Agronomic Evaluation of 324 Intraspecific Hybrids of \u3cem\u3eBrachiaria decumbens\u3c/em\u3e in Brazil

Brachiaria decumbens cv. Basilisk is the most planted pasture grass in the tropics owing to its adaptation to poor and acid soils, typical of the tropics, plus good animal performance. This cultivar was responsible for a radical change of scenario in central Brazil in the early 1970s and is the only cultivar available commercially. Efforts to breed this species have been recent, as the successful somatic chromosome duplication of sexually reproducing diploid plants of B. decumbens was accomplished only in 2009 (Simioni and Valle 2009). Subsequently, intraspecific crosses with natural apomictic tetraploid accessions were carried out. Breeding is needed since cv. Basilisk is susceptible to grassland spittlebugs, which limit its widespread use. A recurrent selection scheme has been devised to improve the species and the first progeny are now under evaluation. This paper reports the preliminary results of the agronomic evaluation of 324 intraspecific hybrids of B. decumbens

Agronomic and Nutritional Evaluation of Intraspecific Crosses in \u3cem\u3eBrachiaria decumbens\u3c/em\u3e

Brachiaria decumbens cv. Basilisk is the single most important forage grass used for pastures in the tropics. This cultivar has exceptional adaptation to acid soils, vigorous growth, ease of establishment, and good forage value throughout the year, but these favourable characteristics are counteracted by its susceptibility to insect pests such as spittlebug. Breeding to produce improved cultivars within this species was impossible until 2009 due to the lack of compatible sexual ecotypes. With the success of somatic chromosome duplication of sexually reproducing diploid plants of B. decumbens (Simioni and Valle 2009), intraspecific crosses with natural apomictic tetraploid accessions were finally possible. This paper reports the results of the agronomic and nutritional evaluation of 50 preselected intraspecific hybrids of B. decumbens

Effect of Season and Year of Evaluation in the Selection of \u3cem\u3eBrachiaria humidicola\u3c/em\u3e Hybrids

Brachiaria humidicola is well adapted to infertile and acid soils with poor drainage or temporary flooding (Keller-Grein et al. 1996). It is widely used in Brazil in wetlands and areas of marginal land characterised by waterlogged soils. During the evaluation stages of the breeding program of this species, genotypes are generally tested using consecutive cuts within different seasons for at least 2 years. The ‘Cerrado’ region, where most animal production takes place in Brazil, has 2 well defined seasons: spring-summer with warm weather and rain; and autumn-winter with cooler, dry weather. Thus, owing to environmental variation, especially related to climate, it is important to investigate the main effects of environmental factors (years and seasons), as well as interactions between genotypes and environmental factors in order to have greater confidence in the selection of superior hybrids of B. humidicola on the basis of agronomic and nutritional traits

Breeding Strategies for \u3cem\u3eBrachiaria\u3c/em\u3e spp. to Improve Productivity–An Ongoing Project

Two strategies have been used in the breeding of Brachiaria (syn. Urochloa) to produce new cultivars. The first involves exploring the natural variability existing in nature, which is the selection of ecotypes, mostly apomicts, from the diversity in germplasm banks. This strategy proved efficient originally and the cultivars in use in Brazil were derived in this way, but progress with this strategy is limited in the medium to long term

Assessment of genetic parameters of degradability in maize grains due to indentation scores

