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1
Fiebelkorn, Wrucke Danielle. "Genetic Analysis of Frost Tolerance in Rapeseed/Canola (Brassica Napus L.)". Diss., North Dakota State University, 2017. https://hdl.handle.net/10365/28362.
Testo completoAbstract (sommario):
Frost can be detrimental to canola (Brassica napus L.) production. Depending on the severity, the entire field can be killed. Having frost tolerance in canola would benefit growers by allowing them to plant early, utilize early season moisture, and avoid high heat during flowering. However, frost tolerance in canola has not been well studied. A protocol was developed that determined 14 day old seedlings should be acclimated at 4?C for 7 days before being exposed to overnight frost (-4?C) in a small freezing chamber. However, when a larger chamber was used for freezing, the protocol was optimized to -8?C instead. A greenhouse study was conducted on a diverse collection of 231 genotypes and genome-wide association scan (GWAS) was conducted to identify potential genes that were related to frost tolerance or abiotic stress tolerance. Thirty-eight significant single nucleotide polymorphism (SNP) markers were selected based on 10,000 bootstraps and 0.1 percent tail of the empirical distribution. The markers were located on chromosomes A01, A02, A03, A04, A07, A08, A09, A10, C03, C05, C06, C07, and C09. Stepwise regression highlighted a QTL located on chromosomes A02. Another GWAS was done on 147 canola germplasm lines phenotyped under natural conditions. Thirty-eight significant SNPs identified from this study were located on chromosomes A05, A07, A09, C01, C02, C03, C04, C05, C06, C07, and C09. Stepwise regression identified a QTL located on chromosome C04. A protocol was developed to measure the freezing induced electrolyte leakage from leaves of rapeseed/canola. A total of 157 germplasm lines were evaluated for freezing induced (-12?C for 2 h) electrolyte leakage. Thirty-six significant SNPs located on chromosomes A01, A02, A03, A04, A05, A06, A07, A08, A09, A10, C01, C02, C04, C05, C06, C07, and C09 were identified. Stepwise regression identified 10 QTL located on chromosomes A01, A02, A04, A06, A07, C02, C05, C07, C09, and one that could not be assigned. All GWAS studies identified potential genes of interest that were related to frost tolerance, abiotic stress, and transcription factors.Northern Canola Growers Association
2
Dovzhenko, Alexander. "Towards plastid transformation in rapeseed (Brassica napus L.) and sugarbeet (Beta vulgaris L.)". Diss., [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=964442035.
Testo completo
3
Rahaman, Md Mizanur. "Genome-Wide Association Study of Heat Tolerance in Rapeseed/Canola (Brassica Napus L.)". Thesis, North Dakota State University, 2016. https://hdl.handle.net/10365/28012.
Testo completoAbstract (sommario):
Genome-wide association study of heat stress tolerance in rapeseed/canola was conducted in greenhouse, growth chamber, and in the field. A total of 37,539 SNP markers were used in this study. In the greenhouse and growth chamber study, 5, 8, and 7 QTL were found associated with pollen sterility, sterile/aborted pods, and number of pods on main raceme, which explained 46.3%, 60.5% and 60.6% phenotypic variations, respectively. In the field study, 6, 11, 7, 11 and 7 QTL were identified causing phenotypic variation of 52.2%, 71.8%, 53.2%, 73.5% and 61.0% for plant height, main raceme height, pods on main raceme, pod length, and pod abortion on main raceme, respectively. Three QTL located on chromosome C05 and, five QTL on chromosome A10 and C03 were identified linked to two common traits sterile/aborted pods, and number of pods on main raceme, respectively. Multiple heat tolerant candidate genes were identified surrounding these QTL.Northern Canola Growers Association
4
Askew, Matthew Carter. "Rapeseed (Brassica napus L.) Termination and Integration of Halauxifen into Virginia Cotton (Gossypium hirsutum L.) Production". Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/86786.
Testo completoAbstract (sommario):
Cover crops have become an important part of cropping systems in the United States, especially in the Mid-Atlantic region. Rapeseed is a popular choice due to its deep growing taproot which creates soil macropores and increases water infiltration. If not properly terminated rapeseed can become problematic due to its pod-shattering tendency and its difficulty to terminate with herbicides once it enters reproductive growth. Results indicate termination of rapeseed is most effective when the cover crop is small. Combinations that successfully terminated rapeseed include glyphosate plus 2,4-D and paraquat plus 2,4-D. Halauxifen-methyl is a new Group 4 herbicide marketed for preplant burndown horseweed (Conyza canadensis L.) control. Previous research indicates that halauxifen effectively controls glyphosate-resistant horseweed. However, little is known about control of other common winter annual weeds by halauxifen. Results indicate halauxifen has a narrow spectrum of control providing adequate control (>80%) of horseweed, henbit (Lamium amplexicaule L.), and purple deadnettle (Lamium purpureum L.), while failing to control cutleaf evening-primrose (Oenothera laciniata Hill), curly dock (Rumex crispus L.), purple cudweed (Gamochaeta purpurea L. Cabrera), common chickweed (Stellaria media L.), and mousear chickweed (Cerastium L.). Little is known of cotton (Gossypium hirsutum L.) tolerance to halauxifen applied preplant burndown. Results indicate cotton is more tolerant to halauxifen than 2,4-D or dicamba when the interval between preplant application and cotton planting is less than 30 days.Master of Science in Life Sciences
Cover crops are an important part of cropping systems in the United States, especially in the Mid-Atlantic region. Producers utilize cover crops to aid in weed suppression, reduce soil erosion, as well as to increase soil health. Cereals, legumes, and Brassicaceae species are popular cover crops planted either as monocultures or mixtures. Rapeseed can become problematic due to its difficulty to terminate once it enters reproductive stage, as well as its podshattering characteristic. Experiments were conducted to evaluate various herbicides and herbicide combinations for rapeseed termination two application timings. At three locations where rapeseed averaged 12 cm in height at early termination, and 52 cm in height at late termination, glyphosate + 2,4-D was most effective, controlling rapeseed (96%) 28 days after early termination (DAET). Paraquat + atrazine + atrazine (92%), glyphosate + saflufenacil (91%), glyphosate + dicamba (91%), and glyphosate (86%) all provided at least 80% control 28 DAET. Paraquat + 2,4-D (85%), glyphosate + 2,4-D (82%), and paraquat + atrazine + mesotrione (81%) were the only treatments to provide at least 80% control 28 days after late termination (DALT). At one location where rapeseed was much taller (41 cm early termination; 107 cm late termination), herbicides were much less effective, as no herbicide treatments provided greater than 80% control. Results indicated that rapeseed size at time of termination was more critical to successful termination than herbicide choice. Prior to the development of glyphosate-resistant horseweed, producers were able to control horseweed and other weeds with glyphosate applied preplant burndown. Producers now rely on auxin herbicides tank mixed with glyphosate and a residual herbicide to control horseweed and other winter weeds prior to cash crop planting. Experiments were conducted to evaluate halauxifen-methyl, a new Group 4 herbicide, for control of horseweed and other commonly encountered winter annual weeds. Halauxifen (89%) controlled small horseweed (<5 cm in height at time of application) similar to dicamba (91%), while providing better control of large horseweed (79%) (>15 cm in height at time of application) than either dicamba (77%) or 2,4-D evaluated (64%). Halauxifen provided adequate control (>80%) of henbit (Lamium amplexicaule L). and purple deadnettle (Lamium purpureum L.), while failing to effectively control of cutleaf evening-primrose (Oenothera laciniata Hill), curly dock (Rumex crispus L.), purple cudweed (Gamochaeta purpurea L. Cabrera), common chickweed (Stellaria media L. Vill.), and mousear chickweed (Cerastium L.). Results indicate that halauxifen has a narrow spectrum of control and should be tank mixed with 2,4-D or glyphosate in order to control weeds other than horseweed and henbit. Glyphosate plus dicamba or 2,4-D plus a residual herbicide is typically applied prior to cotton planting. Previous research has shown that as long as rainfall requirements and rotation intervals are met, no adverse effects on cotton is observed from 2,4-D or dicamba herbicides. Little is known of cotton tolerance to halauxifen applied preplant burndown. Experiments were conducted to determine if halauxifen applied sooner than the labeled 30-day rotation interval would injure cotton. Very little injury was observed from halauxifen (9%) applied at-planting, however dicamba (26%) and 2,4-D (21%) applied at the same timing did injure cotton. Auxin herbicides applied earlier in the season resulted in little injury (<2%). Early season injury was transient as cotton recovered later in the season and seedcotton yield was unaffected.
5
Nehlin, Lilian. "The use of rapeseed (Brassica napus L.) microspores as a tool for biotechnological applications /". Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1999. http://epsilon.slu.se/avh/1999/91-576-5490-5.pdf.
Testo completo
6
Arif, Uz Zaman Muhammad. "Delineating Root System Architecture in Rapeseed/Canola (Brassica napus L.) through Molecular and Transcriptomic Approaches". Diss., North Dakota State University, 2018. https://hdl.handle.net/10365/29308.
