Extraction of inbred lines is a very important step in maize breeding since these lines will be used to obtain hybrids intended for the market. However, this expensive process, hinders genotype evaluation in contrasting environments, especially regarding nitrogen (N) content. This study aimed to evaluate the potential of maize populations for line extraction and select partially inbred lines under different soil nitrogen (N) availability. Five populations were evaluated regarding their potential for line extraction. Fifty-five S1 partially inbred lines were extracted from these populations. The top-cross method was used to evaluate lines by crossing them with two testers. Hybrids evaluation used 110 top-cross hybrids, five base populations, and six checks. Two trials were carried out in Dourados and Caarapó. One trial had adequate fertilization (high N) while the other was under stress condition (low N). Hybrid DKB 789 showed potential for extraction of partially inbred lines, aiming at selecting N use efficiency. Base population BP (07) was the most suitable for the extraction of partially inbred lines aiming at N use efficiency. Partially inbred lines BP (07) 13, BP (07) 14, and BP (07) 17 are the most suitable for the extraction of top-cross hybrids with high grain yield, efficiency, and responsiveness to N.

La extracción de líneas endogámicas es un paso muy importante para el mejoramiento del maíz, ya que estas líneas se utilizan para obtener híbridos destinados al mercado. Sin embargo, este es un proceso costoso que dificulta la evaluación de genotipos en ambientes contrastantes, especialmente respecto del contenido de Nitrógeno edáfico. El objetivo de este estudio fue evaluar el potencial de las poblaciones de maíz para la extracción de líneas y seleccionar líneas parcialmente endogámicas con diferente respuesta a la disponibilidad de nitrógeno (N). Se evaluaron cinco poblaciones en cuanto a su potencial de extracción de líneas. A partir de estas poblaciones, se extrajeron cincuenta y cinco líneas S1 (parcialmente endogámicas). El método de top-cross se usó para evaluar líneas cruzándolas con dos probadores. La evaluación de los híbridos utilizó 110 híbridos superiores, cinco poblaciones base y seis controles. Se realizaron dos ensayos en Dourados and Caarapó, uno con una fertilización adecuada (alto N) y otro en condiciones de estrés (bajo N). El híbrido DKB 789 mostró potencial para extraer líneas parcialmente endogámicas con el objetivo de mejorar la eficiencia de uso de N. La población base BP (07) fue la más adecuada para la extracción de líneas parcialmente endogámicas destinadas a eficiencia de uso de N. Las líneas BP (07) 13, BP (07) 14 y BP (07) 17 son las más adecuadas para la extracción de híbridos top-cross con alto rendimiento de grano, eficiencia y capacidad de respuesta a N.

Resumo Este artigo tem por tema a questão da terra e os índios na Amazônia, de meados do século XVII a meados do século XVIII. O objetivo é discutir os processos de expropriação ensejados pela conquista europeia, pensados no tempo e no espaço, e refletir como, para além desta perspectiva, é preciso entender de que maneira os índios coloniais buscaram construir espaços de autonomia por meio da agricultura. Trata-se de mostrar que, se a colonização implicou um processo de apagamento dos espaços e das práticas agrícolas indígenas, os índios conseguiram construir novas práticas ou legitimar novos espaços de produção agrícola, no interior do próprio mundo colonial.

Abstract This article addresses the question of land and the Indians in the Amazon region, during the colonial period spanning the mid-seventeenth century to the mid-eighteenth century. The objective is to discuss the processes of expropriation derived from the European conquest, considered in terms of time and space, and also to reflect on how, beyond the perspective of expropriation, one must understand how the colonial Indians sought to carve out spaces of autonomy through agriculture. Here we show that while colonization eliminated indigenous agricultural spaces and practices, the Indians developed new practices and legitimized new spaces of agricultural production within the colonial world.

ABSTRACT An alternative to increase yield without raising the production costs and minimizing the dependence of agricultural inputs is the development of maize genotypes presenting high nitrogen (N) use efficiency under low N level conditions. Thus, the objective of this study was to estimate the specific combining ability of maize top-crosses under high and low nitrogen (N) conditions and to select high-yielding hybrids for both conditions. The grain yield of 110 top-cross hybrids was evaluated in 2012 in two locations in the Brazilian Midwest. Partial diallel analysis was performed with the adjusted means of each of the individual top-cross analyses. Specific combining ability (SCA) of the hybrids and their interaction with N levels was estimated for each location. The mean grain yield of the 11 hybrids selected by the highest SCA estimates for high and low N was higher than the controls mean in approximately 330 and 241 kg∙ha-1. These results demonstrate that the selection for each environment was efficient and reveals the possibility of developing new hybrids for the Brazilian Cerrado region.

