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Auteur Adia Madjiguène Diallo
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Caractérisation des peuplements et de la variabilité morphologique des gousses et des graines de provenances locales de Acacia senegal (L.) Willd [texte imprimé] / Adia Madjiguène Diallo, Auteur . - DAKAR, SENEGAL : Université Cheikh Anta Diop de Dakar, 2010 . - 44p. Langues : Français ( fre) Catégories : | FORESTERIE
| Mots-clés : | Caractères morphologiques, gousses, graines, peuplement, provenances, Acacia senegal | Résumé : | Les pressions anthropiques et les changements climatiques ont induit une régression des peuplements naturels d’Acacia senegal (L.) Willd. d’où la nécessité de sélectionner des individus élites en termes de production de semences pour élaborer des stratégies de conservation et de multiplication. Dans ce cadre, une étude a été réalisée d’une part sur la caractérisation des peuplements naturels de Diéry Biram et de Séoudji et d’autre part sur la variabilité morphologique des gousses et des graines de peuplements naturels et de provenances de A. senegal. Les données obtenues ont été soumises à une analyse de variance afin de déterminer les variations intersites de la structure et de la morphologie des gousses des peuplements naturels de Acacia senegal de Séoudji et de Diéry Biram. Cette étude est complétée par une analyse en composantes principales des peuplements naturels et des quatre provenances de l’essai de Dahra. Elle a permis de déceler trois formes différentes de gousses (tordue en spirale, oblongue, étalée) et deux formes de graines (arrondie, ovale). Les gousses des peuplements naturels de Séoudji plus lourdes que celles de Diéry Biram comptent plus de graines. Dans l’essai provenance de Dahra, le poids des 100 graines des provenances Daïba et Ngane est nettement supérieur à celui des provenances Diamenar et Kidira. A l’exception de la largeur de la gousse qui est plus importante pour la provenance Kidira, tous les autres paramètres suivis sont plus importantes pour la provenance Ngane et Daïba. L’analyse en composantes principales discrimine deux groupes. Le groupe représenté par Ngane se caractérise par des gousses à faible nombre de graines mais à poids élevé. Cependant, le groupe représenté par la provenance Kidira produit plus de graines par gousses mais à faible poids. |
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Coexistence and performance of diploid and polyploid Acacia senegal (L.) Willd. : Implications for adaptation and domestication in the Sahel [texte imprimé] / Adia Madjiguène Diallo, Auteur . - COpenhagen, Danemark : University of Copenhagen., 2015. Langues : Anglais ( eng) Catégories : | FORESTERIE
| Mots-clés : | Acacia senegal, adaptation, distribution, drought, genetic differentiation, genetic relationship, gum arabic, heritability, origins, polyploidy, Sahel regions | Index. décimale : | K030- Génétique et amélioration des plantes | Résumé : | Acacia senegal, is the most important gum arabic producer and represents an active component in traditional dryland agroforestry systems in Africa. The species has been recently found to consist of both diploid and polyploid individuals, which opens for interesting questions since polyploidy is considered a major evolutionary process in plants. This thesis aims to contribute new knowledge about potential role of polyploidization in A. senegal in relation to adaptation, gum arabic production and evolutionary success. For these purposes, different approaches such as field trial assessment, stress trial experiment, microsatellite markers and flow cytometry were used. Results reveal polyploid individuals are also found in Senegal, but frequences vary among populations. Comparision of growth performance in both a progeny trial and in a growth chamber under drought stress test indicated that polyploids perform better than diploid under dry conditions. The quantitative genetic analysis reveal different sibling-relationship between diploids and polyploids were observed. Diploids were mainly outcrossed and families consisted of half-sib progenies. In contrast, polyploid individuals within families were more related than half-sib. Narrow sense heritability was estimated to 0.38 for gum yield suggesting that a breeding program for increased gum yield can be effective in providing gain after selection of trees with superior phenotypes based on careful testing. The study of distribution of polyploids and their genetic structure compared to diploids across different environmental ranges in Senegal show no simple geographic pattern in the level of polyploids in natual populations, but frequency of polyploids appeared to be positively correlated with increased salinity. Polyploids were found to be more genetically differentiated compared to diploids and based on study of genetic relationship between cytotypes, it is argued that polyploid A. senegal are likely to have multiple origins |