Testo completoAbstract (sommario):
Root system architecture of plant plays a key role in water and nutrient uptake from the soil, provides anchorage and acts as a storage organ. In this current research, we have focused on the molecular and physiological basis of root system variation in canola (Brassica napus L.). Genome wide association mappings in a diverse canola germplasm panel with ~37,500 and ~30,200 single nucleotide polymorphism (SNP) markers were conducted under greenhouse and field conditions, respectively. A total of 52 significant SNP markers associated with different root architectural traits were identified in the greenhouse study. Majority of the markers were distributed on five chromosomes, A01, A02, A04, C03 and C06, of B. napus. Twenty-two candidate genes related to root growth and development were detected within 50 kbp upstream and downstream of the significant markers. Three of these candidate genes, P-glycoprotein 6 (PGP6), Tetraspanin 7 (TET7) and ARABIDILLO-2, were co-localized with three markers on chromosome C03, A01 and A04, respectively. In the field study, 31 significant SNP markers associated with different root traits were detected. A total of 15 root related candidate genes were identified within 100 kbp upstream and downstream of different significant markers. We also analyzed and compared the transcriptomes from the root systems of spring (weak root system) and winter (vigorous root system) growth habits at two different time points, 30 and 60 days. A total of 169,646 transcripts were analyzed, of which, 582 and 555 transcripts were found to be significantly differentially expressed between spring and winter types at 30 and 60 days, respectively. Several cytokinin and gibberellin associated genes and genes sets were found to be upregulated in spring type compared to winter type at 60 days. Cytokinin has proven inhibitory effect on root system architecture in different crops, whereas, gibberellin promote root elongation but inhibit lateral root growth. Therefore, we suggest that cytokinin and gibberellin may play an important role in root system variation between spring and winter growth habits. Significant marker loci, candidate genes and transcriptome profile identified in this research will assist future research to understand the root system variation in rapeseed/canola.North Dakota State University. Center of Excellence for Agbiotechnology
National institute of Food and Agriculture (U.S.)
Northern Canola Growers Association
7
Handa, Hirokazu. "Molecular genetic studies of mitochondrial genome in rapeseed(Brassica napus L.) in relation to cytoplasmic male-sterility". Kyoto University, 1992. http://hdl.handle.net/2433/168799.
Testo completoAbstract (sommario):
本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものであるKyoto University (京都大学)
0048
新制・論文博士
博士(農学)
乙第7961号
論農博第1783号
新制||農||636(附属図書館)
学位論文||H4||N2501(農学部図書室)
UT51-92-S470
(主査)教授 常脇 恒一郎, 教授 大山 莞爾, 教授 矢澤 進
学位規則第4条第2項該当
8
Louvieaux, Julien. "Exploiting the genetic diversity of rapeseed (Brassica napus L.) root morphology to improve nitrogen acquisition from soil". Doctoral thesis, Universite Libre de Bruxelles, 2020. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/313193.
Testo completoAbstract (sommario):
Nitrogen (N) is a central nutrient in cropping systems. However, a considerable N fraction is lost through runoffs and leaching with detrimental consequences for environment and controversial effects on human health. Increasing the plant N uptake by optimizing the degree of root branching for exploring a larger soil volume in search of the mobile nitrate resource may contribute to limit soil leaching and subsequently to rely more efficiently on the soil mineralization and fertilizer inputs. Rapeseed (Brassica napus L.) is a major oil crop that highly depends on N fertilization. This doctoral thesis aims at exploring the diversity of root morphology in recently selected cultivars and in a large set of rapeseed inbred lines, and at understanding the genetic control on root morphology and how it is impacted by N nutrition.Firstly, a panel of twenty-eight European recently selected cultivars of winter oilseed rape were tested in laboratory and field conditions. Upon hydroponic culture, these hybrids showed a great diversity for biomass production and root morphological traits. Differences in root and shoot dry biomasses and lateral root length were mainly explained by the genotype, while differences in primary root length by the nutrition. The cultivars were tested in a pluriannual field trial. The observed variation for yield and seed quality traits attributed to the genotype was more important than the year or the genotype x year interaction effects. The total root length measured in laboratory could predict the proportion of nitrogen taken-up from the field and reallocated to the seeds. The genetic interrelationship between cultivars, established with polymorphic markers, indicated a very narrow genetic base. Positive correlations were found between the genetic distance measures, root morphological trait distances during nitrogen depletion conditions, and agronomic performance. Secondly, three cultivars previously selected from a root morphology screen at a young developmental stage were field tested with two nitrogen applications. The purpose was to examine the relationship between root morphology and Nitrogen Uptake Efficiency (NUpE) and to test the predictiveness of canopy optical indices for seed quality and yield. A tube-rhizotron system was used to incorporate below-ground root growth information. One-meter length clear tubes were installed in soil at an angle of 45°. The root development was followed with a camera at key growth stages in autumn (leaf development) and spring (stem elongation and flowering). Autumn was a critical time window to observe the root development and exploration in deeper horizons (36-48 cm) was faster without any fertilization treatment. Analysis of the rhizotron images was challenging and it was not possible to clearly discriminate between cultivars. Canopy reflectance and leaf optical indices were measured with proximal sensors. The Normalized Difference Vegetation Index (NDVI) was a positive indicator of biomass and seed yield while the Nitrogen Balance Index (NBI) was a positive indicator of above-ground biomass N concentration at flowering and seed N concentration at harvest.Thirdly, the natural variability offered by a diversity set of 392 inbred lines was screened to apprehend the genetic control of root morphology in rapeseed and how it is impacted by nitrogen nutrition. Seedlings grew hydroponically with low (0.2 mM) or elevated (5 mM) nitrate supplies. Low nitrate supply triggered the primary root and lateral root growth, while elevated supply promoted shoot biomass production. A considerable variation degree in the root morphological traits was observed across the diversity set, and there was no trade-off between abundant lateral root branching and shoot biomass production. Root traits were mainly dependent on the genotype and highly heritable. A genome wide association study identified some genomic regions associated with biomass production and root morphological traits. A total of fifty-nine QTLs were identified and thirty of them were integrated into seven clusters on chromosomes A01 and C07. Some candidate genes were identified with Arabidopsis orthologs related to root growth and development, nitrogen nutrition or hormone regulation.This study provides promising routes for redesigning the root system architecture by uncovering nitrogen-interactive genomic regions shaping root morphology. A perspective is to develop genetic markers associated with root morphological traits that could be used for assisted breeding.Doctorat en Sciences agronomiques et ingénierie biologique
info:eu-repo/semantics/nonPublished
9
Kuprienė, Ramunė. "Geltonsėklių vasarinių rapsų (Brassica napus L.) kūrimas biotechnologiniais ir tradiciniais selekcijos metodais". Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2006. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2006~D_20061121_110825-64679.
Testo completoAbstract (sommario):
Genotypes of rapeseeds producing yellow seeds were not found in nature. Breeders yellow-seeded rapeseeds have been developed applying different combinations of interspecific crosses. In the Laboratory of Genetics-Biotechnology at the Lithuanian Agricultural University, yellow-seeded spring rapeseeds were developed for the first time without interspecific crosses (Burbulis, 2001). All cultivars of yellow-seeded rapeseed have one essential drawback – unblocking of pigmentation takes place in other generations and seeds of different colours (yellowish brown, brown or black) are formed. Breeders, working with the cultivars of yellow-seeded rapeseed, admit that environmental temperature is one of the factors limiting the manifestation of the trait.
10
Lüders, Wolfgang [Verfasser]. "Analyses of virulence of European isolates of clubroot(Plasmodiophora brassicae Wor.)and mapping of resistance genes in rapeseed (Brassica napus L.) / Wolfgang Lüders". Gießen : Universitätsbibliothek, 2017. http://d-nb.info/1144828104/34.
Testo completo
11
Moroni, Juan Sergio. "Studies on the efficiency of rapeseed (Brassica napus L.) germplasm for the acquisition and the utilization of inorganic nitrogen". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq23040.pdf.
Testo completo
12
Ijaz, Muhammad [Verfasser]. "Effect of Triazole and Strobilurin fungicides on seed yield and grain quality of winter rapeseed (Brassica napus L.) / Muhammad Ijaz". Gießen : Universitätsbibliothek, 2012. http://d-nb.info/106395522X/34.
Testo completo
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Jonytienė, Vaida. "Endogeninių ir egzogeninių veiksnių poveikis žieminio rapso (Brassica napus L.) užsigrūdinimui ir atsparumui šalčiui in vitro ir in vivo". Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20120529_211218-52148.
