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Vincent Lebot - One of the best experts on this subject based on the ideXlab platform.
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Screening for Drought Tolerance in Thirty Three Taro Cultivars
Notulae Botanicae Horti Agrobotanica Cluj-Napoca, 2018Co-Authors: Jose F. T. Gananca, Jose G. R. Freitas, Humberto G. M. Nobrega, Vanessa Rodrigues, Goncalo Antunes, Carla S. S. Gouveia, Miguel Rodrigues, Hana Chaïr, Miguel A. A. Pinheiro De Carvalho, Vincent LebotAbstract:Taro [Colocasia esculenta (L.) Schott] is a Root Crop which is an important staple food in many regions of the world, producing 10.5 million tonnes on 1.4 million hectares a year. The Crop is cultivated in wet (rain fed) or irrigated conditions, requiring on average 2,500 mm water per year, and in many countries it is cultivated in flooded plots. It is estimated that taro production could decrease by 40% as a result of the increase in drought and other severe events. In this work, thirty three accessions, including local cultivars, selected and hybrid lines were submitted to long duration drought stress and screened for tolerance. Twelve physiological, morphological and agronomic traits were measured at harvest, and subject to multivariate analysis. Stress indices, Water Use Efficiency and Factorial Analysis were useful for discriminating accessions regarding drought tolerance and yield stability, and drought tolerant and susceptible cultivars were identified. Our results confirm that different taro cultivars have different drought avoidance and tolerance strategies to cope with water scarcity. Better yield performers minimised biomass and canopy loss, while tolerance was observed in cultivars that presented low potential yield, but efficiently transferred resources to enhance corm formation. Among the 33 accessions, two local cultivars showed high yield stability and could be considered as suitable parents for breeding programs, while two others are well adapted to drought, but with overall low yield potential.
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variation of mineral composition in different parts of taro colocasia esculenta corms
Food Chemistry, 2015Co-Authors: Andrej Mergedus, Janja Kristl, Anton Ivancic, Andreja Sober, Vilma Sustar, Tomaz Krizan, Vincent LebotAbstract:Taro (Colocasia esculenta) is an important Root Crop in the humid tropics and a valuable source of essential mineral nutrients. In the presented study, we compared the mineral compositions of four main parts of taro corm: the upper, marginal, central and lower (basal) parts. The freeze-dried taro samples were analysed for eleven minerals (K, P, Mg, Ca, Zn, Fe, Mn, Cu, Cd, Pb and Cr). The upper part, which plays a critical role in vegetative propagation based on headsets, contained high levels of P, Mg, Zn, Fe, Mn, Cu and Cd. The central part, which is essential for human nutrition, was characterised by higher concentrations of K, P, Mg, Zn, Fe, Cu and Cd. Ca was concentrated in the lower and marginal parts. The effect of the genotype was significant for more than half of the analysed minerals (i.e., Mg, Ca, Zn, Fe, Mn).
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Strengthening smallholders' capacity to adapt to agro-climatic changes: Optimization of Root Crops germplasm management and use
Journal of Root Crops, 2014Co-Authors: Vincent LebotAbstract:Since their domestication, Root Crops have been clonally distributed over wide geographical distances. The bottle necks induced by the introduction process often resulted in varieties with narrow genetic bases, now increasing smallholders’ vulnerability to forthcoming agro-climatic changes. The question is: how can we develop adapted varieties, considering climatic uncertainties, the constraints in developing countries and the characteristics of the Root Crop species involved? These species share common biological traits: they are asexually propagated in farmers’ fields, flowering ability of varieties is erratic, they have variable ploidy levels but are predominantly allogamous and highly heterozygous. Breeding is a slow process conducted on research stations even though it is widely accepted that G x E interactions are highly significant. The distribution of selected clones is then constrained by their low multiplication rate, the large number of smallholders, their geographical isolation, the absence of a ‘seed’ industry and strict international regulations. This paper presents a review of studies on Root Crops genetic diversity, their germplasm management systems and breeding constraints. It attempts to propose a new approach to strengthen smallholders’ capacity to adapt to forthcoming changes. Suggestions are made for future research to address adaptation, taking into consideration improvement programs needs at the national level. The geographical distribution of allelic diversity appears as a practical and cost-efficient approach.
