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Statistical analysis of tree growth and some environmental factors of plant communities in a selected area of the coastal western hemlock zoneEis, Slavoj January 1962 (has links)
A study of productivity and environment of forest plant communities was carried out in a selected area of the Coastal western hemlock zone. This study is a part of the composite ecological project on this zone, which includes investigations of soils and vegetation by George Lesko and Laszlo Orloci respectively.
In the present investigation, climate, site productivity and environmental characteristics of the associations were statistically evaluated using correlation and regression analyses. The purpose of the study was to assess the degree to which the productivity and the plant community are influenced by individual environmental factors as well as by groups of factors.
It was found that almost all the stands investigated were severely affected by fire and that most stands in lower altitudes have developed following destruction of the previous stands by fires. The history of major fires was traced back at least 500 years.
The pattern of ecosystem forest communities has been used as a basis for the separation of biologically equivalent forest habitats.
Microclimates of seven of the most important associations were studied in detail over a period of twelve months. It was concluded that topography is the primary factor influencing soil and water conditions within a given macroclimatic region. This results in the development of a certain microclimate and an accompanying association.
The greatest differences among the plant communities were in temperature maxima and relative-humidity minima. Temperature means and minima, humidity means and maxima and rainfall all differed substantially only between the two subzones.
Forest stand statistics were compared with conventional stand tables. Site-index curves for Douglas-fir, western hemlock, western red cedar, amabilis fir and Sitka spruce indicate differences between associations, and show typical trends which reflect site quality.
It was concluded that a set of physiographic characteristics is typical for each association as well as for each productivity class. However, wide standard deviations and large overlaps indicate that similar physiographic locales may be occupied by different associations and by stands of different productivity. Topographical features were found to be more closely correlated with plant communities than with productivity.
Many significant correlations between site index and sixteen environmental factors were found within individual associations. General trends in the site index - environmental factor relationships were also studied.
The results of the investigations have shown that it is possible to use many combinations of environmental factors for an estimation of forest productivity and of plant community. However, it was found that, due to high correlations among environmental factors, only two or three characteristics need be used for estimation of either productivity or plant community with an accuracy approaching cases in which many environmental factors were considered.
Almost all of the variability of the plant communities studied can be accounted for by differences in the soil and moisture regime. Similar correlation of site index with soil and moisture was found to be substantially lower. Seepage water and soil permeability were found to be the two most important characteristics of both plant community and site index. / Science, Faculty of / Botany, Department of / Graduate
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The isozyme technique - a short-cut to the genes of our forest trees? illustrations using Pinus sylvestris L Isozymtekniken - en genväg till generna i våra skogsträd? illustrationer med hjälp av Pinus sylvestris L. /Rudin, Dag. January 1977 (has links)
Thesis (doctoral)--Umeå Universitet, 1977. / Summaries in English and Swedish. Includes bibliographical references.
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Variation and inheritance of some physiological and morphological traits in Pseudotsuga menziesii (Mirb.) Franco var. menziesii.Sziklai, Oscar January 1963 (has links)
The objectives of this study were to describe the variability, to evaluate the combining ability, and to calculate the heritability values for certain characteristics
of Coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii. Four trees (A, B, E, and 11) were selected on the University of British Columbia Campus. Three of them were selected from the local natural population while the fourth came from an unknown provenance. The investigation of variation included phonological observations on flushing and flowering times, and quantitative descriptions of pollen,
seed and cone size.
A survey of Campus trees showed that Douglas-fir is extremely variable in the time of flushing and flowering, the size of pollen, seed and cones, and the total number of filled seeds. Times of flushing did not determine times of flowering. There was a strong negative correlation
between pollen size and time of flowering. This suggests existence of adaptive significance to adverse climatic condition. Variation in width of the cone was greater than in cone length.
Seed germination percentage appeared to be inherited on a single factor basis, and the results from Fl crosses substantiated the suggestion that tree E might possess a homozygous dominant state. Filled seeds have not been obtained from tree B when it was self-pollinated. This supports Orr-Ewing's theory, that self-sterility might be an inbreeding effect caused by the action of lethal genes, when brought together in a homozygous state.
Combining ability of the four study trees was tested by a polyallel cross with all sixteen possible combinations.
