Yeirme Yaneth Jaimes Suárez

: Black pod disease is a major threat to global cacao ( Theobroma cacao L.) production. It is caused by multiple Phytophthora species with geographic ranges from regionally restricted to pantropical, and developing resistant cultivars requires screening against the diversity of these pathogens. This study evaluated the response of 25 cacao clones to 13 isolates of P. palmivora (eight), P. megakarya (two), and P. theobromicola (three) by nonwounding inoculation of detached pods. Lesion size and lesion expansion status were evaluated 4 days after inoculation. The linear mixed model included 178 combinations among 17 clones and 12 isolates, each represented by at least two biological replicate pods. Lesion size differed among clones (F _{(16, 449.2)} = 25.16) and among isolates (F _{(11, 416.0)} = 32.90), and the clone by isolate interaction was significant (F _{(150, 465.4)} = 1.72; all P < 0.001). PENTAGONA-17 had the smallest estimated marginal lesion size (9.3 mm) and fitted values of 3.8 to 16.9 mm across 11 isolates representing all three species. ARF-31, ICS-47, POUND-7, and PMCT-73 had the next four smallest estimates, whereas NA-246 had the largest (36.7 mm). Isolate estimates varied more than fourfold, from 9.6 to 42.0 mm. Despite a marginal estimate of 12.9 mm, POUND-7 had a fitted estimate of 49.2 mm with P. megakarya GH34. The probability of lesion expansion also differed among clones and isolates (both P < 0.001). Together, these findings identify candidates for further resistance evaluation and show that multi-isolate screening provides a stronger basis for selecting materials for black pod resistance breeding.

Ceratocystis wilt, caused by Ceratocystis cacaofunesta , and black root rot, caused by species of Dematophora , are emerging threats to cacao ( Theobroma cacao ) production in tropical regions. Because symptoms usually appear only at advanced stages of infection, early detection tools are needed to enable timely disease management. In this study, loop‐mediated isothermal amplification (LAMP) assays were developed and optimised for the genus‐level detection of Ceratocystis sp. and Dematophora sp. in cacao, using primer sets designed for the rRNA internal transcribed spacer (ITS) region of Ceratocystis sp. and the large subunit (LSU) of the 28S rRNA of Dematophora sp. Reaction conditions were standardised at 65°C for 45–60 min, and assay specificity and sensitivity were evaluated against a panel of cacao‐associated pathogens and host DNA, with amplification confirmed by UV fluorescence, agarose gel electrophoresis and real‐time LAMP with melting curve analysis. The LAMP assays detected as little as 0.005 ng/μL of C. cacaofunesta DNA and 0.0005 ng/μL of Dematophora pepo DNA, being approximately 1000‐fold more sensitive than endpoint PCR and showed no cross‐reaction with non‐target DNA. Pathogenicity tests on susceptible cacao genotypes (CCN‐51 for C. cacaofunesta and IMC‐67 for D. pepo ) demonstrated infection and early LAMP molecular detection of both pathogens from 4 days post‐inoculation (dpi); this was before symptom appearance, in the case of C. cacaofunesta and 10 dpi for D. pepo. These LAMP assays provide rapid, robust and sensitive tools for early diagnosis of vascular and root diseases of cacao, with potential application in nurseries and field surveillance.

Este manual sintetiza el conocimiento generado en la ejecución del proyecto “Plan de Vinculación Agroalimentario en los departamentos de Santander, Norte de Santander, Bolívar y Boyacá”, con énfasis en el Magdalena Medio y el Catatumbo, y aborda cinco cadenas productivas de alta relevancia socioeconómica: cacao, aguacate, cítricos, caña panelera y ganadería. Además, constituye un gran esfuerzo colectivo que busca fortalecer las capacidades técnicas de las comunidades campesinas, de extensionistas y promotores rurales, mediante la transferencia de conocimiento y tecnologías apropiadas para los principales sistemas agroalimentarios en los territorios. A lo largo del contenido se abordan, con rigor científico y enfoque territorial, cinco cadenas productivas de alta relevancia socioeconómica: cacao, aguacate, cítricos, caña panelera y ganadería. En cada una de ellas se presentan diagnósticos actualizados, análisis de contexto regional, resultados de investigación aplicada y recomendaciones tecnológicas que responden a las condiciones agroecológicas y agroclimáticas de los territorios, enmarcadas en estrategias de adaptación al cambio climático y producción sostenible. Asimismo, se destaca el papel del conocimiento como motor del desarrollo rural, integrando saberes científicos y tradicionales. Esta publicación es una herramienta de consulta y aplicación práctica para todo público interesado en la transformación del campo colombiano. Sus aportes demuestran que la ciencia agrícola adquiere sentido cuando se traduce en prácticas que mejoran la productividad, la sostenibilidad y la calidad de vida de las comunidades rurales. Desde el Centro de Investigación La Suiza, AGORSAVIA reafirma su compromiso con el fortalecimiento de los territorios rurales, la gestión del conocimiento y la construcción de un modelo de agricultura más inclusivo, resiliente y competitivo, basado en la ciencia, la innovación y la colaboración interinstitucional.

