Two eucalypt clines were examined using morphological, ecophysiological and molecular analyses. The species complexes examined were an ironbark complex (Eucalyptus melanophloia x E. whitei) and a box complex (E. brownii x E. populnea). Both of these complexes demonstrate continuous morphological variation across their clines. The origin of these morphological clines has previously been interpreted as the product of secondary contact between allopatric species. In this study, an analysis of morphological variation across the clines did not identify an increase in trait variance in the intermediate populations, which suggests that previous theories concerning the origin of these clines may not be valid. Genetic structuring in nuclear and chloroplast DNA was examined across the clines to investigate whether the morphological clines were the product of secondary contact between two independent evolutionary lineages, or whether the clines represent a single evolutionary lineage that has undergone primary differentiation. The microsatellite analyses indicated that there was little genetic structuring across either cline, and that there were only low levels of population differentiation. The lack of hierarchical structuring in the distribution of nuclear genetic variation suggests that these clines are unlikely to be the product of recent gene flow between two formerly allopatric species/populations. A nested clade analysis of the JLA+ region of the cpDNA provides additional evidence to reject the null hypothesis that the morphospecies classifications represent distinct evolutionary lineages. Instead the analyses indicate that each cline represents a single cohesion species and a single evolutionary lineage. The phylogeographic distribution of cpDNA haplotypes is likely to have resulted from restricted seed mediated gene flow with isolation by distance. A more cogent explanation for the clines, based on the genetic data, is that they have arisen through the process of continuous morphological diversification that has been promoted by a directional selection gradient. Drought experiments were conducted in the glasshouse to investigate whether differences in physiological performance under water stress helps to explain the maintenance of the ironbark cline. Under increasing water stress, the morphotypes showed differences in their ability to maintain water status and photosynthetic rates, yet there was no obvious pattern to these differences across the cline. Physiological differences are therefore inadequate to explain the maintenance of the ironbark cline and highlight the compensatory role that morphological variation may play in alleviating water stress. The value of adopting the cohesion species concept and a hypothesis-testing framework to assess species status is demonstrated in this study. This framework provided a statistical approach to distinguish independent evolutionary lineages from interspecific populations and provides evidence to refute the current species status of the species complexes studied. Eucalypt classification is predominantly based on morphology, which results in taxonomic classification that may not reflect genealogical relationships. This is due to the disparity between morphological and phylogenetic relationships. I therefore suggest that current presumptions regarding the prevalence and importance of hybridisation within the genus may reflect taxonomic classification. An accurate assessment of the prevalence and importance of hybridisation requires species classification to be based on genealogical relationships.

The goal of this work was to quantify the effects of eucalypt woodland blocks on the productivity of native pastures. This research was conducted on the Southern Tablelands of New South Wales. Tree planting or retention is seen by many as an important tool in addressing the problems of soil degradation resulting from clearing and pasture improvement that threaten the sustainability of pasture systems. In particular these are dry land salinity and erosion, both of which affect large areas of agricultural lands in the south east of Australia. Whilst native tree cover remains over substantial portions of Australian pasture lands, mainly on steeper slopes and poorer soils, little has been done to measure the effects of trees on pasture productivity and soil fertility on the Southern Tablelands. Previous studies in other areas have shown a range of effects�from facilitation to inhibition�of pasture growth in the presence of trees. Soil fertility beneath trees has been shown by a number of workers to be elevated in comparison with situations in the open. Given that the range of effects may be highly site dependent, application of results from one area to another may not be valid. Thus it is necessary to measure tree effects on a regional scale if results are to be reliable. Pasture productivity was assessed over a two year period on four