The cross was completed in 1962, using three different pollination methods; dry, wet and dry-wet. Mortality of conelets was lowest in the case of wet pollination. Losses were doubled with dry pollination. Of 302 seed conelets pollinated, 201 were collected and 8,004 seeds were extracted from them. The number of
filled seeds per cone was lowest in the cases of self-pollination (1.91) and wind pollination (3.05). Cross pollination on the average surpassed wind pollination by 4.6 times, and the self-pollination by 7.3 times, producing
13.81 filled seeds per cone.
In order to minimize and test the variability due to environmental effects, the seedlings were grown under controlled environmental conditions. Two Percival (PGC-78) units were employed, one of them simulated long-day (15 hours illumination) and the other short-day (10 hours illumination) effects for 132 days.
Tree 11, which was different in origin from the local provenance trees, showed the best combining ability as a seed parent. Progeny from crosses between trees from the same populations showed smaller values compared to progenies from crosses between trees from different populations.
Epicotyls, for example, were 73-78 per cent longer on seedlings from tree 11 compared to seedlings from trees B and E, when pollen from tree A was applied. Obviously, further investigation of intra-specific crosses has practical merit.
Heritability values in the narrow sense were calculated
for twelve different juvenile seedling characteristics,
and the practical application in relation to forest tree improvement was briefly discussed. / Forestry, Faculty of / Graduate
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Some problems in testing provenance with special reference to the co-operative Douglas-fir provenance test at the University of British Columbia Research ForestReuter, Franz January 1971 (has links)
Importance of research on the provenance problem, which is basically one of seed transfer from collection site to outplanting area, is discussed with special emphasis on coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii).
The "Co-operative Douglas-fir provenance test," begun in 1957 and involving sixteen coastal seed sources from British Columbia, Washington and Oregon, is described in detail. Height measurements collected at the University of British Columbia Research Forest, when the trees were eleven years old, are analysed and the results are discussed. Due to site heterogeneity
and young age of the Co-operative test, no significant height growth differences between provenances can be shown, although the local seed source, from the University of British Columbia Research Forest, seems to be the fastest growing and the southernmost origin, Butte Falls, the slowest of all provenances
investigated. The Co-operative test is critically evaluated and specifications for further studies are recommended. / Forestry, Faculty of / Graduate
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Adaptabilidade, estabilidade, eficiência nutricional e do uso da água em famílias de polinização aberta de Eucalyptus grandis / Genotype-by-environment interaction and nutritional and water use efficiency in open pollinated families of Eucalyptus grandisCastro, Carlos Eduardo Caixeta de [UNESP] 02 February 2017 (has links)
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Previous issue date: 2017-02-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os programas de melhoramento florestal no Brasil têm o desafio de atender à demanda crescente por produtos madeireiros. Por outro lado, a ocorrência de secas sucessivas no Brasil vem criando uma instabilidade produtiva nas florestas plantadas. Com isto, este trabalho teve como objetivos: i) estimar parâmetros genéticos e avaliar a adaptabilidade, estabilidade e produtividade de famílias de polinização aberta de Eucalyptus grandis em diferentes locais no Brasil e propor estratégia de seleção para o conjunto desses locais; ii) avaliar o comportamento de uma amostra destas famílias, cultivadas em vasos em casa de vegetação, submetidas a dois regimes hídricos na presença e ausência de adubação potássica e iii) relacionar os resultados obtidos em casa de vegetação com aqueles obtidos em campo. A primeira parte do trabalho foi realizada com os dados de altura, diâmetro à altura do peito e volume de madeira, cedidos pelo