La cebolla ocañera se mantiene actualmente en el campo de algunos productores de la provincia que la consideran un legado, tan importante como su parcela y sus tradiciones. Otros productores que la han reemplazado por la cebolla foránea proveniente de Perú reconocen que la cebolla ocañera nativa ha sido clave para el desarrollo de sus fincas: “nosotros tenemos fincas gracias a la cebolla ocañera”, además de ser un producto reconocido en Ocaña. A pesar de sus características gastronómicas preferidas y menores costos de producción, la falta de un precio justo por parte de los intermediarios ha hecho que los productores no obtengan las ganancias adecuadas. En las indagaciones de este proyecto se destacó la necesidad urgente de mejorar la semilla de cebolla ocañera, identificar zonas de producción con ventajas competitivas, disminuir la mano de obra y mejorar las integraciones con los actores del territorio para asegurar que todos los bulbos que se producen tengan una articulación comercial para las calidades distintas a las de cebolla fresca e identificar zonas para siembra de cebolla ocañera. Esta cartilla muestra innovaciones para dar respuesta a estas preocupaciones, ya que describe prácticas que optimizan los recursos para la producción de bulbos de calidad comercial y la obtención de semilla de calidad para la cebolla ocañera nativa.

Este manual ofrece una guía completa para el reconocimiento y diagnóstico de la muerte descendente en aguacate, una enfermedad limitante para este cultivo en Santander, Colombia, causada por el hongo Lasiodiplodia spp. Un diagnóstico preciso es crucial para el manejo efectivo de esta enfermedad, y este documento proporciona las herramientas para lograrlo. Aquí se detalla el proceso de aislamiento del hongo, desde la recolección de muestras de tejido vegetal hasta la descripción macro y microscópica del patógeno. También se incluye el procedimiento para realizar pruebas de patogenicidad, confirmando la capacidad del hongo para causar la enfermedad. Además, se describe la técnica de PCR para la identificación molecular de Lasiodiplodia spp. Este proceso implica la extracción de ADN, la amplificación de tres regiones génicas (ITS, tef1-α y tub2) y un análisis de secuencias multilocus para una identificación precisa de la especie. La difusión de esta información entre técnicos y científicos es fundamental para promover el conocimiento y la prevención de la muerte descendente en aguacate en Santander y otros departamentos productores de la fruta en Colombia.

Cocoa phytosanitary problems in Colombia are one of the main causes of the decline in cocoa production, with losses that can reach 100% due to inadequate management. Ceratocystis wilt is a prevalent disease affecting cocoa crops in the country, with C. fimbriata identified as its causal agent. However, there are still inconsistencies at the morphological level regarding the causal species, which contradict the causal relationship of the pathogen with the disease, affecting its diagnosis. Studies based on the phenotypic and genotypic characterization of Ceratocystis species are imperative for reliable identification of the pathogen. The objective of this study was to morphologically and molecularly characterize isolates of Ceratocystis spp. obtained from symptomatic samples in the cocoa-producing regions of Colombia. Morphological characteristics were evaluated at the macro and microscopic levels. Additionally, isolates were identified at the species level through multi-locus analysis and phylogenetic characterization using the β-tubulin (βT-1), guanine nucleotide-binding protein (MS204), second largest subunit of RNA polymerase II (RPBII), and 60 S ribosomal protein L37 (FG1093) gene regions. The results revealed variations in the colony development and microscopic morphology. Molecular and phylogenetic analyses consistently classified all isolates as Ceratocystis cacaofunesta, confirming that this species is the causal agent of cocoa Ceratocystis wilt in Colombia.

The accumulation of high cadmium (Cd) levels in cacao beans (Theobroma cacao) generate several commercial and health issues. We hypothesized that cacao phenotypic and genotypic diversity could provide new insights to decrease Cd accumulation in cacao beans. Nine cacao rootstock genotypes were evaluated for up to 90 days under 0, 6, and 12 (mg·kg⁻¹) of CdCl₂ exposure and Cd content and plant growth dynamics were measured in leaves, stems, and roots. Data revealed that all cacao genotypes studied here were highly tolerant to Cd, since they presented tolerance index ≥ 60%. In shoots, EET61 and PA46 presented the higher (~270 mg·kg DW⁻¹) and lower (~20 mg·kg DW⁻¹) Cd concentration, respectively. Accordingly, only the EET61 showed an increase in the shoot cadmium translocation factor over the 90 days of exposure. However, when analyzing cadmium allocation to different organs based on total plant dry mass production, none of the genotypes maintained high Cd compartmentalization into roots, since P46, which was the genotype with the highest allocation of Cd to the roots, presented only 20% of total cadmium per plant in this plant organ and 80% allocated into the shoots, under Cd 12 (mg·kg⁻¹) and after 90 days of exposure. Thus, genotypic/phenotypic variability in cacao rootstocks may provide valuable strategies for maximizing the reduction in Cd content in shoots. In this sense, IMC67 and PA46 were the ones that stood out in the present study.

