5 research outputs found

    Phenotyping root systems in a set of japonica rice accessions: can structural traits predict the response to drought?

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    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

    Novel insights into the genomics of rice root adaptive development

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    Deciphering the genetic and molecular mechanisms controlling the development of the root system and its adaptive plasticity under adverse environments is of primary importance for the sustainable establishment of the rice crop. Rice displays a complex root structure comprising several root types mostly of postembryonic origin. The large natural variation in root architecture among cultivars reflects their adaptation to contrasting agro-environmental conditions. This article reviews the current knowledge on the organization and anatomy of the various types of roots of the fibrous root system of rice, the diversity and genetic basis of natural variation of root system architecture and performance, and the molecular mechanisms underlying constitutive and adaptive root development. This paper also throws light on how the integrated approach of new tools in high-resolution microscopy imaging, expression profiling, mutant screening, and reverse genetics could facilitate the rapid discovery and analysis of the key genes and regulatory networks involved in root architectural traits affecting plant performance under field conditions

    Rainfed Food Crops in West and Central Africa: Points for Analysis and Proposals for Action

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    Ouvrage en libre accĂšs, document disponible en ligne : http://www.afd.fr/webdav/site/afd/shared/PUBLICATIONS/RECHERCHE/Scientifiques/A-savoir/06-VA-A-Savoir.pdfInternational audienceThe rise in world agricultural prices in 2008 revealed the fragility of food security in many developing countries. Poor populations in sub-Saharan Africa are the biggest victims of this fragility. Rainfed food crops can play a unique role on the continent by supplying regional markets, increasing farmers' incomes, and creating jobs in rural areas. Working within the framework of the regional dynamics launched in West and Central Africa, AFD, CIRAD and IFAD initiated three studies to (i) map the food crop production and consumption areas in the zone, (ii) identify the contributions of research on these supply chains, and (iii) analyze food crop project practices. This book summarizes this research, accomplished with African research and regional expertise centers (AGRHYMET, WECARD). It reports on current knowledge of the main food crop supply chains in the region: rice, corn, cassava, millet-sorghum, yam, groundnut and cowpea. Other areas remain to be explored to strengthen existing dynamics: how can intermediation professions be supported? How can a regional approach to these supply chains be developed so as to disseminate best practices, expand markets and foster synergy? What role in supporting these supply chains could be (re)assigned to research? How can the financing constraint, which is present throughout the supply chain, be overcome? This book aims to provide keys to decipher supply chain operations and the challenges facing food crop supply chains in this region