Background The root system plays a major role in plant growth and development and root system architecture is reported to be the main trait related to plant adaptation to drought. However, phenotyping root systems in situ is not suited to high-throughput methods, leading to the development of non-destructive methods for evaluations in more or less controlled root environments. This study used a root phenotyping platform with a panel of 20 japonica rice accessions in order to: (i) assess their genetic diversity for a set of structural and morphological root traits and classify the different types; (ii) analyze the plastic response of their root system to a water deficit at reproductive phase and (iii) explore the ability of the platform for high-throughput phenotyping of root structure and morphology. Results High variability for the studied root traits was found in the reduced set of accessions. Using eight selected traits under irrigated conditions, five root clusters were found that differed in root thickness, branching index and the pattern of fine and thick root distribution along the profile. When water deficit occurred at reproductive phase, some accessions significantly reduced root growth compared to the irrigated treatment, while others stimulated it. It was found that root cluster, as defined under irrigated conditions, could not predict the plastic response of roots under drought. Conclusions This study revealed the possibility of reconstructing the structure of root systems from scanned images. It was thus possible to significantly class root systems according to simple structural traits, opening up the way for using such a platform for medium to high-throughput phenotyping. The study also highlighted the uncoupling between root structures under non-limiting water conditions and their response to drought.

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Upland rice is cultivated mostly in Latin America and Africa by small farmers and in areas with risk of dry spells. This study evaluated morphophysiological mechanisms of upland rice associated to drought adaptation. A set of 25 upland rice genotypes were grown in a plant phenotyping platform during 2015 and 2017 under regular irrigation and water restriction. We evaluated morphophysiological traits in shoots (vegetative structures growth, gas exchange, water use efficiency, carboxylation efficiency, water status) and roots (length, surface area, volume and diameter), as well as agronomic traits (grain yield and its components). There was a reduction in grain yield by up to 54 % and 58 % in 2015 and 2017, respectively, under water deficit. Five upland rice genotypes with the best yield performances in both water treatments applied were recommended to the upland rice-breeding program: Bico Ganga, BRS Esmeralda, BRSMG Curinga, Guarani, and Rabo de Burro. In this study, morphophysiological traits associated to drought tolerance concerned the plant high capacity to save water in the leaves, low leaf water potential, high ability to reduce vegetative structures, high water use efficiency, high photosynthetic capacity, and improved capacity to absorb water from drying soil, either by osmotic adjustment or additional investment into the root system. Therefore, we concluded that different secondary traits contributed to drought tolerance and should be evaluated along with grain yield to improve efficiency of breeding selection.

1295RESEARCH P roduction and consumption of white rice (Oryza sativa L.) are prevalent in the world, although the original pigmentation of the pericarp of all rice species is red. The white pericarp, a colorless phenotype, is determined by the rc allele that originated from a loss-of-function mutation at the Rc locus on chromosome 7 in Oryza rufipogon Griffiths-a wild relative of cultivated rice. The red coloration, in turn, is determined by the complementary effect of two genes, Rc and Rd, each one inherited monogenically. The original dominant allele (Rc) interacts with the Rd allele on chromosome 1 to synthesize the proanthocyanidin compound that determines red pericarp pigmentation in rice grains. Specifically, the Rc allele that encodes the basic helix-loop-helix (bHLH) protein is responsible for the accumulation of pigments in the pericarp of brown-colored grains, whereas the Rd allele that encodes the dihydroflavonol-4-reductase (DFR) enzyme is required to increase the content of the pigment, resulting in redcolored grains (Nagao et al., 1957;Furukawa et al., 2007).ABSTRACT Cultivated red rice (Oryza sativa L.) is the most important special type of rice in Brazil and makes an excellent food, mainly because of its nutritional value. Genetic variability, useful for rice breeding programs, exists among red rice accessions. The objectives of the present study were: (i) to determine the nature of gene action and magnitude of genetic components conditioning grain yield (GY), plant height (PH), and days to flowering (DTF); and (ii) to determine the combining ability for these traits in nine red rice lines (female parents) and four commercial cultivars (male parents). Thirteen parents, an F 2 generation of 18 crosses, and a check cultivar were evaluated at two locations (Goianira and Teresina, Brazil) using a randomized complete block design with four replications. Data (unbalanced because of lost plots) from this incomplete set of crosses in a factorial mating design were subjected to variance analyses using a general linear model. According to Baker's ratio, nonadditive genetic effects were more important than additive effects for the expression of the three traits. The dominance deviations were predominantly negative for GY and DTF and were positive for PH.

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Selecting appropriate donors and acquiring information about the genetic basis of inheritance is essential for breeding programs. In this study, a diallel cross was produced by crossing 15 progenies with five commercial lines of wide diversity for different rice traits (grain yield, plant height, days to flowering, panicle blast, brown spots, leaf scald, and grain discoloration) in an incomplete crossing design. The 20 parents and the 25 F2 crosses constituting the diallel cross were evaluated in a triple lattice design for different traits in a field test. The analysis of variance revealed significant differences between parents and their crosses for all traits, showing high variability. The general combining ability (GCA) and the specific combining ability (SCA) were significant, with a greater contribution of the SCA compared to GCA for the variation among crosses, indicating that non-additive effects were more prevalent for the traits evaluated. The results suggested that commercial lines such as IRGA 424 and BRS Catiana can be used to improve CNA 12T population.

O DERGeo é um ambiente virtual de engajamento baseado em nuvem que permite acesso e interação às informações referentes aos mapas rodoviários produzidos, bem como aos dados vetoriais, às aplicações desenvolvidas na autarquia e outras informações pertinentes ao Sistema Rodoviário do Distrito Federal (SRDF), como o histórico de publicações dos mapas rodoviários, às legislações do SRDF, aos downloads de dados públicos e abertos tanto os produzidos pelo Departamento de Estradas de Rodagem do Distrito Federal (DER/DF) quanto por outros entes da Administração Distrital. Também é possível acessar outras funcionalidades às aplicações desenvolvidas para temas específicos como o Painel Analítico de Acidentes Rodoviários do Distrito Federal (PARE/DF) e a confecção e impressão de mapas personalizados, além da consulta a uma gama de assuntos de natureza espacial pertinentes ao SRDF. O artigo descreve o desenvolvimento de um SIG baseado na web com o intuito de permitir o acesso e a interação de informações referentes aos mapas temáticos produzidos, bem como a dados livres e outras informações pertinentes ao Sistema Rodoviário do Distrito Federal.