Call number: LD2668 .T4 1948 V35 / Master of Science

Der tropische Regenwald im südwestlichen Amazonasgebiet ist durch den zunehmenden Bevölkerungsdruck, die wirtschaftliche Ausbeutung, die Abholzung und das Abbrennen großer Flächen für die Viehwirtschaft bedroht. Allgemein zeichnen sich tropische Regenwälder durch eine hohe Diversität von Baumarten und daraus folgenden niedrigen Populationsdichten und entsprechend hohen Distanzen zwischen den Artgenossen aus. Die räumliche Verteilung der Individuen hat grundlegende Konsequenzen auf die Bewegung der Bestäuber und den intraspezifischen Genfluss, was somit die sexuelle Fortpflanzung beeinflusst. Daher ist das Wissen über den Genfluss grundlegend für das Verständnis von Reproduktionserfolgen und dem Management tropischer Baumarten. In dieser Studie untersuchte ich unterschiedliche Aspekte der sexuellen Fortpflanzung von wildem und kultiviertem Kakao (Theobroma cacao) und zwei weiteren Theobroma-Arten in Bolivien. Folgende Hypothesen wurden angenommen: 1) Wilde und kultivierte Pflanzen von T. cacao in Bolivien sind genetisch unterschiedlich; 2) Die Verteilungsdistanz der Pollen wilder Kakaopflanzen ist größer als die der kultivierten Pflanzen; 3) Es existiert ein gewisser Genfluss zwischen den wilden und den kultivierten Pflanzen von T. cacao; 4) Die Ansammlung der Bestäuber unterscheidet sich zwischen den Populationen wilder und kultivierter Pflanzen von T. cacao, sowohl in Bezug auf die taxonomische Zusammensetzung als auch in der Abundanz der Blütenbesucher; 5) Die kleinräumige genetische Struktur der Theobroma-Arten ist aufgrund der Abhängigkeit von Tieren bezüglich Bestäubung und Samenverbreitung gemäßigt. Zu diesem Zweck wurden im Tiefland von Bolivien drei verbreitete Arten der Gattung Theobroma ausgewählt: T. cacao L. (wild und kultiviert), T. speciosum Willd. ex Spreng und T. subincanum Mart. Diese Arten sind stammblütige Bäume des Unterwuchses. Sie haben zahlreiche kleine Blüten und schwere Früchte mit essbaren Samen, welche von Fruchtfleisch umgeben sind. Um den Pollenfluss des Kakaos zu untersuchen, schätzte ich den Grad der Selbstbestäubung und die Distanz der Pollenverbreitung sowie den Genfluss zwischen wildem und kultiviertem Kakao. Ich untersuchte zudem, ob sich die wilden von den kultivierten Kakaobäumen genetisch unterscheiden. Um die Kakaobestäuber zu identifizieren, dokumentierte ich die Zusammensetzung der Blütenbesucher auf wildem und kultiviertem Kakao. Weiterhin ermittelte ich die genetische Diversität und die kleinräumige genetische Struktur (SGS) der drei Theobroma-Arten, um die Distanzen der genetischen Verbreitung aus den Mustern der SGS zu schätzen. Die Ergebnisse zeigen, dass wilder und kultivierter Kakao sich genetisch unterscheiden, woraus geschlussfolgert wird,  dass die „wilden“ Populationen des Kakaos im Tiefland Boliviens tatsächlich wilde Formen oder zumindest sehr alte Sorten darstellen. Wilde Populationen zeigten eine geringere genetische Diversität als kultivierter Kakao, was möglicherweise durch die unterschiedliche Herkunft der kultivierten Sorten (z.B. Costa Rica, Trinidad y Tobago) begründet ist. Im Unterschied zu früheren Studien konnte ich Hinweise für die Selbstbestäubung in wildem und kultiviertem Kakao finden, auch wenn die Fremdbestäubung klar dominiert. Selbstbestäubung war häufiger in kultiviertem als im wilden Kakao festzustellen. Die gesamtdurchschnittliche Distanz der Pollenverbreitung betrug 867 m. Die Distanz der Pollenverbreitung des wilden Kakaos lag in einem Bereich von 10 und 3007 m, während die der Pollen des kultivierten Kakaos über Distanzen von 13 bis 2360 m verbreitet wurden. Die Bestäubungsdistanzen des Kakaos waren höher als die der typischen Unterwuchsbaumarten, wenn man die geringen Größen der bestäubenden Mücken berücksichtigt. Der relativ hohe Pollenaustausch von kultiviertem zu wildem Kakao (20%) gefährdet die genetische Identität der wilden Populationen. Weiterhin wurde eine große Auswahl an Blütenbesuchern dokumentiert und erhebliche Unterschiede zwischen den Besuchern des wilden und des kultivierten Kakaos festgestellt. Die Ergebnisse lassen vermuten, dass die Mücken als Haupt- oder gar alleinige Bestäuber in unserem Untersuchungsgebiet nicht in Betracht kommen, da sie zu selten vorkommen. Potenzielle zusätzliche Bestäuber sind die kleine Diptera (z.B. Chloropidae und Phoridae) und Hymenoptera (z.B. Eulophidae und Platygastridae). Die wilden Verwandten des T. cacao, T. speciosum und T. subincanum zeigten eine relativ hohe genetische Diversität. Die Arten von Theobroma hatten eine niedrige, aber signifikant kleinräumige genetische Struktur. T. speciosum zeigte die höchste Distanz der Pollenverbreitung, was auf eine effiziente Samen- und Pollenverbreitung hindeutet, wohingegen T. subincanum die strukturiertere Art mit der geringsten Distanz der Genverbreitung war.  Abschließend sollten bei verbessertem Management der Kakao-Populationen folgende Punkte beachtet werden: Die hohe Distanz der Pollenverbreitung bei Kakao und der relativ hohe Pollenaustausch von kultiviertem zu wildem Kakao zeigt die Notwendigkeit des Schutzes weitläufiger Naturwälder. Um die genetische Identität des wilden Kakaos in Bolivien zu schützen und zusätzlich den genetischen Austausch zwischen den wilden Populationen zu unterstützen, sollte die genetische Variabilität lebensfähiger Populationen zu erhalten werden. Die kleinräumige genetische Struktur in Theobroma macht die Bedeutung des Schutzes der samenverbreitenden Tiere deutlich, um die genetischen Ressourcen dieser tropischen Baumgattung zu erhalten.