sites in the vicinity of Bungendore, New South Wales. A pair of plots was selected on each site, one plot in a block of eucalypt woodland, and the other nearby in an exposed, open situation. Plots were chosen to be as similar to each other as possible with the exception of tree cover. Treed plots had a tree basal area of between 10 and 20 m2 ha-1 and plots had an area of 900 m2. Two of the sites were on granitic soils and had a tree cover consisting predominantly of Eucalyptus pauciflora. The remaining two sites were on soil derived from sedimentary rocks with tree cover consisting mainly of E. mannifera, E. dives and E. melliodora. Perennial native pasture species present were similar across all sites, although their relative contributions to standing biomass varied between sites. As the plots were grazed during the period of measurement, productivity and offtake were measured seasonally using exclosure cages on each plot. Pasture standing biomass was assessed using the comparative yield technique. Microclimate was monitored in each plot by automatic weather stations. Soil moisture to a depth of 45 cm was measured by time domain reflectometry using permanent probes in each plot. Ten additional survey plots on each site, covering the range of tree basal area from 0 - 30 m2 ha-1, were assessed each season in the second year for standing biomass, soil fertility and pasture quality; expressed by nitrogen content and dry matter digestibility. Pasture floristics were measured using the dry-weight-rank method. These additional plots were chosen to be as representative of the paddocks as possible. Over the two years that productivity was measured, it was found to be higher under trees than in the open. This was predominantly due to higher winter and spring growth within treed plots. Grazing offtake was also found to be higher under trees, partly accounting for lower standing biomass found in the treed plots. Wind run, evapotranspiration and photosynthetically active radiation were all reduced by the presence of trees. Beneficial effects of shelter from winds may largely explain the higher productivity observed in the treed plots, and could outweigh negative effects of below ground competition and radiation interception by tree canopies at low to moderate tree densities. Soil moisture was not affected by the presence of trees. Soil fertility also did not differ between treed and open plots nor was there any difference in pasture nitrogen content or dry matter digestibility. On the sites where soils were derived from sedimentary rocks, pasture floristics were found to be related to tree basal area. Themeda ausfralis biomass was negatively related to tree basal area, and was partially replaced by large tussock species such as Poa sieberiana and Chionochloa pallida. A reduction of pasture quality resulted, particularly as the latter species is not grazed to any significant extent. Given the desirability of having deep rooted perennial components in grazing lands, the results of this study indicate that it may be possible to utilise trees to assist in preventing or reducing a range of adverse environmental consequences arising from agricultural activities, without unduly compromising pasture productivity. Additionally, the wide range of environmental conditions provided by a mix of treed and open pasture promotes a higher degree of heterogeneity of the herbaceous layer. This may assist in maintaining productivity over a greater range of climatic conditions than would be the case with a more homogeneous pasture.

The ability of eucalypt trees to grow in different soil aspects, under variable climatic and environmental conditions and to grow fast consistently producing straight stems has made them preferred plantation trees in many parts of the world. The world‘s increased demand for pulp wood has been the major contributor to the aggressive extensive development of eucalyptus plantations around the world. The productivity of these trees is however hindered in both native and introduced plantations by pests and pathogens. Chapter 1 of this thesis is a literature review on Teratosphaeria suttonii as the causative agent of Teratosphaeria Leaf Disease on Eucalyptus. The chapter highlights the taxonomic placement of T. suttonii in the genus Teratosphaeria and the name changes of the species as a consequence of molecular taxonomy. The effects of the pathogen on Eucalyptus plantations in different parts of the world as well as the incidence and range of Eucalyptus species that host the pathogen are presented. In addition the review summarizes much of the information published on the distribution, hosts range and evolutionary relationships of T. suttonii with closely related species in the genus Teratosphaeria. In conclusion, it highlights the lack of understanding of the degree of diversity of the pathogen from different parts of the world. In order to characterize and establish the