Instituto de Pesquisas e Estudos Florestais (IPEF), provenientes de testes de 165 famílias de polinização aberta de Eucalyptus grandis avaliados em oito locais no Brasil. Estes dados foram submetidas à análise de adaptabilidade, estabilidade e produtividade pelo método da Média Harmônica da Performance Relativa dos Valores Genéticos (MHPRVG). Com base neste estudo, uma amostra de 15 das 165 famílias foi usada para o experimento conduzido em casa de vegetação, onde estas foram submetidas a dois regimes de irrigação, na presença e ausência de adubação potássica, avaliando-se caracteres de crescimento, nutricionais e fisiológicos. No experimento de campo, observou-se interação genótipo por ambiente, com alteração no ordenamento dos genótipos nos diferentes ambientes, conforme detectado pelo método MHPRVG comparado com as ordenações dos genótipos por local, o que indica que a seleção simultânea para todos os locais não é a melhor estratégia de melhoramento. Os locais Pratânia e Monte Dourado B podem ser utilizados para obtenção de genótipos representativos e superiores para a maior parte das regiões estudadas. No experimento em casa de vegetação, observou-se a existência de variabilidade entre as progênies de famílias de polinização aberta de E. grandis possibilitando a obtenção de sucesso na seleção de famílias superiores para as características de crescimento; em contrapartida existe pequena variabilidade nas progênies quanto às características fisiológicas e nutricionais, o que dificulta o sucesso na seleção. Porém, mesmo perante a baixa variabilidade genética, de uma forma geral, é possível obter ganhos com a seleção das famílias superiores. Ao associar os resultados para as 15 famílias avaliadas em comum, nos experimentos de campo e em casa de vegetação, verificou-se que as relações entre os dois experimentos são fracas, com grandes alterações na classificação das famílias de uma condição para outra, demonstrando a dificuldade de usar resultados de experimentos sob condições semicontroladas para predizer o comportamento em campo. / The programs of forest improvement in Brazil have the challenge of meeting this rising demand. On the other hand, the occurrence of repeated droughts in Brazil has been creating a productive instability in commercial forests. Likewise, this work had the objective: i) estimated genetic parameters and evaluating the adaptability, stability and productivity of open-pollinated families of Eucalyptus grandis in different sites in Brazil, and proposing selection strategy for the set of these sites; ii) evaluating the behavior of a sample of these families, cultivated in pots at greenhouse, subject to two hydric regimes in the presence and absence of potassium fertilizations and iii) relating the results obtained in greenhouse with those obtained in the field. The first part of this work was done with height, diameter at breast height and wood volume data, provided by the Instituto de Pesquisas e Estudos Florestais (IPEF), from tests of 165 open-pollinated families of Eucalyptus grandis evaluated in eight places. These data were submitted to analysis of adaptability, stability and productivity through the method of Harmonic Mean of the Relative Performance of the Genetic Values (HMRPGV). Based on this study, a sample of 15 out of 165 families was used for the experiments realized in greenhouse, where these were submitted to two irrigation regimes, in the presence and absence of potassium, evaluating the growth, nutritional and physiological traits. There was genotype by environment interaction with change in the order of genotypes in different environments as detected by the method HMRPFV compared with the order of genotypes in each site, which shows the simultaneous selection for all sites is not the best strategy of improvement. The sites Pratânia and Monte Dourado B can be used for obtaining representative and superior genotypes for most regions studied. Even with a small genetic variance when the selection was done, small gains were obtained. By associating the results to as 15 families in field and greenhouse experiments, it was verified that as relations between the two experiments are weak, with large changes in the classification of families from one condition to another, demonstrating a difficulty of using experiment results under semicontrolled conditions to predict field behavior.