Testo completoAbstract (sommario):
Darbo tikslas – nustatyti endogeninių ir egzogeninių veiksnių poveikį žieminio rapso atsparumui šalčiui in vitro ir in vivo. Ginamieji disertacijos teiginiai: 1. Žieminio rapso atsparumas šalčiui didžiąją dalimi lemiamas endogeninio prolino, o ne tirpiųjų sacharidų kiekio augalų audiniuose. 2. Grūdinant ūglius in vitro egzogeniniai priedai (abscizo rūgštis, prolinas, tirtas aminorūgščių kompleksas) maitinamojoje terpėje didina atsparumą šalčiui. 3. In vitro sistemoje L-prolinas ir tirtas aminorūgščių kompleksas atstato atlydžio metu sumažėjusį užsigrūdinimo tvarumą. 4. Endogeninio prolino kiekis yra membranos stabilumo atsparumo šalčiui žymuo ir gali būti naudojamas kuriant atsparius šalčiui genotipus.Aim of the work – to determine the effect of endogenous and exogenous factors on the cold tolerance of winter rapeseed in vitro and in vivo. Proposition to be defended: 1. Cold tolerance of winter rapeseed mainly determining by content of endogenous proline but not by soluble sugars. 2. Exogenous additives (abscisic acid, proline, amino acids) in nutrient medium increases the cold tolerance of rapeseed shoots in vitro. 3. In in vitro system the abscisic acid, proline and amino acids restore the reduced acclimation which occurs during de-acclimation period. 4. Endogenous proline content is the marker of membrane stability and cold tolerance and may be used to create cold-tolerant genotypes.
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Bouchet, Anne-Sophie. "Architecture génétique du rendement et de ses composantes chez le colza d’hiver (Brassica napus L.) cultivé sous contrainte azotée". Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S150/document.
Testo completoAbstract (sommario):
L'augmentation de la production d'huile de colza (Brassica napus L.) pour répondre à la demande alimentaire et industrielle exige d'optimiser le rendement dans un contexte de réduction des intrants, notamment azotés. Les approches de génétique offrent une voie pour répondre à ces enjeux. En effet, la connaissance des régions génomiques (QTLs) et des mécanismes qui contrôlent l'élaboration des composantes du rendement sous contrainte azotée est un prérequis à la création variétale. Dans ce contexte, les questions de recherche posées dans cette thèse sont les suivantes: i) quelle est l'architecture génétique du rendement en huile chez le colza cultivé en bas intrants azotés?, ii) quelles sont les interactions des QTLs avec l'environnement et plus particulièrement avec l'intensité du stress azoté?, et iii) comment la combinaison de données agronomiques, génétiques et génomiques peut-elle contribuer à l'amélioration de caractères d'intérêt chez le colza? Une stratégie de détection de QTLs par analyse de liaison et analyse d'association a été mise en place sur deux populations biparentales et un panel de colzas d'hiver. Ces populations ont été expérimentées sur sept lieux et six années de culture (2009-2014) en condition de nutrition azotée limitante ou suffisante. Pour chaque essai, sept caractères phénotypiques relatifs à l'élaboration du rendement ont été mesurés. Peu d'interactions génotype × azote ont été détectées sur les caractères étudiés et un nombre important de QTLs a été retrouvé dans les deux conditions azotées. A l'inverse, de fortes interactions génotype × environnement ont été mises en évidence pour la majorité des caractères et les QTLs étaient pour la plupart spécifiques d'un lieu de culture. Dix régions génomiques d'importance, stables entre environnement et populations ont ainsi été identifiés et leur organisation structurale dans le génome du colza a été analysée. Le contrôle génétique de la teneur en huile des graines de colza a ensuite été étudié en combinant à la fois les informations de dix études indépendantes, les informations procurées par la récente publication du génome de B. napus et la recherche de variabilité haplotypique dans une région d'intérêt identifiée sur le chromosome A1 dans une population de colzas d'hiverThe increase of rapeseed (Brassica napus L.) oil production to answer the demand for human consumption and industrial applications requires the optimisation of seed yield in a context of reduction of inputs, including the nitrogen fertilization. Genetic approaches are a way to respond to this challenge. Indeed, determining the genomic regions (QTLs) and mechanisms controlling seed yield components under nitrogen limitation is a prerequisite for plant breeding programs. In this context, the scientific questions raised in this thesis are: i) what is the genetic architecture of seed yield components in rapeseed grown under limiting nitrogen condition? ii) how do the QTLs interact with the environment, and especially with the nitrogen stress?, and iii) how the combination of agronomic, genetic and genomic information can lead to the improvement of traits of interest in rapeseed? A strategy of QTL detection by linkage and linkage disequilibrium analyses was set up on two biparental populations and a winter oilseed rape diversity set. Those populations were trialled in seven location and six growing seasons (2009-2014) under low and sufficient nitrogen conditions. For each trial, seven seed yield-related traits were acquired. Few genotype × nitrogen condition interactions were detected and an important number of QTLs were common to the two nitrogen regimes. On the contrary, strong genotype × environment interactions were evidenced for most of the traits under study and the majority of the QTLs were location-specific. Ten critical genomic regions for yield associated traits stable through the environments and populations were identified and their structural organization in the rapeseed genome was investigated. The genetic control of oil content was then studied by combining the information from ten independent reports, the genomic information provided by the recent release of the B. napus genome and the haplotype variations among a winter oilseed rape population within one particular region identified on the A1 chromosome
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Guo, Yuan [Verfasser]. "Mutations in FT-, TFL1-, and FRI paralogs of rapeseed (Brassica napus L.) and their effect on flowering time and heterosis / Yuan Guo". Kiel : Universitätsbibliothek Kiel, 2015. http://d-nb.info/1070819239/34.
Testo completo
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James, Maxence. "Etude de systèmes protéolytiques et anti-protéolytiques impliqués dans la remobilisation de l'azote au cours de la sénescence chez les Brassicacées (Arabidopsis thaliana L., Brassica napus L)". Thesis, Normandie, 2018. http://www.theses.fr/2018NORMC275/document.
Testo completoAbstract (sommario):
Le colza (Brassica napus L.) est une plante de grande culture particulièrement exigeante en azote (N) et caractérisée par une faible Efficience d’Usage de l’Azote (EUA), principalement due à une mauvaise Efficience de Remobilisation de l’Azote (ERA) au cours de la sénescence foliaire. L’optimisation de l’ERA est donc un enjeu majeur pour améliorer le bilan agro-environnemental de cette culture. La dégradation des protéines étant l’un des processus clés de la remobilisation de l’N associée à la sénescence, l’objectif de ce travail est d’identifier et caractériser les principaux acteurs de la protéolyse lors de la sénescence naturelle ou induite par une limitation en N. Chez la plante modèle Arabidopsis thaliana cultivée en condition de forte disponibilité en N (HN), nous avons montré que SAG12 est une protéase majeure lors de la sénescence foliaire afin d’assurer la remobilisation de l’N essentielle à l’élaboration du rendement et au remplissage en N des graines. En effet, nos travaux montrent que le rôle de SAG12 est central et qu’en absence de son activité, d’autres protéases appartenant au CPs, mais aussi à d’autres classes (protéases à aspartate ; APs), sont sollicitées pour soutenir la remobilisation de l’N foliaire. Dans ce contexte, AED1 (une APs CND41-like) est particulièrement intéressante puisqu’elle semble collaborer étroitement avec SAG12. Par ailleurs, cette étude met en évidence pour la première fois une localisation racinaire de SAG12. Dans cet organe, le rôle de SAG12 est crucial pour remobiliser l’N des racines pour maintenir le rendement et la teneur en N des graines lorsque les plantes sont soumises à une limitation en N. Un autre volet de ce travail a consisté à étudier d’autres moyens de réguler l’activité protéolytique en se focalisant notamment sur des systèmes anti-protéolytiques. Cette étude suggère qu’une Water Soluble Chlorophyll binding Protein (WSCP), la protéine WSCP1, porte effectivement une double fonction de protection des chlorophylles et d’inhibiteur de protéases à sérine, ce qui en fait un potentiel candidat pour prolonger la durée de vie des feuilles et ainsi réduire l’asynchronisme entre la période de vidage des feuilles et la période de remplissage en N des graines.L’ensemble de ces travaux permet de proposer de nouveaux candidats pertinents pour la sélection de variétés de colza présentant une remobilisation efficiente de l’N dans un contexte de limitation des intrants azotésRapeseed (Brassica napus L.) is a field crop plant that is particularly requiring nitrogen (N) and characterized by a low Nitrogen Use Efficiency (NUE), mainly due to a poor Nitrogen Remobilization Efficiency (NRE) during foliar senescence. The optimization of NRE is therefore a major challenge to improve the agro-environmental balance of this crop. Since protein degradation is one of the key processes in the remobilization of N associated with senescence, the objective of this work is to identify and characterize the main actors of proteolysis during natural or induced by N limitation senescence. In the plant model Arabidopsis thaliana grown under high N conditions (HN), we have shown that SAG12 is a major protease during leaf senescence to ensure the remobilization of N essential for yield and seed N filling. Indeed, our work shows that the role of SAG12 is pivotal and that in the absence of its activity, other proteases belonging to the CPs but also to other classes (aspartate proteases; APs) are requested to support the remobilization of foliar N. In this context, AED1 (a CND41-like APs) is particularly interesting since it seems to collaborate closely with SAG12. In addition, this study shows for the first time a root localization of SAG12. In this organ, the role of SAG12 is crucial, in particular to remobilize N from the roots to sustain yield and N content of the seeds when plants face an N limitation. Another aspect of this work was to study other ways of regulating proteolytic activity, focusing in particular on anti-proteolytic systems. This study suggests that a Water Soluble Chlorophyll binding Protein (WSCP), the WSCP1 protein, has effectively a dual function of chlorophyll protection and serine proteases inhibition, which make it a potential candidate to extend leaf lifespan and thus, reduce asynchronism between leaf emptying time and the N seed filling time.Altogether, these results allow to suggest new relevant candidates for the selection of rapeseed varieties with an efficient N remobilization in a context of nitrogen input limitation
17
Qian, Lunwen [Verfasser]. "Functional markers, sub-genomic selection patterns and haplotype regions associated with seed glucosinolates and chlorophyll content in rapeseed (Brassica napus L.) / Lunwen Qian". Gießen : Universitätsbibliothek, 2016. http://d-nb.info/1106014235/34.