phylogenetic relationships between T. suttonii isolates from different countries, chapter 2 of this thesis considered microscopic examination and DNA sequence comparisons of isolates from its native and introduced localities. The isolates were classified into a single genetically and morphologically diverse group within which representatives of different countries were intermixed in smaller groups. A high level of genetic variation was evident among Australia isolates but despite the diversity there was no overwhelming evidence for sibling species. In Chapter 3 of this thesis eleven microsatellite markers were developed from three T. suttonii isolates obtained from 2 geographic areas. The markers were used in Chapters 4 and 5 to investigate the genetic diversity of T. suttonii in both its native and introduced environments and to establish factors underlying such diversity. The application of the markers in Chapters 4 and 5 provide the first consideration of the diversity of T. suttonii in both its native and introduced localities respectively. Both native and introduced pathogen populations exhibit substantially high genotypic diversities. It is evident from these studies that Australia is the point of origin of T. suttonii and that anthropogenic activities have resulted in repeated introductions of the pathogen from Australia into many countries. Teratosphaeria suttonii is of great significance to the eucalyptus plantation industry across the world. Movement of diseased germplasm and introduction of new genotypes favors pathogen adaptability. In order to reduce the distribution of the pathogen into new areas or any other places where it might have negative effects, strict quarantine procedures should be followed. / Thesis (PhD)--University of Pretoria, 2013. / gm2013 / Microbiology and Plant Pathology / Unrestricted

A pluridade de características de espécies nativas, aliada a leis que limitam sua exploração, acarreta na necessidade de estabelecimento de novas espécies capazes de suprir a demanda madeireira brasileira. Os Eucalyptus spp. são altamente produtivos sob clima tropical, sendo extensamente plantados no país para diversas finalidades, em especial papel e celulose, energia, painéis e serraria, entretanto, pouca ênfase tem sido dada a esta última, devido ao horizonte longo de planejamento, dificuldades no processamento primário e defeitos na madeira apresentados pelas espécies mais produtivas do gênero. Visando traçar estratégias que minimizem essas dificuldades, analisamos o efeito de 2 formas de manipulação de copa - destopo e desrama -, sob diferentes regimes de luminosidade, em parâmetros da copa e do tronco em híbridos de Eucalyptus urophylla dos 11 aos 23 meses de idade. Tanto o destopo quanto a desrama afetaram negativamente o incremento diamétrico e volumétrico do híbrido, entretanto, árvores destopadas sob níveis maiores de luminosidade exibiram fatores de afilamento menores, quando comparadas ao tratamento Controle. Dentro do mesmo regime de luminosidade, árvores desramadas também apresentaram fatores de afilamento inferiores. Apesar de sua alta demanda por luz, o híbrido foi capaz de alterar sua estrutura foliar de acordo com o nível de luminosidade: árvores sob regimes de luminosidade reduzida adaptaram suas folhas à sombra (folhas de sombra), enquanto que àquelas sem limitação de luminosidade folhas adaptadas ao sol (folhas de sol). Brotações em resposta ao destopo se resumiram à brotações epicórmicas próximo à seção destopada. / The diversity of characteristics of native species, allied to laws that limit their exploration, reinforces the need of establishing news species to supply the national wood demand. The Eucalyptus spp. are highly productive under tropical whether, being extensively planted in the country to many finalities, especially paper, pulp, energy, panels and sawn wood, however, low attention is being given to the last due to the long term planning, difficulties in the primary processing and wood blemishes present in the most productive species of the gender. Aiming to trace strategies that minimize these hardships, we analyzed the effects of two forms of crown manipulation - topping and pruning -, under different light patterns, in parameters of crown and bole of Eucalytpus urophylla hybrids from 11 to 23 months of age. Both topping and pruning impacted negatively the diametric and volumetric increment, although topped trees showed smaller taper when compared to the Control treatment. Within the same light pattern pruned trees also presented smaller taper. Although the hybrid demands high amounts of light, it was capable of altering its foliage structure according to the light level: trees under reduced light adapted its leaves to shadow (\"shadow leaves\"), while those without light limitation leaves adapted to sun (\"sunleaves\"). Shoots in response to topping were resumed to epicormic shoots close to the topped section.

