O cultivo do milho safrinha tem se expandido consideravelmente nos ultimos anos. Porem devido as condicoes ambientais contrastantes entre safra e safrinha, deve ocorrer pronunciada interacao genotipos x safras, indicando que os genotipos selecionados para a safra podem nao ser adequados para a safrinha. Assim, os objetivos deste trabalho foram investigar a magnitude e natureza da interacao genotipos x safras e a necessidade de conduzir programas de melhoramento de milho distintos para o cultivo de safra e safrinha. Foram utilizadas 100 progenies S1fs derivadas do cruzamento entre as linhagens endogamicas L08- 05F e L38-05D, as quais foram retrocruzadas com ambas as linhagens genitoras e, posteriormente, estas foram cruzadas com a linhagem endogamica L02-03D para obtencao de 200 testecrosses (100 RC1 TC e 100 RC2 TC ). Os testecrosses obtidos foram avaliados nos ambientes de safra e safrinha em dois anos agricolas no municipio de Piracicaba/SP no delineamento ?¿-latice com duas repeticoes por ambiente por ano. Os caracteres analisados foram producao de graos (PG), prolificidade (PROL), acamamento e quebramento de plantas (ACQ), altura de planta (AP) e de espiga (AE), posicao relativa da espiga (PRE), florescimento masculino (FM) e feminino (FF) e intervalo entre florescimentos (IF). Diferencas entre as medias nas duas safras foram significativas para todos os caracteres, reduzindo significativamente a PG na safrinha devido a menor disponibilidade hidrica. A variancia genetica dos testecrosses para PG na safrinha foi inferior a da safra para os testecrosses RC2 TC , enquanto que para os testecrosses RC1 TC a variancia genetica nao diferiu de zero na safrinha. Consequentemente, o coeficiente de herdabilidade na safrinha para os RC1 TC nao diferiu de zero e os RC2 TC apresentaram coeficientes de herdabilidade de magnitudes similares nas duas safras. Para os demais caracteres as magnitudes das variancias geneticas e coeficientes de herdabilidade diferiram entre as safras e os dois grupos de testecrosses. As magnitudes dos componentes da interacao testecrosses x safras mostraram que o tipo complexa explica a maior parte da interacao, sendo causada pelas baixas magnitudes de correlacoes entre os caracteres nas diferentes safras. As respostas diretas e indiretas a selecao mostraram que a selecao direta foi mais eficiente que a indireta em todas as situacoes, com excecao daquelas em que nao foi detectada variancia genetica na safrinha. As respostas a selecao baseadas nas medias das safras resultaram em progressos na safra e na safrinha proximos aos observados pela selecao direta. Porem, a coincidencia de testecrosses selecionados em ambas as safras foi muito baixa para os dois testecrosses. Assim, os resultados deste estudo sugerem que os programas de melhoramento de milho devem ser distintos para safra e safrinha. / Maize second crop season, known as gsafrinhah, has increased considerably in the last years in Brazil. However, because of the different environmental conditions between the two crop seasons strong genotype by environment interaction is expected to occur, and then maize genotypes selected in the first crop season (known as gsafrah) could not be those ones that would be selected in the safrinha. Thus, objectives of this research were to investigate the magnitude and the nature of the genotype x crop season interaction and whether separate maize breeding programs for each crop season should be conducted. One hundred S1Ls progenies developed from a population produced from the cross of inbred lines L08-05F (P1) and L38-05D (P2), were backcrossed to both parental inbred lines and, subsequently, these backcrosses were crossed to the inbred line L02-03D giving rise to the 200 testcrosses, thereafter named as TBC1 and TBC2 for the backcrosses to P1 and P2, respectively. The testcrosses were evaluated in two crop seasons in two years at the Piracicaba city, Sao Paulo State, in the ?¿-lattice designs with two replications per crop season and year. The traits analyzed were grain yield (GY), prolificacy (PROL), plant lodging (PL), plant (PH) and ear (EH) heights, ear placement (EP), days to anthesis (DA), days to silking (DS), and anthesissilking interval (ASI). Significant differences for the means of all traits in the two crop seasons were detected, and GY reduced significantly in the safrinha because of the moisture stress. The magnitude of the genetic variance for GY in the safrinha was inferior to that in the safra for the TBC2, and for the TBC1 this parameter did not differ from zero in the safrinha. Consequently, the heritability coefficient in the safrinha for the TBC1 did not differ from zero and the TBC2 presented similar magnitudes of the heritability coefficients in both crop seasons. For the other traits, the magnitudes of the genetic variances and of the heritability coefficients were different between the crop seasons and for the two sets of testcrosses. The magnitudes of the components of the interactions testcrosses x crop seasons showed that the complex type i.e., the cross-over interaction type, accounted for the major part of the interactions, which were due to the low magnitudes of the correlations of the traits in the two crop seasons. Estimates of the direct and indirect responses to selection showed that the direct selections were more efficient than the indirect selections, except to that trait in which the genetic variance did not differ from zero in the safrinha. The responses to selection based on the means of the two crop seasons presented similar magnitudes of the direct responses in both crop seasons. However, the coincidence of testcrosses selected in the two crop seasons was very low for both sets of testcrosses. Therefore, the results of this study suggest that separate maize breeding programs should be conducted for each crop season.