ABSTRACT. The objective of this work was to estimate the general combining ability of partially inbred lines under high and low nitrogen (N) conditions and to select promising lines to obtain high yields for both conditions. Fifty-five partially inbred S1 progenies were evaluated using the top-cross method, where the lines were crossed with two testers. The 110 top-cross hybrids were evaluated for grain yield during the off-season of 2012 at two sites in the Brazilian Midwest. Partial diallel analysis was performed with the adjusted means of each of the individual analyses of the top crosses. The combining ability of partially inbred lines and testers as well as their interaction with N levels, was estimated for each site. The coefficient of concordance among 15 partially inbred lines selected by the highest general combining ability estimates for each N level was 0.60. The S1 lines 39, 11, 41, 55, 38, 37, 6, 8, and 14 were selected at both N levels. This indicates that these lines can be used to identify ideal hybrids for growing in the off-season in the Brazilian Midwest.

Objetivo: desarrollar una guía de práctica clínica con la evidencia más reciente para la tamización de cáncer de colon y recto en población asintomática de riesgo promedio, dirigida a pacientes, personal asistencial, administrativo y entes gubernamentales de cualquier servicio de atención en Colombia. Materiales y métodos: esta guía fue desarrollada por un equipo multidisciplinario con apoyo de la Asociación Colombiana de Gastroenterología, el Grupo Cochrane ITS y el Instituto de Investigaciones Clínicas de la Universidad Nacional de Colombia. Se desarrollaron preguntas clínicas relevantes y se realizó la búsqueda de guías nacionales e internacionales en bases de datos especializadas. Las guías existentes fueron evaluadas en términos de calidad y aplicabilidad; ninguna de ellas cumplió el criterio de adaptación, por lo que se decidió construir una guía de novo. El Grupo Cochrane realizó la búsqueda sistemática de la literatura. Las tablas de evidencia y recomendaciones fueron realizadas con base en la metodología GRADE. Las recomendaciones de la guía fueron socializadas en una reunión de expertos con entes gubernamentales y pacientes. Resultados: se desarrolló una guía de práctica clínica basada en la evidencia para la tamización del cáncer de colon y recto en Colombia. Conclusiones: la tamización de pacientes asintomáticos de riesgo promedio en Colombia en forma adecuada con estándares de calidad tiene el potencial de impactar la carga de cáncer de colon en el país.

Objective: To provide an evidence-based clinical practice guideline for the screening of colon and rectal cancer for patients, caregivers, administrative and government bodies at all levels of care in Colombia. Materials and Methods: This guide was developed by a multidisciplinary team with the support of the Colombian Association of Gastroenterology, Cochrane STI Group and Clinical Research Institute of the Universidad Nacional de Colombia. Relevant clinical questions were developed and the search for national and international guidelines in databases was performed. Existing guidelines were evaluated for quality and applicability. None of the guidelines met the criteria for adaptation, so the group decided to develop a de novo guideline. Systematic literature searches were conducted by the Cochrane Group. The tables of evidence and recommendations were made based on the GRADE methodology. The recommendations of the guide were socialized in a meeting of experts with government agencies and patients. Results: An evidence-based Clinical Practice Guidelines for the screening of colorectal cancer was developed for the Colombian context. Conclusions: The opportune detection of colon cancer would have an impact of the disease in Colombia

O trabalho teve por objetivo estimar os parâmetros e os ganhos genéticos na seleção de progênies de meio-irmãos para eficiência no uso de nitrogênio, por meio de seleção simultânea de caracteres. Foram instalados dois experimentos, diferenciados pela adubação nitrogenada, sendo um com adubação adequada (alto N) e outro em condição de estresse (baixo N). O delineamento experimental utilizado foi em látice 10x10, com duas repetições. Nos ensaios foram utilizadas 84 progênies de meio-irmãos e 16 testemunhas. A partir dos quadrados médios das análises de variâncias de cada ambiente foram realizadas as estimativas dos parâmetros genéticos. Após as análises, foram selecionadas em cada ambiente 17 progênies de meio-irmãos, por meio do índice clássico de seleção, e verificou-se a repetibilidade das progênies entre os ambientes. Observou-se variabilidade entre as progênies, determinando o potencial da população para a seleção considerando-se a eficiência no uso de nitrogênio. As estimativas de parâmetros e ganhos genéticos foram maiores em alto N. O uso do índice de seleção promoveu estimativas de ganho por seleção de 24,43 e 21,05% para alto e baixo N, respectivamente, para a produtividade de grãos. As progênies selecionadas apresentaram médias de produtividade de grãos de 13,45 e 19,47% maiores que as testemunhas, em alto e baixo N, respectivamente.

