Biblioteca Digital

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...

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Pós-graduação em Agronomia (Genética e Melhoramento de Plantas) - FCAV; O trabalho objetivou avaliar o efeito do suprimento de potássio no desempenho de clones de eucalipto submetidos a duas condições de disponibilidade hídrica em casa de vegetação utilizando características biométricas e fisiológicas. Cinco genótipos de eucalipto foram submetidos a dois níveis de adubação potássica (K0 – sem complementação potássica e K1 – adição de 166 mg.dm-3 de K) e a dois regimes de irrigação (RI1 – irrigação diária, até o solo atingir 60% dos poros preenchidos com água (PPA), ou seja, plantas sem restrição hídrica, e RI2 - plantas irrigadas até o solo atingir 60% PPA, com posterior suspensão da irrigação, até o aparecimento de sintomas iniciais de deficiência hídrica). Foram conduzidos sete ciclos de suspensão de irrigação, sendo a quantidade de água reposta em cada vaso determinada pelo método gravimétrico. No início e ao final do experimento, foram avaliados o diâmetro do coleto, a altura, o número de folhas, a área foliar e a massa de matéria seca de folhas, caule, raízes, da parte aérea e total. Nos momentos de máximo estresse hídrico...

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Pós-graduação em Agronomia (Genética e Melhoramento de Plantas) - FCAV; O objetivo deste trabalho foi avaliar o comportamento de cinco híbridos de Eucalyptus grandis x Eucalyptus urophylla (H1, H2, H3, H4 e H5) submetidos a quatro regimes de irrigação (RI1 – irrigação diária; RI2 – irrigação a cada dois dias; RI4 – irrigação a cada quatro dias e RI6 – irrigação a cada seis dias). O experimento foi implantado em casa de vegetação no delineamento de blocos casualizados no esquema fatorial 5 x 4 (cinco híbridos e quatro regimes de irrigação), com quatro repetições, usando como substrato 10,5 Kg de um Neossolo Quartzarênico. Foram avaliadas características de crescimento como: incremento relativo em diâmetro de coleto, em altura, em número de folhas, em área foliar, em massa seca de folhas, de caule, de raízes e total e razão raiz- parte aérea; fisiológicas como: taxa de assimilação líquida, transpiração, condutância estomática, concentração interna de CO2, potencial hídrico foliar, conteúdo relativo de água, eficiência fotoquímica e índice de conteúdo de clorofila total; e bioquímicas como: teores foliares de prolina livre e de glicina betaína. As avaliações fisiológicas foram realizadas em sete ciclos; mas...

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Pós-graduação em Agronomia (Genética e Melhoramento de Plantas) - FCAV; Objetivo deste trabalho foi a identificação das formas de competição em testes de progênies de eucalipto e a influencia desta nos parâmetros genéticos e na seleção. Foram usados dados de dois testes de progênies de polinização aberta de eucalipto, instalados no delineamento em blocos casualizados. O experimento 1 (EXP1) foi constituído por quatro testemunhas (clones) e 49 progênies e o experimento 2 (EXP2) por 44 progênies, ambos com seis repetições e parcelas lineares de 10 plantas. Em três idades (aos 2, 4 e 7 anos para o EXP1 e aos 3, 5 e 7 anos para o EXP2), avaliou-se o crescimento em altura (ALT), o diâmetro à altura do peito (DAP) e o volume comercial de madeira com casca (VOL), analisando-se os dados pela metodologia REML/BLUP. Para VOL aos sete anos de idade foi feita a análise de covariância para identificação da competição e suas formas através de sete covariáveis: índice de competição de Hegyi (IC), auto-competição (AT), alo-competição (AL), média da autocompetição (MAT), média da alocompetição (MAL) e media aritmética dos quatro (M4) e oito vizinhos mais próximos (M8). O efeito dessas covariáveis foi estudado individualmente e em todas as suas possíveis combinações...

