Browsing by Author "Antonio Figueira"

Now showing 1 - 4 of 4
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    Description of Amazonian Theobroma L. collections, species identification, and characterization of interspecific hybrids
    (2004) Carlos Rogerio Sousa Silva; Giorgini Augusto Venturieri; Antonio Figueira
    (Description of Amazonian Theobroma L. collections, species identification, and characterization of interspecific hybrids). There are two major in vivo collections of species of the genus Theobroma L. in Belem and Marituba, state of Para, Brazil, and in both there are natural species, as well as natural and artificial interspecific hybrids. In order to organize a database of Brazilian Theobroma species, a description of the existing collections and detailed information about the interspecific hybrids, including an artificial key for their identification, are presented in this article.
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    Genetic diversity and natural population structure of cacao (Theobroma cacao L.) from the Brazilian Amazon evaluated by microsatellite markers
    (Springer, 2006) Maria L. Sereno; Paulo S.B. Albuquerque; Roland Vencovsky; Antonio Figueira
    A sample of 94 accessions of Theobroma cacao L. (cacao), representing four populations from the Brazilian Amazon (Acre, Rondoˆ nia, lower Amazon and upper Amazon) were analyzed using microsatellite markers to assess the genetic diversity and the natural population structure. From the 19 microsatellite loci tested, 11 amplified scorable products, revealing a total of 49 alleles, including two monomorphic loci. The Brazilian upper Amazon population contained the largest genetic diversity, with the most polymorphic loci, the highest observed heterozygosity; and the majority of rare alleles, thereby this region might be considered part of the center of diversity of the species. The observed heterozygosity for all the Brazilian populations (Ho=0.347) was comparable with values reported for other similar upper Amazon Forastero cacao populations, with the Acre and Rondoˆ nia displaying the lowest values. The lower Amazon population, traditionally defined as highly homozygous, presented an unexpectedly high observed heterozygosity (Ho=0.372), disclosing rare and distinct alleles, with large identity with the upper Amazon population. It was hypothesized that part of the lower Amazon population might derive from successive natural or intentional introduction of planting material from other provenances, mainly upper Amazon. Most of the loci exhibited a lower observed heterozygosity than expected, suggesting that self-pollination might be more common than usually assumed in cacao, but excess of homozygotes might also derive from sub-grouping (Wahlund effect) or from sampling related individuals. Most of the gene diversity was found to occur within groups, with small differentiation between the four Brazilian Amazon populations, typical of species with high gene flow.
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    Genomics of Theobroma cacao, "the Food of the Gods"
    (2008) Joseph Verica; Mark J. Guiltinan; Dapeng Zhang; Antonio Figueira
    Theobroma cacao, the chocolate tree. is an important tropical tree-cropthat provides sustainable economic and environmental benefits to some of the poor-est and most ecologically sensitive areas of the world. Recent progress in thedevelopment of genomics tools for cacao is reviewed. These include a referencemolecular genetic map, simple sequence repeats and other molecular markers, twogermplasm databases with microsatellite DNA fingerprints and other moleculardata, many quantitative trait loci mapping projects which have identified disease re-sistance and yield component loci, several expressed sequence tag resources, a cacaomicroarray, bacterial artificial chromosome libraries, and a genetic transformationsystem. The evolutionary relatedness of cacao with other important crops and modelplant systems positions cacao genomics to play a significant role in translationalplant genomics. The future prospects for the contribution of cacao genomics to im-provement of this crop for sustainable cacao production and as a tool for povertyalleviation and environmental stabilization are discussed.
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    Novel sources of witches’ broom resistance (causal agent Moniliophthora perniciosa) from natural populations of Theobroma cacao from the Brazilian Amazon
    (2010) Paulo S.B. de Albuquerque; Stela D.V.M. Silva; Edna D.M.N. Luz; Jose L. Pires; Afranio M.C. Vieira; Clarice G.B. Deme trio; Sergio F. Pascholatti; Antonio Figueira
    Witches broom is a severe disease of Theobroma cacao L. (cacao), caused by the basidiomycete Moniliophthora perniciosa. The use of resistant cultivars is the ultimate method of control, but there are limited sources of resistance. Further, resistance from the most widely used source (Scavina 6) has been overcome after a few years of deployment. New sources of resistance have been intensively searched for in the Amazon basin. Here, we evaluated for witches broom resistance, cacao accessions from various natural cacao populations originally collected in the Brazilian Amazon. Resistance of 43 families was evaluated under nursery and/ or field conditions by artificial or natural infection, respectively, based on disease incidence. Screening for resistance by artificial inoculation under nursery conditions appeared to be efficient in identifying these novel resistance sources, confirmed by natural field evaluation over a nine-year period. The increase in natural field infection of Scavina 6 was clearly demonstrated. Among the evaluated families with the least witches broom incidence, there were accessions originally collected from distinct river basins, including the Jamari river (CAB 0371; CAB 0388; CAB 0392; and CAB 0410); Acre (CAB 0169); Javari (CAB 0352); Solimoes (CAB 0270); and from the Purus river basin, the two most outstanding resistant accessions, CAB 0208 and CAB 0214. The large genetic diversity found in cacao populations occurring at river basins from Acre and Amazonas states, Brazil, increased the chance that the selected resistant accessions would be genetically more dissimilar, and represent distinct sources of resistance to M. perniciosa from Scavina 6.