As posições críticas dos estatísticos, que atuam em programas de melhoramento genético, referem-se à falta de uma análise criteriosa da estrutura da interação do genótipo com o ambiente (G x E) como um dos principais problemas para a recomendação de cultivares. Tradicionalmente, a análise dessa estrutura á superficial não detalhando os efeitos da complexidade da interação. Com isso, os ganhos genéticos podem ser diminutos, pela não seleção de genótipos superiores melhores indicados a um ambiente específico. A busca constante por novos métodos e algoritmos, visando eliminar ou minimizar esse problema, tem proporcionado uma inegável evolução científica, com a geração de tecnologias de ponta que envolvem grande capacidade de processamento computacional. Atualmente, a metodologia AMMI (additive main efects and multiplicative interaction analysis) propõe ser mais eficiente que as análises usuais na interpretação e compreensão da interação G x E. Entretanto, os principais pontos negativos dessa metodologia dizem respeito à dificuldade de se interpretar a interação quando há baixa explicação do primeiro componente principal; à dificuldade de se quantificar os escores como baixos, considerando estável os genótipos e/ou ambientes, além de não apresentar o padrão de resposta do genótipo, o que caracteriza os padrões de adaptabilidade. Nesse contexto, essa metodologia apresenta alguns inconvenientes de ordem estatística, fazendo com que suas interpretações sejam vistas com ressalvas. Assim, o objetivo desta tese foi o desenvolvimento de procedimentos estatísticos que minimizem esses problemas, tornando a metodologia AMMI mais precisa e confiável na caracterização da estabilidade e adaptabilidade fenotípica de plantas. Nesse sentido, foi desenvolvido uma metodologia via reamostragem "bootstrap", no modelo AMMI, que possibilitou as análises gráficas e numéricas, das estabilidades e adaptabilidades fenotípicas de 75 progênies de Eucalyptus grandis, procedentes de três localidades australianas, e implantadas em sete testes de procedências e progênies nas regiões Sul e Sudeste do Brasil. Os resultados indicaram comportamentos diferenciados dos genótipos e dos ambientes, sendo a interação G x E significativa ao nível de 1% de probabilidade. As interpretações das estabilidades e adaptabilidades fenotípicas foram melhores compreendidas com a realização da reamostragem "bootstrap". A metodologia "bootstrap" AMMI, eliminou as dúvidas relacionadas à quantificação dos escores como baixos, tornando a metodologia AMMI mais precisa e confiável, na predição da estabilidade fenotípica de genótipos e de ambientes. O coeficiente "bootstrap" de estabilidade (CBE), baseado na distância quadrada de Mahalanobis, sobre o modelo AMMI2, obtidos através da região de predição para o vetor nulo, permitiu classificar os genótipos e ambientes em cinco escalas de estabilidade, e, conjuntamente com as representações gráficas das regiões de confiança para a estabilidade e gráficos de dispersões dos escores bootstrap", em biplot AMMI2, apresentaram melhores qualidades para predições das estabilidades fenotípicas, do que o método tradicional AMMI, com representação gráfica em biplot. / Reliable evaluation of the stability of genotypes and environment is of prime concern to plant breeders, who have Undertaken much research into the development of methods for studying in detail the structure of genotype-environment interaction. The lack of a comprehensive analysis of the structure of the GEI interaction has been a stumbling block to the recommendation of cultivars. Traditionally, the analysis of that structure was superficial and stopped short of detailing the efects of the complexity of the interaction. However, recent advances in computer science have allowed the development of interactive systems of data processing with fast and precise algorithms. Consequently, statistical methods are being developed to study in detail the structure and stability of GEI interaction. At the moment, the Additive Main Efects and Multiplicative Interaction (AMMI) Model promises to be more eficient than the usual analyses in the interpretation and understanding of the GEI interaction. The main drawbacks of the AMMI methodology are the dificulty of interpreting the interaction when there is a poor explanation of the first principal component; the dificulty of determining low scores, which relates to the statistical stability of the genotypes and/or environments; and the lack of presentation of the pattern of response of the genotype, which characterizes the adaptability patterns of the groups formed through significant parameters. Thus care needs to be exercised in the interpretation. The present contribution proposes the use of bootstrap re-sampling in the AMMI Model, and applies it to obtain both a graphical and a numerical analysis of the phenotypic stability and adaptability of 75 progenies of Eucalyptus grandis from Australia that were planted in seven environments in the South and Southeast regions of Brazil. The results show diderential behavior of genotypes and environments, the genotype x environment interaction being significant (p value < 0.01). The interpretation of the phenotypic stability through graphical analysis of the AMMI biplot is better understood with the aid of the bootstrap. The bootstrap coeficient of stability based on the squared Mahalanobis distance of the scores bootstrap, shows that genotypes and environments can be diferentiated in terms of their stabilities. The AMMI bootstrap proposal thus provides better and more precise predictions of phenotypic stability and adaptability of the geno- types than the traditional AMMI analysis, and eliminates the doubts related to the identification of the low scores.