Trees in cacao Agroforestry systems (AFS) may present a high potential for cadmium (Cd) phytoextraction, helping to reduce Cd in cacao (Theobroma cacao L.) plants grown in contaminated soils. To assess this potential, four forest fine-woody species commonly found in cacao high-productive sites in Colombia (Tabebuia rosea, Terminalia superba, Albizia guachapele, and Cariniana pyriformis) were exposed to contrasting CdCl₂ contamination levels (0, 6, and 12 ppm) on a hydroponic medium. Growth dynamics, tolerance index (TI), and Cd concentration and allocation in leaves, stems, and roots were evaluated for up to 90 days after initial exposure. T. superba, A. guachapele, and C. pyriformis were classified as moderately tolerant (TI > 0.6), and T. rosea was considered a sensitive species (TI < 0.35) under 12 ppm Cd contamination. Despite showing a high stem Cd concentration, C. pyriformis also showed the lowest relative growth rate. Among the evaluated forest species, A. guachapele exhibited the highest Cd accumulation capacity per plant (2.02 mg plant⁻¹) but also exhibited a higher Cd allocation to leaves (4%) and a strong decrease in leaf and stem dry mass after 90 days of exposure (~75% and 50% respectively, compared to control treatments). Taking together all the favorable features exhibited by T. superba as compared to other CAFS tree species and recognized phytoextractor tree species in the literature, such as Cd hyperaccumulation, high tolerance index, low Cd concentration in leaves, and high Cd allocation to the stem (harvestable as wood), this species is considered to have a high potential for cadmium phytoextraction in cocoa agroforestry systems.

Background: In Colombia, most traditional cocoa crops are developed under agroforestry systems (SAF), associating shrubs and trees that provide shade for cocoa. They generate additional economic income and various ecosystem services. Objective: To characterize agroforestry systems with cocoa in three municipalities in eastern Boyacá (Miraflores, Berbeo, and Páez) belonging to the province of Lengupá. Methodology: A semi-structured interview was applied in 15 selected farms to learn about socioeconomic aspects, agronomic management of cocoa, and the use and management of trees. The botanical and structural composition and the Simpson (S), Shannon-Weaver (H´), and Jaccard (J) plant diversity indices were determined. Results: Cocoa producers in that region develop smallholder production under agroforestry systems with irregular tree species distribution, which are used for wood, firewood, shade, and food. At the regional level, 189 forest individuals accompanying cocoa were found, grouped into 18 families, 17 genera, and 28 species. The municipality of Berbeo presented the highest abundance (73 individuals), followed by Miraflores (67) and finally, Páez (49). In Berbeo, the species with a high importance value index (IVI) were Ceiba pentandra and Cedrela odorata (35 and 33, respectively), in Miraflores Trichanthera gigantea and Persea americana (44 and 42) and, in Páez Cedrela odorata (104). Implications: The selective felling of forests in SAF with cocoa, which intensifies the production of wood, has favored the loss of diversity; Therefore, the floristic composition studies serve as a basis to identify other potential forest species for the establishment of SAF to promote the diversification of the productive system and contribute to its resilience and sustainability. Conclusion: The agroforestry systems with cocoa in three municipalities in eastern Boyacá presented a differential composition and diversity, marked by a lower diversity in the municipality of Páez, where the species C. odorata had greater representation, related to the affinity of farmers for timber species of commercial interest.

El cultivo de cacao en Colombia ha venido creciendo en los últimos años y se consolida como un renglón de la economía agrícola del país. Cada vez más se requiere de desarrollos tecnológicos que contribuyan a mejorar la productividad y rentabilidad. Una de las causas del bajo rendimiento es la falta de genotipos y variedades productivas adaptadas y seleccionadas para las diferentes zonas con condiciones óptimas para el cultivo. El objetivo del presente estudio fue la evaluación agronómica de ocho genotipos de cacao TCS13, TCS19 (Theobroma Corpoica La Suiza), SCC53, SCC82, SCC83 (selección Colombia Corpoica) y CCS73, CCS77, CCS80 (colección Corpoica La Suiza), comparados frente a un testigo comercial ICS95 (imperial collage selection), en cuatro localidades productoras de las subregiones naturales Montaña Santandereana y Magdalena Medio en el nororiente colombiano, establecidos en sistemas agroforestales con maderas finas tropicales. Los resultados permitieron la identificación de dos genotipos superiores TCS13 y TCS19 por su rendimiento (producción de 1.5 y 1.8 kg árbol-1 año-1, respectivamente), baja incidencia de enfermedades limitantes como moniliasis y autocompatibles. Estos resultados permitieron la inclusión de dos nuevas variedades en el registro nacional de cultivares comerciales ante el Instituto Colombiano Agropecuario en el año 2017.