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Leaf morphology and stable isotope ratios of carbon and nitrogen in Acacia senegal (L.) Wild trees vary with climate at the geographic origin and ploidy level [texte imprimé] / Oulimata Diatta, Auteur ; Erik Dahl Kjær, Auteur ; Adia Madjiguène Diallo, Auteur ; Lene Rostgaard Nielsen, Auteur ; Vlastimil Novak, Auteur ; Diaminatou Sanogo, Auteur ; Kristian Holst Laursen, Auteur ; Anders Ræbild, Auteur . - 2021 . - 18p. : cart ; tab ; ill. ; graph ; photos ; ref. Langues : Anglais ( eng) Catégories : | FORESTERIE
| Mots-clés : | Adaptation of arid zone tree species · Flow cytometry · Isotopes · Leaf morphology · Senegalia senegal | Index. décimale : | K030- Génétique et amélioration des plantes | Résumé : | Key message Leaf morphology, total leaf nitrogen (N) content and carbon and nitrogen isotope ratios of Acacia senegal trees vary among ploidy levels and geographic origins. Leaf morphology was significantly correlated with carbon isotope composition (δ13C) among diploid trees, while a significant correlation was observed with nitrogen isotope composition (δ15N) among tetraploid trees. Abstract Leaf morphology and ploidy level can influence plants' ability to adapt to climatic conditions. Here we study Acacia senegal that has multiple ploidy levels and grows across a geographic range of mainly dry environments. We test if and how ploidy level and climate at the site of origin influence leaf shape and ratios of stable carbon and nitrogen isotopes of A. senegal. The study is based on leaves collected from 225 A. senegal trees representing 16 populations across the species
range, grown in a common garden trial in Senegal. Leaf morphological parameters were measured, and ploidy level, total leaf nitrogen (N), carbon isotope ratios (δ13C) and nitrogen isotope ratios (δ15N) were determined. Three levels of ploidy were found, namely diploid, triploid and tetraploid, but at highly different frequencies among the 16 origins. Leaf morphology varied significantly among both geographic origins and ploidy levels, with especially triploid trees having distinct leaf shapes. Tetraploids displayed high δ13C and low δ15N values compared to diploids. For diploids, leaf length and number of leaflets were correlated with precipitation and latitude, respectively. Leaf morphology and isotopic discrimination in A. senegal vary according to ploidy level and geographic origin. Our analysis suggests that the differences likely reflect adaptation to different environments, but the patterns tend to differ between diploids and tetraploids |
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FT2200028 | K030- DIA | Article scientifique | CNRF | Dépot numérique | A télécharger Disponible |
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Variation in phenology of Acacia senegal (L.) Wild. in relation to origin and ploidy level: Implications for climatic adaptation [texte imprimé] / Oulimata Diatta, Auteur ; Adia Madjiguène Diallo, Auteur ; Diaminatou Sanogo, Auteur ; Lene Rostgaard Nielsen, Auteur ; Anders Ræbild, Auteur ; Jon Kehlet Hansen, Auteur . - 2021 . - 15p. : tab ; diagramm ; ref. Langues : Anglais ( eng) Catégories : | FORESTERIE
| Mots-clés : | Flowering Fruiting Genetic variation Leafing Sahel Senegalia senegal | Index. décimale : | K040-Ecologie forestière | Résumé : | long dry seasons. Nevertheless, knowledge on genetic variation and adaptive patterns in phenology in deciduous African dryland species is limited. Here we study the variation in phenology of diploid and polypoid A. senegal trees from rangewide populations growing in a common garden trial in Senegal and test correlations between population phenology and climate at the site of origin. The leafing, flowering and fruiting phenology was monitored during 17 months and compared to detailed observations of the rainfall in the common garden during theperiod. We found that A. senegal trees in general started development of leaves prior to the beginning of the rainy season with flowering and fruiting initiation occurring during the rainy season. The results lead us to conclude that is was not the rain per se that initiated leaf development. We also conclude that phenology in A. senegal is under genetic control, because significantdifferences could be observed among populations and ploidy levels when grown at the same
site. In general, early leaf flushing trees had a longer growing period and performed better in terms of growth at the tested site and the results thus support that leaf phenology influence fitness. We further found that differences among trees in phenology seem to be associated with
differences in climate at their site of origin, because the timing of leaf development in the common garden and the timing of the rainy season at the site of origin was significantly correlated for the diploid trees (not for tetraploids). However, it was diploid trees from sites with a late
arriving rainy season that developed leaves earliest in the year. The environmental cues that control leafing phenology and the associated physiological mechanisms therefore still need to be identified in order to understand how the variation among populations has evolved, its relationship to local adaptation and the implication for smart transfer of seed sources as mean to mitigate changing growing conditions related to global warming |
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