Em experimentação agrícola, é freqüente a necessidade de análise conjunta de grupos de experimentos. Em muitos casos, o pesquisador deseja generalizar resultados para condições gerais de regiões e/ou em avaliar o desempenho de vários genótipos (tratamentos) em diversos ambientes (locais e/ou ano). Quando um conjunto de experimentos é planejado para vários locais é necessário considerar o delineamento individual em cada local e a combinação total dos genótipos com os locais (interação genótipo × ambiente). Logo, os dados observados podem ser organizados em uma tabela de dupla entrada. Existem várias metodologias de análise e interpretação para a interação genótipo × ambiente proveniente de um grupo de cultivares testados em vários ambientes. Entre essas metodologias destaca-se os modelos AMMI (“additive main effects and multiplicative interaction model”), como o próprio nome diz é um método uni-multivariado, que engloba uma análise de variância para os efeitos principais, que são os efeitos dos genótipos (G) e os ambientes (E) e para efeitos multiplicativos (interação genótipo × ambiente), utiliza-se a decomposição em valor singular (DVS). Essa técnica multivariada baseia-se no uso dos autovalores e autovetores provenientes da matriz de interação genótipo × ambiente. Araújo e Dias (2005) verificaram o problema de superestimação e subestimação de autovalores estimados da maneira convencional. Para superar esses problemas de estimação de autovalores, Muirhead (1987) apresenta três métodos para corrigir autovalores estimados a partir das matrizes de covariâncias amostral e alerta que nem sempre essas correções mantêm a ordem decrescente de valores, assim é sugerido o uso de regressão isotônica para ordenar esses dados, mas propriamente um algoritmo apresentado por Lin e Pearlman (1985). Os resultados indicaram que: A regressão isotônica juntamente com o algoritmo foi necessária e se mostrou muito importante em todos conjuntos de dados; Houve uma redução no número de componentes significativos para serem retidos nos modelos, fazendo com que os modelos AMMI selecionados sejam mais parcimoniosos quando se utiliza qualquer um dos métodos de correção; O método 2 apresentou as menores taxa de correção da soma de quadrados da interação genótipo × ambiente e o método 3 apresentou a maiores taxa de correção; Em relação a medida RMSPDPRESS, os menores valores foram obtidos quando se utilizou o método de correção 2. Já o método de correção 3 apresentou os maiores valores para RMSPDPRESS; O método 2 também se mostrou melhor quando o interesse era verificar o ganho em número de repetições, sendo que este benefício esteve sempre próximo de 3 repetições. Já o método 3 é o que apresenta um menor ganho em número de repetições, em torno de duas repetições. / In agricultural research is common to analyse groups of experiments. In many cases, the researcher intends to generalize results to general conditions of areas and/or evaluate the responses of several genotypes (treatments) in several environments (places and/or years). When a group of experiments is planned for several places it is necessary to consider the of design in each place and the combinations of the genotypes with the places (the interaction of genotype × environment). The observed data can be organized in an array. There are several methods of analysis and interpretation for the genotype × environment interaction from a group of genotype tested in several environments. These methods include AMMI models (“additive main effect and multiplicative interaction models”). As the name says it is a uni-multivariate method, that includes an analysis of variance for the main effects (the effects of the genotypes (G) and environments (E)) and assumes multiplicative effects for the genotype × environment interaction, using a singular value decomposition (DVS). This method estimates the eigenvalues and eigenvectors deriving from the matrix of genotype × environment interaction. Araújo and Dias (2005) found an overestimation and underestimation problem with the eigenvalues in the conventional way. To correct these problems Muirhead (1987) presents three methods to correct the eigenvalues from covariance the matrix and noted that these do not always maintain the order of values. The author suggested the use of isotonic regression to correct the eigenvalues, using an algorithm presented by Lin and Pearlman (1985). The results indicated that: The isotonic regression with the algorithm is necessary and it showed very important in all groups of data; There was a reduction in the number of significant components to be kept in the models and the order that the AMMI model selected is more parsimonious when any of the correction methods is used; The method 2 has the smallest rate of correction to the sum of squares of the genotype × environment interaction and method 3 has the largest correction rate; The measure RMSPDPRESS was smallest when method of correction 2 was used. The method of correction 3 has the largest values for RMSPDPRESS; Method 2 was also better when the interest was to verify the gain in number of replicates, and this benefit was always close to 3 replicates. The method 3 gives the smaller gain in the number of replicates, of around two replicates.

