The primary gene pool of cassava (Manihot esculenta Crantz subspecies esculenta, Euphorbiaceae).

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Biodiversity measures in agriculture using DNA.

Introduction; From nature to agriculture: why we need diversity?; Microrganisms and pests associated to plants; Genetic markers and molecular markers; How measures are taken: a brief review on the simplest and most popular tools; Random amplified DNA reveals polymorphism; Repetitive sequences can be especially polymorphic; Sequencing and single nucleotide polymorphism; Markers may help to understand evolution; The gains in plant breeding depends of variance; Conclusion

Identificação e ocorrência de begomovírus em algodoeiro em regiões de Goiás.

O objetivo do trabalho é verificar se o vírus do mosaico comum do algodoeiro em regiões de Goiás é um begomovírus. Foram localizadas e coletadas 69 plantas com aparentes sintomas de begomovírus

The primary genepool of cassava (Manihot esculenta Crantz).

The cultivated genepool comprises all comercial stocks of the crop besides all ingenous landraces and folk varieties of the domesticate.Suplemento. Edição dos Resumos do IV International Scientific Meeting of the Cassava Biotechnology Network, Salvador,1998

The primary gene pool of cassava (Manihot esculenta Crantz).

A crop gene pool comprises three distinct categories of gene suppliers, primary, secondary, and tertiary gene pools. The primary gene pool (GP-1) is composed of gene reservoirs that cross easily with the domesticate and the crosses produce fertile offspring regularly. The secondary (GP-2) and tertiary (GP-3) gene pools comprise gene sources that cross with variable degrees of diffilculty with the crop species, this implies less close genetic distances. The GP-1 is further subdivided in cultivated and wild gene pools. The cultivated gene pool englobes commercial stocks of the crop besides indigenous landraces and folk varieties of the domesticate. The wild GP-1 of a crop comprises putative ancestors and closely related species that show a fair degree of fertile relationships with the domesticate. Two Douth American wild subspecies of cassava (M. flabellifolia and M. peruviana) are natural members of the wild GP-1 of the species. Another Brazilian species (M. pruinosa) is so close morphologically to the two wild subspecies of cassava that it may turn out another member of the wild GP-1 of the indigen. The GP-2 of cassava is more difficult to delimit as few species have been tested for genetic compatibility. Biosystematic crosses carried out between the crop and a number of wild species suggest a dozen of them as components of the GP-2, the majority are Brazilian species

Conservacao e uso sustentavel de recursos geneticos de Manihot.

Recursos geneticos de especies brasileiras de Manihot (Euphorbiaceae) foram estudados numa abordagem interdisciplinar que visou a produzir conhecimentos em areas de pesquisa pouco exploradas ou em areas cujo conhecimento e considerado carente. Nesta comunicacao apresentam-se sequencialmente resultados das seguintes pesquisas inter-relacionadas: 1. estudos etnobotanicos da mandioca na Amazonia brasileira; 2. estudos taxonomicos de especies silvestres da Amazonia brasileira; 3. estudos sobre a origem geografica da mandioca; 4. estudos de mapas ambientais georeferenciados aplicados a distribuicao ecogeografica de especies; 5. estudos de tecnicas de conservacao ex situ de especies, em especial o estabelecimento de protocolos para a quebra da dormencia e melhorar os indices de germinacao de sementes, conservacao de sementes a longo prazo em temperatura sub-zero, regeneracao de eixos embrionarios e conservacao de vitroplantulas; 6. producao de germoplasma-semente em campos de polinizacao aberta e por polinizacao controlada

High genetic diversity among and within bitter manioc varieties cultivated in different soil types in Central Amazonia

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. © 2017, Sociedade Brasileira de Genética