Campanha "São Sebastião inova no combate à dengue" continua com bons resultados e muito apoio da população.

bitstream/CENARGEN/30148/1/bpecuario090207.pdfPublicado em 05/02/2007. Disponível em: ClicNews, clicnews090207; Pets, pets090207; Ruralnet, ruralnet090207; Agrosoft, agrosoft090207; Boletim Pecuário, bpecuario090207; Hotel Virtual, hvirtual090207; Zoonews, zoonews110207

The evolutionary ecology of interactive synchronism: The illusion of the optimal phenotype

In this article, we discuss some ecological-evolutionary strategies that allow synchronization of organisms, resources, and conditions. Survival and reproduction require synchronization of life cycles of organisms with favourable environmental and ecological features and conditions. This interactive synchronization can occur directly, through pairwise or diffuse co-evolution, or indirectly, for example, as a result of actions of ecosystem engineers and facilitator species. Observations of specific interactions, especially those which have coevolved, may give the false impression that evolution results in optimal genotypes or phenotypes. However, some phenotypes may arise under evolutionary constraints, such as simultaneous evolution of multiple traits, lack of a chain of fit transitional forms leading to an optimal phenotype, or by limits inherent in the process of selection, set by the number of selective deaths and by interference between linked variants. Although there are no optimal phenotypes, optimization models applied to particular species may be useful for a better understanding of the nature of adaptations. The evolution of adaptive strategies results in variable life histories. These strategies can minimize adverse impacts on the fitness of extreme or severe environmental conditions on survival and reproduction, and may include reproductive strategies such as semelparity and iteroparity, or morphological, physiological, or behavioural traits such as diapause, seasonal polyphenism, migration, or bet-hedging. However, natural selection cannot indefinitely maintain intra-population variation, and lack of variation can ultimately extinguish populations

Embrapa Recursos Genéticos e Biotecnologia presente no Show Rural 2007.

bitstream/CENARGEN/30149/1/bpecuario010207.pdfPublicado em 05/02/2007. Disponível em: Boletim Pecuário, bpecuario010207; Agrosoft, agrosoft020207; Pets, pets040207; Portal Agronegócio, pagronegocio050207; Hotel Virtual, hvirtual020207; Agroagenda, agroagenda060207; Clicnews, clicnews040207; Ruralnet, ruralnet090207a

Une nouvelle histoire du café

Le café est aujourd?hui la première richesse de nombreux pays tropicaux. Seules deux espèces sont cultivées, qui produisent les célèbres Arabica et Robusta. Mais il existe au total près de 120 espèces sauvages, qui ont colonisé en 400000 ans toute l?Afrique équatoriale et la région malgache à partir de leur origine, en Basse Guinée. C?est ce que montre une récente étude de chercheurs de l?IRD et de leur partenaire brésilien 1, grâce au séquençage de l?ADN de 26 espèces. Jusque là, du fait de la présence des caféiers en Afrique, à Madagascar et en Inde, les botanistes pensaient que les arbustes provenaient de la corne de l?Afrique, avant que le supercontinent Gondwana ne se disloque, il y a plus de 100 millions d?années. Ces travaux réorientent les recherches sur le génome du café, en vue de l?amélioration de cette plante d?un grand intérêt agronomique et socio-économiquebitstream/item/123108/1/Une-nouvelle.pd