Stevia rebaudiana Bertoni, une herbe vivace de la famille des Asteraceae originaire du Paraguay, est d'un intérêt croissant en tant que source d’édulcorants naturels acoloriques, les glycosides de steviol (SVglys). Ces diterpénoïdes sont organisés autour d’un noyau de steviol et diffèrent par le nombre et la nature d’unités de sucre liées à ce noyau. Ils sont accumulés à des concentrations allant de 4 à 20% de la masse sèche des feuilles, selon le génotype, le stade phénologique et les conditions de croissance. S. rebaudiana apparaît comme une espèce alternative prometteuse en Europe, mais nécessite au préalable une évaluation de ses besoins en culture et un travail de sélection variétale afin d’optimiser la teneur et la composition en SVglys en milieu tempéré. L'objectif de ce travail était d'étudier les sources de variabilité génotypique et environnementale pour l’accumulation en SVglys et la production de biomasse foliaire. Une forte variabilité génotypique a été observée pour la composition en SVglys et, à un degré moindre, pour la teneur en SVglys ainsi que pour des critères morphologiques et de précocité. L’environnement (fertilisation, durée du jour, stade phénologique, âge de la plante) a également eu un effet sur l’élaboration de la biomasse foliaire et sur la teneur en SVglys, alors que la composition en SVglys a été moins affectée par ces facteurs. Ces résultats suggèrent des mécanismes biochimiques et génétiques complexes régissant la voie de biosynthèse des SVglys. Ils laissent également entrevoir des possibilités de sélection variétale et donnent des indications sur les exigences de S. rebaudiana pour sa culture sous nos climats. / Stevia rebaudiana Bertoni, a perennial shrub of the Asteraceae family originating from Paraguay, is of increasing interest as a source of zero-calorie natural sweeteners: the steviol glycosides (SVglys). These diterpenoids differ in the number and the nature of sugar units bound to a steviol skeleton. They accumulate in leaves at concentrations ranging from 4 to 20%, according to genotype, phenological stage, and growth conditions. S. rebaudiana appears as a promising alternative culture in Europe, but requires investigations to assess its cultivation plant requirements and a breeding effort to optimize SVgly content and composition under temperate climate. The objective of this work was to explore the sources of genotypic and environmental variability for SVglys accumulation and leaf biomass production. High genotypic variability has been observed for SVgly composition and, to a lesser extent, for SVgly content as well as for morphological criteria and precocity. Leaf biomass and SVgly content varied also with the environment (fertilization, daylength, phenological stage) and over the years in perennial culture, while SVgly composition was less affected by these factors. These results suggested complex biochemical and genetic mechanisms regulating SVglys biosynthetic pathway. In parallel they revealed breeding potentialities and gave indications on S. rebaudiana requirements for its cultivation under temperate climate.

É comum o estudo da estabilidade fenótipica em genoótipos de cana-de-açúcar. Varias são as metodologias para estudar a interação genótipos x ambientes (G x E). O desafio para os melhoristas é encontrar variedades de cana-de-açúcar com desempenho superior em diversos ambientes, ou seja, que sejam altamente produtivas e também responsivas com a melhoria do ambiente. O estudo das metodologias permite verificar se determinada técnica biométrica é eficiente para expressar o comportamento de genótipos em vários ambientes e tambem permite aprimorá-las para que as conclusões sejam mais confiáveis. Este trabalho teve como objetivo comparar dois métodos de regressão utilizados para avaliar a estabilidade fenótipica em variedades de cana-de-açúcar: o linear, de Cruz, Torres e Vencovsky (1989) e o não-linear, de Toler e Burrows (1998). Foram utilizados dados da variável tonelada de cana por hectare - TCH, fornecidos pelo Programa de Melhoramento Genetico da Cana-de- Acucar da UFSCar, compreendendo sete locais e 18 genótipos de cana-de-açúcar. Quando se realizou o enquadramento dos genotipos nos diferentes grupos, 17 genotipos dos 18 avaliados enquadraram-se nos mesmos grupos em ambos os métodos. Os coeficientes de determinação foram similares, sendo que 11 genótipos apresentaram melhor ajuste ao modelo de Cruz et al., enquanto que este numero foi de sete para o modelo de Toler e Burrows. As análises indicaram que ambas metodologias produziram resultados similares. / It is common to study the phenotypic stability of sugarcane genotypes. There are several methods to study the genotype by environment interaction . The challenge for breeders is to nd varieties of sugarcane with superior performance dierent environments, i.e, that are highly productive and responsive to environmental improvement. The study of methodologies allows to verify whether certain technique biometrics is eective to express the behavior of genotypes in several environments and it also allows improving them so that the conclusions are more reliable. This study aimed to compare two regression methods used to evaluate the phenotypic stability of varieties of sugarcane: the linear method by Cruz, Torres e Vencovsky (1989), and non-linear, by Toler and Burrows (1998). We used the variable data tons of cane per hectare - TCH, which were provided by the Genetic Improvement Program of Sugarcane in UFSCar, including seven locations and 18 genotypes. When genotypes were grouped according to stability and yield, 17 of the 18 genotypes evaluated were classied in the same groups, in both methods. The coecients of determination were similar, 11 genotypes showing better adjustment to the model of Cruz et al., while this number was seven for the Toler and Burrows\' model. The analysis indicated that both methodologies produced similiar results.