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The development of clone-unspecific micropropagation protocols for three commercially important Eucalyptus hybrids.Chetty, Senica. January 2001 (has links)
Micropropagation methods are often used to supplement existing clonal programmes for Eucalyptus species. However, genotypic differences among clones require the implementation of clone-specific protocols, an expensive and labour-intensive exercise. Hence, this study aimed at determining high-yielding hybrid-specific rather than clone-specific, micropropagation protocols for E. grandis x nitens (GN), E. grandis x nitens (NH), and E. grandis x urophylla (GU). Different conditions for surface sterilisation, bud-break (3 protocols, 2 media), multiplication (4 media), elongation (2 protocols) and rooting (4 media) were tested. A single successful surface sterilisation approach was possible for all clones of the tested hybrids (0.0-11.8% contamination, 0.0-22.9% necrosis). It involved rinsing nodal explants in a fungicide mixture (lg/l Benlate, 1g/1 boric acid, 0.5ml/1 Bravo, Tween 20) for 15 minutes followed by calcium hypochlorite (10g/l with Tween 20) for three minutes. Results at each culture stage were dependent on genotypes, and results indicated here represent ranges in values among the clones of each hybrid. The highest bud-break values for GN clones (87-90%) and NH clones (17-75%) were achieved on a medium containing MS, 0.1mg/1 biotin, 0.1mg/l calcium pantothenate, 0.04mg/1 NAA, 0.11mg/l BAP and 0.05mg/1 kinetin. In GU clones, bud-break values on this medium (84-97%) were not significantly different to those achieved directly on a multiplication medium (80-91%) (MS, 0.1 mg/l biotin, 0.1 mg/l calcium pantothenate, 0.2mg/l BAP, 0.01mg/1 NAA). Shoot multiplication yields for GN clones (4-13 shoots/bud) and GU clones (2-6 shoots/bud) were achieved on a medium consisting of MS, 0.1mg/1 biotin, 0.1 mg/l calcium pantothenate, 0.2mg/1 BAP and 0.01 mg/l NAA. As genotypic effects were highly significant among NH clones, a single multiplication medium for all clones of this hybrid could not be determined. The best method of elongation for clones of all three hybrids involved culturing shoots on MS, 0.1 mg/l calcium pantothenate, 0.1mg/1 biotin, 0.35mg/1 NAA, 0.1mg/l kinetin and 0.1mg/1 IBA, under photoperiod conditions, rather than total darkness, for 6 weeks. This resulted in 82.3-86.6% elongation and shoot lengths increasing by 22.9-35.2 mm for GN clones, 80.2-82.3 % elongation and an increase in length of 24.7-32.2 mm for NH clones and 70.8-78.1 % elongation, and shoot elongation of 21.6-29.3 mm for GU clones from passage 1-2. For all the above stages, media contained 20/25 g/l sucrose and 3.5g/l Gelrite, and cultures were maintained at 25°C ± 2°C day/ 21°C night with a 16 h light/ 8 h dark photoperiod (PPFD 66µmol/m2/s). In terms of rooting, cultures on different media were initially subjected to a 72 hour period of total darkness at room temperature, then a 16 h light/8 h dark photoperiod (PPFD 37µmol/m2 /s) at 24°C day/ 21°C night for 7 days. This was followed by a 16 h light/ 8 h dark photoperiod (PPFD 66µmol/m2/s) at 25°C ± 2°C day/ 21°C night for 21 days. Tested clones of the three hybrids were all rooted successfully (56-93% rooting in GN clones, 36-76% rooting in NH clones and 46-96% rooting in GU clones) on a medium containing ¼ MS, 0.1 mg/l biotin, 0.1 mg/l calcium pantothenate, 0.1mg/l IBA, 0.22g/1 CaCI2 .2H20, 0.185g/l MgS04.7H2O, 15g/l sucrose and 3.5g/1 Gelrite. Predicted yields from the established protocol are also presented (168-667 plants of E. grandis x nitens (GN), 35- 854 plants of E. grandis x nitens (NH) and 54-349 plants of E. grandis x urophylla from 100 initial nodal explants, depending on the clone). Hence, the established protocols can be used successfully for some of the clones, but the implementation of specific media and methods to obtain high yields may still be necessary for certain clones. / Thesis (M.Sc.)-University of Natal, Durban, 2001.
