South Africa, with more than 400 ha planted by 2006. Cherry, a high chilling fruit variety, is however not suited for the mild winter climate of South Africa. This was recognizable through common observed symptoms of delayed foliation and poor fruit set. In addition, cherry is exposed to long and hot summers in the postharvest period. The objective of this study was to evaluate cherry cultural practices that can manipulate (reduce) the trees chilling requirement under South African conditions. Cultural practices where aimed at increasing reserves (nitrogen, cytokinin and carbohydrates) in the tree. In addition, bud dormancy progression of cherry buds was quantified to determine the bud dormancy progression pattern under mild winter conditions. This was achieved through sampling of cherry shoots from different cherry production areas which was then forced in the growth cabinets. A model was developed to identify possible factors and groupings that can explain the cherry bud dormancy pattern. A model, comprising two joined straight lines, was fitted in order to characterize bud dormancy behaviour for sweet cherry cultivars under mild winter conditions. All cherry cultivars followed the expected pattern of entrance and exit from dormancy. Factor analysis showed that factors related to the entrance into dormancy primarily characterize bud dormancy behaviour. Bud dormancy patterns were also a function of environmental conditions within a year as shown by cluster analysis. In addition, buds entered dormancy in mid-summer and remained dormant until chilling accumulation commenced. Bud dormancy release was generally extended over a three to five-month period for all cultivars. Prior to spring budburst exit of both lateral and terminal buds occurred rapidly. Data indicate that there is no ecodormant phase for cherry under the prevalent climatic conditions in South Africa. Further experimentation was aimed at increasing reserves within the trees through cultural practices. In the nitrogen trials, fertilization in the postharvest period had no significant effect on field budburst or bud dormancy progression in one-year-old shoots. Time of flowering was advanced in N treatments during 2007 only. Yield was not significantly increased. Therefore, in this trial, N fertilization in the postharvest period did not significantly reduce the chilling requirement of mature sweet cherry trees under mild winter conditions. Application of particle films (Surround® and Raynox®) or ethylene inhibitors (Retain®) in the summer did not reduce the heat stress the trees experienced. Treatments had no significant effect on carbon assimilation, stomatal conductance, leaf surface temperature, fluorescence, bud dormancy, budburst, flowering and fruit set. Cytokinins sprays (benzyladenine) in autumn did not affect bud dormancy progression, spring budburst or flowering. Hydrogen cyanamide application in spring significantly advanced budburst, time to full bloom and increased yield. Promalin® and Retain®, however, had no significant effect on budburst, flowering or yield. It is therefore evident that cherry, due to its unexpected bud dormancy behaviour and its inability to be significantly influenced by several cultural practices, adapts poorly to South African climatic conditions through not reducing its chilling requirement significantly.

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