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Pós-graduação em Agronomia - FEIS; O Eucalyptus camaldulensis, espécie nativa da Austrália, é plantada com sucesso em vários países em função da sua superioridade na produção de madeira, em relação a outras espécies sob condições ambientais adversas, com destaque para tolerância ao déficit hídrico e à alta temperatura. Em abril de 1986 instalou-se uma população base de Eucalyptus camaldulensis, em Selvíria-MS, na Fazenda de Ensino e Pesquisa e Extensão - Faculdade de Engenharia de Ilha Solteira/UNESP, constituída por 25 matrizes, sendo 13 (Lote 14517) procedentes da região de Nott’s Crossing, Katherine River, Austrália, e as 12 restantes pertencentes ao lote 13923 da CSIRO. O objetivo principal deste trabalho foi investigar a variabilidade genética da população base e do teste de progênies, baseado na caracterização molecular (locos microssatélites) e quantitativa (caracteres quantitativos DAP, altura, forma do fuste, volume, brotação, densidade básica da madeira e resistência à penetração), para fins de conservação e melhoramento genético. Os caracteres quantitativos foram avaliados dos 20 aos 23 anos após a instalação da população base...

A maximização do ganho genético para características de valor econômico por unidade de tempo é o principal objetivo de um programa de melhoramento florestal. A obtenção de resultados mais precisos em um menor intervalo de tempo está vinculada à adoção de procedimentos de seleção precoce e metodologias de análise mais apropriadas para seleção genética. O emprego de variáveis que melhor expressem características que reflitam valor comercial da árvore devem também ser embutidas nas estratégias de seleção. Como o delineamento de cruzamentos dialélicos desconectados é uma ferramenta importante no melhoramento genético de Pinus taeda, também tem se tornado necessário o emprego de metodologias que possibilitem a sua análise na íntegra. Esse estudo focou o a definição de variáveis que quantifiquem valores comerciais para seleção genética, procedimentos para análise de delineamentos dialélicos desconectados e estratégias para seleção precoce para Pinus taeda. Numa primeira instância, metodologias foram desenvolvidas para quantificação e estimativa de várias características de interesse, gerando recomendações que contribuirão diretamente no processo de avaliação para seleção genética de árvores. Procedimentos para quantificação de ganhos genéticos econômicos...

O objetivo dos programas de melhoramento é maximizar o ganho genético para características de valor econômico, com o uso de modelos estatísticos específicos, considerando o delineamento utilizado, buscando alta precisão experimental e acurácia seletiva elevada. Atualmente, o uso de modelos mistos tem sido mais indicado em programas de melhoramento genético, através da metodologia da máxima verossimilhança restrita (REML) para estimar os componentes de variância e melhor predição linear não viciada (BLUP), para a predição dos valores genéticos, pois atendem a situações de dados balanceados e desbalanceados. O BLUP considera os componentes de variância para todos os genótipos de forma igual. Em situações com heterogeneidade de variâncias, é preciso considerar a variância residual e estimar, para cada tratamento, as acurácias, coeficientes e herdabilidades. Esta metodologia está disponível através do BLUP-HET, que utiliza uma variância residual para cada tratamento genético. O presente estudo objetivou avaliar, em duas condições distintas, a heterogeneidade de variâncias residuais e comparar os resultados obtidos pelos procedimentos BLUP e BLUP-HET. Estas análises são apresentadas em dois capítulos. A primeira avaliação foi realizada através de simulação...

Resumo: Espécies florestais de rápido crescimento suprem de forma sustentável a demanda por biomassa lenhosa, reduzindo a pressão sobre as florestas naturais. No entanto, reflorestamentos com Pinus vêm produzindo madeira juvenil de baixa qualidade. Assim, o melhoramento genético para características relacionadas à qualidade da madeira ou outras de difícil mensuração, torna-se prioritário aos programa de melhoramento florestal. Fortes expectativas têm sido direcionadas aos estudos de genética de associação, via genes candidatos, para estimar a correlação genética e fenotípica entre os alelos polimórficos e as características de interesse. Tal estratégia representaria uma possibilidade de predizer ganhos a partir da implantação de um programa baseado em seleção assistida por marcadores. Contudo, a existência de estrutura genética espúria é apontada na literatura como uma das maiores causas de viés estatístico nos estudos de mapeamento de associação. Um dos maiores desafios, mesmo com o avanço de todas as tecnologias genômicas e analíticas, é a definição de quais são os verdadeiros grupos genéticos existentes dentro de uma determinada população. Definir os grupos genéticos em uma população artificial torna-se ainda mais desafiador...