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Micropropagation and in vitro studies of Pinus patula Scheide et Deppe.McKellar, David Stuart. January 1993 (has links)
For the South African forestry industry, the patula pine (Pinus patula) is the most commercially important softwood species. A pine clonal programme has yet to be fully implemented in this country and at present much effort is being made to establish clonal plantings of selected trees. In order to accomplish this, it is essential that satisfactory commercially viable propagation technologies be developed for this species. This study examined the possibilities and constraints of three different in vitro systems for mass propagation of rare and important P. patula material. Seed germination and sterilisation techniques were developed for adventitious bud and somatic embryogenesis experimentation. Adventitious buds were initiated from excised 'mature P. patula embryos cultured on LM medium containing 5 mg 1-1 BA. Although, between 50 and 60% of the embryo explants produced adventitious buds, only 3-5 buds per explant actually developed further to form distinct shoots. The adventitious shoots elongated slowly (±8 mm in 2 months) on LM medium, containing 10 g 1-1 activated charcoal. Axillary buds were induced on 10 week-old juvenile shoots, after the development of an effective surface sterilisation procedure, using 0.02% HgCL2. The
effect of removing the apex and trimming the needles on bud induction was significant. Dwarf shoots elongated at a rate of 25 mm in 5 weeks. Rooting studies conducted on juvenile P. patula shoots indicated that the most effective treatment was wounding the shoot base and placing the shoot in composted bark growing medium, under a greenhouse mist regime. Rooting percentages were low (50%). Included in this study is the first successful production of somatic pro-embryos from mature Pinus patula embryos. Calli were produced on LM induction medium containing 2 mg 1-1 2,4-D. Cultures were first placed in the dark for 4 weeks and then transferred to a 16 h photoperiod for a further 2 weeks,
after which Stage 1 embryogenic cells were observed. When calli were placed on LM maturation medium, containing 12 mg 1-1 ABA, for a further 6-8 weeks, pro-embryo structures (maximum of 7 pro-embryos per callus) were detected embedded In the callus mass. Hence, investigations into the development of protocols for the micropropagation of Pinus patula, were undertaken. Two major constraints for applying in vitro techniques to the commercial production of pine were identified: the poor yield of shoots and pro-embryos and the length of time
taken for plantlets to be produced. This study, however, provides some fundamental knowledge and background work required by tree breeders who wish to implement biotechnological techniques in the selection and improvement of P. patula genotypes. / Thesis (M.Sc.)-University of Natal, Durban, 1993.
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Bridging genomics and quantitative genetics of Eucalyptus: genome-wide prediction and genetic parameter estimation for growth and wood properties using high-density SNP data / Conectando a genômica à genética quantitativa de Eucalyptus: predição genômica e estimação de parâmetros genéticos para crescimento e propriedades de madeira usando alta densidade de SNPsLima, Bruno Marco de 25 April 2014 (has links)
Convergence of quantitative genetics and genomics is becoming the way that fundamental genetics and applied breeding will be carried out in the next decades. This study bridges the quantitative genetics of complex growth and wood properties traits with genomic technologies towards a more innovative approach to tree breeding. Planted forests play a major role to fulfill the growing world demand for wood products and energy. Eucalypts stand out for their high productivity and versatile wood resulting from the advanced breeding programs associated to clonal propagation and modern silviculture. Despite their fast growth, breeding cycles still take several years and wood properties assessment is limited to a sample of trees in the late stages of selection due to the costs involved in wood phenotyping, not exploitingthe range of genetic variation in wood properties. In this study, we examined fifteen traits including growth and wood chemical and physical properties in 1,000 individuals sampled from an elite Eucalyptus breeding population. Near-infrared spectroscopy (NIRS) models were developed and used for high-throughput phenotyping of wood traits.Highdensity data for 29,090 SNPs was used to obtain accurate pedigree-record-free estimates of trait variance components, heritabilities, genetic and phenotypic correlations, based on a realized relationship matrix, comparing them to pedigree-based estimates. To the best of our knowledge, this is the first study to do this in plants. NIRS predictions were accurate for wood chemical traits and wood density, and variably successful for physical traits. Heritabilities were medium for growth (0.34 to 0.44), high for wood chemical traits (0.56 to 0.85) and variable for wood physical traits (0.11 to 0.63). High positive