The impact of in vitro ozone and sulfur dioxide fumigation on pollen from two Fraser fir populations was examined. Populations were located at Mt. Rogers, Va, and Mt. Mitchell, S.C.. Two age groups "young" (less then 30 years old) and "old" (more then 40 years old) were examined within each population. No statistically significant age group differences in pollen germination percentage or pollen tube length were found. Mt. Mitchell pollen had a higher germination percentage than Mt. Rogers population. The statistically significant differences in pollen germination between populations were most probably due to the confounding effect of collection practices, and environmental conditions during 1986 pollen collection, rather than actual differences between populations. In vitro pollen fumigation with sulfur dioxide had no impact on pollen germination while fumigation with ozone decreased pollen germination percentage but did not change pollen tube length. Most of the variation in pollen germination percentage, and pollen tube length was due to genotype of the pollen parent tree. The phenotypic expression of six isozymes (previously correlated with resistance to air pollutants) in pollen was studied using polyacrylamide gel electrophoresis. The pattern of isozyme distribution among pollen phenotypes confirmed results from pollen germination studies. There was a difference between locations but no difference between age groups. None of isozyme phenotypes was correlated with a "resistance" to pollen fumigation with ozone or sulfur dioxide. / Master of Science

The importance of maize in sub-Saharan Africa and the potential of quality protein maize (QPM) to alleviate the nutritional gap caused by lack of access to adequate protein rich foods were highlighted. Frustrations from complex inheritance systems of the QPM trait leading to calls for more information on the inheritance and stability of the QPM trait, fear of total loss of the QPM trait due to the recessive nature of the opaque-2 gene to the wild type gene in normal endosperm maize when QPM and normal endosperm maize coexist, lack of information on the nutritional value of contaminated QPM grain, and poor linkages with the smallholder farmers were all cited as drawbacks in the promotion and adoption of QPM. Therefore the objectives of the study were: 1) To solicit the participation of smallholder farmers in the development and setting up of QPM breeding goals, objectives and dissemination strategies; 2) To estimate general combining ability (GCA), specific combining ability (SCA) and reciprocal cross effects on anthesis days, quality traits and grain yield among the publicly available elite QPM inbred lines; 3) To compare experimental QPM hybrids with selected check cultivars, and normal endosperm maize hybrids for grain yield performance and kernel endosperm modification scores; 4) To evaluate QPM hybrids for grain yield and kernel endosperm modification scores in selected sub-Saharan Africa target environments. 5) To determine the level of normal endosperm maize pollen contamination that can occur in quality protein maize without loss of nutritional superiority; 6) To estimate the average levels and the patterns of foreign maize pollen contamination in QPM crops coexisting with normal endosperm maize varieties. The contribution of smallholder farmers in setting breeding goals and dissemination strategies for QPM was solicited. One major finding was that the kernel endosperm qualities of landrace “Hickory King” need to be incorporated into new QPM varieties so as to encourage adoption. Farmers preferred getting information on QPM varieties through their local Agricultural Research and Extension (AREX) officers. A diallel study of 36 F1 QPM hybrids and their reciprocals was conducted across seven environments for agronomic traits and three environments for nutritional value traits. There were significant differences for all traits analysed using Griffing Method 3 model 1. General combing ability effects were significant and important in the control of anthesis days, kernel endosperm modification, protein content, tryptophan content, and Quality