title: High genetic diversity among and within bitter manioc varieties cultivated in different soil types in Central Amazonia.
abstract: Although manioc is well adapted to nutrient-poor Oxisols of Amazonia, ethnobotanical observations show that bitter manioc is also frequently cultivated in the highly fertile soils of the floodplains and Amazonian dark earths (ADE) along the middle Madeira River. Because different sets of varieties are grown in each soil type, and there are agronomic similarities between ADE and floodplain varieties, it was hypothesized that varieties grown in ADE and floodplain were more closely related to each other than either is to varieties grown in Oxisols. We tested this hypothesis evaluating the intra-varietal genetic diversity and the genetic relationships among manioc varieties commonly cultivated in Oxisols, ADE and floodplain soils. Genetic results did not agree with ethnobotanical expectation, since the relationships between varieties were variable and most individuals of varieties with the same vernacular name, but grown in ADE and floodplain, were distinct. Although the same vernacular name could not always be associated with genetic similarities, there is still a great amount of variation among the varieties. Many ecological and genetic processes may explain the high genetic diversity and differentiation found for bitter manioc varieties, but all contribute to the maintenance and amplification of genetic diversity within the manioc in Central Amazonia.
authors.affiliation: Departamento de Genética, Escola Superior de Agricultura "Luiz de Queiróz", Universidade de São Paulo, Piracicaba, SP, Brazil.|Laboratório de Evolução Aplicada, Universidade Federal do Amazonas, Manaus, AM, Brazil.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Alves-Pereira
authors.affiliation: Universidade Federal de Santa Catarina, Departamento de Ecologia e Zoologia, Florianópolis, SC, Brazil.
authors.forename: Nivaldo
authors.initials: N
authors.lastname: Peroni
authors.affiliation: Empresa Brasileira de Pesquisa Agropecuária, EMBRAPA COCAIS, São Luis, MA, Brazil.
authors.forename: Marcelo Mattos
authors.initials: MM
authors.lastname: Cavallari
authors.affiliation: Instituto Nacional de Pesquisas da Amazônia, Manaus, AM, Brazil.|Laboratório de Genética e Biologia Reprodutiva de Plantas, Instituto Nacional de Pesquisas da Amazônia, Manaus, AM, Brazil.
authors.forename: Maristerra R
authors.initials: MR
authors.lastname: Lemes
authors.affiliation: Agência Paulista de Tecnologia dos Agronegócios, Pólo Regional Centro-Sul, Piracicaba, SP, Brazil.
authors.forename: Maria Imaculada
authors.initials: MI
authors.lastname: Zucchi
authors.affiliation: Laboratório de Evolução Aplicada, Universidade Federal do Amazonas, Manaus, AM, Brazil.|Instituto Nacional de Pesquisas da Amazônia, Manaus, AM, Brazil.
authors.forename: Charles R
authors.initials: CR
authors.lastname: Clement