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18
Marschalek, Rubens. "Marker Assisted Selection for the development of intervarietal substitution lines in rapeseed (Brassica napus L.) and the estimation of QTL effects for glucosinolate content". Doctoral thesis, Göttingen : Cuvillier, 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969942842.
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19
Marschalek, Rubens [Verfasser]. "Marker assisted selection for the development of intervarietal substitution lines in rapeseed (Brassica napus L.) and the estimation of QTL effects for glucosinolate content / Rubens Marschalek". Göttingen : Cuvillier, 2003. http://d-nb.info/969942842/34.
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20
Coquerel, Raphael. "Etude d'un appοrt en silicium sur le métabοlisme azοté et les perfοrmances agrοnοmiques du cοlza (Brasscia napus L.) et du trèfle (Τrifοllium incarnatum L.) cultivés en mοnοculture et en assοciatiοn". Electronic Thesis or Diss., Normandie, 2024. http://www.theses.fr/2024NORMC246.
Testo completoAbstract (sommario):
Chaque année, plus de 3,7 millions de tonnes d'engrais azotés sont utilisées par l'agriculture française. Bien qu'étant un élément essentiel au bon développement et à la bonne croissance des plantes, la fertilisation azotée est de plus en plus décriée en raison des nombreuses nuisances aux écosystèmes et à la biodiversité qu'il induit. Le colza (Brassica napus L.) est l'une des plantes de grandes cultures les plus exigeantes en azote (N), en raison de sa faible efficience d'usage de cet élément. Dans le but de maintenir une croissance et des rendements optimaux de la culture de colza tout en limitant les apports en fertilisants azotés, il est essentiel de mettre au point de nouvelles pratiques culturales plus respectueuses de l'environnement. Dans ce contexte, l'utilisation combinée des cultures associées à base de Fabacées et de produits biostimulants constitue une alternative intéressante aux pratiques actuelles de la culture de colza. Du fait de ses nombreux effets bénéfiques lors de stress biotiques et abiotiques, le silicium (Si) semble être un biostimulant pertinent. Les objectifs de ces travaux de thèse visent à observer les effets d'un apport en Si sur (i) les performances agronomiques du colza et du trèfle en monoculture cultivés en conditions contrôlées et (ii) sur une possible potentialisation du fonctionnement de l'association colza-trèfle incarnat. Dans un premier temps, nos travaux ont permis de montrer qu'en condition de carence en soufre (S), un apport de Si s'accompagne d'une baisse du stress oxydatif et d'une modulation de l'expression des gènes codant les transporteurs racinaires de sulfate qui permet aux plantes traitées au Si d'être plus efficaces pour absorber le S lorsque celui-ci est à nouveau disponible. Dans un second temps, l'apport de Si à une culture de trèfle incarnat soumis à une carence en S ou cultivé avec une solution nutritive dépourvue d'N a un impact positif sur la nodulation et les capacités de fixation du diazote atmosphérique. Le Si induit une augmentation significative du nombre de nodules racinaires ainsi que de leur teneur en nitrogénase. En outre, l'étude du ionome et du protéome des nodules a permis de mieux comprendre les effets d'un apport en Si en montrant notamment l'accumulation d'éléments et de protéines impliqués directement ou indirectement dans la fixation de diazote atmosphérique. Enfin, nos travaux ont mis en lumière les effets bénéfiques d'un apport en Si sur une association colza-trèfle notamment en augmentant le transfert d'N de la Fabacée vers la Brassicacée et en améliorant le rendement grainier du colzaOver 3.7 million tonnes of N fertilizers are used in French agriculture every year. Although N fertilization is an essential element for the growth of crops, it is increasingly criticized for its harmful effects on ecosystems and biodiversity. rapeseed (Brassica napus L.) is one of the most N requiring field crops, due to its low N use efficiency. To maintain optimum the growth and the yield of rapeseed with lower N fertilizer inputs, it is crucial to develop new cultural practices more respectful of environment. In this context, the combination of rapeseed-clover intercrops and biostimulants is an interesting alternative to the current cultivation practices of rapeseed. Considering its numerous beneficial effects under biotic and abiotic stresses, Silicon (Si) appears to be a relevant biostimulant. The aim of this PhD work was to observe the effects of Si supply on (i) the agronomic performance of monoculture rapeseed and clover grown under controlled conditions, and (ii) the possible potentiation of the functioning of the rapeseed-clover intercrop. Firstly, our work has shown that under sulfur (S) deficiency conditions, the supply of Si leads to a reduction in oxidative stress and modulation of the expression of genes encoding root sulfate transporters, allowing +Si plants to take up S more efficiently when it becomes available again. Secondly, the Si supply to crimson clover subjected under S-deficiency or or grown without N in the nutrient solution, had a positive impact on nodulation and atmospheric dinitrogen fixation capacities. Si induces a significant increase in the number of root nodules and their nitrogenase content. In addition, the study of the nodule ionome and proteome has enhanced our knowledge of the benefit effects of Si supply, particularly by showing the accumulation of elements and proteins directly or indirectly involved in the fixation of atmospheric dinitrogen. Finally, our work has highlighted the beneficial effects of Si supply on a rapeseed-clover intercrop, notably by increasing the N transfer from the Fabaceae to the Brassicaceae and improving the yield of the rapeseed
21
Weis, Daniela Katja [Verfasser], Wolfgang [Akademischer Betreuer] Ecke e Reiner [Akademischer Betreuer] Finkeldey. "Genotypic and phenotypic analysis of the allelic diversity in candidate genes for oil content in exotic plant materials of rapeseed (Brassica napus L.) / Daniela Katja Weis. Gutachter: Wolfgang Ecke ; Reiner Finkeldey. Betreuer: Wolfgang Ecke". Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2014. http://d-nb.info/1062770722/34.
Testo completo
22
Lüders, Wolfgang [Verfasser], Wolfgang [Gutachter] Friedt, Frank [Gutachter] Ordon e Rod [Gutachter] Snowdon. "Analyses of virulence of European isolates of clubroot (Plasmodiophora brassicae Wor.) and mapping of resistance genes in rapeseed (Brassica napus L.) / Wolfgang Lüders ; Gutachter: Wolfgang Friedt, Frank Ordon, Rod Snowdon ; Faculty of Agricultural Sciences, Nutritional Sciences, and Environmental Management, Justus Liebig University Giessen; Institute for Resistance Research and Stress Tolerance, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, Quedlinburg". Quedlinburg : Julius Kühn-Institut, 2017. http://d-nb.info/1142535169/34.
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23
Napis, Suhaimi. "Molecular genetic studies on Brassica napus L". Thesis, Durham University, 1991. http://etheses.dur.ac.uk/6037/.
Testo completoAbstract (sommario):
The feasibility of using two different methods of assaying for DNA polymer phisms has been assessed. They were Restriction fragment length polymorphisms (RFLPs) as revealed by a range of characterised Brassica cDNA sequences and Random amplified polymorphic DNA (RAPD). These techniques have been shown to reveal DNA polymorphisms between varieties of Brassica napus L. Further more, the sequence and organisation of a Hind III family of highly repetitive DNA sequences were also studied on Brassica napus L. RFLPs associated with rape extensin, ext A, and Brassica oleraceae self- incompatibility genes were observed when DNA samples from 19 commercial varieties of B. napus were analysed using the cDNA probes pRR566 (coding for root-specific extensin) and pBOS2 (coding for S(_5) self-incompatibility allele in B. oleraceae). Both cDNA clones were able to reveal RFLP patterns with varying degrees of polymorphism depending on the restriction enzymes used in the digestion of genomic DNAs. Although both probes could generate complex RFLP band patterns, those revealed by pB0S2 were generally easier to analyse and more suitable for DNA fingerprinting while those revealed by pRR566 were less distinct as a result of extensive background hybridisations. The probe pRR566, with certain restriction enzymes generated simpler RFLP band patterns that were more suitable for segregation analyses. Segregation analysis of F(_1) individuals revealed additive RFLP band patterns of both parental varieties, while that of F(_2) individuals revealed RFLP band patterns of each parental varieties as well as the additive pattern. When analysed for possible association with varietal glucosinolate content, none of the RFLP band patterns showed such linkage. A cDNA library was constructed from pod material of a high glucosinolate variety in an attempt to obtain clones which could reveal RFLP patterns associated with glucosinolate content. Differential screening using total cDNAs from pod materials of high and low glucosinolate varieties failed to isolate any cDNA clones useful as RFLP markers. Another DNA polymorphism assay studied, RAPD, was able to detect inter- and intraspecific variation in Brassica sp. Analysis of six phylogenetically-related but distinct Brassica sp. revealed extensive variation in the RAPD band patternsof amplification products; with some amphidiploid species sharing conserved band patterns with their ancestral species. RAPD analysis on 17 varieties of rape revealed polymorphic as well as highly conserved RAPD band patterns depending on the primer used. One of the primers was able to amplify a polymorphic band which could be associated with low glucosinolate varieties i.e. present almost exclusively in low glucosinolate varieties. Species-specific as well as variety-specific band patterns were also observed during the RAPD analysis. Finally, sequence and organisation of a Hind III family of repetitive sequences was studied. The monomeric and polymeric forms (trimer and tetramer) of the repetitive sequences were successfully cloned into pUCl8. Sequence analysis of the two clones containing the polymeric forms revealed that the monomers were arranged in tandem array and that all internal Hind III recognition sites were lost due to point mutation(s) which occurred within the six basepair recognition site. A consensus monomeric sequence was deduced from sequence comparison of the 8 copies of the monomeric sequences present in the 3 clones and the deviation from the consensus sequence of each of the eight monomers was less than 3%. No two monomeric sequences were identical. It was estimated that the number of copies of the monomeric sequences in a haploid genome was approximately 0.3 million copies. Estimates of the proportional representation of each of the polymeric sequences based on the number of copies of the monomers in each polymer were also calculated.