Breeding maize (Zea mays L.) for tolerance to acidic soils could improve maize yields. The current study aims to identify maize genotypes with tolerance to acidic soils, as well as identifying secondary traits associated with the tolerance to soil acidity. Ten maize varieties were screened for tolerance to aluminium (Al) toxicity under glasshouse, laboratory and field conditions. In the glasshouse, two soil acidity levels (limed and unlimed soil) were used and the experiment was set up in a complete randomised design (CRD) with three replications. The experiment lasted for 10 days and measurements were taken on plant height (PH), leaf area, stem diameter and dry matter. In the laboratory, a haematoxylin staining (HS) experiment was conducted to determine the response of 10 maize varieties to Al toxicity. Two Al concentrations (0 and 222 μM) were used and the experiment was set up in a completely randomized design with three replications. After 7 days, shoot length, was recorded. Five stress tolerance indices were estimated to determine the resilience of each genotype. A root growth stress tolerance index was also computed for both experimental procedures. In the field, two trials were established at two sites, namely Mbinja and Mpumaze. Limed and unlimed plots were used, and the trial was set up in a randomized complete block design with three replications. Maize kernel yield and other standard field parameters were recorded. Selection of tolerant genotypes from the field screening was also done using three indices, namely harmonic mean (HM), stress tolerance index (STI) and stress susceptibility index (SSI). Both the glasshouse and laboratory assays identified similar genotypes of maize as being tolerant. These tolerant genotypes were Ngoyi, PANBG3492 BT, PAN 6Q408 and PHB 3442 based on the root growth stress tolerance index (RGSTI). It was therefore demonstrated that these two assays produced the same level of efficiency in identifying tolerant genotypes using this index. Based on ranking of seedling vigour index under soil acidity stress, the top three genotypes at Mpumaze were PHB32W71, PAN6616 and Sahara while at Mbinja, the top three were PAN6616, PAN6Q408 CB and PAN6P110. The genotypes PANBG3492 BT, PAN6Q408 and PHB3442 were also found to be tolerant to acidic soils at seedling stage. These genotypes are recommended for further evaluation in more sites to confirm their tolerance and yield potential under acidic soils. The study also revealed that plant height, leaf area and stem diameter could be used for indirect selection for tolerance to Al toxicity under glasshouse conditions. The seedling vigour index was also effective in identifying tolerant genotypes under glasshouse conditions. On the other hand, shoot length stress tolerance index and the haematoxylin score were useful for indirect selection for tolerance to Al toxicity in the laboratory. In the field, it was observed that ear length, leaf area and ear diameter can be useful in identifying genotypes that are tolerant to soil acidity. They can therefore be useful as indirect selection criteria under field conditions. Additionally, the best selection indices for identifying soil acidity tolerant genotypes under field conditions were the HM and the STI. It is recommended that varieties that were identified as tolerant be further evaluated in several soil acidity hot spots to confirm their tolerance and stability of performance under field conditions. / Agriculture and  Animal Health / M. Sc. (Agriculture)

Thesis (MPhil)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: A thesis undertaken to quantify genotype-by-environment interaction within Eucalyptus grandis clones growing in the eastern portion of South Africa. Thirty one sites were selected to represent the "traditional" E. grandis growing areas of South Africa. Eleven common macro- site variables and twelve common micro- site soil variables were recorded at each site. Twenty seven E. grandis clones and four E. grandis hybrid clones were then evaluated over these 31 sites. An incomplete latin square design was used to evaluate the 31 test clones, and five E. grandis controls were incorporated into the trial design to link the 31 sites. Volume production, stem form, stem defects and survival were assessed at two and five years, as well as the disease infestation of three stem cankers at five years. The analytical methods which were used to evaluate and quantify the GEl portion of the study are the analysis of variance (ANOV A), correlation analysis, and joint regression analysis (IRA) together with the analysis of co-variance (ACOV AR). The growth-site association for volume production, stem form and Endothia disease infestation were investigated using factor analysis (FA), and equations derived for the species and for the individual clones using a stepwise multiple regression approach. GEl, as evaluated through JRA, revealed that an increase in site productivity lead to a positive linear response in productivity on a clonal level, and that there was a diverging or fanning pattern among the regression lines of the clones. This tendency was also observed for both the stem form and the Endothia infestation. Hence, no significant changes in the rankings of the clones were found, and only relevant differences between the clones were found to change significantly. Juvenile-mature genetic correlations for volume production and the stem form showed