The plant genetic resources stored ex situ are considered as a genetic repository, and are raw material for the development of the world agriculture. In rice, despite its high genetic variability, the lack of information of accessions to compose a databank prevents its use to help the choice of genitors for the breeding programs. The Embrapa Rice Core Collection (ERiCC) was developed from 10,000 accessions from Embrapa GeneBank, and it was set up by 550 accessions, divided in three subsets: 1) 94 lines and cultivars from Brazil (LCB); 2) 148 lines and cultivars from abroad (LCI); and 3) 308 traditional varieties (VT), obtained from germplasm collection expeditions in Brazil. This work aimed: 1) to evaluate the extension of genetic variability of 550 accessions from ERiCC by means of agronomic traits characterization using mixed models and multivariate statistics; 2) to perform a comparative analysis of the genetic divergence considering the agronomical and SSR markers characterizations; and 3) to identify the genotypes with higher genetic diversity and with the best agronomic performances, aiming to promote the most efficient use of such germplasm in breeding programs. The agronomic characterization of 550 accessions was performed in nine field experiments...

The mangaba tree (Hancornia speciosa Gomes) is a fruit tree native from Brazil with potential for domestication, due to its excellent smell, flavor and texture. However, genetic conservation and breeding programs of these species are in an initial developmental phase. This way, this research aimed to characterize trees and fruits of natural populations of H. speciosa, as well as evaluate the distribution of phenotypic variability among them; evaluate progenies of mangaba trees that compose the Escola de Agronomia e Engenharia de Alimentos of Universidade Federal de Goiás (EA/UFG) germplasm collection and estimate genetic parameters for the initial development of plants in the field. Mangaba trees populations have been sampled in different locations of the Brazilian Cerrado, including the states of Goiás, Tocantins, Mato Grosso, Mato Grosso do Sul, and Bahia, totaling 109 mother plants of 35 populations of the botanic varieties pubescens, gardneri, speciosa and cuyabensis. In relation to the trees, plant height, stem perimeter, and number of fruits per plant were taken. From a sample of five fruits per plant, individual measures have been taken, such as: length, diameter, weight, total weight of seeds, average seed weight, pulp plus peel weight...

Recombination is one of the most important factors in the evolution of genome organization. It provides the links between homologous chromosomes that ensure their proper segregation during the first meiotic division. It is responsible for the creation of novel allele combinations and yields genetic diversity on which evolutionary selection can act. Double-strand DNA breaks (DSB) initiate meiotic recombination and when the 3 terminus of one of the broken strands invades the unbroken DNA molecule and primes DNA synthesis a double Holliday junction must be resolved through some alternative pathways. When homologous chromosomes exchange genetic material with each other, an event of recombination or a crossover takes place, which may be seen through chiasma. Citological, genetics, and molecular studies in many organisms have demonstrated that crossovers have a non homogeneous distribution across chromosomes, and rather concentrated in relative small DNA fragments usually called recombination hotspots. In searching for genomic features associated with recombination hotspots a model fitted to human genome data explained 42% of recombination rate variation in a 5 mega base pairs scale. Despite the fact that genomes of some plant species have been already sequenced...

Recurrent Selection is a population inbreed method that is not traditionally used in autogamous species as rice. However, it is still an interesting methodology to the implementation of recurrent selection populations, due to the possibility of obtaining genotypes with wide genetic base and adequate agronomical traits. It is even more attractive when a great genetic variability is easily available, as it is for rice and could be largely used in the development of more productive elite cultivars and with a better production stability even under low input agricultural systems. Two recurrent selection irrigated rice populations, developed by Embrapa Arroz e Feijão, were synthetized using different recombination methods. The CNA-IRAT 4 population was developed in field conditions using male-sterelity, while the CNA 12 population originated from manual crosses in a circulant partial diallel scheme. The aim of this work was the evaluation of the genetic variability among cycles of the two recurrent selection populations using fourteen SSR markers. Hundred and eighty genotypes of the cycles 1, 2 and 5 of CNA-IRAT 4 population and cycles 1 and 2 of CNA 12, were evaluated. The AMOVA did not indicate any genetic structure among the cycles of selection...