The study aimed to estimate the parameters and the genetic gain in selection of half-sib for nitrogen use efficiency, through simultaneous selection of characters. Two experiments were established, differentiated by nitrogen fertilization, one with proper fertilization (high N) and another in stress conditions (low N). The experiment was using a 10x10 lattice with two replications. In the tests we used 84 different half-sib and 16 witnesses. From the mean squares of analysis of variance in each environment were the estimates of genetic parameters. After the analysis were selected in each environment 17 different half-brothers, through the classical index selection, and verified the repeatability of the progeny in both environments. Observed variability among progenies, determining the potential for population screening for nitrogen use efficiency. The parameter estimates and genetic gains were higher in high N The use of selection index promoted estimates of selection gain of 24.43 and 21.05% for high and low N, respectively, for grain yield. The progenies showed average yield of 13.45 and 19.47% higher than control in high and low N, respectively.

RESUMO Esse trabalho foi desenvolvido com o objetivo de avaliar o potencial de emergência das plântulas e o crescimento das mudas do baru (Dipteryx alata Vog.) em diferentes níveis de sombreamento. Para avaliar a emergência, a semeadura foi realizada em bandejas de células contendo substrato Plantmax(r) + terra + areia + cama de frango na proporção de 1:1:1:0,5 e mantidas a pleno sol, 50 % e 70 % de sombreamento. O experimento foi realizado em delineamento inteiramente casualizado com três níveis de sombreamento em quatro repetições de 25 sementes. Foram avaliados a porcentagem e o índice de velocidade de emergência. Para avaliar o crescimento inicial, as plântulas foram transplantadas e três repetições de 15 mudas, totalizando 45 mudas, foram mantidas em seus respectivos sombreamentos. O experimento foi realizado em delineamento inteiramente casualizado em esquema fatorial 3 (níveis de sombreamento) x 5 (épocas de avaliação para a altura, diâmetro do coleto, clorofila total, transpiração, condutância estomática e taxa fotossintética) e 2 (épocas de avaliação para área foliar, comprimento de raiz, massas fresca e seca). Os níveis de sombreamento não influenciaram na porcentagem nem no índice de velocidade de emergência das plântulas (71,3 % e 1,08, respectivamente). Os maiores valores de altura (16 cm), área foliar (220,2 cm2), comprimento de raiz (14,9 cm), massa fresca e seca (9,71 g e 3,21 g) das mudas foram observados sob sombreamento, não variando entre eles. As mudas apresentaram a menor taxa fotossintética a 70 % de sombreamento (6,8 µmol m-2 s-1). Os níveis de sombreamento avaliados não influenciaram na emergência das plântulas, entretanto, as mudas apresentaram melhor crescimento quando mantidas até os 125 dias de idade sob 50 % de sombreamento.

ABSTRACT This work was carried out in order to evaluate the potential of germination of the seeds and the seedlings growth of baru (Dipteryx alata) in different levels of shading. To evaluate the emergency, the sowing was realized in trays of cells filled with Plantmax(r) substratum + land + sand + chicken manure in proportion of (1: 1: 1: 0.5) and kept in the full sun, 50 % and 70 % of shading. The experiment was carried out in design entirely randomized with three levels of shading in four repetitions of 25 seeds. It was evaluated the percentage and the velocity of the emergency index. To evaluate the initial growth, the seedlings were transplanted and, three repetitions of 15 changes totalizing 45 seedlings were kept in its respective shading. The experiment was realized in a complete randomized design in factorial 3 (shading levels) x 5 (times of evaluation for height, diameter of collect, total chlorophyll, transpiration, stomatal conductance and photosynthetic rate) and 2 (times of evaluation for leaf area, length of root, fresh and dry mass). The shading levels did not influence the percentage and the velocity index of seedling emergency (71.3 % and 1.08 respectively). High value of height (16 cm), leaf area (220.2 cm²), length of root (14.9 cm), fresh and dry mass (9.71 g and 3.21 g) of seedlings were observed under shading not varying between them. The seedlings presented lower photosynthetic rate in the 70 % of shading (6.8 µmol m-2 s-1). The levels of shadings did not influence in seedling emergency.

