Browsing by Autor "Ricardo Zambrano"

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    Diversity in the invasive cacao pathogen <i>Moniliophthora roreri</i> is shaped by agriculture
    (Wiley, 2022) Jorge R. Díaz‐Valderrama; Ricardo Zambrano; Sergio Cedeño‐Amador; Ulises Córdova‐Bermejo; Gianmarco Goycochea Casas; Nilda García‐Zurita; Juan A. J. Sánchez‐Arévalo; Enrique Arévalo‐Gardini; Darío Dávila Paredes; Juan José Ruiz Martínez
    Abstract Frosty pod rot disease of cacao (FPR), caused by the fungus Moniliophthora roreri , has severely impacted the production of cocoa in Latin America since its discovery. Prior to the 1950s, FPR was known only from Colombia and Ecuador. However, beginning in the 1970s, its geographical range has dramatically expanded throughout most of the cacao‐producing regions of the Americas. The origin of the pathogen remains unknown. In this study, we evaluated the genetic diversity of M . roreri from areas spanning, as much as possible, its current geographical range using simple‐sequence repeat markers and a publicly available single‐nucleotide polymorphism data set. Two hotspots of genetic diversity were found: coastal Ecuador and the inter‐Andean Magdalena Valley of Colombia, neither of which correspond to the Amazonian origin of the host. However, both areas were early centres of intense cultivation of cacao. Our results indicate that M . roreri was introduced into both areas from its centre of origin, where intensive cacao cultivation probably led to the increase of inoculum and further dissemination of the disease. Current invasions can be traced to two genotypes responsible for all known instances of the pathogen in Central America, the Caribbean, Peru and Bolivia. We also report for the first time M . roreri in Maynas (Peruvian Amazon), which is probably the result of a recent introduction from Colombia.
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    Posición de Venezuela Frente a Guyana en la Controversia Territorial por el Esequibo
    (2020) Ricardo Zambrano
    Para el año 1811 en Venezuela se suscribe el Acta de Independencia respecto de la Corona Española, estableciéndose como territorio de la República el perteneciente a la Capitanía General de Venezuela y fijándose como frontera occidental el Río Esequibo. En 1897, de la firma del Tratado Arbitral de Washington, derivaría el Laudo de París de 1899, despojando a Venezuela de 159.000 Km2 siendo denunciado éste último en 1962 ante la AG-ONU por considerarse nulo e irrito. Desde entonces, se recurrió a los diversos medios de solución pacífica de controversias, sin obtener ningún resultado. En 2018, Guyana solicitó que la controversia fuera dirimida por la CIJ, cuya jurisdicción no ha aceptado Venezuela. El presente artículo analiza la posición de Venezuela, frente a Guyana en su controversia, a partir de una investigación de enfoque cualitativo, enmarcado en la descripción y análisis con un alcance descriptivo y documental, concluyendo que Venezuela tiene argumentos que demuestran sus derechos sobre ese territorio, a los fines de recuperarlo.