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Diversity of anthocyanins and other phenolic compounds among tropical Root Crops from Vanuatu, South Pacific
Journal of Food Composition and Analysis, 2011Co-Authors: Antoine Champagne, Laurent Legendre, Ghislaine Hilbert, Vincent LebotAbstract:To study the composition and amounts of phenolic compounds in ten tropical Root Crop species consumed daily worldwide and particularly in South Pacific, acidified aqueous extracts were analyzed. Among 134 samples, 78 components were found. Among total peaks detected from these fractions, 3 anthocyanins (peonidin-caffeoyl-feruloylsophoroside-5-glucoside, petunidin-3-glucoside and pelargonidin-3-glucoside), 5 flavonols (hyperoside, isorhamnetin-3-glucoside, kaempferol-3-glucoside, quercetin-3-glucopyranoside and quercetin-3′-glucoside,6′-acetate), 3 flavanols (catechin, epicatechin and epicatechin-3-gallate), and 3 phenolic acids (caffeic acid, chlorogenic acid and 3,5-dicaffeoylquinic acid) were tentatively identified by HPLC-DAD. Although many compounds remain to be identified, results suggest that these tropical Root Crops are good sources of anthocyanins and phenolic compounds. The greater yam (Dioscorea alata) had the highest anthocyanin content (up to 93.3 mg CGE/100 g DW), while taro (Colocasia esculenta) had the widest range of flavonols (up to 326.7 mg QGE/100 g DW). Cultivars of these staples should be exploited in breeding programs for the development of varieties with enhanced health and nutritional benefits.
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ON-FARM ASSESSMENT OF CLONAL INTRODUCTION OF Root CropS DIVERSITY IN VANUATU, MELANESIA
Experimental Agriculture, 2010Co-Authors: P. Camus, Vincent LebotAbstract:Ex-situ collections of vegetatively propagated Root Crops are difficult to maintain in developing countries. On-farmconservation could be a solution but is more complex for vegetatively propagated than for sexually propagated species. In Vanuatu, a Melanesian archipelago where yam, taro, sweet potato and cassava are staples, a study was undertaken to develop an on-farm conservation system based on the geographic distribution of allelic diversity. Two years after the introduction of new varieties, a survey was conducted with 449 farmers located on 10 different islands. In order to evaluate on-farm conservation efficiency, qualitative and quantitative investigations were conducted and data were analysed. The conclusion was that farmers do enrich their varietal portfolioswith introduced exotic genotypes thus broadening the narrow genetic bases of some species. Nevertheless, no local varieties were lost. Significant geographic distribution of clones of new varieties throughout the archipelago also took place via spontaneous, informal distribution to farmers' relatives. These encouraging results point to the potential impact of the geographic distribution of allelic diversity on smallholders' varietal portfolios. On-farm conservation appears to be an appropriate strategy for the conservation of Root Crop germplasm diversity inVanuatu. Potential applications for transfer of the methodology to other locations are discussed. (Resume d'auteur)
Antoine Champagne - One of the best experts on this subject based on the ideXlab platform.