A região compreendida entre os trechos alto do rio Paranapanema, médio do rio Tietê e o rio Sorocaba possui longo histórico de influência humana na paisagem. Esta influência intensificouse nos dois últimos séculos com a passagem de estradas de ferro e a construção de hidroelétricas, entre outras modificações que implicaram em alterações do uso da terra. Uma das mudanças significativas foi a chegada e expansão rápida da silvicultura de eucalipto. A estrutura desta vegetação cultivada e seu ciclo produtivo têm influência sobre as comunidades vegetais e animais nativas. Neste estudo foi avaliada a influência da conformação geométrica da paisagem e da idade de plantio de áreas de silvicultura de eucalipto sobre padrões de distribuição e abundância de mamíferos de médio e grande porte. Foi possível demonstrar que herbívoros são favorecidos por áreas extensas de vegetação nativa com geometria simples, enquanto onívoros se beneficiam da ausência de grandes predadores e da geometria convoluta da vegetação nativa em áreas onde a matriz de eucalipto domina a paisagem. Onde o eucalipto é a feição dominante da paisagem agrícola, estas espécies utilizam o interior dos talhões em fase intermediária de cultivo, quando existe sub-bosque que ofereça abrigo e recursos alimentares. Tais observações reforçam a importância da manutenção de Áreas de Preservação Permanente e de Reserva Legal em paisagens agrícolas, assim como questionam o conservadorismo na aplicação da legislação que leva ao embargo do corte de eucaliptais com sub-bosque, diminuindo o valor de conservação desta cultura sobre a fauna de médios e grandes mamíferos nativos. Palavras-chaves: mamíferos de médio e grande porte, padrões de distribuição e abundância, paisagem agrícola, eucalipto. / The region comprehended amid the high portion of river Paranapanema, mid portion of river Tietê and the river Sorocaba, has a long history of human influence on landscape. This influence was intensified during the past two centuries through the passage of railroads and hydroelectric dam constructions along with other modifications that had implications on land use changes. One of the significant modifications was the arrival and rapid expansion of eucalypt silviculture. The structure and cycle of production of this cultivated vegetation have influence on plant and animal native communities. In this study, geometric conformity and age of planted stands in eucalypt silviculture areas were evaluated on patterns of distribution and abundance of medium to large size mammals. It was possible to demonstrate that herbivores are favored by extensive areas of native vegetation, while omnivores benefit from the absence of large predators and complex geometry of native vegetation in landscapes with dominant eucalypt matrix. Where eucalypt plantations are the commonest landscape features, these species use central areas of silviculture stands in intermediate stages of cultivation, when there is undergrowth that offers shelter and food resources. These observations reinforce the importance of Permanent Preservation Areas and Legal Reserves in agricultural landscapes, as well as they question the conservatism on application of environmental laws that leads to the legal impediment of harvest on eucalypt stands with undergrowth, decreasing conservation value of this culture for medium to large size mammals fauna.

No Brasil, está ocorrendo a expansão da área florestal plantada com espécies do gênero Eucalyptus, sendo que a elevada produtividade pode ser atribuída às pesquisas e melhorias operacionais introduzidas nas ultimas décadas. Nos experimentos realizados em diferentes regiões do Brasil, tem se observado maior incremento dos eucaliptos com o aumento das doses de fertilizantes. Mas o excesso ou a aplicação inadequada de fertilizantes gera freqüentemente o desperdício dos insumos e a lixiviação dos elementos, que podem contaminar o solo e o lençol freático. Portanto, foi objetivo deste trabalho analisar o efeito de doses, bem como do parcelamento da aplicação de fertilizantes na produtividade e na ciclagem de nutrientes em plantios de eucaliptos, além de avaliar a lixiviação de nitrogênio e potássio no solo, após a fertilização de cobertura parcelada em comparação à aplicação em dose única, três meses após o plantio. O experimento foi implantado no município de Anhembi-SP, sendo constituído por cinco tratamentos com a aplicação de doses crescentes e eqüidistantes de N, P e K com a aplicação da fertilização de cobertura (N e K) em 4 parcelas e por um tratamento com fertilização de cobertura aplicada em dose única, três meses após o plantio. Foram avaliados o incremento volumétrico e a produção da biomassa aérea e radicular das árvores, as concentrações e os estoques de nutrientes nos eucaliptos (mineralomassas), a eficiência do uso dos nutrientes, a transferência de nutrientes das