Produção e avaliação de cultivares do azevém no sul do Rio Grande do Sul.

Este trabalho teve por objetivo avaliar a produção de matéria verde e matéria seca de sete cultivares de azevém na região sul do Rio Grande do Sul

Sowing rate and its effects on forage yield of tetraploid ryegrass.

There is a shortage of information about the ryegrass crop (Lolium multiflorum Lam.), especially regarding the suitable sowing rate. Thus, the present work aimed to determine the most adequate sowing rate for tetraploid ryegrass cultivars. A tetraploid ryegrass population was sown at different densities: 150, 300, 600, 900, 1200, 1500, 1800 seeds/m². The number of plants per m², percentage of soil cover, leaf yield and green and dry forage yield were evaluated. The experimental design was randomized blocks with three replications. To observe the behavior of the pasture at different densities for each cut, regression analysis was performed, through which it was possible to verify that the sowing rate has greater influence on the initial cut of the crop. In all the variables analyzed by regression, only the second cut presented a linear trend favorable to the increase in density. In the other cuts, an increase was observed, both in the height of plants and in the yield variables, up to the density of 1500 seeds/m², with a subsequent fall to the highest density, indicating that higher densities may be detrimental to pasture yield. Therefore the density of 1500 seeds/m² is the most suitable for tetraploid ryegrass cultivars

Produtividade de matéria seca de forragem e massa seca de folhas de genótipos de Cynodon e Digitaria implantados na região Sul do Brasil.

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Admixture in Latin America: Geographic Structure, Phenotypic Diversity and Self-Perception of Ancestry Based on 7,342 Individuals

The current genetic makeup of Latin America has been shaped by a history of extensive admixture between Africans, Europeans and Native Americans, a process taking place within the context of extensive geographic and social stratification. We estimated individual ancestry proportions in a sample of 7,342 subjects ascertained in five countries (Brazil, Chile, Colombia, México and Perú). These individuals were also characterized for a range of physical appearance traits and for self-perception of ancestry. The geographic distribution of admixture proportions in this sample reveals extensive population structure, illustrating the continuing impact of demographic history on the genetic diversity of Latin America. Significant ancestry effects were detected for most phenotypes studied. However, ancestry generally explains only a modest proportion of total phenotypic variation. Genetically estimated and self-perceived ancestry correlate significantly, but certain physical attributes have a strong impact on self-perception and bias self-perception of ancestry relative to genetically estimated ancestry