moderate (rg = 0,66 and rg = 0,70) correlations between the two and the five year assessments. On a species level, rainfall was the main environmental factor responsible for volume production, while latitude was the main influence on stem form and Endothia infestation. On an individual clone basis, some micro-site soil factor interaction within the clones was found for the growth-site response models. Keywords: Eucalyptus grandis, genotype environment interaction, clones, site factors, growth-site response, ANOV A, ACOV AR, GEl, FA, JRA, / AFRIKAANSE OPSOMMING: 'n Studie is ondemeem om die genotipe-omgewingsinteraksie van Eucalyptus grandis klone, wat in die oostelike deel van Suid-Afrika groei, te kwantifiseer. Eenen- dertig groeiplekke is geselekteer om die "tradisionele" E. grandis groeiplekke in Suid-Afrika te verteenwoordig. Elf gemeenskaplike makro-groeiplek veranderlikes en twaalf gemeenskaplike mikro-groeiplek veranderlikes is by elk van die groei areas opgeteken. Sewe-en-twintig E. grandis klone en vier E. grandis basterklone is daama oor hierdie 31 groeiplekke geevalueer. 'n Onvolledige Latynse roosterontwerp is gebruik om die 31 toetsklone te evalueer en vyf kontroles is gebruik om die groeiplekke gemeenskaplik te verbind. Volume produksie, stamvorm, stamdefekte en oorlewing is op twee- en vyfjarige ouderdomme geevalueer terwyl besmetting met drie stamkankers op vyf jaar beoordeel is. Die analitiese metodes wat gebruik was om genotipeomgewingsinteraksie te evalueer en te kwantifiseer is die variansie analise (ANOYA), korrelasie analise, en gesamentlike regressie analise (JRA) tesame met ko-variansie analise (ACOY AR). Die groeiplek assosiasie vir volume produksie, stamvorm en Endothia besmetting is ondersoek deur gebruik te maak van faktor analise (FA), en vergelykings is verkry vir die spesies en individuele klone deur gebruik van 'n stapsgewyse meervoudige regressie benadering. Genotipe-omgewingsinteraksie, soos geevalueer deur JRA, wys dat 'n toename in groeiplek produktiwiteit lei tot 'n positiewe lineere reaksie in produktiwiteit op klonale vlak en dat daar 'n divergerende patroon tussen die regressielyne van die klone is. Hierdie tendens is ook vir beide die stamvorm en Endothia besmetting waargeneem. Gevolglik is nie-beduidende veranderings in die rangorde van die klone gevind en slegs reletiewe verskille tussen klone is gevind. Onvolwasse-volwasse genetiese korrelasies vir volume produksie en stamvorm toon matige korrelasies (rg =0.66 en rg =0.70) tussen die twee- en vyfjaar metings. Op 'n spesiesvlak was reenval die oorheersende omgewingsfaktor verantwoordelik vir volume produksie terwyl die breedtegraad ligging stamvorm en Endothia besmetting bemvloed het. Op individuele kloonvlak het sommige mikro-groeiplek interaksie binne klone bygedra tot die groei en groeiplek reaksie modelle. Sleutelwoorde: Eucalyptus grandis, Genotipe-omgewingsinteraksie, klone, groeiplek faktore, groeiplek reaksie, ANOY A, ACOY AR, FA, JRA

Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2017-05-05T14:57:53Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Parâmetros genéticos e correlações para caracteres de qualid.pdf: 655495 bytes, checksum: 394a538a094198fedbd0b5c7ec964be4 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-05-10T15:47:22Z (GMT) No. of bitstreams: 2 Parâmetros genéticos e correlações para caracteres de qualid.pdf: 655495 bytes, checksum: 394a538a094198fedbd0b5c7ec964be4 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-05-10T15:47:22Z (GMT). No. of bitstreams: 2 Parâmetros genéticos e correlações para caracteres de qualid.pdf: 655495 bytes, checksum: 394a538a094198fedbd0b5c7ec964be4 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-03-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / A busca incessante por maior produtividade e qualidade dos alimentos é uma das maiores preocupações mundiais. O arroz (Oryza sativa L.) é uma das bases na alimentação e segundo cereal mais produzido no mundo, sendo considerada uma das principais culturas com potencial para combater a fome. Desta forma, os programas de melhoramento desse cereal têm intensificado a busca por genótipos superiores, prioritariamente para produtividade, contudo, atualmente também estão focando neste mesmo nível de prioridade os atributos de qualidade de grãos. Sendo estes atributos decisivos na adoção de uma linhagem melhorada como uma cultivar comercial, pois reflete diretamente no seu valor de mercado e aceitação do consumidor. Neste sentido, o presente trabalho teve por objetivo determinar a adaptabilidade e estabilidade, bem como, estudar as correlações genéticas, dos caracteres de qualidade de grão de cultivares e linhagens elites de arroz irrigado para facilitar as inferências requisitadas pelos melhoristas. Dois ensaios experimentais foram conduzidos em diferentes ambientes, nas safras agrícolas de 2014/15 e 2015/16. O primeiro experimento teve como objetivos avaliar a adaptabilidade e estabilidade de linhagens elites de arroz irrigado em oito ambientes distintos, pelos métodos de MHVG, PRVG e MHPRVG. As linhagens AB11502, AB10501, AB13008, AB13002 e AB13003 apresentaram bom desempenho agronômico, além de adaptabilidade e estabilidade para os caracteres de qualidade de grãos, perante os métodos propostos. O segundo experimento teve o objetivo de evidenciar as correlações genéticas e as associações diretas e indiretas de caracteres agronômicos e atributos de