O cultivo de milho pipoca em consórcio com feijão é uma alternativa para o pequeno produtor, por proporcionar maior retorno econômico e aproveitamento da área de cultivo, além de diminuir os riscos de perda. Neste trabalho, avaliaram-se diferentes sistemas de consórcio de milho pipoca com feijão. O experimento foi realizado em campo experimental da Universidade Federal da Grande Dourados, em Dourados (MS). Utilizou-se delineamento experimental de blocos ao acaso, com quatro repetições, e tratamentos em esquema de parcelas subdivididas, no qual as parcelas constituíram-se de duas cultivares de milho pipoca (Zélia e BRS Ângela) e as subparcelas de três sistemas de consórcio de milho pipoca com feijão BRS MG Pioneiro (milho + feijão na linha do milho, milho + feijão na entrelinha do milho e milho + feijão na linha do milho + feijão na entrelinha do milho) e milho pipoca em monocultivo. Os sistemas de consórcio avaliados não afetaram a produtividade do milho pipoca e a semeadura do feijão na linha + entrelinha do milho resultou em maior produtividade da leguminosa. De maneira geral, o consórcio das duas espécies reduziu os rendimentos do feijoeiro, entretanto, devido aos valores do Índice de Equivalência de Área, foi 50% a 91% mais eficiente que os monocultivos.

The intercropping of popcorn and bean is an alternative for small farmers, by providing higher profits and a better use of the crop area, besides reducing loss risks. This study aimed to evaluate different popcorn and bean intercropping systems. The experiment was carried out in an experimental field owned by the Universidade Federal da Grande Dourados, in Dourados, Mato Grosso do Sul State, Brazil. The experimental design was randomized blocks, with four replications, with treatments arranged in a split-plot scheme, with plots consisting of two popcorn cultivars (Zélia and BRS Ângela) and subplots consisting of three intercropping systems with popcorn and the BRS MG Pioneiro bean (popcorn + bean in the popcorn row, popcorn + bean between the popcorn rows, and corn + bean in the popcorn row + bean between the popcorn rows), and popcorn under monocropping system. The intercropping systems evaluated did not affect the popcorn yield, and bean sown in the popcorn row + between the popcorn rows resulted in a higher yield. In general, the intercropping between the two species decreased bean yield, however, due to the equivalent area index values, it was 50% to 91% more efficient than the monocropping systems.

Este estudo teve como objetivo avaliar a decomposição e liberação de nutrientes dos resíduos culturais do nabo forrageiro e do crambe na implantação do sistema de plantio direto. O experimento foi realizado em um Latossolo Vermelho Distroférrico, com 762g kg-1 de argila. O delineamento experimental foi em blocos casualizados, com quatro repetições. Os tratamentos foram aplicados no esquema de parcelas subdivididas, sendo as espécies de cobertura do solo (nabo forrageiro e crambe) alocadas nas parcelas e as épocas de coleta das bolsas de decomposição (0, 15, 30, 45, 60, 75 dias após o manejo) nas subparcelas. As culturas foram manejadas 60 dias após a emergência, em florescimento pleno. O nabo forrageiro produziu 5.586kg ha-1 de massa seca (MS) e o crambe atingiu 2.688kg ha-1 de MS. A liberação de nutrientes acompanhou a cinética de decomposição da palhada, apresentando uma fase inicial rápida seguida de outra mais lenta. O K, o P e o Mg são os nutrientes liberados mais rapidamente para a cultura subsequente. A maior taxa de liberação de macronutrientes pelas culturas ocorreu ao redor de 15 dias após o manejo da fitomassa.

This study aimed to evaluate the decomposition and nutrient release from crop residues of fodder radish and crambe in the implementation of no-tillage system. The experiment was conducted in a Distroferric Red Latossol with 762g kg-1 of clay. The experimental design was randomized blocks with four replications. The treatments were applied in split plots, considering the species of cover crops (radish and crambe) as the main plots and harvest dates of decomposition bags (0, 15, 30, 45, 60, 75 days after management) as subplots. The cover crops were treated 60 days after management, in full bloom. Radish presented a dry mass production of 5586kg ha-1 and crambe of 2688kg ha-1. The kinetics of residue decomposition had a behavior similar to the dynamics of nutrient release, with an initial rapid phase followed by a slower one. The K, P and Mg are released more quickly for subsequent crops. The increased speed of nutrients release by crops occurred around 15 days after the biomass management.