correlations among growth traits and negative between cellulose and lignin content were observed, while correlations between wood chemical and physical traits and between growth and wood quality traits were low although significant. Phenotypes and SNP markers were then used to build genomic predictive models using a marker density higher than any previous genomic selection study in trees (1 SNP/21 kbp). Two models (RR-BLUP and Bayesian LASSO) that differ regarding the assumed distribution of marker effects were used for genomic predictions. Predictions were compared to those obtained by phenotypic BLUP. Predictive abilities very similar by the two models and strongly correlated to the heritabilities. Accurate genomic-enabled predictions were obtained for wood chemical traits related to lignin, wood density and growth, although generally 15 to 25% lower than those achieved by phenotypic BLUP prediction. Nevertheless, genomic predictions yielded a coincidence above 70% in selecting the top 30 trees ranked by phenotypic selection for growth, wood density and S:G ratio, and 60% when tandem selection was applied. The results of this study open opportunities for an increased use of highthroughput NIRS phenotyping and genome-wide SNP genotyping in Eucalyptus breeding, allowing accurate pedigree-record-free estimation of genetic parameters and prediction of genomic breeding values for yet to be phenotyped trees. These applications should become routine in tree breeding programs for the years to come, significantly reducing the length of breeding cycles while optimizing resource allocation and sustainability of the breeding endeavor. / A convergência da genética quantitativa com a genômica está se tornando a maneira pela qual a genética fundamental e aplicada serão conduzidas nas próximas décadas. Este estudo buscou conectar a genética de fenótipos complexos de crescimento e propriedades de madeira às tecnologias genômicas, em uma abordagem inovadora para o melhoramento florestal. Florestas plantadas têm papel fundamental para satisfazer a crescente demanda mundial por produtos madeireiros e energia. O eucalipto,com sua alta produtividade e madeira versátil, é resultado de programas avançados de melhoramento associados à propagação clonal e silvicultura moderna. Apesar de seu rápido crescimento, ciclos de melhoramento ainda levam muitos anos e a avaliação detalhada de propriedades da madeira é limitada a apenas uma amostra das árvores em estágios avançados de seleção, devido aos altos custos de fenotipagem, não explorando assim toda a variação genética disponível. Neste estudo, examinamos quinze caracteres, incluindo crescimento e propriedades químicas e físicas da madeira, em 1000 indivíduos amostrados de uma população elite de melhoramento. Modelos de espectroscopia de infravermelho próximo (NIRS) foram desenvolvidos e utilizados para fenotipagem de alto desempenho de propriedades de madeira. Genotipagem de alta densidade com 29.090 SNPs foi utilizada para obter estimativas acuradas de componentes de variância, herdabilidades e correlações genéticas baseadas em uma matriz de parentesco realizado, ou seja,sem o uso de pedigree. Este é o primeiro estudo de que temos conhecimento a fazer isso em plantas. Predições NIRS foram precisas para caracteres químicos da madeira e densidade, e apresentaram sucesso variável para caracteres físicos. As herdabilidades foram médias para crescimento (0,34 a 0,44), altas para caracteres químicos de madeira (0,56 a 0,85) e variáveis para caracteres físicos da madeira (0,11 a 0,63). Altas correlações positivas entre caracteres de crescimento e negativas entre celulose e lignina foram observadas, enquanto correlações entre caracteres químicos e físicos da madeira foram baixas, porém significativas. Fenótipos e marcadores SNP foram em seguida utilizados na construção de modelos preditivos com a maior densidade de marcadores já utilizada em estudos de seleção genômica em espécies florestais (1 SNP/21 kpb). Dois modelos de predição (RR-BLUP e LASSO Bayesiano)foram usados nas predições genômicas e comparados ao BLUP fenotípico. Os modelos apresentaram capacidades preditivas similares, fortemente correlacionadas às herdabilidades. Predições genômicas precisas foram obtidas para caracteres relacionados à lignina, densidade e crescimento, embora geralmente 15 a 25% menores do que as predições obtidas por BLUP fenotípico. Contudo, predições genômicas alcançaram coincidências acima de 70% na seleção das melhores 30 árvores ranqueadas pela seleção fenotípica para crescimento, densidade e relação S:G, e de 60% quando seleção em tandem foi aplicada. Os resultados deste estudo abrem enormes oportunidades para o uso combinado de fenotipagem NIRS e genotipagem com SNPs no melhoramento do eucalipto, permitindo estimativas acuradas de parâmetros genéticos e a predição de valores genéticos genômicos para plantas jovens ainda não fenotipadas. Estas aplicações deverão se tornar rotineiras nos programas de melhoramento florestal nos próximos anos, reduzindo significativamente a duração dos ciclos de seleção e, consequentemente, otimizando a alocação de recursos e a sustentabilidade do melhoramento.