Index (QI). Specific combining ability effects were highly significant and important in the control of grain yield. There were significant SCA effects for anthesis days and QI but the proportions were lesser than the corresponding GCA effects in both traits. Kernel endosperm modification had significant GCA effects and nonsignificant SCA effects. Reciprocal-cross differences were significant for anthesis days, tryptophan content and QI. Nonmaternal effects were significant for tryptophan content whilst both maternal and nonmaternal effects were significant for QI and anthesis days. Nonmaternal effects were relatively more important than maternal effects in all the cases where there were significant reciprocal-cross differences. The cross with the highest SCA effects for grain yield was CZL03016/CML144. The most desirable cross with the lowest anthesis days was CZL03016/CML144 whilst the most desirable inbred line with the lowest anthesis GCA effects was CZL03016. The inbred line with the most desirable GCA effects for protein content, tryptophan content and QI was CML264Q. Inbred line CML264Q crossed to CZL03016 had significant SCA effects for QI. The most desirable GCA effects for kernel endosperm modification were associated with inbred line CZL03016 followed by CZL01006. Maternal effects for both tryptophan content and QI were associated with inbred line CML264Q. Genotype by environment interaction effects across all the seven environments were significant for grain yield and kernel endosperm modification. Check hybrids performed better than experimental hybrids for grain yield but were not different for kernel endosperm modification. The normal endosperm maize hybrids were significantly better for both grain yield and kernel endosperm modification. However, in all the comparisons the best check or normal endosperm maize hybrid was not significantly better than the best experimental or QPM hybrid, respectively. The most desirable score for kernel endosperm modification was from the cross of CZL01006 to CZL03016 though not significantly different from the check hybrid with the best score. AMMI1 was the best model for kernel endosperm modification scores and AMMI2 was suitable for grain yield. Both environments and hybrids were diverse. Grain yield of most hybrids was not stable with specific adaptation to environments. The most stable hybrid with no specific adaptation was CML176/CML181f with a mean yield of 6.51t ha-1. The putative nutritional superiority of normal endosperm maize pollen contaminated QPM as measured by the QI depended on the environmental conditions. The moisture stressed environment (CIMMYT Harare) had a lower QI value (0.858) and a lower tolerance to pollen contamination of 15.3% whereas the grain produced under near to optimum growing conditions (ART farm) had a higher QI value (0.915) and a higher tolerance to pollen contamination of 31.9% before total loss of nutritional superiority. Thus contaminated QPM grain had nutritional superiority up to a certain point before total loss of nutritional superiority. Geostatistical analysis was used to determine the levels and patterns of pollen contamination that occur when QPM and normal endosperm maize crops coexist under conditions minimising both temporal and geographical isolation to the lowest possible levels for the two independent crops. Higher pollen contamination levels were restricted mostly to the sections of the QPM crop proximal to the rows of normal endosperm maize crop, with the central parts of the QPM crops experiencing relatively low levels of contamination. For the four experiments (QCS200711, QCS200712, QCS200721 and QCS200722) in which the thresholds to nutritional superiority were determined, 87.9%, 94.8%, 62.2% and 65.6% of the crop areas passed for superior QPM grain, respectively. Estimates for average contamination levels of homogenous mixtures of grain from each of the nine experiments were below 20% contamination. The contamination levels were far less than previously thought. “Hickory King” kernel quality attributes were important in breeding QPM varieties for the smallholder farmers. Parents of the 72 hybrids were diverse for the agronomic characters studied and three of the experimental hybrids were found to be adapted and comparable to the check varieties. Quality protein maize tolerance to foreign pollen contamination without loss in nutritional superiority depended on growing conditions. The coexistence of QPM and normal endosperm maize without total loss of QPM nutritional superiority was feasible. / Thesis (PhD.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

