A variety of modern software packages are available for genotype imputation relying on advanced concepts such as pre-phasing of the target dataset or utilization of admixed reference panels. In this study, we performed a comprehensive evaluation of the accuracy of modern imputation methods on the basis of the publicly available POPRES samples. Good quality genotypes were masked and re-imputed by different imputation frameworks: namely MaCH, IMPUTE2, MaCH-Minimac, SHAPEIT-IMPUTE2 and MaCH-Admix. Results were compared to evaluate the relative merit of pre-phasing and the usage of admixed references. We showed that the pre-phasing framework SHAPEIT-IMPUTE2 can overestimate the certainty of genotype distributions resulting in the lowest percentage of correctly imputed genotypes in our case. MaCH-Minimac performed better than SHAPEIT-IMPUTE2. Pre-phasing always reduced imputation accuracy. IMPUTE2 and MaCH-Admix, both relying on admixed-reference panels, showed comparable results. MaCH showed superior results if well-matched references were available (Nei’s GST ≤ 0.010). For small to medium datasets, frameworks using genetically closest reference panel are recommended if the genetic distance between target and reference data set is small. Our results are valid for small to medium data sets. As shown on a larger data set of population based German samples, the disadvantage of pre-phasing decreases for larger sample sizes.

Enterococos resistentes aos glicopeptídeos representam, atualmente, importantes patógenos causadores de infecção nosocomial, sendo isolados em várias regiões do mundo, inclusive no Brasil. Dos fenótipos de resistência descritos até o momento, VanA e VanB são os mais encontrados. O fenótipo VanA é caracterizado por linhagens resistentes a altos níveis de vancomicina e teicoplanina, enquanto VanB é representado por linhagens com altos níveis de resistência à vancomicina, mas com sensibilidade à teicoplanina. O fenótipo VanA é codificado por um grupamento de genes (vanRSHAXYZ) localizados em um elemento genético móvel denominado Tn1546 ou elemento VanA, freqüentemente inserido em plasmídeo conjugativo. Quatro linhagens de enterococos resistentes à vancomicina e sensíveis à teicoplanina que apresentaram genótipo vanA e fenótipo VanB foram estudadas com objetivo de se determinar qual o mecanismo responsável por esta incongruência. A identificação das espécies foi realizada por multiplex PCR, sendo três linhagens identificadas como Enterococcus faecalis e uma linhagem Enterococcus faecium. Todas confirmaram a presença do gene vanA por PCR e, no entanto, apresentaram sensibilidade à teicoplanina, determinada por Etest, condizente com o fenótipo VanB. Reações de Long-PCR e overlapping PCR foram realizadas para amplificação e caracterização do elemento VanA. O elemento VanA das linhagens de E. faecalis mostrou deleção da extremidade direita, correspondente à perda dos genes vanY e vanZ. Na linhagem de E. faecium foi detectada a inserção da ISEfa5 na região intergênica vanXY, como reportado em estudo prévio. A tipagem molecular das linhagens foi realizada pelo perfil de PFGE após macrorestrição do DNA com enzima SmaI e indicou que duas linhagens de E. faecalis pertenciam ao mesmo clone, enquanto a outra era geneticamente não relacionada. Estudos de hibridação com sonda para localização do gene vanA indicaram que este gene estava associado a um plasmídeo de 70Kb. Para verificar a presença de eventuais mutações no gene vanS, relatadas em alguns estudos como causa da perda da sensibilidade à teicoplanina, os elementos VanA das linhagens foram seqüenciados, contudo nenhuma mutação foi encontrada. Os experimentos de clonagem para analisar a possível presença de uma região promotora entre os genes vanY e vanZ indicaram a viii não existência de um promotor nesta região. A presença de elemento VanA com a mesma característica, sendo carreado por plasmídeos de mesmo tamanho em linhagens de E. faecalis com perfil de PFGE diferentes, sugere que este elemento foi transferido horizontalmente. O estudo molecular deste elemento de resistência gerou informações sobre a epidemiologia e eventos genéticos no elemento VanA que estão ocorrendo nas linhagens de VRE isoladas no Brasil. / Vancomycin-resistant enterococci (VRE) have emerged worldwide including in Brazil as