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Diversity of anthocyanins and other phenolic compounds among tropical Root Crops from Vanuatu, South Pacific
Journal of Food Composition and Analysis, 2011Co-Authors: Antoine Champagne, Laurent Legendre, Ghislaine Hilbert, Vincent LebotAbstract:To study the composition and amounts of phenolic compounds in ten tropical Root Crop species consumed daily worldwide and particularly in South Pacific, acidified aqueous extracts were analyzed. Among 134 samples, 78 components were found. Among total peaks detected from these fractions, 3 anthocyanins (peonidin-caffeoyl-feruloylsophoroside-5-glucoside, petunidin-3-glucoside and pelargonidin-3-glucoside), 5 flavonols (hyperoside, isorhamnetin-3-glucoside, kaempferol-3-glucoside, quercetin-3-glucopyranoside and quercetin-3′-glucoside,6′-acetate), 3 flavanols (catechin, epicatechin and epicatechin-3-gallate), and 3 phenolic acids (caffeic acid, chlorogenic acid and 3,5-dicaffeoylquinic acid) were tentatively identified by HPLC-DAD. Although many compounds remain to be identified, results suggest that these tropical Root Crops are good sources of anthocyanins and phenolic compounds. The greater yam (Dioscorea alata) had the highest anthocyanin content (up to 93.3 mg CGE/100 g DW), while taro (Colocasia esculenta) had the widest range of flavonols (up to 326.7 mg QGE/100 g DW). Cultivars of these staples should be exploited in breeding programs for the development of varieties with enhanced health and nutritional benefits.
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Carotenoid profiling of tropical Root Crop chemotypes from Vanuatu, South Pacific
Journal of Food Composition and Analysis, 2010Co-Authors: Antoine Champagne, Stéphane Bernillon, Annick Moing, Dominique Rolin, Laurent Legendre, Vincent LebotAbstract:Tropical Root and tuber Crops are staple foods in developing countries where they are the main source of carbohydrates and a potential source of secondary metabolites such as carotenoids. Enhancing carotenoid content has considerable potential for improving human nutrition in these areas. Except for cassava and sweet potato, carotenoid content has not been evaluated in large germplasm collections. We describe a simple HPLC-DAD-based protocol for the reliable characterization of carotenoids in Root Crops. Less than 5% variation in carotenoid content was found among samples collected from tubers of the same plant or from clones of the same genotype. Carotenoids were evaluated in 153 accessions representing 10 different species. Each species had a specific profile of carotenoids, and accessions of the same species differed greatly in their individual content. The database assembled during this study represents a useful tool for nutritionists and breeders working on biofortification of Root Crops with carotenoids.
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Chemotype Profiling To Guide Breeders and Explore Traditional Selection of Tropical Root Crops in Vanuatu, South Pacific
Journal of Agricultural and Food Chemistry, 2009Co-Authors: Antoine Champagne, Laurent Legendre, Vincent LebotAbstract:The objectives of the present study were to characterize good-quality cultivars, identify relationships between local eating preferences and primary compound content, and reveal biofortification potential in tropical Root Crop species aroids, yams, cassava, and sweet potato. A core sample of about 500 cultivars was assembled to represent the widest agro-morphological diversity. Very high coefficients of variation were found within species for proteins, sugars, cellulose, and mineral contents, whereas starch exhibited the lowest variation. Starch content was negatively correlated with other primary compound contents. For the national dish in Vanuatu, consumers prefer cultivars with high starch content. In contrast, preferences for daily consumption of boiled or roasted tubers are linked to average starch content, indicating great potential for improving primary compounds. Interestingly, relationships between flesh color and requirements for the traditional dish were revealed, suggesting opportunities for biofortification. The data produced will assist breeders in adopting appropriate biofortification strategies. The objectives of the present study were to characterize good-quality cultivars, identify relationships between local eating preferences and primary compound content, and reveal biofortification potential in tropical Root Crop species aroids, yams, cassava, and sweet potato. A core sample of about 500 cultivars was assembled to represent the widest agro-morphological diversity. Very high coefficients of variation were found within species for proteins, sugars, cellulose, and mineral contents, whereas starch exhibited the lowest variation. Starch content was negatively correlated with other primary compound contents. For the national dish in Vanuatu, consumers prefer cultivars with high starch content. In contrast, preferences for daily consumption of boiled or roasted tubers are linked to average starch content, indicating great potential for improving primary compounds. Interestingly, relationships between flesh color and requirements for the traditional dish were revealed, suggesting opportunities for biofortification. The data produced will assist breeders in adopting appropriate biofortification strategies.
Peng Zhang - One of the best experts on this subject based on the ideXlab platform.