La perspective de la culture de variétés transgéniques pose, pour de multiples raisons, le problème de la ségrégation de filières de production basées sur la même espèce dans les paysages agricoles : demande d'une filière « sans OGM » ; coexistence de productions alimentaires et non alimentaires… La réglementation européenne fixe un seuil de présence fortuite d'OGM au-delà duquel un produit, même issu d'une variété non-OGM, doit être étiqueté comme contenant des OGM. La Commission européenne a émis des recommandations sur l'adoption de pratiques favorisant la coexistence entre cultures OGM et non-OGM de façon à ce que les agriculteurs puissent garder la liberté de choisir le mode de production qu'ils souhaitent. Dans ce contexte, il est important de pouvoir estimer a priori le taux d'impuretés OGM dans les récoltes de parcelles non-OGM, en fonction de leur organisation spatiale et du climat, mais aussi de comprendre et prédire l'effet de modifications de pratiques agricoles sur ce taux. L'expérimentation peut apporter des éléments de connaissances des phénomènes, la modélisation s'avère cependant plus pertinente pour répondre aux demandes d'aide à la décision (principalement publique) pour des situations agricoles et climatiques diversifiées. L'objectif de la thèse est donc de dégager un cadre méthodologique générique pour le développement de modèles de flux biologiques combinant de façon dynamique modélisation, évaluation et expérimentation. Le travail de thèse a consisté en la conception et l'évaluation du modèle MAPOD qui simule les flux de gènes chez le maïs à l'échelle du paysage. Ce modèle est basé sur une fonction de dispersion individuelle qui dépend de paramètres biologiques et climatiques et qui calcule une probabilité de fécondation en un point (x, y) en fonction de la distance à la source émettrice de pollen (pollinisation efficace). Il comporte un module de dynamique de floraison qui rend compte des conséquences des synchronismes ou asynchronismes de floraison entre champs sur les taux d'OGM dans les récoltes. Le modèle permet de déterminer l'effet de la distribution spatiale des parcelles de maïs, des caractéristiques variétales, du climat et des itinéraires techniques sur les taux de pollinisation croisée. MAPOD a été mis au point à partir de données de la littérature et d'expérimentations menées par le GEVES. Cette première version a été évaluée grâce à un second jeu de données provenant du GEVES. Elle a aussi fait l'objet d'une analyse de sensibilité. Les résultats obtenus ont permis de définir les pistes d'amélioration de l'algorithme. La qualité prédictive de MAPOD a ensuite été estimée grâce à des données issues de suivis effectués pendant 5 ans dans des parcelles d'agriculteurs en Catalogne, région où le maïs Bt est cultivé à grande échelle. La pertinence des décisions prises grâce aux sorties du modèle a aussi été caractérisée. MAPOD a été utilisé pour simuler différents scénarios d'introduction de variétés OGM dans les systèmes de culture européens. L'efficacité de mesures individuelles de coexistence a été testée. Ensuite, c'est l'effet de combinaison de pratiques qui a été simulé, aboutissant à l'établissement de tables de décision en fonction du contexte de culture. À l'échelle du bassin de collecte, l'efficience des stratégies de ségrégation (spatiale, temporelle) pouvant être mises en place par les organismes de collecte-stockage a aussi été étudiée grâce au modèle. Enfin, les sorties de MAPOD ont servi comme support pour la mise au point d'un outil d'aide à la décision à destination des agriculteurs et de leurs conseillers. / Consumer demand for food free of GMOs is growing and if production standards are to be met, food and non-food chains must be separated. Indeed, European Commission regulations 1829/2003 and 1830/2003 stipulate that food and feed thought to be GMO-free but found to be containing more than a 0.9% portion of an adventitious presence of authorized GMOs have to be distinguished, traced and labelled as such. Moreover, to ensure that producers have a choice a choice among differing types of production, the European Commission has issued recommendations that permit the coexistence of non-GM and GM crops. This poses the problem of how to deal with coexistence in an agricultural supply chain dedicated to handling a single crop species. To help in the elaboration of coexistence rules, and then assess their feasibility and their consequences as well as for setting up monitoring and control schemes, specific field experiments, even if necessary, are not sufficient as their predictive value remains restricted to a given context. It is necessary to be able to forecast the fate of GM crops at the landscape level taking into account the various cropping systems and agricultural practices that may occur across Europe. The key to forecasting spread and behaviour of GM plants and seeds as well as their impacts under a wide range of agro-ecosystems is modelling. Models reproduce the functioning of agro-systems and take into account the relevant factors and processes as well as their