Examinando por Autor "Cobos, Marianela"

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Caracterización molecular de Heliconia sp. utilizando la técnica RAPD
(Centro de Preparación para la Ciencia y Tecnología, 2019-01-14) Gutierrez, Freddy; Ramirez, Roberson; Adrianzén Julca, Pedro Marcelino; Cobos, Marianela; Pinedo Freyre, Sergio Fernando; Imán Correa, Sixto Alfredo; Castro, Juan
Este trabajo se realizó entre los meses de Julio a Setiembre del 2010, con el objetivo de caracterizar molecularmente a la especie Heliconia sp. Utilizando el marcador molecular RAPD. Para esto, se realizó la purificación del ADN genómico de la especie en estudio obteniéndose buenos resultados en cuanto a la calidad y la cantidad del ADN purificado, el cual fue verificado con los métodos electroforético y espectrofotométrico, la cantidad de ADN obtenido en promedio fue de 92.8 ng/ μl, asimismo el ratio de calidad promedio fue de 2.2. Para la amplificación de los productos de la PCR se empleó el iniciador MT3R, obteniéndose mucho polimorfismo. Los productos de la PCR tuvieron tamaños de 750 pb hasta 2050 pb. En cuanto a la caracterización molecular, se realizó un dendograma (UPGMA) utilizando el programa estadístico NTSIS versión 2.0. Asimismo se obtuvo la formación de 2 grupos (clusters) y 2 fugas donde se observó la aparición de “aparentes duplicados” en algunos de ellos, es decir, que comparten el mismo patrón genético con un 100% de similitud. Además el valor de la heterocigosidad esperada fue de 0.14, valor relativamente bajo, posiblemente al tipo de reproducción que posee este género, el cual es la autogamica.
Development and application of microsatellite markers for genetic diversity assessment and construction of a core collection of Myrciaria dubia (Kunth) Mcvaugh germplasm from the peruvian Amazon
(MDPI, 2024-10-25) Castro, Juan C.; Vasquez Guizado, Stalin Juan; Vigil Santillan, Bianca Estefani; Ascue, Francisco; Rojas Villa, Naysha; Paredes, Jae D.; Cobos, Marianela; Castro, Carlos G.; Motta, Daniel E.; Adrianzén, Pedro M.; Imán Correa, Sixto Alfredo; Maddox, J. Dylan
The Amazonian shrub Myrciaria dubia (camu-camu) produces vitamin C-rich fruits of growing commercial interest. However, sustainable utilization requires assessment and protection of the genetic diversity of the available germplasm. This study aimed to develop and apply microsatellite markers to assess genetic diversity and construct a core collection of M. dubia germplasm from the Peruvian Amazon. Sixteen polymorphic microsatellite loci were developed using an enrichment approach. The evaluation of 336 genotypes from 43 accessions of the germplasm bank, originating from eight river basins, was conducted using these newly developed markers. Genetic diversity parameters, including observed and expected heterozygosity, were calculated. Analysis of molecular variance (AMOVA) was performed to assess the distribution of genetic variation within and among accessions and river basins. Bayesian clustering analysis was employed to infer population structure. A core collection was constructed to maximize allelic richness. High genetic diversity was observed, with heterozygosity values ranging from 0.468 to 0.644 (observed) and 0.684 to 0.817 (expected) at the river basin level. AMOVA indicated significant genetic variation within (73–86%) compared to among (14–27%) accessions and river basins. Bayesian clustering detected ten genetic clusters, with several degrees of admixture among river basins, except for the genetically homogeneous Putumayo River basin. A core collection comprising 84 plant genotypes (25% of the full collection) was established, representing 90.82% of the overall allelic diversity. These results have important implications for M. dubia conservation strategies and breeding programs, in demonstrating a need for genetic connectivity between populations but preserving unique genetic resources in isolated basins. These results validate the expected levels of diversity and population subdivision in a crop and stress the need to secure genetically diverse germplasms, underscoring the importance of thorough genetic characterization for ex situ germplasm management.