24
Guerche, Philippe. "Transformation génétique du colza (Brassica napus L. )". Paris 11, 1988. http://www.theses.fr/1988PA112134.
Testo completoAbstract (sommario):
Des plantes de colza transgéniques ont été obtenues en utilisant deux stratégies de transformation différentes. La régénération et la caractérisation de plantes issues de racines transformées par Agrobacterium rhizogenes est décrite dans la première partie. Une deuxième partie est consacrée à l'étude de la transformation directe de protoplastes par électroporation. La mise au point de cette technique a été réalisée sur des protoplastes de tabac par utilisation d'un dosage d'expression transitoire. L'application de l'électroporation aux protoplastes de colza a permis d'obtenir des plantes transgéniques exprimant un gène de résistance à la kanamycine. Différentes applications agronomiques possibles de ces méthodes de transformation sont envisagées pour le colzaTransgenic rapeseed plants have been obtained using two transformation procedure. The regeneration and caracterization of rapeseed plants derived from hairy roots induced by Agrobacterium rhizogenes are describe in the first part. The second part is devoted to the study of direct gene transfer by electroporation. This technique was optimized on tobacco protoplasts using a transient expression assay. The application of this technique to rapessed protoplasts made it possible to obtain transgenic rapeseed plants resistant to the antibiotic kanamycin. Possible agronomy applications of this strategy of transformation to rapeseed improvement are considered
25
Guerche, Philippe. "Transformation génétique du colza, Brassica napus L". Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb376140414.
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26
Blary, Aurélien. "Towards a functional characterization of meiotic recombination in rapeseed : analysis of the meiotic transcriptome and hyper-recombinant mutants". Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS576/document.
Testo completoAbstract (sommario):
La recombinaison méiotique produite par les Crossing Overs (COs) est un facteur limitant pour l’efficacité de la sélection variétale. Une possibilité pour produire des plantes hyper-recombinantes serait d’exploiter la variabilité intraspécifique pour les fréquences de recombinaison. L’identification des polymorphismes causaux, liés à la séquence ou l’expression, représente un travail de longue haleine. Une approche alternative serait de produire des mutants pour des régulateurs négatifs des fréquences de recombinaison. Chez le colza, jeune allotétraploïde (AACC, 2n=38), il est possible de jouer sur ces 2 approches. Dans un premier temps j’ai cherché à vérifier dans quelle mesure pouvait varier le transcriptome méiotique entre 2 variétés ayant servi à cartographier un QTL pour le contrôle de la recombinaison entre chromosome homoéologues (hérités des génomes parentaux). Ce transcriptome méiotique s’est révélé de façon inattendue très variable ; les principales sources de cette variation étant notamment la nature du génome (A ou C) ainsi que l’effet variété. J’ai montré que les HEs (le remplacement d’une région chromosomique par la duplication de la région homoéologue) contribuent de façon importante aux différences d’expression observées à la fois entre variétés ou au sein d’un même génotype. Dans un second temps, j’ai vérifié que FANCM décrit chez Arabidopis thaliana comme un régulateur négatif pour les fréquences de recombinaison avait bien la même fonction chez les Brassica. Chez Brassica rapa j’ai vérifié qu’un mutant fancm complémente comme attendu un mutant déficient pour la voie majoritaire de formation des COs. Chez Brassica napus j’ai observé une faible augmentation à la fois des fréquences de recombinaison entre chromosomes homologues et homoéologues. Ce travail souligne l’importance de la caractérisation des HEs chez les allopolyploïdes. Au-delà de leurs impacts sur le contenu et l’expression génique, les HEs ont très certainement des conséquences phénotypiques. Cette étude présente aussi un exemple de biologie translationnelle pour un trait important en amélioration des plantesMeiotic recombination driven by Crossing-Over (CO) is a limiting factor for the efficiency of plant breeding. One way to produce hyper-recombinant plants is to use the existing interspecific variability for recombination frequencies. Identification of the causal polymorphisms, either link to gene sequence or expression, represents a long-term endeavour. Another possibility is to mutate anti-meiotic CO genes. In rapeseed, a young allotetraploid species (AACC, 2n=38), both of these approaches are possible. First I wanted to check how much varies the meiotic transcriptome between 2 varieties that differ in term of recombination between homoeologous chromosomes (inherited from parental genomes). Unexpectedly, the meiotic transcriptome turned out to be very variable, the main source of this variation being notably the origin of the genome (A or C) and the variety. I also showed that homoeologous exchanges (HEs; the replacement of one chromosomal region with a duplicate of the homeologous region) contributed to this variation and led to large changes in expression both between and within varieties. Then I assessed whether FANCM, an anti-CO protein identified in Arabidopis thaliana had the same function in the Brassica genus. In Brassica rapa, a fancm mutant complements as expected a meiosis mutant defective in the main formation pathway for the formation of meiotic COs. In Brassica napus, I observed a slight increase in both homologous and homoeologous recombination frequencies. This work emphasizes the importance of characterizing HEs in allopolyploids species. Beyond their impact on gene content and expression, HEs most have likely phenotypic consequences. This study also presents an example of translational biology for an important trait in crop breeding
27
Leino, Matti. "Mitochondrial genetics of alloplasmic male-sterile Brassica napus lines /". Uppsala : Dept. of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, 2005. http://epsilon.slu.se/200546.pdf.
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Gonzalo, Adrian. "Voies de formation des crossovers méiotiques chez une espèce allopolyploïde, le colza (Brassica napus)". Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS352.