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improved tolerance to various abiotic stresses in transgenic sweet potato ipomoea batatas expressing spinach betaine aldehyde dehydrogenase
PLOS ONE, 2012Co-Authors: Min Zhang, Hongxia Zhang, Peng ZhangAbstract:Abiotic stresses are critical delimiters for the increased productivity and cultivation expansion of sweet potato (Ipomoea batatas), a Root Crop with worldwide importance. The increased production of glycine betaine (GB) improves plant tolerance to various abiotic stresses without strong phenotypic changes, providing a feasible approach to improve stable yield production under unfavorable conditions. The gene encoding betaine aldehyde dehydrogenase (BADH) is involved in the biosynthesis of GB in plants, and the accumulation of GB by the heterologous overexpression of BADH improves abiotic stress tolerance in plants. This study is to improve sweet potato, a GB accumulator, resistant to multiple abiotic stresses by promoted GB biosynthesis. A chloroplastic BADH gene from Spinacia oleracea (SoBADH) was introduced into the sweet potato cultivar Sushu-2 via Agrobacterium-mediated transformation. The overexpression of SoBADH in the transgenic sweet potato improved tolerance to various abiotic stresses, including salt, oxidative stress, and low temperature. The increased BADH activity and GB accumulation in the transgenic plant lines under normal and multiple environmental stresses resulted in increased protection against cell damage through the maintenance of cell membrane integrity, stronger photosynthetic activity, reduced reactive oxygen species (ROS) production, and induction or activation of ROS scavenging by the increased activity of free radical-scavenging enzymes. The increased proline accumulation and systemic upregulation of many ROS-scavenging genes in stress-treated transgenic plants also indicated that GB accumulation might stimulate the ROS-scavenging system and proline biosynthesis via an integrative mechanism. This study demonstrates that the enhancement of GB biosynthesis in sweet potato is an effective and feasible approach to improve its tolerance to multiple abiotic stresses without causing phenotypic defects. This strategy for trait improvement in sweet potato not only stabilizes yield production in normal soils in unpredictable climates but also provides a novel germplasm for sweet potato production on marginal lands.
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transcriptome profiling of low temperature treated cassava apical shoots showed dynamic responses of tropical plant to cold stress
BMC Genomics, 2012Co-Authors: Jun Yang, Peng ZhangAbstract:Cassava is an important tropical Root Crop adapted to a wide range of environmental stimuli such as drought and acid soils. Nevertheless, it is an extremely cold-sensitive tropical species. Thus far, there is limited information about gene regulation and signalling pathways related to the cold stress response in cassava. The development of microarray technology has accelerated the study of global transcription profiling under certain conditions. A 60-mer oligonucleotide microarray representing 20,840 genes was used to perform transcriptome profiling in apical shoots of cassava subjected to cold at 7°C for 0, 4 and 9 h. A total of 508 transcripts were identified as early cold-responsive genes in which 319 sequences had functional descriptions when aligned with Arabidopsis proteins. Gene ontology annotation analysis identified many cold-relevant categories, including 'Response to abiotic and biotic stimulus', 'Response to stress', 'Transcription factor activity', and 'Chloroplast'. Various stress-associated genes with a wide range of biological functions were found, such as signal transduction components (e.g., MAP kinase 4), transcription factors (TFs, e.g., RAP2.11), and reactive oxygen species (ROS) scavenging enzymes (e.g., catalase 2), as well as photosynthesis-related genes (e.g., PsaL). Seventeen major TF families including many well-studied members (e.g., AP2-EREBP) were also involved in the early response to cold stress. Meanwhile, KEGG pathway analysis uncovered many important pathways, such as 'Plant hormone signal transduction' and 'Starch and sucrose metabolism'. Furthermore, the expression changes of 32 genes under cold and other abiotic stress conditions were validated by real-time RT-PCR. Importantly, most of the tested stress-responsive genes were primarily expressed in mature leaves, stem cambia, and fibrous Roots rather than apical buds and young leaves. As a response to cold stress in cassava, an increase in transcripts and enzyme activities of ROS scavenging genes and the accumulation of total soluble sugars (including sucrose and glucose) were also detected. The dynamic expression changes reflect the integrative controlling and transcriptome regulation of the networks in the cold stress response of cassava. The biological processes involved in the signal perception and physiological response might shed light on the molecular mechanisms related to cold tolerance in tropical plants and provide useful candidate genes for genetic improvement.