interactions. They thus make it possible to simulate the behaviour of agro-systems in non-observed situations and on a long term basis.This doctoral thesis establishes a methodological framework for the development of biological flow models thanks to the dynamic interactions of modelling, evaluation and experimentation. In a first phase, the work involved the design of the MAPOD® model developed in relationship to literature and varietal experiments carried out by GEVES. MAPOD® simulates gene flow between maize crops at the landscape scale. It is based on an individual dispersal function which depends on biological and climatic parameters. It calculates the probability of fecundation at a (x, y) point as a function of distance from the pollen emitter (efficient pollination). Its flowering dynamics module makes it possible to take into account of the consequences of flowering time - lags on GM adventitious presence in harvests. MAPOD® evaluates the effect of the spatial distribution of maize plots, varietal characteristics, and climate as well as agricultural practices on cross-pollination. In this investigation, in a second phase the initial version of MAPOD® was evaluated with another dataset provided by GEVES. Ways to improve the algorithm were thereby defined. In a third phase, the predictive quality of MAPOD® was estimated by comparing model outputs to cross-pollination rates which were obtained by monitoring farmers' fields in Catalonia (Spain) over a 5-year period. The relevance of decisions made according to model output was also evaluated.In a fourth phase, MAPOD® was used to simulate different scenarios involving the introduction of GM varieties into European cropping systems. The efficiency of individual coexistence measures was tested. Afterwards, the effect of combining different types of practices was simulated, leading to a set of decision-support tables elaborated according to the cropping context. At the scale of the collecting basin, with the enhanced version of MAPOD®, the efficiency of segregation strategies (spatial or temporal) that could be implemented by collecting and storing organisations was also studied. Lastly, model outputs were used as a basis for the design of a decision-support tool for use by farmers and extension workers.

A two-year analysis of pollen rain was conducted in the Pretoria-Witwatersrand-Vereeniging district of the Transvaal, South Africa. Poaceae WaS the major component of the pollen assemblage, comprising 52% regionally. Of the total pollen count, 58.8% was non-seasonal and present throughout the year. During the analysis it became apparent that fungal spores dominated the atmospheric content, accounting for 94% of total airspora, considered here to incl ude pollen and fUngal spores.[Abbreviated Abstract. Open document to view full version]. / AC2017

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2017-05-26T13:04:27Z No. of bitstreams: 2 Dissertação - Eduardo Borges Rodrigues - 2012.pdf: 6019074 bytes, checksum: f7a43bf329af77b351ce74ec756dc615 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-05-26T13:04:48Z (GMT) No. of bitstreams: 2 Dissertação - Eduardo Borges Rodrigues - 2012.pdf: 6019074 bytes, checksum: f7a43bf329af77b351ce74ec756dc615 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-05-26T13:04:48Z (GMT). No. of bitstreams: 2 Dissertação - Eduardo Borges Rodrigues - 2012.pdf: 6019074 bytes, checksum: f7a43bf329af77b351ce74ec756dc615 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2012-09-03 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The success of any breeding program or genetic resources conservation depends on the knowledge about gene flow, reproductive system and genetic variability in the studied populations. For perennial plants, germplasm collection maintained ‘in vivo’ and ‘ex situ’ can be an efficient method for conserving the genetic variability of a species is maintained outside its original habitat. This study aimed to evaluate the reproductive system and pollen-mediated gene flow in one generation of Eugenia dysenterica DC. from the germoplasma collection of the Escola de Agronomia e Engenharia de Alimentos from Universidade Federal de Goiás. We collected leaves from 404 adult plants and seeds from 23 mother-trees in the germplasm collection. Genotypes were obtained using eight microsatellite loci, four of them developed for E. dysenterica, and four transferred from Eucalyptus spp. The total number of alleles was 88, ranging from 4 to 20 for the eight loci analyzed (mean of 11 alleles per locus). The mean expected (He) and observed (Ho) heterozygosity were equal to 0.646 and 0.423, respectively. Additionally, the high combined paternity exclusion probability (QC= 0.99579), and the low combined probability of identity (IC = 7.9 x10-5) indicate that markers can be reliable for this kind of analysis. Multilocus