Testo completoAbstract (sommario):
La recombinaison méiotique est au cœur de l'hérédité Mendélienne, de l'évolution et de l'amélioration des plantes, car elle assure, grâce aux crossovers, une transmission fidèle des chromosomes et le brassage de l’information génétique au fil des générations. Deux voies de formation des crossovers coexistent chez les plantes. La voie principale (voie I) dépend de la protéine MSH4 (et de quelques autres). La voie secondaire ne produit que quelques crossovers (dits de voie II) au cours de la méiose d’une plante de type sauvage ; ils sont indépendants de MSH4 et leur nombre est limité par des protéines telles que FANCM. Si ces deux voies ont été bien décrites chez des espèces diploïdes, ce n’est pas le cas chez des plantes allopolyploïdes, pourtant très fréquentes parmi les plantes cultivées. Il s'agit là d'une lacune importante, car la présence de plusieurs jeux de chromosomes apparentés conduit à augmenter le nombre de partenaires susceptibles de former des crossovers et le nombre de copies de tous les gènes méiotiques, rendant la recombinaison méiotique plus complexe. Cette thèse vise à explorer l'interaction entre les voies de formation des crossovers et la polyploïdie en utilisant des mutants de colza (Brassica napus; AACC) et d’un de ces parents diploïdes (B. rapa; AA) pour deux gènes de la recombinaison méiotique.J'ai tout d'abord testé dans quelle mesure la formation de crossovers entre chromosomes homologues et entre homéologues (chromosomes A et C) est tributaire des voies I et II en évaluant l’effet d’une diminution du nombre de copies fonctionnelles de MSH4 sur le nombre de crossovers. J'ai montré que ce dernier n'est altéré que lorsque les deux copies MSH4 sont inactivées, toute autre combinaison de mutations conduisant au même nombre de crossovers inter-homologues que chez le sauvage. J'ai également montré que la proportion de crossovers de voie II chez des mutants msh4 de colza est bien supérieure à celles observées chez d’autres plantes mutantes pour msh4. Cette observation reste vraie chez des mutants msh4 de B. rapa, suggérant que la proportion accrue de crossovers de voie II n’est pas spécifique au colza, mais probablement une caractéristique des Brassicaceae. Chez des plantes allohaploïdes (AC) de colza, chez lesquelles les crossovers ne peuvent se former qu’entre homéologues, les copies MSH4 ne se compensent plus complétement ; le nombre de crossovers de voie I fluctue au contraire proportionnellement au dosage de MSH4, devenant presque nul lorsque toutes les copies sont inactivées. Mes résultats illustrent deux nouvelles propriétés spécifiques des crossovers entre homéologues: une plus grande sensibilité vis-à-vis du dosage MSH4 pour les crossovers de voie I et une plus faible efficacité des crossovers de voie II.Dans un second temps, j'ai caractérisé cytologiquement des mutants fancm de colza pour vérifier que l'augmentation des crossovers de voie II ne nuit pas à au bon déroulement de sa méiose. Cette question est restée en suspens, les mutants fancm de colza n’étant pas complètement nuls. Cet écueil m'a incité à développer une approche de TILLING par séquençage pour identifier de nouveaux mutants de recombinaison chez le colza. J'ai alors combiné les mutations fancm et msh4 chez B. rapa pour vérifier si les premières suffisent à corriger les défauts méiotiques induits par les secondes. J'ai montré que, conformément à ce qui avait été observé chez Arabidopsis thaliana, la mutation fancm augmente le nombre de crossovers à un point tel qu’elle restaure la formation de bivalents dans un mutant msh4. La fonction de FANCM est donc conservée chez B. rapa.Mes résultats ont fait progresser la compréhension des voies de formation des crossovers lors d’une méiose allopolyploïde. Ils indiquent que la transmission des chromosomes chez ces espèces implique principalement des crossovers de voie I, et qu’elle pourrait être assurée en limitant l’efficacité de cette voie (e.g. en diminuant le nombre de copies de gènes)Meiotic recombination ensures, through the formation of crossovers (COs), both faithful chromosome transmission and allelic shuffling over generations; it is at the heart of Mendelian heredity, evolution and plant breeding. Two crossover pathways co-exist in plants. The main pathway (class I) is dependent on MSH4 (and additional proteins). The secondary pathway produces only a few MSH4-independent (class II) crossovers during wild-type meiosis that are limited in number by anti-crossover proteins such as FANCM. These pathways have been extensively described in diploid species, disregarding one of the most pervasive features of crop genomes: polyploidy. This is a major gap in our understanding because the presence of more than two related sets of chromosomes leads both to extra partners for crossover formation and additional copies for all meiotic genes, which make meiotic recombination more intricate. This thesis aims at exploring the interplay between meiotic recombination pathways and polyploidy using mutants for two recombination genes in allotetraploid Brassica napus (AACC; 2n=38) and its diploid progenitor, B. rapa (AA; 2n=20). I have first tested the extent to which class I and class II pathways contribute to inter-homolog and inter-homoeolog (between A and C chromosomes) crossover formation by analyzing how crossovers are affected as the number of functional MSH4 copies decreases. I showed that inter-homolog crossover formation is impaired only when the two MSH4 copies are lost, any other combination of msh4 mutations resulting in wild-type crossover numbers. I also observed that, when class I crossovers are completely abolished in B. napus, the highest frequency of class II crossover ever reported among plant msh4 mutants is observed. I reproduced this result using B. rapa msh4 mutants, thereby demonstrating that increased class II crossover frequencies is not specific to B.napus, but could instead be a general feature of the Brassicaceae. In B. napus allohaploids (AC), where crossovers are forced to occur between homeologs, MSH4 copies no longer complement each other perfectly; counter to the situation in euploids, the number of MSH4-dependent crossovers formed between homoeologs fluctuates with MSH4 dosage in these plants, and approximate zero when all MSH4 copies are depleted. Altogether, my results illustrate two novel specific properties of inter-homeolog crossovers: a greater sensitivity to MSH4 dosage for class I pathway and a lower efficiency for class II.Next, I characterized cytologically B. napus fancm mutants to confirm that boosting class II crossovers would not be detrimental to B. napus meiosis. However, a prudential interpretation of these results is demanded since the B. napus fancm alleles retained residual anti-crossover activity. This has prompted me to set up a TILLING-by-sequencing procedure in order to produce new recombination mutants in B. napus. I also combined the B. rapa fancm and msh4 mutations to test whether the former is sufficient to fix the meiotic defects resulting from the latter. I showed that, similarly to what had been observed in Arabidopsis thaliana, fancm mutation boost COs to such a point that it restores bivalent formation in B. rapa msh4 background. My results therefore confirmed that the function of FANCM is conserved in B. rapa. Overall, the findings and achievements of this thesis make a step forward dissection of CO pathways during allopolyploid meiosis. They indicate that meiotic adaptation to allopolyploidy mainly involve the class I crossover pathway and could be achieved by limiting its efficiency (e.g. by decreasing gene copy number)
29
Cooper, Lol L. D. "Characterization of the suboxic response in Brassica napus L". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq22970.pdf.
Testo completo
30
Murphy, Lee Anne. "Vernalization response in spring oilseed rape, Brassica napus L". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq23642.pdf.
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31
Hayter, Katrina Elizabeth. "The pollination dynamics of oilseed rape (Brassica napus L.)". Thesis, University of Exeter, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439826.
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Rezgui, Cyrine. "Etude du potentiel d'introduction de la culture du pois d'hiver dans les successions culturales en Normandie : conséquences sur les communautés microbiennes du sol et les flux d'azote Impacts of the winter pea crop (instead of rapeseed) on soil microbial communities, nitrogen balance and wheat yield Quantification et analyse des exsudats racinaires de pois, de blé et de colza : mise au point d’une méthodologie de collecte des exsudats racinaires N rhizodeposition quantification and root exudates characterization of pea (Pisum Sativum L.), rapeseed (Brassica napus L.) and wheat (Triticum aestivum L.) under controlled conditions Linking soil microbial community to C and N dynamics during crop residues decomposition". Thesis, Normandie, 2020. http://www.theses.fr/2020NORMR047.
Testo completoAbstract (sommario):
La transition agroécologique vise la triple performance agronomique, écologique et sociétale des exploitations agricoles. Un certain nombre de pratiques agricoles permet d’envisager la construction et le développement de systèmes de culture répondant à ces contraintes. Les légumineuses, par leur capacité à fixer l’azote atmosphérique, sont une alternative intéressante aux intrants azotés. Outre l’absence de fertilisation lors de leur culture, elles fournissent de l’azote à la culture suivante. Il existe cependant un manque de références sur certaines légumineuses à graines et notamment la culture du pois d’hiver. En effet, si des données acquises dans différentes régions françaises sont disponibles, aucune référence n’a été publiée pour la Normandie où la culture du pois d’hiver connaît un récent regain d’intérêt. Cette thèse propose d’évaluer, sur une période de deux ans, l’effet du remplacement du colza par le pois d’hiver en tête de rotation en réalisant une analyse comparative de ces deux successions (pois d’hiver-blé et colza-blé). L’objectif était d’évaluer l’effet de ce changement de tête de rotation (pois d’hiver vs colza) sur l’état biologique du sol et les flux d’azote à différentes échelles spatiotemporelles. Les résultats ont révélé une forte variabilité spatio-temporelle dans la réponse des communautés microbiennes du sol, et mis en évidence l’importance du contexte pédoclimatique dans le déterminisme de l’abondance et de l’activité des communautés microbiennes du sol. Ils ont montré par ailleurs, l’effet positif du pois d’hiver sur la disponibilité de l’azote minéral au cours du cycle cultural et pour les cultures suivantes, ici le blé puis l’orge. Les apports d’azote minéral dans le sol lié à la contribution des parties racinaires via la rhizodéposition et à la dégradation des résidus de culture après récolte ont été évalués au cours de ce travail de thèse. En effet, si la rhizodéposition s’est révélée plus importante sous pois d’hiver, elle n’a pas eu d’impact significatif sur les communautés microbiennes rhizosphériques. Contrairement à ces observations, la dégradation des résidus de culture a significativement modifié la composition des communautés bactériennes en lien avec leur composition biochimique initiale. La succession culturale incluant le pois a enrichi le sol en azote minéral mais des risques de perte d’azote par lixiviation de l’ordre de 23 kg N. ha-1 ont été estimés. Ces constats soulignent l’importance d’adapter la conduite des systèmes de culture incluant le pois d’hiver, en limitant les pertes d’azote par lixiviation et en maximisant son utilisation par les cultures suivantes. Les résultats de ces travaux ont confirmé la diminution des quantités d’engrais azoté utilisées dans la succession contenant le pois, sans préjudice de productivité, ni pour le pois, ni pour la culture suivante, ici, le blé. Finalement, introduire le pois d’hiver dans la rotation de culture en région Normandie, semble permettre de répondre à la problématique d’augmentation du coût des intrants, et aux enjeux de transition agroécologique et d’autonomie protéique régionaleThe agroecological transition targets triple agronomic, ecological, and societal performance of farms. Some new agricultural practices had emerged to develop a new cropping system to respond to these constraints. Legumes constitute an interesting alternative. Indeed, legumes are advantageous for soils due to their symbiotic relationship with nitrogen-fixing bacteria. The presence of compatible rhizobia combined to nitrogen-limited conditions promotes symbiosis which is the most efficient way for legumes to acquire more nitrogen. Compared with non-nodulated plants, symbiosis provides a competitive advantage by increasing soil nitrogen pool. However, some grain legumes, notably winter pea, are rarely studied, especially in the Normandy region where no reference has been published for this crop. The objective of this study is to compare two crop successions for a period of two years (winter pea-wheat and rapeseed-wheat), in order to assess the effect of replacing rapeseed by winter pea at the head of the rotation .We evaluated the effect of these two crops (winter pea vs rapeseed) on the biological state of the soil and nitrogen fluxes at different spatio-temporal scales. The results showed a significant spatio-temporal effect on the response of soil microbial communities and highlighted the importance of the pedoclimatic context in determining the abundance and activity of soil microbial communities. A positive effect of winter pea has been demonstrated on the availability of mineral nitrogen during the crop cycle and for following crops (wheat and barley). The supply of nitrogen to the soil is linked to the rhizodeposition of nitrogen via plants roots and the degradation of crop residues after harvest. Our results showed that winter pea exhibited the greatest amount of nitrogen rhizodeposition. However, rhizodeposition did not have a significant impact on rhizospheric microbial communities. Contrary to these observations, the degradation of crop residues significantly modified the composition of bacterial communities linked to their initial biochemical composition. Crop succession including winter pea enriched the soil with mineral nitrogen but simulation with STICS software revealed a nitrogen leaching around of 23 kg N. ha-1 during the cropping cycle. These findings underline the importance of adapting an adequate crop management system, including winter pea, to limit nitrogen losses. The results showed also that wheat yields after winter pea without the use of nitrogen fertilizers were equivalent to those obtained after rapeseed. However, rapeseed required significant nitrogen fertilization. Including winter pea in crop rotation in Normandy region may be a key to enhance productivity, to respond to the challenges of agroecological transition, regional protein autonomy, and to reduce environmental and economic costs, by reducing notably, the costs of fertilizers production and uses
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Nicolas, Stéphane. "Contrôle génétique de la recombinaison homéologue chez les hapoloïdes de Colza (Brassica Napus L. )". Rennes, Agrocampus, 2007. http://www.theses.fr/2006NSARH069.