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dose dependent rnai mediated geminivirus resistance in the tropical Root Crop cassava
Plant Molecular Biology, 2009Co-Authors: Herve Vanderschuren, Peng Zhang, Adrian Alder, Wilhelm GruissemAbstract:Cassava mosaic disease is a major constraint for cassava production in Africa, resulting in significant economic losses. We have engineered transgenic cassava with resistance to African cassava mosaic virus (ACMV), by expressing ACMV AC1-homologous hairpin double-strand RNAs. Transgenic cassava lines with high levels of AC1-homologous small RNAs have ACMV immunity with increasing viral load and different inoculation methods. We report a correlation between the expression of the AC1-homologous small RNAs and the ACMV resistance of the transgenic cassava lines. Characterization of the small RNAs revealed that only some of the hairpin-derived small RNAs fall into currently known small interfering RNA classes in plants. The method is scalable to stacking by targeting multiple virus isolates with additional hairpins.
Laurent Legendre - One of the best experts on this subject based on the ideXlab platform.
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Diversity of anthocyanins and other phenolic compounds among tropical Root Crops from Vanuatu, South Pacific
Journal of Food Composition and Analysis, 2011Co-Authors: Antoine Champagne, Laurent Legendre, Ghislaine Hilbert, Vincent LebotAbstract:To study the composition and amounts of phenolic compounds in ten tropical Root Crop species consumed daily worldwide and particularly in South Pacific, acidified aqueous extracts were analyzed. Among 134 samples, 78 components were found. Among total peaks detected from these fractions, 3 anthocyanins (peonidin-caffeoyl-feruloylsophoroside-5-glucoside, petunidin-3-glucoside and pelargonidin-3-glucoside), 5 flavonols (hyperoside, isorhamnetin-3-glucoside, kaempferol-3-glucoside, quercetin-3-glucopyranoside and quercetin-3′-glucoside,6′-acetate), 3 flavanols (catechin, epicatechin and epicatechin-3-gallate), and 3 phenolic acids (caffeic acid, chlorogenic acid and 3,5-dicaffeoylquinic acid) were tentatively identified by HPLC-DAD. Although many compounds remain to be identified, results suggest that these tropical Root Crops are good sources of anthocyanins and phenolic compounds. The greater yam (Dioscorea alata) had the highest anthocyanin content (up to 93.3 mg CGE/100 g DW), while taro (Colocasia esculenta) had the widest range of flavonols (up to 326.7 mg QGE/100 g DW). Cultivars of these staples should be exploited in breeding programs for the development of varieties with enhanced health and nutritional benefits.
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Carotenoid profiling of tropical Root Crop chemotypes from Vanuatu, South Pacific
Journal of Food Composition and Analysis, 2010Co-Authors: Antoine Champagne, Stéphane Bernillon, Annick Moing, Dominique Rolin, Laurent Legendre, Vincent LebotAbstract:Tropical Root and tuber Crops are staple foods in developing countries where they are the main source of carbohydrates and a potential source of secondary metabolites such as carotenoids. Enhancing carotenoid content has considerable potential for improving human nutrition in these areas. Except for cassava and sweet potato, carotenoid content has not been evaluated in large germplasm collections. We describe a simple HPLC-DAD-based protocol for the reliable characterization of carotenoids in Root Crops. Less than 5% variation in carotenoid content was found among samples collected from tubers of the same plant or from clones of the same genotype. Carotenoids were evaluated in 153 accessions representing 10 different species. Each species had a specific profile of carotenoids, and accessions of the same species differed greatly in their individual content. The database assembled during this study represents a useful tool for nutritionists and breeders working on biofortification of Root Crops with carotenoids.