outcrossing rates (t ̂_m= 0.957) and single locus outcrossing rates (t ̂_s= 0.848) were high. Biparental inbreeding (t_m-t_s =0,109) ) combined for all families analyzed was also high and significant, sugesting the occurrence of 10.9% of cross-fertilization between related individuals. Paternity correlation was also low (r ̂_p=0,119), with 11.9% of the progeny sired by cross-fertilization with the same pollen donor. On average 10.79% of the progeny analyzed were derived by biparental cross, whereas 84.70% were formed by multi-parental crosses, being related to the degree of half-sibs. Only 4.6% of the seeds were formed by selfing. Paternity was successfully assigned with 95% of confidence to 32% (171) of the seeds analyzed, most likely due to non-sampled candidate pollen donors or because the loci battery could not demonstrated the optimal values for the combined exclusion. The maximum pollen dispersal distance (224 m) corresponded to the length of the orchard. The “big-bang” flowering pattern and the aggregated spatial distribution of adults may have favored short distance pollen dispersal at the germplasm collection of E. dysenterica. Our results show that the E. dysenterica germplasm collection preserves the genetic diversity present in natural populations of southeastern Goiás and can be a reliable approach for maintenance of genetic diversity of the species for the future. / A definição de qualquer programa de melhoramento ou de conservação de recursos genéticos depende, inicialmente, do conhecimento do fluxo gênico, do sistema reprodutivo e da variabilidade genética existente nas populações. Nesse sentido, as coleções de germoplasma podem funcionar como um método de conservação in vivo e ex situ, em que amostras da variabilidade genética de determinada espécie é conservada fora do habitat da espécie. O objetivo geral desse estudo foi avaliar o fluxo via pólen de uma geração, o sistema reprodutivo e caracterizar molecularmente os indivíduos que compõem a coleção de germoplasma in vivo e ex situ de Eugenia dysenterica DC., mantida pela Escola de Agronomia e Engenharia de Alimentos da Universidade Federal de Goiás. Para tanto, foram coletadas folhas das 404 árvores e frutos de 23 árvores (matrizes) que compõem a coleção de germoplasma. Para a obtenção dos genótipos das árvores e das progênies foram utilizados oito locos microssatélites, quatro desenvolvidos para espécie e os outros quatro desenvolvidos para Eucalyptus ssp. e transferidos para E. dysenterica. Com base nos genótipos foram realizadas as análises descritivas de variabilidade genética, testes de paternidade, distância de dispersão de pólen e taxa de fecundação cruzada para todas as progênies. Para os oito locos analisados, o número de alelos foi igual a 88, variando entre 4 e 20 com uma média igual a 11 alelos por loco. Os valores médios de heterosigozidade esperada (He) e observada (Ho) foram iguais a 0,646 e 0,423. Avaliada a variabilidade genética nas duas gerações foi possível concluir que a coleção de germoplasma de E. dysenterica está preservando bem a diversidade genética oriunda das populações naturais da região sudeste do Estado de Goiás. Adicionalmente, a probabilidade de exclusão combinada (QC) foi igual a 0,99579 e a probabilidade de identidade combinada (IC) foi igual a 7,9x10-5. As taxas de cruzamento multiloco (t ̂_m) e uniloco (t ̂_s) foram altas e iguais a 0,957 e 0,848, respectivamente. A diferença da taxa de cruzamento multiloco e uniloco (t_m-t_s ) combinada para todas as famílias analisadas também foi positiva e significativa, indicando a ocorrência de 10,9% (t_m-t_s=0,109) de fecundação cruzada entre indivíduos aparentados. A correlação de paternidade foi baixa (r ̂_p=0,119) sugerindo que 11,9% dos indivíduos das progênies são filhos do mesmo doador de pólen. Em média 10,79% das progênies analisadas foram originadas por cruzamentos biparentais, sendo aparentados no grau de irmãos germanos, 84,70% foi formada por cruzamentos, sendo aparentados no grau de meios-irmãos e somente 4,6% das sementes foram formadas por autofecundação. Na análise de paternidade, apenas 32% (171) das sementes tiveram seus doadores de pólen atribuídos para um nível de confiança de 95%, o que pode ser explicado por três fatores: a presença de indivíduos juvenis não amostrados; a presença de outros indivíduos de E. dysenterica em outras estações experimentais próximas a coleção de germoplasma; ou pela bateria de locos, que não apresentou os valores considerados ótimos para a probabilidade de exclusão combinada. O efeito da floração “big-bang” e a distribuiçao agregada dos indivíduos adultos torna predominante os eventos de fecundação cruzada em curtas distâncias na coleção de germoplasma de E. dysenterica. O alcance máximo de dispersão de pólen foi de 224 m, esse valor abrange quase toda a área experimental da coleção de germoplasma.