árvores para o solo através da produção de folhedo (ciclo biogeoquímico), a ciclagem interna dos nutrientes (ciclo bioquímico), bem como o fluxo de água e a lixiviação do N e K no solo nas profundidades de 20 e 90 cm. Os eucaliptos responderam positivamente ao aumento das doses de fertilizantes, principalmente na fase inicial, apresentando maior produtividade (altura, volume e biomassa). O tratamento com a maior dose obteve, aos 24 meses de idade, 105 t ha-1 de biomassa total, sendo 48% superior ao tratamento sem fertilização, com apenas 71 t ha-1. Entretanto o efeito das maiores doses de fertilizantes foi mais acentuado na fase inicial do crescimento, até os 12 meses de idade. Ocorreu a atenuação do incremento ao longo do tempo, sendo que aos 24 meses não foram observadas diferenças significativas entre os tratamentos com a aplicação de doses de fertilizantes. A fertilização também propiciou maior acúmulo de nutrientes (mineralomassa) nos componentes das árvores (folhas, galhos, lenho, casca e raízes) e maior transferência de nutrientes para o solo, através do folhedo. Assim, os eucaliptos com a adição das doses mais elevadas de fertilizantes devolveram ao solo, via folhedo, aproximadamente 50 kg ha-1 ano-1 de N, 20 kg ha-1 ano-1 de K e 80 kg ha-1 ano-1 de Ca, enquanto o tratamento sem fertilização transferiu para o solo apenas 25 kg ha-1 ano-1 de N, 6,5 kg ha-1 ano-1 de K e 47 kg ha-1 ano-1 de Ca, no período entre 12 a 24 meses de idade. Foi observado que os eucaliptos com menor disponibilidade de nutrientes foram mais eficientes no uso do N e K. Não foram observadas diferenças significativas na produção de biomassa lenhosa entre os tratamentos com aplicação da fertilização de cobertura de forma parcelada ou em dose única, sendo observado maior lixiviação do N e do K, aos 90 cm de profundidade, com a aplicação em dose única. / It is occurring, in Brazil, the expansion of planted forest area with species that belong to the Eucalyptus genus, one of the reasons is the high biomass productivity resulting from the research and the operational improvements that have been implemented during the last decades. In several field experiments, has been observed an increase of eucalypts growth by using a higher amount of fertilizers. But excessive or inappropriate application of fertilizers may generate the fertilizer waste and nutrients leaching that may contaminate soil and watertable. The objective of this study was to evaluate the effect of fertilization doses in the biomass production and nutrient cycling from the eucalypt plantation, as well as evaluating the N and K leaching in the soil after the application of split and single dose of N and K fertilization. The experiment was set up in the Anhembi city (State of São Paulo), and it was constituted by five treatments with doses of fertilizers and N and K in split application (4 times) and also a treatment with a single dose of N and K application, 3 months after planting. It was evaluated the wood volume, root and shoot biomass, concentrations and stocks of nutrients in eucalypts biomass (mineralomass), the efficiency of nutrient use, the nutrient transference from the canopy to the soil through litter production (leaf-fall), internal nutrients cycling (biochemical cycle), the water flow and leaching of N and K in the soil at the depths of 20 and 90 cm. The eucalypts responded positively to the increased fertilization doses, especially in the first year, with higher productivity (height, DBH and biomass). Treatment with the highest dose for 24 months produced 105 tons ha-1 of biomass, 48% higher than the treatment without fertilization, with only 71 tons ha-1. However the effect of higher doses was more evident at an early stage of tree growth, up to 12 months of age. However, the difference decrease over time, and at 24 months there were not significant differences among the treatments with fertilization application. Fertilization also resulted in higher nutrients accumulation (mineralomass) in all tree components (leaves, branches, wood, bark and roots) and increased nutrient transfer to the soil through deposition of leaf litter. Thus, the eucalypts applied the highest addition of fertilization dose returned to the soil through litter, about 50 kg ha-1 yr-1 of N, 20 kg ha-1 yr-1 of K and 80 kg ha-1 yr-1 of Ca, while the treatment without fertilization transferred to the soil only 25 kg ha-1 yr-1 of N, 6.5 kg ha-1 yr-1 of K and 47 kg ha-1 yr-1 of Ca during 12 months (between 12 to 24 months after planting). It was observed more efficient use of nutrients from the eucalypts with lower nutrients availability. Also, there were no significant differences in the growth of eucalypts from the treatments with split N and K application and single N and K application. However, there was a higher leaching of K and N, 90 cm deep, in the single application treatment.

