Examinando por Materia "Manihot esculenta"

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Análisis de diversidad genética y distribución espacial del germoplasma de Manihot esculenta Crantz (yuca) en Ucayali-Perú, mediante marcadores SSR.
(Universidad Nacional San Agustín, Escuela de Ciencias Biológicas y Agropecuarias, Escuela de Biología, 2006) Aquino Villasante, Yeny Natali
Ante el grave problema de pérdida progresiva de la diversidad genética muchas entidades hacen esfuerzos por evitar dicho proceso, conservando en bancos de germoplasma especies con valor cultural, social y nutricional, como es el caso de Manihot esculenta Crantz comúnmente llamada yuca. En el Perú se cuenta con germoplasma de yuca conservado en el Instituto Nacional de Investigación y Extensión Agraria (INIEA), del cual se tomó 100 accesiones colectadas de ocho sectores de la región Ucayali, distribuidos en tres cuencas (Aguaytía, Ucayali y San Alejandro) y márgenes de una carretera (San Alejandro). Además, estas accesiones provienen de dos grupos socioculturales (nativos y colonos). El análisis de diversidad genética y distribución espacial, se realizó en el Laboratorio de Biología Molecular de la Sub Dirección de Recursos Genéticos y Biotecnología (SUDIRGEB) del INIEA en el periodo del 2003 a 2005, mediante marcadores moleculares SSR, para lo cual se seleccionaron 25 iniciadores. Los resultados muestran que la yuca tiene alta diversidad genética en el área de colecta Ht = 0.67). Mediante el análisis de agrupamiento se formaron 22 grupos, conformados por accesiones no relacionadas por origen geográfico. También se halló que entre la cuenca del Aguaytía y Ucayali, la primera es más diversa genéticamente (Hei = 0.67) y que es probable un intercambio de germoplasma limitado entre estas (Fst = 0.34). En la cuenca y carretera San Alejandro se conserva alta diversidad (Hei = 0.66), pero no diferente genéticamente una de la otra (Fst = 0.004). Los dos grupos socioculturales conservan alta diversidad, presentándose el mayor valor en comunidades de colonos (Hei = 0.68), mas el análisis de diferenciación genética indica haber un intercambio de germoplasma (Fst = 0.004). Además se identificó 10 posibles duplicados con una distribución geográfica que fortalece los valores de diversidad y diferenciación genética hallados, así también 6 accesiones genéticamente distantes de las demás y un subgrupo cuya característica es la presencia de tres alelos para el locus SSRY106. El análisis de distribución geográfica de la diversidad genética, con el Programa DIVA- GIS usando los datos moleculares, confirmó los resultados obtenidos del análisis de riqueza alélica, agrupamiento (similitud genética) y diferenciación genética (F).
Descriptores para yuca
(Instituto Nacional de Innovación Agraria, 2023-01) Marcelo Salvador, Mavel Nancy; Celestino Avelino, Doris; Martínez Lermo, Benito Leoncio; Hinostroza García, Luisa Del Rosario; Vasquez Oroya, Jhair; García Serquén, Aura Liz
El Instituto Nacional de Innovación Agraria (INIA) cuenta con la colección de yuca (Manihot esculenta Crantz) que está conformada por 757 accesiones y se encuentra en la Estación Experimental Agraria Donoso(Huaral). En el presente documento “Descriptores para yuca” muestra el resultado de las investigaciones de caracterización agromorfológica en yuca, permitiendo la identificación de accesiones con características deseables que puedan ser utilizadas en futuros programas de fitomejoramiento.