L’intérêt pour la dispersion des gènes via le pollen a augmenté avec les cultures de plantes génétiquement modifiées. A ce jour, les données expérimentales ainsi que la modélisation portant sur les mouvements du pollen de colza, Brassica napus L., à l’échelle du paysage ne différencie pas clairement la part du vent et des insectes dans cette dispersion. Cependant, l’estimation de la dispersion des gènes par le pollen reste une condition nécessaire pour la gestion des risques d’échappement des (trans-)gènes vers l’environnement et les cultures conventionnelles. A travers cette thèse, nous avons pu mettre en évidence qu’une grande diversité d’insectes pollinisateurs pouvait transporter du pollen viable entre différentes plantes de colza sur des distances importantes (>1.1 km). La diversité d’insectes varie d’une région à l’autre et d’une année sur l’autre. Cependant, bien que la majorité des insectes sur une zone de grande production de colza ait du pollen de cette culture sur leur corps, seulement 39,4 % des insectes capturés sur des plantes mâle-stériles transportent du pollen de colza viable. Bien que nous n’ayons pas pu déterminer avec précision la part du vent et des insectes dans le pollinisation du colza, il semblerait que les insectes participent de façon plus importante à la pollinisation de plantes présentes en bordures de champs, augmentant ainsi le taux de pollinisation croisée. Nos résultats fournissent des données fiables pour améliorer les modèles de dispersion pollinique pour des cultures entomophiles à l’échelle du paysage. Ces modèles sont essentiels pour l’aide à la gestion afin de réduire la dispersion des gènes par le pollen des cultures génétiquement modifiées vers les plantes sauvages ou les cultures conventionnelles / Interest in pollen-borne gene dispersal has grown with the cultivation of genetically modified plants. To date both experimental data and models of oilseed rape (OSR) Brassica napus pollen movement at the landscape scale do not clearly differentiate between wind- and insect-mediated dispersal. Estimations of pollen-borne gene dispersal would be valuable for managing potential escapes of transgenes. Our study provides clear evidence that a large variety of insect species can transfer viable pollen between oilseed rape plants over considerable distances (>1.1 km). Insect’s diversity according to geographical site and years. However, the majority of pollinator have OSR pollen in their body hairs, only 39.4% of the insects caught on male-sterile flowers carried OSR pollen. Although we could not determine with precision the role of the wind and the insects in the OSR pollination, it would seem that insects take part in a more important way in pollination of plants present in edges of fields, thus increasing cross pollination rate. Our results provide valuable data to improve models of pollen dispersal for entomophilous crops at the landscape scale. These models are essential to help land-managers reduce pollen-borne gene dispersal from genetically modified plants to wild relative and field planted with non-GM crops

Made available in DSpace on 2016-12-12T20:12:31Z (GMT). No. of bitstreams: 1 PGEF14MA023.pdf: 1162043 bytes, checksum: 8432963324a52811e61e2d071eacc033 (MD5) Previous issue date: 2014-07-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Gene flow is a determining component of persistence and adaptation of local populations, and may influence their ecological properties. Understand the behavior of this flow in natural or altered populations is essential for developing effective conservation plans by the use of natural resources. We investigated the influence of Pinus plantations in the pollen dispersal patterns in remaining Araucaria angustifolia populations (patches), using paternity analysis with eight microsatellite locos. For this, we sampled two patches in the grassland area and two patches in the pine plantations area, located in southern Santa Catarina plateau. In the study areas all male reproductive individuals (68) and 400 seeds from 20 seed-tree (five per population) were mapped and genotyped. The paternity analysis revealed higher average distance of pollination for grassland area (170 m) than Pinus plantation area (67 m). The effective number of pollen donors (Nep) was 16.4 and 8.9 for grassland area and Pinus, respectively. Grassland areas showed a pollen immigration rate of 46%, and the plantation area showed a 36%. These results are an indication that the Pinus plantation can act as barrier to pollen flow, although, pollen dispersal occurs through plantings. There was no significant spatial genetic structure for adults, and high levels of genetic diversity were verified in both areas (He, ranging 0.16 to 0.829), with no significant differences, suggesting presence of historic gene flow between locals. While the seeds from natural grasslands seed-tree