Maize (Zea mays L.) cultivars with dent grains present higher starch and dry matter ruminal degradability than those with flint grains. This study aimed to assess genetic parameters of degradability in maize grains of different textures and to verify whether there is an association between grain indentation score and ruminal dry matter (RDM) degradability. The evaluated progenies were obtained from the cross between the varieties Cristal (flint) and Cunha (dent), previously selected for grain hardness. Progenies were evaluated for an indentation score using a visual grading scale ranging from 1 (flint) to 5 (dent). To assess the RDM degradability, 5 g were cut into halves, weighed (five grams), stored in bags made of 100% "failet" cloth and incubated for 24 h in the rumen of three ruminally cannulated cows. There was genetic variability for RDM degradability and heritability was 46%, indicating the possibility of success using a selection. There was no association between indentation score and RDM degradability percentage; thus, visual evaluation not always reflects grain hardness per se since it indicates the pericarp aspect but not the endosperm constitution.Cultivares de milho (Zea mays L.) com grãos do tipo dentado possuem maior porcentagem de amido e degradabilidade ruminal da matéria seca do que os com grãos do tipo duro. Estimaram-se parâmetros genéticos da degradabilidade de grãos de milho com diferentes texturas e verificou-se se ocorre associação entre o escore de identação dos grãos visualmente avaliados e a degradabilidade in situ da matéria seca (DISMS). Foram avaliadas progênies oriundas do cruzamento entre a variedade Cristal, de grãos duros, e a variedade Cunha de grãos dentados, previamente selecionadas para a dureza dos grãos. As progênies foram avaliadas com relação ao escore de identação por meio de uma escala visual de notas variando de 1 (duro) a 5 (mole). Para a avaliação da DISMS os grãos foram cortados ao meio, pesados 5 g colocados em saquinhos de tecido "failet" e incubados no rúmen, por 24 h, em três vacas portadoras de cânula ruminal. Há variabilidade genética para a DISMS, com herdabilidade de 46%, indicando ser possível o sucesso com a seleção. Não há associação entre o escore de identação e a porcentagem de DISMS. Assim, a avaliação visual nem sempre reflete a dureza per se dos grãos, pois o que se vê é o aspecto do pericarpo e não a constituição do endosperma

The effect of environmental parameters and cyanobacterial blooms on phytoplankton dynamics of a Portuguese temperate Lake

Abstract The increasing occurrence of cyanobacterial blooms in freshwaters is of great concern due to the ability of many cyanobacteria to produce cyanotoxins. In the present work, the eutrophied Vela Lake (Central Portugal), used for recreational purposes and as a water source for agriculture, was monitored every fortnight between 2000 and 2001. Phytoplankton diversity and densities were measured and correlated to environmental parameters. A seasonal phytoplanktonic succession was observed and it was mainly correlated with conductivity, temperature, total suspended solids and nutrients availability (particularly phosphorus). Diatoms were dominant during winter months (inferior temperatures and higher nutrients availability) followed by green algae in early spring and then cyanobacteria from late spring until early autumn (less nutrient availability and higher temperatures). A massive cyanobacterial bloom of Aphanizomenon flos-aquae occurred early in May 2001 and was preceded by the lowest nitrogen levels measured in the water during all the study period. At the time of this bloom senescence, dissolved oxygen was severely depleted and a massive death of ichthyofauna was recorded. A Microcystis aeruginosa bloom was also detected in July 2001 and it occurred following a rapid decrease in abundance of green algae and diatoms. By considering not only the environmental parameters but also the occurrence of cyanobacterial blooms as explanatory variables in a canonical correspondence analysis, the variance explained for the phytoplanktonic assemblage during the study period was increased in about 7% achieving a total of 61.0%, indicating a correlation that may be due to the known competitive advantage and/or allelopathy of the bloom-forming cyanobacteria towards microalgae

Democratização e reforma do Estado: o desenvolvimento institucional dos tribunais de contas no Brasil recente Democratization and state reform: the institutional development of the courts of accounts in recent Brazil

Este artigo analisa as transformações das últimas décadas nos tribunais de contas no Brasil, à luz da discussão da temática do desenvolvimento institucional. Essa perspectiva analítica permite olhar os processos de mudanças nas arenas políticas, no longo prazo, enfatizando não só a resistência dos atores institucionais ou sociais com poder de veto e os mecanismos de path dependence, mas igualmente as conjunturas críticas que permitem levar adiante as transformações, mesmo que de forma incremental. No caso em estudo, a conjuntura crítica da democratização e da Constituição de 1988 trouxe mudanças, mas estas foram neutralizadas pela capacidade de veto da elite dirigente especialmente em alguns tribunais. Por outro lado, a nova conjuntura crítica representada pela Lei de Responsabilidade Fiscal, de 2000, alterou a dinâmica política e institucional, permitindo que, até muito recentemente, as mudanças que permaneciam bloqueadas começassem, a partir de então, a ser efetivadas diante da menor capacidade de exercício de tais vetos.<br>This article analyzes the transformations of Brazilian courts of account since the democratization process occurred in the 1980s. The theoretical perspective of institutional development allows us to consider the long-term processes of political change, stressing not only the resistance of institutional and social actors, the situation of path dependence, but also the critical junctures. In this article, the changes brought by the 1988 Constitution in the courts of accounts structure were neutralized by the veto of powerful actors. Only a new critical juncture of the 2000 Fiscal Responsibility Law could alter the political and institutional dynamics and put into practice new changes in these institutions