The common bean (Phaseolus vulgaris L.) is part of the daily diet of more than 300 million people worldwide, being an essential food for low income human populations, since it is a cheaper protein source. The beans protein content can be improved by breeding programs since the existence of genetic variability for this character can be explored. It is important to have the relative efficiency of the available methods evaluated. The objective of this research was to evaluate the genetic potential for protein content of segregant populations of common beans submitted to different breeding methods and evaluate the potential of the populations of the bulk method inside F2 families for the traits yield and flowering. The parental utilized in this study was from the bean group carioca , CNFC 7812 with 23% of total protein content and CNFC 8056 with 23% of total protein content. Starting with the F1 generation, was obtained the segregant population F2, witch were selected 150 plants wich families was utilized to produce the populations by three methods: Bulk, Bulk within of F2 and SSD method until the F5 generation. The average protein content of the families obtained by this cross was 16,58% for the method SSD, 20,37% for the method Bulk e 20...

Rice (Oryza sativa) stands out in Brazil for its economic and social importance, being an important source of protein and energy. Selecting lines of upland rice adapted to different environments is critical to the success of breeding programs targeted to family farmers in the state of Goiás, The objective of this work was to evaluate S0:2 families drawn from CNA9 population of the upland rice breeding program in greenhouse and in the field, aiming to select families for recombination and obtainment of a new selecting cycle. 50 families from CNA9 population from recurrent selection were used, in four experiments, with N, P, and inoculant combinations, in a randomized bloc design arrangement with two replicates in greenhouse. Traits evaluated were: plant height, chlorophyll content, canopy dry matter, roots dry matter and volume. The field experiment was arranged in a 14 X 14 square lattice, with 194 families, two controls, and three replicates. Traits evaluated were: plant height, flowering and yield, besides the following diseases: leaf and neck blast, scald, brown spot, grain spot, and narrow leaf spot. Results obtained from greenhouse indicate that families studied performed similarly in the absence of the inoculant, but responded differently for plant height...

The araticunzeiro (Annona crassiflora Mart.) is a tropical fruit tree species from the Cerrado (Brazilian Savannah) with high economic potential. The strong degradation of the Cerrado, allied to the predatory extractivism that threatens the species, points out to the necessity of development of research to support future conservation programs. With the aim to furnish information about the genetic status of this species and to guide future conservation strategies, 82 individuals from 11 natural populations were submitted to genetic analysis. The coalescent based analysis of the polymorphism present in the trn-L cpDNA allowed the detection of high levels of genetic diversity in the species. In spite of the high level of genetic similarity among different populations the results produced suggested that, , there is an incipient, but statistically significant, increasing differentiation process taking place due to current status of geographical isolation and genetic drift. The genetic differentiation coefficient estimated was equal to 7.3%. The spatial genetic divergence analyses suggested that the genetic distances are not associated to geographical distances between populations, evidencing the absence of current gene flow between adjacent populations. The coalescent based approach allowed the identification of different evolutionary scenes to the investigated populations. Among sampled populations cases from well conserved status to dangerous low levels of genetic diversity were detected. Results obtained by the use of coalescent models to infer the divergence time between populations suggested that natural populations of A. crassiflora were...

The Species Palicourea coriacea (Cham) K,Shum is a species little know, it is belonging to the Rubiaceae family, popularly known as douradinha. The popular use medicine in the therapy of kidneys illnesses. The popular name douradinha is associated with the color of the bracts and of the stem and the species occurs in Cerrado s Bioma, however in different environments. Studies about the genetic diversity and its distribution in natural populations of P. coriacea are of extreme importance for the definition of adequate strategies of handling and cultivation, however they do not exist in literature, studies of this nature. This work had as objective to evaluate the genetic structure from nine natural populations of P. coriacea, collected in States of Goiás and Bahia and to evaluate the genetic diversity of these populations through markers RAPD. The P. coriacea species presented one high level of genetic diversity, or heterozygosity waited by Nei (1972) that it varied between 0,259 and 0,338 in the populations, with equal on average value the 0,296. The AMOVA disclosed that 23% of the total variability is meeting each other between populations. Although the estimates of apparent gene flow (Nm) have disclosed values inferior to one, on the other hand...