qualidade de grãos, relacionados ao rendimento de grãos inteiros em arroz irrigado pela análise de trilha. A área gessada total, juntamente com a brancura total são os fatores que mais influenciaram no percentual de grãos inteiros, tanto via correlações genotípicas, quanto via efeitos diretos pela análise de trilha, demonstrando assim, potencial para utilização como critérios de seleção indireta para rendimento de grãos inteiros. Cabe ressaltar que ainda há poucos trabalhos na área de genética quantitativa para o caráter de qualidade dos grãos, de maneira que o progresso genético da mesma está apenas no começo. Neste sentido, novas pesquisas devem ser realizadas, visando utilizar cada vez mais, tais ferramentas no processo de seleção. Palavras-chave: Oryza sativa L.; rendimento de engenho; grãos inteiros; / Nowadays, the incessant quest for greater productivity and food quality is one of the world's biggest concerns. Rice (Oryza sativa L.) is one of the bases in human nutrition, being the second most produced cereal in the world, considered one of the main crops with potential to fight hunger. In this way, they are highly important among breeding programs. These factors that intensify the search for superior genotypes, mainly for productivity, however, the attributes of grain quality are also classified at this same level of priority. These attributes are decisive in the adoption of an improved lineage as a commercial cultivar, as it directly reflects its market value and consumer acceptance. In this sense, the objective of the present work was to determine the adaptability and stability, as well as to study the genetic correlations of grain quality traits of cultivars and elite breeding lines of irrigated rice to facilitate the inferences requested by breeders. Two experimental trials were conducted in different environments, in the agricultural crops of 2014/15 and 2015/16. The first experiment had as objectives to evaluate the adaptability and stability for elite breeding lines of irrigated rice in eight different environments, by the methods of MHVG, PRVG and MHPRVG. The lines AB11502, AB10501, AB13008, AB13002 and AB13003 showed good agronomic performance, besides adaptability and stability for grain quality characters, in relation to the proposed methods. The second experiment had the objective of evidencing the genetic correlations and the direct and indirect associations of agronomic traits and grain quality attributes, related to the yield of whole grains in rice irrigated by path analysis. The total chalky area together with the total whiteness were the factors that influenced the percentage of whole grains, both via genotypic correlations and via direct effects through path analysis, thus showing potential for use as indirect selection criteria for yield whole grain. It should be emphasized that there are still few studies in quantitative genetics for the grain quality traits, so that the genetic progress is only at the beginning. In this sense, new research must be carried out, aiming to use these tools more and more in the selection process.

<p>У раду су приказани резултати огледа са једанаест сорти пшенице (Triticum aestivum L.) и једном сортом тритикалеа (Triticosecale W.) на локалитету Кумане у Банату, у стресним условима халоморфног земљишта типа солоњец. Током три вегетационе сезоне је испитана генотипска варијабилност, праћењем фенотипске варијације и интеракције генотип/спољна средина за принос и компоненте приноса (висина биљке, дужина класа, маса класа, маса зрна по класу и број зрна по класу). Оглед је постављен на контролној варијанти (солоњец без поправке) и третманима са мерама поправке, уз примену фосфогипса у количини од 25 t/ha и 50 t/ha. За анализу интеракције генотипа и спољне средине је примењен Модел главних ефеката и вишеструке интеракције-AMMI (Аdditive Мain Еffects and Мultiplicative Interaction). Међузависност испитиваних особина је утврђена анализом једноструких корелација. У циљу дефинисања реакције генотипова на стресне услове солоњеца, испитанa је активност ензимских и неензимских компоненти антиоксидативног система, као и липидне пероксидације.<br />Испољена је статистичка значајност главних ефеката генотипа, агроекосредина и њихове интеракције на варијабилност свих испитиваних својстава. Уочени су генотипови мале интеракције генотип/спољна средина за поједине особине, што би могло да се окарактерише као стабилна реакција тих генотипова у променљивим условима средине, у односу на мелиоративни третман и вегетациону сезону. Корелационом анализом су<br />установљене значајне и високозначајне вредности коефицијената корелације између већине испитиваних својстава. Разлике у активности ензима и неензимских компоненти антиоксидативног система заштите указују да су генотипови различито реаговали на стресне услове солоњеца.<br />Добијени резултати могу да помогну процес стварања генотипова пшенице, који ће да се гаје на земљиштима са вишим концентрацијама натријума и неповољним физичким особинама, са добром стабилношћу.