A pluridade de características de espécies nativas, aliada a leis que limitam sua exploração, acarreta na necessidade de estabelecimento de novas espécies capazes de suprir a demanda madeireira brasileira. Os Eucalyptus spp. são altamente produtivos sob clima tropical, sendo extensamente plantados no país para diversas finalidades, em especial papel e celulose, energia, painéis e serraria, entretanto, pouca ênfase tem sido dada a esta última, devido ao horizonte longo de planejamento, dificuldades no processamento primário e defeitos na madeira apresentados pelas espécies mais produtivas do gênero. Visando traçar estratégias que minimizem essas dificuldades, analisamos o efeito de 2 formas de manipulação de copa - destopo e desrama -, sob diferentes regimes de luminosidade, em parâmetros da copa e do tronco em híbridos de Eucalyptus urophylla dos 11 aos 23 meses de idade. Tanto o destopo quanto a desrama afetaram negativamente o incremento diamétrico e volumétrico do híbrido, entretanto, árvores destopadas sob níveis maiores de luminosidade exibiram fatores de afilamento menores, quando comparadas ao tratamento Controle. Dentro do mesmo regime de luminosidade, árvores desramadas também apresentaram fatores de afilamento inferiores. Apesar de sua alta demanda por luz, o híbrido foi capaz de alterar sua estrutura foliar de acordo com o nível de luminosidade: árvores sob regimes de luminosidade reduzida adaptaram suas folhas à sombra (folhas de sombra), enquanto que àquelas sem limitação de luminosidade folhas adaptadas ao sol (folhas de sol). Brotações em resposta ao destopo se resumiram à brotações epicórmicas próximo à seção destopada. / The diversity of characteristics of native species, allied to laws that limit their exploration, reinforces the need of establishing news species to supply the national wood demand. The Eucalyptus spp. are highly productive under tropical whether, being extensively planted in the country to many finalities, especially paper, pulp, energy, panels and sawn wood, however, low attention is being given to the last due to the long term planning, difficulties in the primary processing and wood blemishes present in the most productive species of the gender. Aiming to trace strategies that minimize these hardships, we analyzed the effects of two forms of crown manipulation - topping and pruning -, under different light patterns, in parameters of crown and bole of Eucalytpus urophylla hybrids from 11 to 23 months of age. Both topping and pruning impacted negatively the diametric and volumetric increment, although topped trees showed smaller taper when compared to the Control treatment. Within the same light pattern pruned trees also presented smaller taper. Although the hybrid demands high amounts of light, it was capable of altering its foliage structure according to the light level: trees under reduced light adapted its leaves to shadow (\"shadow leaves\"), while those without light limitation leaves adapted to sun (\"sunleaves\"). Shoots in response to topping were resumed to epicormic shoots close to the topped section.

A videografia aérea é uma técnica que vem sendo utilizada nos EUA para avaliação, detecção e prevenção de problemas na agricultura, agricultura de precisão e no manejo de áreas naturais. Um dos motivos para o emprego desta técnica é o seu baixo custo para a obtenção das imagens e a rapidez com que podem ser captadas, processadas e analisadas. Assim sendo, o objetivo deste trabalho foi verificar a utilidade da técnica videográfica no levantamento de problemas nutricionais em plantações de eucalipto, utilizando-a como ferramenta no monitoramento nutricional, tornando-o mais preciso e menos dispendioso que os métodos utilizados atualmente. Para isto, instalou-se um experimento com tratamentos de subtração de nutrientes com a finalidade de verificar a potencialidade da videografia aérea como técnica para distinguir os tratamentos com deficiência nutricional nos plantios deeucalipto. Foram obtidas imagens nos espectros verde, azul, vermelho e infravermelho próximo, 12 meses após o plantio. Essas imagens foram capturadas com duas câmeras S-VHS: uma capaz de captar a faixa do espectro visível (400 - 700 nm) e, outra capaz de captar a faixa do espectro visível mais infravermelho próximo (400 - 1100 nm). Nestas câmeras foram também utilizados filtros de subtração para separar as faixas do espectro a serem trabalhadas. Além disso, com a utilização do software ENVI, foi feita uma análise dos valores de pixels de cada parcela, obtendo-se os valores mínimos, médios, máximo e o desvio padrão da média. Estes valores foram, então, comparados e agrupados conforme análise estatística multivariada, buscando encontrar relações entre os dados das imagens e os tratamentos. Relações significativas entre os dados dendrométricos e os dados de pixel foram encontradas para as imagens obtidas a 1500 metros de altitude pela câmera COHU nos espectros azul e infravermelho próximo e, pela câmera PANASONIC no espectro vermelho. / The aerial videography is a technique that has been used in the USA to evaluate, detect and prevent agricultural problems, as well as in the handling of natural areas. One of the reasons for the employment of this technique is its low cost for obtaining the images and the speed with that they can be captured, processed and analyzed. The aim of this work was to verify the usefulness of the videography technique in detecting nutritional deficiency in eucalyptus plantations, using it as a tool in the nutritional monitoring, turning it more precise and less costly than the methods used at present. For this, an experiment was settled with treatments of subtraction of nutrients with the purpose of verifying the potentiality of the aerial videography as technique to distinguish the treatments with nutritional deficiency in eucalyptus plantation. Images were obtained in the green, blue, red and infrared close spectrum, after 12 months of plantation. Those images were obtained with two cameras S-VHS: one capable of capturing the bands of the visible spectrum (400 - 700 nm) and other capable of capturing the bands in the visible and near infrared band (400 - 1100 nm). In these cameras, subtraction filters were also used to separate the bands of the spectrum to work. Besides, with the use of the software ENVI, it was made an analysis of the values of pixels of each portion, being obtained the minimum, medium, maximum values and the mean standard deviation. Then, these values were compared to each other and put together according to the multivariate statistical analysis, looking for relationships between the data of the images and the treatments. Significant relationships between the tree and pixel values data were found for the images obtained in 1500 m high by the camera COHU, in the spectra blue and close infrared and for the camera PANASONIC, in the red band.