Testo completoAbstract (sommario):
Valoriser les gènes d’intérêt présents au sein des espèces sauvages apparentées aux espèces cultivées et/ou exploiter le polymorphisme structural susceptible d’exister au seuil des génomes polyploïdes implique de mieux comprendre quels sont les facteurs génétiques et structuraux contrôlant les échanges entre les génomes apparentés (homéologues) et comment ils –inter-agissent. Pour répondre à ces questions, j’ai développé une stratégie originale permettant d’analyser la fréquence et la nature des remanimements structuraux qui surviennent au court de la méiose de plantes haploïdes (Ac, n=19) de colza (Brassicas Napus) présentant des comportements métiotiques très contrastés. J’ai d’abord montré que les gamètes fonctionnels produit par un haploïde de colza sont très majoritairement des gamètes non-réduits de type FDR, que ces gamètes transmettent pratiquement l’intégralité des réarrangements structuraux générés au cours de la méiose et que la plupart de ces remaniements résultent de crossing-overs qui se réalisent de façon privilégiée entre les régions homéologues, mais qui peuvent également se former entre des régions para(homéo)logues. J’ai alors montré que les différences de comportement méiotique observées entre génotypes haploïdes en Metaphase I reflètent des différences de fréquence de recombinaison. J’ai observé que les remaniements effectuent différemment les génomes A et C, ce qui suggère qu’il pourrait y avoir une sélection contre certains d’entre eux. J’ai enfin montré que la fréquence de remaniements varie d’un groupe de liaison à l’autre (cela dépend du génotype haploïde) et en fonction de la position sur les groupes de liaisonNatural biodiversity and beneficial chromosome rearrangements are an under exploited sustainable resource that can be used to enrich the genetic basis of cultivated plants. A lot is still to be done to make a more efficient use of these vast reservoirs of variation. This process is related to meiosis and recombination between related but divergent genomes. In this study, I have genotyped progenies of haploid x euploid B. Napus with molecular markers and analysed the rate and nature of chromosomal rearrangements originating at meiosis in two haploid genotype (n=19) that display very different meiotic behaviour at metaphase I. I show that a high number of chromosomal rearrangements occur during meiosis of B. Napus haploid and are transmitted by FDR-like unreduced gametes to their progeny ; most of these rearrangements are produced by crossing-overs that occur preferentially between regions of primary homeology (Muller), but may also take place between other duplicated regions showing intragenomic or intergenomic homology. I show that the two haloid genotypes display sharp differences of meiotic “homeologous” recombination and that the two genomes of B. Napus are differentially affected by rearrangements, which suggests that some rearrangements are counter-selected. Finally I show that the rate of chromosomal reshuffling varies within and among chromosomes
34
Ili´c-Grubor, Katica. "A novel approach to microspore embryogenesis in Brassica Napus L". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ32787.pdf.
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Bouttier, Claire. "Pod and seed development in oilseed rape (Brassica napus L)". Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277706.
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Chia, Tansy Mee Peing. "Fatty acid breakdown in developing embryos of Brassica napus (L)". Thesis, University of East Anglia, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251645.
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Lacey, Dominic Jamie. "Synthesis of triacylglycerols in developing seeds of Brassica napus L". Thesis, University of East Anglia, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338217.
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Bilsborrow, P. E. "Physiology of yield production in oilseed rape (Brassica napus L.)". Thesis, University of Nottingham, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370355.
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Millam, Stephen. "Studies on the application of biotechnology to Brassica napus L". Thesis, University of Wolverhampton, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328263.
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Scott, Susan Elizabeth. "Predicting transgene movement from GM oilseed rape (Brassica napus L.)". Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314253.
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Norris, Carol Eileen. "Components of gene flow in oilseed rape (Brassica napus L.)". Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620546.
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Garnier, Aurélie. "Dynamique et dispersion d'une espèce cultivée échappée des champs : le cas du colza". Paris 11, 2006. http://www.theses.fr/2006PA112199.
Testo completoAbstract (sommario):
Cette thèse identifie et quantifie certains processus gouvernant l'échappement du colza, sa persistance et son expansion en milieu hors-champ. Tout d'abord, des analyses d'élasticité réalisées sur deux modèles montrent que la banque de graines, l'immigration et la dispersion à longue distance déterminent la dynamique et la dispersion du colza hors-champ. Ensuite, un modèle statistique fournit des paramètres démographiques à partir d'un suivi pluriannuel. Il montre que l'immigration est stochastique et apporte en moyenne quelques centaines ou dizaines de graines par mètre de bordure de route, selon sa provenance. Seules 5% des plantes parviennent à maturité, chacune ne produisant que 2 à 3 rosettes. Des simulations, réalisées avec les précédents paramètres, montrent que les populations hors-champ persistent de 5 à 7 ans, essentiellement via une banque de graines alimentée par l'immigration. Pour finir, des approches complémentaires permettent d'estimer plusieurs modes de dispersion de graines. Une expérience montre que les graines tombées sur le sol peuvent être ré-entraînées, probablement par les véhicules. Une méthode de maximisation de vraisemblance, utilisant un modèle de flux de graines et des données spatiales et génétiques, montre que la moitié des plantes hors-champ proviennent de sources inconnues, les autres provenant des champs à maturité adjacents. La majorité des graines dispersées ainsi restent sur la bordure adjacente aux champs. Les rares populations de colza hors-champ de grande taille doivent être étudiées finement car elles pourraient avoir des capacités de persistance et de dispersion plus importantes et donc influencer les flux de (trans-)gènesThis thesis identifies and quantifies some key-processes governing the escape of oilseed rape from crops, its persistence and expansion in uncultivated areas. First, elasticity analyses, performed with two models, show that persistence of seeds within seedbanks, immigration and long-distance dispersal determine the dynamic and dispersal of feral populations. Secondly, a statistical model provides demographical parameters of feral populations from the explicit likelihood of observed and unobserved stages, obtained from a three-year survey. It shows that immigration is stochastic and provides on average several hundreds and tens of seeds per meter of road verges, depending on its source type (adjacent mature crops or grain trucks). It also shows that only 5% of plants survive until maturity and produce 2 to 3 rosettes. Simulations performed with the above parameters show that feral populations can persist between 5 and 7 years, mainly via a seedbank and immigration. Third, complementary approaches estimate several seed dispersal modes. An experiment shows that seeds fallen on the ground can be re-entrained, probably by vehicles. The best-fitting estimates of a seed flow model, based on both spatial and genetic data and a likelihood-based method, show that half of feral plants originates from unknown seed sources while the other half originates from mature crops. The majority of seeds dispersed from mature crops are likely to remain in front of borders. Rare but large and persisting feral populations should be studied because they could have persistence and dispersal abilities higher than those found here and may therefore influence (trans-)gene flow
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Gibot-Leclerc, Stéphanie. "Etude épidémiologique, écophysiologique et agronomique du couple Orobanche ramosa L. /Brassica napus L". Paris 6, 2004. http://www.theses.fr/2004PA066133.