First report of cassava common mosaic disease and Cassava Common Mosaic Virus infecting cassava (Manihot esculenta) in Peru
(American Phytopathological Society, 2017-04-03) Fernandez Huaytalla, Elizabeth; Espinoza, Ivonne; Lozano, Ivan; Bolaños, Carmen; Carvajal Yepes, Monica; Cuellar, Wilmer
Cassava common mosaic disease (CCMD) can cause root yield losses of approximately 30% (Venturini et al. 2016) in cassava (Manihot esculenta Crantz) and it has already been reported in Brazil, Colombia, Paraguay, and Argentina (Calvert et al. 2012; Di Feo et al. 2015). Most of Peru’s cassava production is in the eastern side of the country (the rainforest region) and is mainly used for direct human consumption. Cultivated area in these regions is approximately 48.1 thousand hectares (MINAGRI 2015). CCMD is caused by Cassava common mosaic virus (CsCMV; Calvert et al. 1996), a mechanically transmitted potexvirus that can be disseminated via infected stem cuttings used for cassava propagation. Given the presence of the disease in neighboring countries, a field survey for virus diseases in cassava was organized during June 2016 in the province of Huaral, in the central coast of Peru, where typical leaf mosaic and leaf deformation symptoms associated to CCMD were observed in local cassava varieties. To verify the presence of CsCMV and CCMD in Peru, the youngest leaves of four plants showing virus-like symptoms and four plants not showing symptoms were collected from one of the affected fields and dried in silica gel for analysis. Double antibody sandwich (DAS)-ELISA tests using a polyclonal antiserum readily detected CsCMV in all symptomatic samples (Nolt et al. 1991). In addition, mechanical transmissions to the experimental host Nicotiana benthamiana induced typical systemic leaf mosaic. RT-PCR tests targeting the replicase region of CsCMV were carried out using primers CsCMV-3269-F: 5′-GAGGCTCTTCTCTGGGAAAC-3′ and CsCMV-3896-R: 5′-CTTGAGTCCAGTTTGATGTC-3′, designed using an alignment of CsCMV-related sequences available in GenBank. An expected PCR fragment of 627 bp was obtained only in samples showing symptoms of CCMD. RT-PCR tests for other cassava-infecting viruses reported in the Americas (Carvajal-Yepes et al. 2014) were negative in these samples. PCR products from two independent CsCMV-positive samples were sent for direct Sanger-sequencing (Macrogen, Korea). CsCMV sequence isolates from Peru (GenBank accession nos. KX964625 and KX964626) show a nucleotide identity of 88 to 93%, and an amino acid sequence identity of 99% with other CsCMV sequences available in GenBank, and phylogenetic analysis clustered Peruvian isolates with CsCMV sequences reported in cassava. These results stress the need to implement surveillance activities and quick diagnostic protocols, as the inadvertent propagation and accumulation of virus infections could cause an increasingly negative effect on cassava and other vegetatively propagated crops.
Resolution of cassava-infecting alphaflexiviruses: Molecular and biological characterization of a novel group of potexviruses lacking the TGB3 gene
(El Sevier, 2017-05-30) Lozano, Ivan; Leiva, Ana M.; Jimenez, Jenyfer; Fernández Huaytalla, Elizabeth; Carvajal Yepes, Monica; Cuervo, Maritza; Cuellar, Wilmer J.
Several potexviruses (Family Alphaflexiviridae) have been reported infecting cassava (Manihot esculenta Crantz) in the Americas. They were isolated from severely diseased plants during the last 30–40 years and include: Cassava common mosaic virus (CsCMV), Cassava Caribbean mosaic virus (CsCaMV), Cassava Colombian symptomless virus (CsCSV) and Cassava virus X (CsVX). However, their definitive classification as distinct species remains unresolved for several reasons, including the lack of sequence data and unavailability of samples from original isolates. This complicates disease diagnostics, cassava germplasm exchange certification, evaluation of virus cleaning protocols and epidemiological studies. Furthermore, a recently detected novel alphaflexivirus, indicates that cassava-infecting potexviruses may be more diverse. To solve the identity of these viruses, we started indexing samples from different parts of Colombia using different sets of PCR primers, antisera available and inoculation to indicator plants. Results show that there are three major phylogenetic groups of potexviruses infecting cassava, and they correspond to CsCMV, CsVX and the newly identified Cassava new alphaflexivirus (CsNAV). Bioassays and sequence analysis established that isolates of CsNAV and CsVX cause latent infections in different cassava landraces, they are not efficiently transmitted to the indicator plant Nicotiana benthamiana and they lack the gene 3 of the conserved potexviral ‘triple gene block’ (TGB). In contrast, all isolates of CsCMV (which have a characteristic potexvirus genome arrangement) caused Cassava Common Mosaic Disease (CCMD) in single infections and were efficiently transmitted to N. benthamiana. Although phylogenetic analysis of the replicase sequence placed CsNAV and CsVX as members of the Potexvirus genus, their distinct genome arrangement and biological characteristics suggest they can be considered as members of a separate taxonomic group.
Spatial patterns of diversity and genetic erosion of traditional cassava (Manihot esculenta Crantz) in the Peruvian Amazon: An evaluation of socio-economic and environmental indicators
(Springer Nature, 2007-02-23) Willemen, Louise; Scheldeman, Xavier; Soto Cabellos, Víctor; Rafael Salazar, Simón; Guarino, Luigi
This study evaluates quantitatively the suitability of the use of site-specific socio-economic and environmental data as indicators to rapidly assess patterns of diversity and genetic erosion risk in cassava. Socio-economic data as well as farmers’ estimation of genetic erosion were collected in the study area, the Ucayali region of the Peruvian Amazon, through interviews with 285 cassava farmers in 50 communities, while diversity was assessed based on agromorphological characterization of 295 cassava accessions. Using multivariate regression analyses, 50 and 45% of the variation in respectively diversity and genetic erosion estimation could be explained by a selected set of socio-economic and environmental indicators. In both regression models four out of the total of 38 variables proved to contribute significantly (at p < 0.10 level). Additionally, the study revealed that farmers are a good direct source of information on the diversity present at community level, which can contribute to the development of methodologies to assess diversity more rapidly. The results of this study are valuable for the development of models to rapidly assess diversity dynamics in large areas.