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Chemotype Profiling To Guide Breeders and Explore Traditional Selection of Tropical Root Crops in Vanuatu, South Pacific
Journal of Agricultural and Food Chemistry, 2009Co-Authors: Antoine Champagne, Laurent Legendre, Vincent LebotAbstract:The objectives of the present study were to characterize good-quality cultivars, identify relationships between local eating preferences and primary compound content, and reveal biofortification potential in tropical Root Crop species aroids, yams, cassava, and sweet potato. A core sample of about 500 cultivars was assembled to represent the widest agro-morphological diversity. Very high coefficients of variation were found within species for proteins, sugars, cellulose, and mineral contents, whereas starch exhibited the lowest variation. Starch content was negatively correlated with other primary compound contents. For the national dish in Vanuatu, consumers prefer cultivars with high starch content. In contrast, preferences for daily consumption of boiled or roasted tubers are linked to average starch content, indicating great potential for improving primary compounds. Interestingly, relationships between flesh color and requirements for the traditional dish were revealed, suggesting opportunities for biofortification. The data produced will assist breeders in adopting appropriate biofortification strategies. The objectives of the present study were to characterize good-quality cultivars, identify relationships between local eating preferences and primary compound content, and reveal biofortification potential in tropical Root Crop species aroids, yams, cassava, and sweet potato. A core sample of about 500 cultivars was assembled to represent the widest agro-morphological diversity. Very high coefficients of variation were found within species for proteins, sugars, cellulose, and mineral contents, whereas starch exhibited the lowest variation. Starch content was negatively correlated with other primary compound contents. For the national dish in Vanuatu, consumers prefer cultivars with high starch content. In contrast, preferences for daily consumption of boiled or roasted tubers are linked to average starch content, indicating great potential for improving primary compounds. Interestingly, relationships between flesh color and requirements for the traditional dish were revealed, suggesting opportunities for biofortification. The data produced will assist breeders in adopting appropriate biofortification strategies.
Suriyan Cha-um - One of the best experts on this subject based on the ideXlab platform.
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Foliar application of glycinebetaine regulates soluble sugars and modulates physiological adaptations in sweet potato (Ipomoea batatas) under water deficit
Protoplasma, 2019Co-Authors: Rujira Tisarum, Cattarin Theerawitaya, Thapanee Samphumphuang, Harminder Pal Singh, Suriyan Cha-umAbstract:Drought tolerance in higher plants can result in enhanced productivity, especially in case of carbohydrate storage Root Crop. Sweet potato has been reported as a drought-tolerant Crop, while it is very sensitive to water shortage in the Root initiation of cutting propagation and tuber initiation stages. In the present study, we aimed to alleviate the drought-tolerant abilities in sweet potato cv. Tainung 57 (drought-sensitive cultivar) using foliar glycine betaine (GlyBet) application as compared with drought-tolerant cultivar (cv. Japanese Yellow). Leaf osmotic potential in GlyBet applied plants under mild- (25.5% soil water content; SWC) and severe-water deficit (15.5% SWC) stresses was maintained through the accumulation of total soluble sugars as a major osmotic adjustment, thus stabilizing the photosynthetic pigments, chlorophyll fluorescence, net photosynthetic rate, and retaining the overall growth performances, i.e., shoot height, number, and length of leaves. In the harvesting process, storage Root weight in water deficit stressed sweet potato cv. Tainung 57 (11.75 g plant^−1) with 50 mM GlyBet application was retained in a similar pattern to cv. Japanese Yellow (12.25 g plant^−1). In the present investigation, exogenous foliar GlyBet application strongly alleviated water deficit stress via sugar enrichment to control cellular osmotic potential, retain high photosynthetic abilities and maintain the yield of storage Root yield. In summary, the regulation on total soluble sugar enrichment in water deficit–stressed sweet potato using GlyBet foliar application may play an important role in maintaining the controlled osmotic potential of leaves, thereby retaining the photosynthetic abilities, overall growth characters and increasing the yield of storage Roots.