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Miller, Claire Anne. "The effect of Brassica pathogens on aspects of metabolism in oilseed rape (Brassica napus L.)". Thesis, University of Sheffield, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296856.
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Bassegio, Doglas [UNESP]. "Potencial produtivo de acessos de espécies brássicas sob condições tropicais". Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/150299.
Testo completoAbstract (sommario):
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O gênero Brassica é a terceira maior fonte de óleo vegetal do mundo, com oleaginosas cultivadas no Hemisfério Norte. No Brasil, apesar do aumento nos últimos anos, a espécie Brassica napus L., não é um cultivo tradicional, devido as limitações de fotoperíodo e altas temperaturas. Outras espécies do gênero, como é o caso da Brassica juncea L. e Brassica rapa L., amplamente cultivadas em zonas de baixa precipitação e fertilidade, podem ser opções de cultivo em áreas marginais de sequeiro em condições tropicais, visto que possuem alto teor de óleo com características propicias para o biodiesel, além de menor sensibilidade ao ambiente. Os objetivos deste trabalho foram caracterizar germoplasma de Brassica juncea L. e Brassica rapa L., avaliar o potencial produtivo e a divergência genética de acessos em Botucatu – SP, Brasil. Os experimentos tiveram início em outono-inverno de 2012, com a avaliação de 424 acessos de Brassica juncea L. e 209 de Brassica rapa L. quanto ao florescimento e produção de sementes. Em outono-inverno de 2015 e 2016 acessos de brássicas e um híbrido comercial da espécie Brassica napus L. foram avaliados, em experimentos em blocos ao acaso com três repetições, em relação aos componentes da produção, à produção grãos e óleo e a divergência genética. Do total de acessos introduzidos e avaliados, apenas 51 (12%) de Brassica juncea L. e 59 (28%) de Brassica rapa L. produziram sementes, devido ao efeito de fotoperiodo. Os componentes da produção variaram entre acessos e espécies, com destaque para precocidade e teor de óleo de acessos da espécie Brassica rapa L.; e o número de síliquas e a produtividade de grãos e óleo de acessos da espécie Brassica juncea L.. A produtividade de grãos e óleo foi em média 15% superior nos acessos de Brassica juncea L. em relação a espécie Brassica rapa L., com destaque para o acesso PI 180266 com 2056 kg ha–1 de grãos e 805 kg ha–1 de óleo. A variabilidade genética entre os acessos de brássicas possibilitou a formação de grupos de acessos para futuros ganhos em melhoramento genético. Conclui-se que os acessos selecionados confirmam a hipótese do potencial produtivo sem efeito de fotoperíodo em condições tropicais, o que demonstra que podem ser opções para cultivo em áreas onde a Brassica napus L. não está bem adaptada.
Brassica is the third largest source of vegetable oil in the world, with oilseeds grown in the Northern Hemisphere. In Brazil, despite the increase in recent years, Brassica napus L., is not a traditional crop due to limitations of photoperiod and high temperatures. Other species of the genus, such as Brassica juncea L. and Brassica rapa L., widely cultivated in low rainfall zones and fertility, may be cultivation options in marginal rainfed areas under tropical conditions, since they have high oil content with characteristics conducive to biodiesel, in addition to lower sensitivity to environment. The objectives of this work were to characterize the germplasm of Brassica juncea L. and Brassica rapa L. and to evaluate the productive potential, as well as the genetic divergence of accesses in Botucatu – SP, Brazil. The experiments started in autumn-winter of 2012, with the evaluation of 424 accessions of Brassica juncea L. and 209 of Brassica rapa L. regarding flowering and seed production. In the autumn-winter of 2015 and 2016, Brassica napus L. and commercial Brassica napus L. were evaluated in randomized blocks with three replicates, in relation to the production components, grain and oil production, and divergence genetic. Of the total number of accesses introduced and evaluated, only 51 (12%) of Brassica juncea L. and 59 (28%) of Brassica rapa L. produced seeds, due to the effect of photoperiod. The components of the production varied between accesses and species, with emphasis on precocity and oil content of Brassica rapa L.; and the growth and number of siliques of the specie Brassica juncea L. The yield of grains and oil was on average 15% higher in the accessions of Brassica juncea L. in relation to the species Brassica rapa L., with emphasis on access PI 180266 with 2056 kg ha–1 of grains and 805 kg ha–1 of oil yield. The genetic variability among the accessions of brassicas allowed the formation of groups of accessions for future gains in genetic improvement. It is concluded that the selected accessions confirm the hypothesis of the productive potential without photoperiod effect in tropical conditions, which demonstrates that they can be options for cultivation in areas where Brassica napus L. is not well adapted.
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Nyikako, John Awan. "Genetic variation for nitrogen efficiency in oilseed rape (Brassica napus L.)". [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969936753.
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Funk, Tristan. "Monitoring der Überdauerung und Verbreitung von transgenem Raps (Brassica napus L.)". [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=978856406.
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Girke, Andreas. "Neue Genpools aus resynthetisiertem Raps (Brassica napus L.) für die Hybridzüchtung". [S.l.] : [s.n.], 2002. http://webdoc.sub.gwdg.de/diss/2002/girke/girke.pdf.
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Eastmond, Peter J. "Carbon partitioning in developing embryos of oilseed rape (Brassica napus L.)". Thesis, University of East Anglia, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266757.
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Szadkowski, Emmanuel. "Devenir des génomes et des gènes dans un contexte polyploïde : cas du colza (Brassica napus L.)". Rennes, Agrocampus Ouest, 2011. http://www.theses.fr/2011NSARC101.
Testo completoAbstract (sommario):
L’allopolyploïdie (plusieurs lots de génomes apparentés dans un individu) joue un rôle majeur dans la spéciation et la biodiversité des Angiospermes contemporaines. Les espèces allopolyploïdes permettent d’aborder les mécanismes de régulation de la redondance d’information génétique lors de la confrontation de deux génomes proches. On peut pour cela utiliser des hybrides polyploïdes synthétisés de novo à partir des espèces parentales préalablement identifiées. Le colza (Brassica napus AACC, 2n=38) est issu du croisement entre B. Rapa (AA, 2n=20) et B. Oleracea (CC, 2n=18). Au cours des premières générations de colzas synthétiques, on observe de la recombinaison entre régions homéologues (mêmes régions sur chaque génome), alors que des modifications fonctionnelles se mettent en place dès la confrontation des deux génomes dans l’hybride F1 (génome AC). L’objectif de ce travail est de déterminer l’importance relative des modifications structurales et leurs conséquences fonctionnelles dans les toutes premières générations après hybridation. Nous avons étudié par analyses cytogénétique et génétique la stabilité de la première méiose d’hybrides F1 (génome AC) et des S0 (génome AACC) correspondantes issus de gamètes non réduits ou de doublement somatique. Nous avons focalisé cette étude sur les deux chromosomes homéologues les plus synténiques (A1 et C1) pour maximiser la probabilité de recombinaison homéologue. Nous avons enfin étudié les conséquences des remaniements faisant varier le nombre de copies de gènes homéologues sur leur niveau d’expression. Nous montrons que la polyploïdie soumet la première génération de colzas synthétiques à une phase de forte restructuration des génomes A et C, les gamètes transmis n’étant pas équivalents selon le mode de formation du polyploïde et le cytoplasme (Szadkowski et al. , 2010). Nous montrons également que ces restructurations à l’état hétérozygote semblent dicter le niveau d’expression des copies de gènes homéologues. Cette étude devrait permettre de mieux comprendre la phase d’instabilité précédant la stabilisation d’une jeune espèce allopolyploïde telle que le colzaAllopolyploidy plays a key role in Angiosperm speciation and biodiversity. Allopolyploid species are good models to understand how genes and genome redundancy are managed at the confrontation of two genomes in resynthesized plants from known progenitors. Progenitors of oilseed rape (Brassica napus (AACC, 2n=38) are close to B. Rapa (AA, 2n=20) and B. Oleracea (CC, 2n=18). Homoeologous recombination (between parental genomes) is detected after some generations of resynthesized B. Napus, while gene expression is strongly modified as early as in F1 hybrids. This work focused on the magnitude of structural modifications at onset of polyploid formation and their consequences on homoeologous gene expression. Using cytogenetic approach, we studied the first meiosis of F1 hybrids (AC genome) and their derived S0 plants (AACC genome) obtained through somatic doubling or using its female unreduced gametes. Homoeologous recombination in their progrenies was studied by molecular approach, focusing on two highly syntenic homoeologous chromosomes (A1 and C1) to maximize homoeologous recombination probability. We finally studied gene expression in homoeologous regions on A1 and C1 where recombination occurred and modulates their copy number. We showed that the first meiosis of B. Napus blends genomes (Szadkowski et al. , 2010), in a magnitude that depend upon polyploid formation pathways and cytoplasm. These genetic rearrangements bias homoeologous gene expression even at heterozygous stage. My results provide new clues to understand genetic and gene expression instability in young polyploid species like B. Napus