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Dive into the research topics where César Ocampo is active.

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Featured researches published by César Ocampo.


Genetic Resources and Crop Evolution | 2005

Tracing the origin of Spanish common bean cultivars using biochemical and molecular markers

César Ocampo; Juan Pedro Martín; María Dolores Sánchez-Yélamo; Jesús María Ortiz; Orlando Toro

Fifty-four accessions of Phaseolus vulgaris cultivated in Spain and representing a broad variability for this country, were studied together with 30 samples of wild forms of American origin. Two reference cultivars (from the Andes and Mesoamerica) plus two outgroups (P. coccineus and Vigna unguiculata) were also included. RAPD analysis of DNA leaf extracts were carried out with four selected primers. We also studied morphological characters of the seeds and the phaseolin electrophoretic patterns. Multivariate analysis with the UPGMA method using RAPD data clustered the samples in four groups and, comparing with morphological data and phaseolin types, showed that the Spanish cultivars were mainly of Andean origin. Nevertheless, occurrence of introgression in Spain and the consideration of the country as a second center of variability for beans can also explain the obtained results.


Genetic Resources and Crop Evolution | 1995

Isozyme polymorphism provides fingerprints for germplasm ofArachis glabrata Bentham

Brigitte L. Maass; César Ocampo

Arachis glabrata Bentham, a wild, perennial relative of the cultivated peanut, has been under development as a forage plant for the subtropics and tropics since the early 1960s. To complement the limited genetic resources available in those years, a significant germplasm collection has been assembled in recent years. But little is known about the genetic diversity in this species because research has focused mainly on agronomy. This study aimed to investigate the utility of isozymes for characterisingA. glabrata germplasm. Polyacrylamide gel electrophoresis (PAGE) was applied to rhizome-tip tissue. Isozyme characterisation by PAGE showed a high degree of intraspecific polymorphism for the isozymes α-EST, ACP, GOT, and DIA. When analysed together, the four isozyme systems could clearly distinguish all 15 accessions ofA. glabrata held in the germplasm collection at CIAT. Although several accessions originated from the same region, similarity in isozyme patterns was not correlated with geographic origin. Examining rhizome-tip tissue is useful inA. glabrata, a species which produces few seeds.


Genetic Resources and Crop Evolution | 2003

Isozyme variation in Passiflora subgenera Tacsonia and Manicata. Relationships between cultivated and wild species

Sergio D. Segura; Géo Coppens D'Eeckenbrugge; César Ocampo; Patrick Ollitrault

Isozyme variation was studied in 87 plants from 32 cultivated and wild accessions of banana passion fruit (P. tripartita var. mollissima, P. tripartita var. tripartita, P. tarminiana, and P. mixta), rosy passion fruit (P. cumbalensis), tin-tin (P. pinnatistipula), gulián (P. ampullacea), P. antioquensis, P. bracteosa, and P. manicata, from the Andes of Venezuela, Colombia, and Ecuador. Six polymorphic enzyme systems (IDH, PGDH, PGM, DIA, PRX, and ACP) revealed 31 zymotypes characterized by the presence or absence of 31 electromorphs. Cluster analysis separated clearly the accessions of P. tarminiana, P. tripartita, P. mixta, and P. cumbalensis from the less typical species of subgenus Tacsonia, which is consistent with morphological evidence. P. mixta showed the highest intraspecific variation and the closest affinity with P. tripartita. The accessions of these two species formed two clusters, one dominated by Colombian genotypes and the other dominated by Ecuadorian genotypes. One of the P. tripartita var. mollissima accessions clustered close to P. tarminiana accessions. The affinity between these three species is particularly interesting for conservation and use of banana passion fruit genetic resources. All the other species formed monospecific clusters.


Euphytica | 1993

Morphological and isozyme characterisation of Arachis pintoi Krap. et Greg. nom. nud. germplasm