Aiming the comprehension of drought defenses mechanisms of Eucalyptus spp. and to obtain tolerant genotypes, this work evaluated, by RT-qPCR, the expression patterns of six genes EgrCPK26, EgrDREB2, EgrNCED3, EgrPYR1, EgrMET1 and EgrDDM1, in two Eucalyptus camaldulensis X Eucalyptus urophylla clones (VM01- drought tolerant and VM05 – drought susceptible) in drought and irrigation conditions. For the expression normalization, references genes was, firstly, used. Besides, this work aimed the development of an Eucalyptus grandis X Eucalyptus urophylla transgenic line with the gene OsCPK5 and evaluated the effect of its insertion in the expression of four genes related to drought response, EgrCPK26, EgrDREB2, EgrNCED3 e EgrPYR1.Primarily, the stability of seven candidates as reference genes (SAND, IDH, PP2A-3, PP2A-1, UBQ, TUB and EF- 1α) was evaluated through the geNorm, NormFinder, BestKeeper and Delta-Ct algorithms, in the two clones of E. camaldulensis X E. urophylla under drought and watered conditions. According to the data found, it was possible to verify a higher stability value of the genes SAND and PP2A-3 in the great part of the samples sets. In addition some studies suggest the normalization using three references genes...

Araucaria angustifolia (Bert.) O. Ktze is an endemic gymnosperm from Brazil, which is widespread in Southern landscapes, and restricted in the Southeast. It is popularly known as Brazilian pine, with a peculiar architecture, beauty and size of adult trees; making forests with Araucaria a unique ecosystem. The Southern Minas Gerais is part of the north boundary of the distribution of this tree species in Brazil, and genetic information related to its population is important for conservation, because these areas may contain adaptive genes restricted to these locations; which should be preserved due to high destruction and fragmentation of these ecossystens. This tree specie is considered endangered on the Oficial List of IBAMA (Ministry of Environment, 2008), and it has been classified as vulnerable to extinction in Minas Gerais (COPAM 085/97). In this study, we aimed to quantify levels of diversity and genetic structure of remaining population of Araucaria angustifolia located in the Serra da Mantiqueira, Southern Minas Gerais, using microsatellite markers (SSR). Studies about genetic diversity and structure were performed on 450 individuals distributed in 9 different populations of A. angustifolia. Eight SSR primers were used to generate 65 alleles. The genetic data point out that the remaining areas retain a high genetic diversity so far (He = 0.77). The analysis of molecular variance indicated that the majority of genetic diversity...

Plant genetic resources maintained ex situ, in germplasm banks, are few used in agricultural systems and genetic plant breeding programs. One of the main reasons of this incipient use is the difficulty to obtain information about stored accessions, especially the characterization and preliminary evaluation data. Stylosanthes guianensis is a predominantly self-pollinated and diploid species, which has a great number of this stored accessions and potential for use in agricultural systems. There are approximately one thousand accessions of the S. guianensis in Embrapa‟s germplasm bank. Moreover, only one genotype of this species is now available to commercial growers in Brazil, the cultivar Mineirão. To promote the use of these resources, this study aimed to characterize accessions of S. guianensis, stored in the germplasm bank of Embrapa, using morpho-agronomic traits and microstellites markers (SSR). In morpho-agronomic characterization 535 accessions were evaluated using 23 quantitative traits. The data were analyzed by a principal component analysis (PCA), the Ward's agglomerative hierarchical clustering method, and by univariate analysis of variance, associated to a Tukey test for comparisons among means of the established groups. Thirteen similarity accession groups were established...

The increase the dimensions of the trees, by genetic improvement, without considering their architectures can make them mechanically unstable in situations of high winds. As consequence may occur falls, breaks and permanent buckling of stems, causing economic losses and environmental damage. In the present study had as objective to estimate genetic parameters and predict wood production gains with improvements in the trees architecture. It was used a test of provenances/progenies/plants of Toona ciliata M. Roemer var. australis, established in Campo Belo, MG, with 74 months old. This test involved 12 provenances of seeds widely distributed in the Australian east coast. Data of diameter to breast height (DBH), total tree height (Ht), volume (Vol), slenderness coefficient (S = Ht.DBH -1 ) and stem form (For), at 31, 54 and 74 months of age, there were obtained in individuals of 63 progenies from all provenances. The genetic parameters and prediction of genotypic values were estimated by REML/BLUP method. There was great genetic variability among and within provenances, showing that the test has an important role for the improvement and conservation of the species ex situ. Whereas the criterion of having a higher frequency of trees with low S or equal to 0.75...