Development and phenotypic characterization of a native Theobroma cacao L. germplasm bank from the Loreto region of the Peruvian Amazon: Implications for ex situ conservation and genetic improvement
(Frontiers Media S.A., 2025-06-16) Imán Correa, Sixto Alfredo; Samanamud, Angelo F.; Ramírez , José F.; Cobos, Marianela; Paredes, Cleydi; Castro, Juan C.
Introduction: The ex situ conservation and characterization of native Theobroma cacao L. genetic resources are critical for sustainable cacao production and breeding programs in the face of climate change and escalating disease pressures. This study aimed to establish and characterize a novel germplasm bank from the Loreto region of the Peruvian Amazon, a key center of cacao diversity. Methods: We collected 140 native cacao accessions across 15 river basins in eight provinces of the Loreto region. Accessions were propagated using optimized grafting techniques with IMC 67 rootstock. Phenotypic evaluation was conducted on 402 plants using 36 standardized descriptors (25 quantitative and 11 qualitative). Data analysis included multivariate analysis using Uniform Manifold Approximation and Projection (UMAP) and Shannon-Weaver diversity indices to assess morphological diversity patterns. Results: Grafting achieved 100% survival rate, establishing a comprehensive germplasm bank. Phenotypic characterization revealed exceptional morphological diversity, with quantitative traits exhibiting substantial variation, particularly in fruit characteristics (CV = 15.82–50.82%) and pod index (CV = 144.82%). Multivariate analysis identified five distinct phenotypic groups, with reproductive traits showing stronger differentiation than vegetative traits. Shannon-Weaver diversity indices highlighted high overall phenotypic diversity (H' ≈ 0.7), with seed longitudinal shape and fruit apex form displaying the highest trait-specific diversity (H' > 1.0). Conclusion: This comprehensive characterization establishes a foundation for future multiomics studies and advanced breeding strategies. The documented diversity offers opportunities to leverage CRISPR-Cas-based editing and omics technologies to develop climate-resilient, high-yielding cacao varieties with superior quality traits, contributing significantly to global cacao conservation and improvement programs.
Optimized In vitro propagation and somatic embryogenesis of camu camu (Myrciaria dubia) cultivar Vitahuayo for enhanced commercial production
(Agricultural Research Communication Centre (ARCC Journals), 2025-03-12) Adrianzén, Pedro M.; Pinedo Freyre, Sergio Fernando; Valles, Barbara S.; Marapara, Jorge L.; Cobos, Marianela; Rodríguez, Hicler N.; Castro, Juan C.
Background: Myrciaria dubia “camu-camu” a fruit-bearing shrub native to the Amazon, is known for its high vitamin C content. However, variations in vitamin C biosynthesis and accumulation among different cultivars present challenges for commercial production. This study aimed to establish an efficient in vitro regeneration protocol for the Vitahuayo cultivar through callus induction and somatic embryogenesis. Methods: Stem and leaf explants were cultured on Murashige and Skoog (MS) medium supplemented with 24-dichlorophenoxyacetic acid (24-D) and 6-benzylaminopurine (BAP) to induce callus formation. Somatic embryos were induced using Woody Plant Medium (WPM) supplemented with 2,4-D, thidiazuron (TDZ), indole-3-butyric acid (IBA), naphthaleneacetic acid (NAA) and kinetin (KIN). Result: The best results for callogenesis were obtained with 1 mg/L of 24-D and 0.5 mg/L BAP. Somatic embryos were successfully induced with treatments T2 (2,4-D at 3 mg/L, NAA at 20 mg/L and KIN at 15 mg/L) showing 90% efficiency, while T3 (KIN at 0.3 mg/L and BAP at 0.05 mg/L) achieved 57.5% effectiveness. These findings offer great potential for the large-scale propagation of Vitahuayo, the optimization of its commercial production and the standardization of vitamin C biosynthesis.