Brigitte L. Maass; Alba M. Torres; César Ocampo

Arachis pintoi, a wild perennial relative of the peanut, originated in Brazil, is of increasing importance to pasture improvement in the tropics. Its available genetic base, however, is very narrow, and intensive collection is being carried out. This study aimed to characterise the existing eight accessions in the CIAT germplasm collection in order to describe the existing variation, identify plant types, and discover possible duplicates. Morphological characterisation, based on 60 morphological descriptors, demonstrated that variation exists. Numerical taxonomic techniques were used to rank the importance of these descriptors. Cluster analysis, conducted on those pre-selected morphological characters, grouped the accessions into two major plant types: one homogenous, and the other falling into four distinct subgroups. Polyacrylamide gel electrophoresis (PAGE) was applied to root-tip tissue. Isozyme characterisation by PAGE showed polymorphisms in the isozymes α-EST, ACP, GOT, and DIA. When analysed together, the four isozymes could uniquely distinguish every accession of A. pintoi held in the CIAT germplasm collection. Correspondence and cluster analyses of these isozyme patterns showed the morphologically homogenous plant type to be heterogenous, and the heterogenous morphotype to have similar banding patterns. The lack of continuous patterns of variation in both morphology and isozymes manifests the need for further germplasm collection of A. pintoi.


Genetic Resources and Crop Evolution | 2005

Isozyme variation in Passiflora subgenus Tacsonia: geographic and interspecific differentiation among the three most common species.

S. D. Segura; G. Coppens d’Eeckenbrugge; César Ocampo; Patrick Ollitrault

In a general study of banana passion fruit genetic resources, diversity was analyzed in the two main cultigens, P. tripartita var. mollissima and P. tarminiana, and their closest wild relative, P. mixta, scoring isozyme bands (IDH,PGM,ACP,PGD,DIA,andPRX) on288 plants from 31 accessions. Polymorphismandallelic richness, Nei diversity indices, and neighbor joining clustering showed that variation was poor in the cultigens in northern and central Colombia, while P. mixta appeared much more polymorphic. The populations of P. tripartita var. mollissima and P. mixta from southern Colombia and Ecuador show higher diversity values and are clearly differentiated from those of central and northern Colombia. This geographic component of variation is even stronger than the interspecific one, which suggests a close relation and a regular gene flow between these two species. In contrast, all the accessions of P. tarminiana constitute a clearly differentiated group, even if some introgression with P. tripartita var. mollissima is also suspected. The high variation observed in the southern region indicates the proximity of a center of diversity for banana passion fruit and collecting in Ecuador, Peru and Bolivia is recommended. The high diversity of P. mixta and the evidence of gene flow with P. tripartita var. mollissima constitute a favorable context for the implementation of in situ conservation strategies.


Bean Improvement Cooperative. Annual Report (USA) | 2003

Monitoring gene flow between wild relatives and landraces of common bean in Costa Rica

Rosa Inés González Torres; Eliana Gaitán Solís; Myriam Cristina Duque E.; Orlando Toro Chica; César Ocampo; Joseph Tohme M.; Daniel G. Debouck


Agronomía Colombiana | 2012

Genetic diversity in a Colombian bean (Phaseolus vulgaris L.) collection as assessed by phaseolin patterns and isoenzymatic markers

Gustavo A. Ligarreto; César Ocampo


Archive | 2004

Efficacy of silver nitrate for slow-growth conservation of cassava (Manihot esculenta Krantz). Determination of viability and genetic stability [poster]

Graciela Mafla B.; Julio César Roa E.; César Ocampo; Gerardo J. Gallego; Gustavo Jaramillo; Daniel G. Debouck


Agronomía Colombiana | 2003

Evidencia fenotípica y bioquímica de introgresión mesoamericana en accesiones de habichuela (Phaseolus vulgaris) cultivadas en centros secundarios de domesticación

Adriana Tofiño; César Ocampo; Orlando Toro


Agronomía Colombiana | 2012

Genetic diversity in a Colombian bean (Phaseolus vulgaris L.) collection as assessed by phaseolin patterns and isoenzymatic markers Diversidad genética en una colección colombiana de fríjol (Phaseolus vulgaris L.) usando patrones de faseolinas y marcadores isoenzimáticos

Gustavo A. Ligarreto; César Ocampo

Collaboration


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Orlando Toro

International Center for Tropical Agriculture

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Adriana Tofiño

National University of Colombia

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Daniel G. Debouck

International Center for Tropical Agriculture

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Gustavo A. Ligarreto

National University of Colombia

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Géo Coppens D'Eeckenbrugge

International Center for Tropical Agriculture

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Patrick Ollitrault

Centre de coopération internationale en recherche agronomique pour le développement

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Brigitte L. Maass

International Center for Tropical Agriculture

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Creuci Maria Caetano

National University of Colombia

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Maria Teresa Restrepo

National University of Colombia

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Maritza Cuervo

International Center for Tropical Agriculture

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