</p> / <p>U radu su prikazani rezultati ogleda sa jedanaest sorti pšenice (Triticum aestivum L.) i jednom sortom tritikalea (Triticosecale W.) na lokalitetu Kumane u Banatu, u stresnim uslovima halomorfnog zemljišta tipa solonjec. Tokom tri vegetacione sezone je ispitana genotipska varijabilnost, praćenjem fenotipske varijacije i interakcije genotip/spoljna sredina za prinos i komponente prinosa (visina biljke, dužina klasa, masa klasa, masa zrna po klasu i broj zrna po klasu). Ogled je postavljen na kontrolnoj varijanti (solonjec bez popravke) i tretmanima sa merama popravke, uz primenu fosfogipsa u količini od 25 t/ha i 50 t/ha. Za analizu interakcije genotipa i spoljne sredine je primenjen Model glavnih efekata i višestruke interakcije-AMMI (Additive Main Effects and Multiplicative Interaction). Međuzavisnost ispitivanih osobina je utvrđena analizom jednostrukih korelacija. U cilju definisanja reakcije genotipova na stresne uslove solonjeca, ispitana je aktivnost enzimskih i neenzimskih komponenti antioksidativnog sistema, kao i lipidne peroksidacije.<br />Ispoljena je statistička značajnost glavnih efekata genotipa, agroekosredina i njihove interakcije na varijabilnost svih ispitivanih svojstava. Uočeni su genotipovi male interakcije genotip/spoljna sredina za pojedine osobine, što bi moglo da se okarakteriše kao stabilna reakcija tih genotipova u promenljivim uslovima sredine, u odnosu na meliorativni tretman i vegetacionu sezonu. Korelacionom analizom su<br />ustanovljene značajne i visokoznačajne vrednosti koeficijenata korelacije između većine ispitivanih svojstava. Razlike u aktivnosti enzima i neenzimskih komponenti antioksidativnog sistema zaštite ukazuju da su genotipovi različito reagovali na stresne uslove solonjeca.<br />Dobijeni rezultati mogu da pomognu proces stvaranja genotipova pšenice, koji će da se gaje na zemljištima sa višim koncentracijama natrijuma i nepovoljnim fizičkim osobinama, sa dobrom stabilnošću.</p> / <p>This paper presents the results of an experiment with eleven varieties of wheat (Triticum aestivum L.) and one triticale variety (Triticosecale W.). The experiment was conducted in stress conditions of the site Kumane in Banat, on solonetz soil. Genotypic variability has been examined, during three growing seasons, through phenotypic variation and genotype/environment interaction for yield and yield components (plant height, spike length, spike weight, seed weight per spike and number of grains per spike). The experiment was set up in the control treatment (solonetz soil without melioration) and the improvement measures with application of phosphogypsum in amount of 25 t/ha and 50 t/ha. The genotype/environment ineraction was analyzed using AMMI model (Additive Main Effect and Multiplicative Interaction). The interrelationship of the studied traits was determined by the single correlation coefficients. In order to define the genotype response to stress of solonetz, the activity of enzimatic and non-enzimatic antioxidant system and lipid peroxidation were examined.<br />The statistical significance of the main effects of genotypes, environments and their interaction on variation of all the traits was observed. The observed genotypes with low genotype/environment interaction for certain traits, which could be characterized as a stable reaction of these genotypes in variable environmental conditions, in relation to the ameliorated measures and growin seson. For the different traits as the most stable ones, various genotypes were obtained. The genotypes in study reacted differently to different levels of melioration, in relation to each treatment<br />and growing season. Correlation analysis were established significant and highly significant values of correlation coefficients between the most of studied traits. Differences in the activity of enzymatic and non-enzymatic components of the antioxidant protection suggests that the genotypes responded differently to stress conditions of solonetz.<br />The results can help the process of creating wheat genotypes, which will be grown on soils with higher concentrations of sodium and unfavorable physical properties, which would have good stability.</p>

[Truncated abstract] Ross River virus (RRV) causes the most common arboviral disease in Australia, with approximately 5000 new cases reported each year, making this virus a major public health concern. The aim of this thesis was to link results from virological, pathogenesis and epidemiological studies to further define RRV disease in the south-west (SW) of Western Australia (WA), a region of endemic and epizootic RRV activity. A crosssectional seroprevalence study was used to show that 7.8 percent of SW communities were seropositive to RRV, comparable to other regions of Australia with similar temperate climates to the SW . . . RRV-specific IgM antibodies were found to persist for at least two years following RRV infection. A murine model was used to conclusively show differences in pathogenesis between RRV genotypes, the SW and northern-eastern (NE) genotypes, which are known to circulate throughout Australia. The SW genotype, unique to the SW of WA induced only poor neutralising antibody production and nonneutralising antibodies after the acute phase of infection. In comparison, the NE genotype which currently predominates in mosquito populations in the SW of WA, induced the most efficient neutralising antibody response and consequently produced the mildest disease in the mouse. These data in the mouse suggest that the infecting genotype will mostly likely influence disease outcome in humans and could at least partially explain why more severe and persistent disease has been reported from the SW of WA. Collectively, results from this thesis provide an important benchmark against which future investigations into BFV and RRV diseases can be measured.