present no significant fixation index, the seeds from seed-tree located into Piuns plantations presented significant fixation indexes (F = 0.076, P<0.05). Both adult population and seeds showed private alleles, evidencing that not all possible reproductive individuals, in the remnants, contributed to seed sampled formation, however, pollen flow from outside contributed effectively to seed formation within patches / O fluxo gênico é um dos componentes determinantes da persistência e adaptação das populações locais, podendo influenciar em suas propriedades ecológicas. Entender o comportamento desse fluxo em populações naturais ou alteradas é essencial para elaboração de planos eficazes de conservação pelo uso dos recursos naturais. Investigou-se a influência de plantios de Pinus no padrão de dispersão de pólen em populações remanescentes de Araucaria angustifolia (capões), por meio análises de paternidade com oito locos microssatélites. Para isso, amostraram-se dois capões em área de campo e dois em área de plantios de Pinus, localizados no planalto sul catarinense. Nas áreas de estudo (capões) foram mapeados e genotipados todos os 68 indivíduos machos reprodutivos e mais 400 sementes retiradas de 20 plantas matrizes (cinco por população). A análise de paternidade revelou que a distância média de polinização para a área de campo (170 m), foi maior do que para área de plantios de Pinus (67 m). O número efetivo de polinizadores (Nep) foi de 16,4 e 8,9 para área de campo e plantio de Pinus, respectivamente. Áreas de campo apresentaram uma taxa de imigração de pólen de 46% e áreas de plantio apresentaram 36%. Esses resultados são um indicio de que os plantios de Pinus podem agir como barreira ao fluxo de pólen, embora ainda ocorre fluxo através dos plantios. Verificou-se a presença de estrutura genética espacial não significativa para os indivíduos adultos em ambas as áreas, além de uma elevada diversidade genética (He, variando de 0,16 a 0,829), sem diferenças significativas, sugerindo a presença de um fluxo gênico histórico entre as áreas. Enquanto as sementes oriundas das matrizes em meio as áreas de campo não apresentaram índice de fixação significativos, as sementes oriundas das árvores em meio aos plantios de Pinus apresentarem índices de fixação significativos (F = 0,076, P<0,05). Tanto a população adulta quanto as sementes apresentaram alelos exclusivos, evidenciando que nem todos os indivíduos reprodutivos presentes nos remanescentes contribuíram para a formação da amostra de sementes, entretanto o fluxo de pólen externo contribuiu efetivamente para formação das sementes de dentro do capão

The genetic diversity and genetic structure of populations, and the processes shaping gene flow within and between populations, are influenced by the landscapes they occur within. Within terrestrial landscapes, rivers and their riparian habitat are among the most dynamic, diverse and complex of landscapes and their linear structure appears as an interlinking feature across large landscapes. This thesis took a landscape genetics approach to examine the influence of river landscape features on Alnus glutinosa populations, a widespread keystone tree species of European riparian ecosystems. By accounting for the differing dispersal mechanisms of A. glutinosa (wind and water), landscape effects on seed- and pollen-mediated gene flow, genetic diversity, demographic and genetic structure were identified at different spatial scales of a large UK river catchment. Widespread gene flow within and between A. glutinosa populations was identified with no apparent limitation of wind-mediated pollen dispersal. Hydrochorous dispersal of seed between populations was evident, and found to increase genetic connectivity between riparian populations; however an isolation by distance effect was identified between populations located further apart from each other. No pattern of genetic diversity was found, with high levels of genetic diversity identified at all spatial and temporal scales. At the river-catchment scale no genetic clustering was observed, either within or between the six rivers studied. Demographic structuring within A. glutinosa populations was evident, and correlated with distance from the main river channel. Interactions between seed dispersal, hydrological disturbance, colonisation, and historical influences are discussed in relation to fine-scale spatial genetic structure between A. glutinosa sapling and adult generations. Central to the landscape genetics approach taken in this thesis was the incorporation of key A. glutinosa life history attributes. By incorporating gene flow analyses, species ecology and landscape features, the research presented here furthers our understanding of riverine landscape influences on their riparian populations at different spatial scales and can be used to inform management principles.