In this study, the relative influences of selection, gene flow, and other evolutionary forces on the spatial structure of genetic variation within a eucalypt species complex (the spotted gums: genus Corymbia, section Politaria) were assessed. The study investigated the spatial genetic structure among four putative species of spotted gum (broad-scale), as well as within a single population (fine-scale)of one species, using both molecular and quantitative markers. The spotted gum complex occurs naturally across a range of 2500 km in eastern Australia. Spatial genetic variation within and between the four putative spotted gum species was examined using both chloroplast and nuclear markers. No significant differentiation was found between the three northern species of the complex, C. citriodora, C. variegata and C. henryi. The southern species, C. maculata, shared no haplotypes with any of the three northern species. These results disagree in part with those reported in a previous allozyme based study in which C. henryi was found to be significantly divergent from C. variegata (with which it is sympatric) and more closely aligned with C. maculata. Re-analysis of the allozyme data provided evidence of selection acting at the PGM2 locus within populations of C. variegata and C. henryi. The exclusion of this locus from the data set led to concordance between the cpDNA and nDNA analyses. Restricted gene flow and evidence of isolation by distance were identified as the dominant processes influencing the contemporary distribution of the cpDNA haplotypes. No geographic structure of haplotypes was found and complex genealogical relationships between haplotypes indicated the combined effects of past fragmentation, range expansion and possible long distance dispersal events. The variation and spatial structure in both neutral molecular markers and quantitative genetic traits were compared to explore the relative influences of dispersal and selection within a single eucalypt population. Both mature trees (n=130) from a natural population of C. variegata and their progeny (n=127) were sampled. A very high outcrossing rate (98%) was estimated for the population based on data from seven microsatellite loci. This suggested regular pollen–mediated gene flow into the population, further supported by the observed high levels of genetic diversity and polymorphism. Significant positive spatial structure was found between parent trees occurring up to 150 m apart in the natural forest, although genetic distance between these individuals suggested limited relatedness (i.e. less than half-sib relatedness). The effect of pollen-mediated gene flow appears, therefore, to swamp any effect of nearest neighbour inbreeding which has been reported in other studies of eucalypt populations and has been attributed to limited seed dispersal. Resistance to the fungal disease Sporothrix pitereka (Ramularia Shoot Blight) was measured on progeny from each of the population study trees. Substantial resistance variability was found, along with a high estimate in heritability of resistance (0.44 ± 0.06), indicating significant additive genetic variation within the population. Spatial analysis showed no significant spatial structure with resistant and susceptible genotypes apparently distributed randomly throughout the population. The lack of concordance between the molecular and quantitative markers suggests that there may be a cost to resistance. Temporal variation in the severity of disease outbreaks may have then led to differential selection of seedlings across many generations, maintaining variability in disease resistance and facilitating the apparent random distribution of disease resistant and susceptible genotypes throughout the population. C. variegata is an important commercial forestry species. The identification of strong genetic control in the disease resistance trait, as well as significant adverse genetic and phenotypic correlations between susceptibility and growth traits, will aid future breeding programs. Controlled crosses between resistant genotypes from this population should result in strong genetic gains in both resistance and growth, with little costs associated with inbreeding depression due to the highly outcrossed nature of the population.

No description available.