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Bridging genomics and quantitative genetics of Eucalyptus: genome-wide prediction and genetic parameter estimation for growth and wood properties using high-density SNP data / Conectando a genômica à genética quantitativa de Eucalyptus: predição genômica e estimação de parâmetros genéticos para crescimento e propriedades de madeira usando alta densidade de SNPsBruno Marco de Lima 25 April 2014 (has links)
Convergence of quantitative genetics and genomics is becoming the way that fundamental genetics and applied breeding will be carried out in the next decades. This study bridges the quantitative genetics of complex growth and wood properties traits with genomic technologies towards a more innovative approach to tree breeding. Planted forests play a major role to fulfill the growing world demand for wood products and energy. Eucalypts stand out for their high productivity and versatile wood resulting from the advanced breeding programs associated to clonal propagation and modern silviculture. Despite their fast growth, breeding cycles still take several years and wood properties assessment is limited to a sample of trees in the late stages of selection due to the costs involved in wood phenotyping, not exploitingthe range of genetic variation in wood properties. In this study, we examined fifteen traits including growth and wood chemical and physical properties in 1,000 individuals sampled from an elite Eucalyptus breeding population. Near-infrared spectroscopy (NIRS) models were developed and used for high-throughput phenotyping of wood traits.Highdensity data for 29,090 SNPs was used to obtain accurate pedigree-record-free estimates of trait variance components, heritabilities, genetic and phenotypic correlations, based on a realized relationship matrix, comparing them to pedigree-based estimates. To the best of our knowledge, this is the first study to do this in plants. NIRS predictions were accurate for wood chemical traits and wood density, and variably successful for physical traits. Heritabilities were medium for growth (0.34 to 0.44), high for wood chemical traits (0.56 to 0.85) and variable for wood physical traits (0.11 to 0.63). High positive correlations among growth traits and negative between cellulose and lignin content were observed, while correlations between wood chemical and physical traits and between growth and wood quality traits were low although significant. Phenotypes and SNP markers were then used to build genomic predictive models using a marker density higher than any previous genomic selection study in trees (1 SNP/21 kbp). Two models (RR-BLUP and Bayesian LASSO) that differ regarding the assumed distribution of marker effects were used for genomic predictions. Predictions were compared to those obtained by phenotypic BLUP. Predictive abilities very similar by the two models and strongly correlated to the heritabilities. Accurate genomic-enabled predictions were obtained for wood chemical traits related to lignin, wood density and growth, although generally 15 to 25% lower than those achieved by phenotypic BLUP prediction. Nevertheless, genomic predictions yielded a coincidence above 70% in selecting the top 30 trees ranked by phenotypic selection for growth, wood density and S:G ratio, and 60% when tandem selection was applied. The results of this study open opportunities for an increased use of highthroughput NIRS phenotyping and genome-wide SNP genotyping in Eucalyptus breeding, allowing accurate pedigree-record-free estimation of genetic parameters and prediction of genomic breeding values for yet to be phenotyped trees. These applications should become routine in tree breeding programs for the years to come, significantly reducing the length of breeding cycles while optimizing resource allocation and sustainability of the breeding endeavor. / A convergência da genética quantitativa com a genômica está se tornando a maneira pela qual a genética fundamental e aplicada serão conduzidas nas próximas décadas. Este estudo buscou conectar a genética de fenótipos complexos de crescimento e propriedades de madeira às tecnologias genômicas, em uma abordagem inovadora para o melhoramento florestal. Florestas plantadas têm papel fundamental para satisfazer a crescente demanda mundial por produtos madeireiros e energia. O eucalipto,com sua alta produtividade e madeira versátil, é resultado de programas avançados de melhoramento associados à propagação clonal e silvicultura moderna. Apesar de seu rápido crescimento, ciclos de melhoramento ainda levam muitos anos e a avaliação detalhada de propriedades da madeira é limitada a apenas uma amostra das árvores em estágios avançados de seleção, devido aos altos custos de fenotipagem, não explorando assim toda a variação genética disponível. Neste estudo, examinamos quinze caracteres, incluindo crescimento e propriedades químicas e físicas da madeira, em 1000 indivíduos amostrados de uma população elite de melhoramento. Modelos de espectroscopia de infravermelho próximo (NIRS) foram desenvolvidos e utilizados para fenotipagem de alto desempenho de propriedades de madeira. Genotipagem de alta densidade com 29.090 SNPs foi utilizada para obter estimativas acuradas