Conservação de recursos genéticos vegetais na Embrapa - histórico e perspectivas futuras.

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

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Coleta de germoplasma de leguminosas no Semi-Árido do Estado da Bahia.

A tradição das famílias rurais do semi-árido nordestino de produzir e guardar sua própria semente em casa tem se consolidado ao longo das décadas, através das práticas de conservação da diversidade agrícola, pela adaptação e seleção de materiais, troca e experimentação do germoplasma, com a comercialização do excedente de produção na comunidade ou em feiras livre. Com o objetivo de coletar essas variedades, ampliando a amostragem dos Bancos de Germoplasma de Feijão, Caupi e Fava, localizados na Embrapa, e identificando preferências das famílias dessa região realizou-se a expedição a Bahia, com apoio da EBDA. Foram coletadas amostras de 91 acessos de germoplasma de feijão, feijão de corda e fava, mantidos por agricultores locais, principalmente para consumo familiar e eventuais trocas com outros agricultores. Observou-se uma grande perda de variabilidade nos últimos anos, decorrente, principalmente, de alterações no regime de chuvas. Ficou evidente, também, a preferência desses consumidores por suas variedades tradicionais, seja por suas características de sabor, seja pelas qualidades agronômicas, e a necessidade de buscar meios para garantir a conservação, em melhores condições técnicas, dos materiais com características de interesse

Measurement of Vibrational Non-Equilibrium in a Supersonic Freestream Using Dual-Pump CARS

Measurements have been conducted at the University of Virginia Supersonic Combustion Facility of the flow in a constant area duct downstream of a Mach 2 nozzle, where the airflow has first been heated to approximately 1200 K. Dual-pump CARS was used to acquire rotational and vibrational temperatures of N2 and O2 at two planes in the duct at different downstream distances from the nozzle exit. Wall static pressures in the nozzle are also reported. With a flow of clean air, the vibrational temperature of N2 freezes at close to the heater stagnation temperature, while the O2 vibrational temperature is about 1000 K. The results are well predicted by computational fluid mechanics models employing separate "lumped" vibrational and translational/rotational temperatures. Experimental results are also reported for a few percent steam addition to the air and the effect of the steam is to bring the flow to thermal equilibrium

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