de componentes de variância, herdabilidades e correlações genéticas baseadas em uma matriz de parentesco realizado, ou seja,sem o uso de pedigree. Este é o primeiro estudo de que temos conhecimento a fazer isso em plantas. Predições NIRS foram precisas para caracteres químicos da madeira e densidade, e apresentaram sucesso variável para caracteres físicos. As herdabilidades foram médias para crescimento (0,34 a 0,44), altas para caracteres químicos de madeira (0,56 a 0,85) e variáveis para caracteres físicos da madeira (0,11 a 0,63). Altas correlações positivas entre caracteres de crescimento e negativas entre celulose e lignina foram observadas, enquanto correlações entre caracteres químicos e físicos da madeira foram baixas, porém significativas. Fenótipos e marcadores SNP foram em seguida utilizados na construção de modelos preditivos com a maior densidade de marcadores já utilizada em estudos de seleção genômica em espécies florestais (1 SNP/21 kpb). Dois modelos de predição (RR-BLUP e LASSO Bayesiano)foram usados nas predições genômicas e comparados ao BLUP fenotípico. Os modelos apresentaram capacidades preditivas similares, fortemente correlacionadas às herdabilidades. Predições genômicas precisas foram obtidas para caracteres relacionados à lignina, densidade e crescimento, embora geralmente 15 a 25% menores do que as predições obtidas por BLUP fenotípico. Contudo, predições genômicas alcançaram coincidências acima de 70% na seleção das melhores 30 árvores ranqueadas pela seleção fenotípica para crescimento, densidade e relação S:G, e de 60% quando seleção em tandem foi aplicada. Os resultados deste estudo abrem enormes oportunidades para o uso combinado de fenotipagem NIRS e genotipagem com SNPs no melhoramento do eucalipto, permitindo estimativas acuradas de parâmetros genéticos e a predição de valores genéticos genômicos para plantas jovens ainda não fenotipadas. Estas aplicações deverão se tornar rotineiras nos programas de melhoramento florestal nos próximos anos, reduzindo significativamente a duração dos ciclos de seleção e, consequentemente, otimizando a alocação de recursos e a sustentabilidade do melhoramento.
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Implications of evolutionary history and population structure for the analysis of quantitative trait loci in the ancient conifer Araucaria cunninghamiiScott, Leon J Unknown Date (has links)
Araucaria cunninghamii is an ancient tropical conifer with substantial value as a forestry species in Australia and Papua New Guinea, and has been subject to a genetic improvement program for more than 50 years. This study was undertaken to demonstrate the utility of quantitative genetic analysis in describing the genetic architecture of commercial traits in A. cunninghamii. Linkage maps were prepared using the pseudotestcross strategy in what was believed to be a wide interprovenance cross using microsatellites and AFLP. A very low rate of marker polymorphism and limited differentiation between the parental provenances was identified, resulting in low mapping efficiency. The population genetic structure of A. cunninghamii was assessed to establish the underlying causes for the limited differentiation and low marker heterozygosity and assess the implications for future analysis of quantitative traits. Despite the limited mapping efficiency, genetic maps were generated for both parents. The maternal map for individual H15 contained 14 linkage groups comprising of 51 AFLP and one microsatellite. The map covered 1290 cM, representing 89% of the estimated genome size. The paternal map for individual Gil24 was 633 cM, consisting of eight linkage groups. Genetic architecture of quantitative traits was examined with putative QTL identified for height, DBH and stem straightness; one was highly significant (p<0.01), three significant (0.01<p<0.05) and 13 suggestive (p<0.10). Significant QTL each accounted for 7-11% of the phenotypic variance with a high allele substitution effect (0.63-0.81). These QTL were likely to be associated with genes of moderate effect. The suggestive QTL each accounted for 3-6% of the phenotypic variance with an allele substitution effect of 0.40-0.63. Three genomic regions contributed to the expression of multiple traits at multiple ages. Stable QTL had decreasing phenotypic effects with increasing age. The population genetic survey characterised low levels of allelic diversity across the geographic range. Three broad regions were characterised; Papua New Guinea, Cape York and northern Queensland to NSW. There was limited differentiation between provenances within these regions, and high diversity within provenances. Limited genetic differentiation between provenances seems to be the result of genetic stability due to long overlapping generations, limited founder effects and a very low mutation rate. The latter may also contribute the low heterozygosity. Limited marker polymorphism and limited differentiation between provenances within broad regions are common features in A. cunninghamii. Therefore careful parental selection and alternative experimental approaches will be required before undertaking further analysis of quantitative traits.
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