important nosocomial pathogens. The most prevalent phenotypes described among glycopeptide resistant enterococci are VanA and VanB. VanA phenotype is characterized by induced high-level resistance both to vancomycin and teicoplanin, whereas VanB resistant strains show inducible resistance to vancomycin and retained susceptibility to teicoplanin. The vanA gene cluster (vanRSHAXYZ) is located in a mobile genetic element called Tn1546 or VanA element, which is often carried by conjugative plasmids. Four VRE showing VanB phenotype and vanA genotype isolated in a Brazilian hospital were investigated to better understand the molecular mechanisms underlying this incongruence. Multiplex PCR was performed for species identification. Three strains were identified as Enterococcus faecalis and the fourth as Enterococcus faecium. All VRE strains harboured gene vanA but showed VanB phenotype as determined by the Etest. Long PCR and PCR amplification of internal regions were employed for Tn1546 structural analysis. Three E. faecalis showed deletion of vanYZ genes corresponding to the inverted repeated right terminal of Tn1546 and E. faecium showed insertion of an IS element, ISEFa5, between vanX and vanY genes, as previously reported. These genetic rearrangements were associated to loss of resistance to teicoplanin. PFGE performed after SmaI digestion of DNA revealed that two E. faecalis were genetically related but the third one was unrelated. Plasmid analysis followed by Southern blotting and hybridization with vanA probe were performed for localization of VanA element. Results indicated that E. faecalis isolates showed the same structure of VanA element and plasmid profile with vanA located into plasmid. Thus, horizontal dissemination of this genetic element was suggested. VanA elements in all isolates were sequenced to detect point mutations in vanS, previously observed in VanB phenotype-vanA-genotype VRE isolates. However, no mutation was found. Assays to detect the presence of a promoter between vanX and vanY genes were negative for this region. Molecular characterization of these VRE furnished additional important information about VanA element epidemiological and evolutionary events in Brazilian isolates.

Orientador: Katia Denise Saraiva Bresciani / Banca: Marcelo Vasconcelos Meireles / Banca: Solange Maria Gennari / Resumo: Doze gatas, sorologicamente negativas para Toxoplasma gondii, foram distribuídas em três grupos de quatro animais cada. Os animais dos grupos 1 e 2 foram infectados com cistos teciduais de T. gondii, por via oral, no terço médio de gestação, sendo: grupo 1 - isolado tipo I altamente virulento para camundongos; grupo 2 - isolado tipo III não virulento para camundongos; e grupo 3 - gatas controle não infectadas. Antes da infecção e durante todo o período experimental foram efetuadas avaliações clínicas. Amostras sangüíneas foram colhidas nos dias 0 (antes da inoculação), 15 e 30 dias pós-infecão para a realização de hemogramas e pesquisa de anticorpos contra T. gondii pela reação de imunofluorescência indireta (RIFI 16). A infecção com o isolado de T. gondii virulento (tipo I) ocasionou diarréia, vômito, secreções ocular e vaginal e aborto de uma cria. Nas gatas inoculadas com o isolado tipo III não patogênico, foram observados diarréia, vômito, hiporexia, secreções nasal e ocular purulentas e um parto prematuro com natimortos. Todas as oito gatas infectadas com cistos teciduais de T. gondii apresentaram anticorpos contra T. gondii pela RIFI. Em dois filhotes da mesma ninhada, pertencentes ao grupo 1, foram detectados títulos de 16 e 64 aos 10 dias de vida. No grupo 2, títulos de 16, 32 e 32 foram detectados em três filhotes da mesma ninhada. Os resultados deste estudo demonstram que cistos teciduais de T. gondii de genótipos dos tipos I e III (pelo marcador SAG 2) provocaram transtornos reprodutivos semelhantes em gatas gestantes primoinfectadas. / Abstract: Twelve pregnant queens, serologically negative to Toxoplasma gondii, were distributed into three groups of four animals each. Animals were infected orally with tissue cysts of T. gondii, in the meddle third of their pregnancies as follows: group 1- was infected with isolate type I highly virulent for mice; group 2 - was infected with isolate type III not virulent for mice; group 3 - no infected control queens. Clinical profiles of the animals were determined before infection and during the whole experimental period. Blood samples of the queens were taken in the following days: 0 (before the inoculation), 15 and 30 days pos infection for blood count and for the antibodies detection against T. gondii by the indirect immunofluorescent antibody test (IFAT 16). Virulent T. gondii (type I) infection caused vomiting, diarrhea, purulent eye secretion, haemorrhagic vaginal secretion and abortion of one pregnancy. Queens infected with non pathogenic type III isolate developed diarrhea, emesis, hyporexia, purulent nose and ocular secretions and one premature stillbirth. In all eight infected queens with tissue cysts T. gondii antibody were detectable by IFAT. In two kittens of the same litter, from group 1, had been detected titers of 16 and 64 at 10 days of age. In group 2, titers of 16, 32 and 32 were detected in 3 kittens of the same litter. Infection with tissue cysts of types I and III (SAG 2 marker) of T. gondii isolates developed similar clinical and reproductive disturbance in primary infected pregnant queens. / Mestre

Sofosbuvir is a uridine based nucleotide inhibitor of the hepatitis C viral (HCV) polymerase that is the backbone of many treatment regimens. In combination with drugs targeting other viral enzymes (including the poorly potent guanosine analogue ribavirin or highly potent inhibitors of viral NS5A or protease) most patients clear virus and resistance to sofosbuvir is rare, allowing effective retreatment with sofosbuvir. Patients with Genotype 3 HCV respond less well than other genotypes and response is reduced in those previously exposed to interferon. Here we show that patientderived virus from patients with Genotype 3 HCV who relapse to sofosbuvir-based therapies have a reduced sensitivity to SOF in an in-vitro phenotyping assay. Analysis of viral sequencing data revealed two distinct polymorphisms (A150V and K206E) in the HCV polymerase that are associated with treatment failure and in-vitro; they reduce sofosbuvir sensitivity against genotype 3 hepatitis C virions. However both polymorphisms modify the cellular response to type I interferon and in cells lacking response to interferon the impact on sofosbuvir sensitivity is minimal. The A150V polymorphism reduces the response to interferon 70 fold whereas the K206E substitution has minimal effects on interferon in isolation but in combination with A150V reduces the response 100 fold. Preliminary data indicates that the A150V polymorphism interferes with the late response to type I interferons enabling the virus to overcome the induction of interferon-stimulated genes. These data indicate a complex interaction between direct acting antiviral drugs and the innate antiviral response.

Submitted by (ana.araujo@ufrpe.br) on 2017-02-17T12:08:29Z No. of bitstreams: 1 Ivanildo Ramalho do Nascimento Junior.pdf: 550438 bytes, checksum: 6a9cb7e8f4ae831e30a138ad05f4a0d1 (MD5) / Made available in DSpace on 2017-02-17T12:08:29Z (GMT). No. of bitstreams: 1 Ivanildo Ramalho do Nascimento Junior.pdf: 550438 bytes, checksum: 6a9cb7e8f4ae831e30a138ad05f4a0d1 (MD5) Previous issue date: 2012-02-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The study of promising genotypes of crown and rootstock in potential regions for the production of fresh citrus fruits is fundamental to the continued development of national citrus sector. The microregion of Garanhuns in Southern Agreste of Pernambuco and other potential areas of northeast of Brazil, due to favorable edafoclimatic conditions for growing citrus, can generate production that could serve both regional and international markets. Thus, the objective was to evaluate genotypes of tangerines and grapefruits at Southern Agreste of Pernambuco conditions, through evaluation of agronomic parameters and physical, chemical and physical-chemical characteristics of fruits, aiming at the diversification of fruticulture. The experiment was conducted at Experimental Station of Brejão (IPA), evaluating thirteen varieties of tangerines and hybrids and three grapefruits. The evaluation of the maturation period was identified with the accompanying from development floral branch to maturation of fruits. For the analysis of plant development, was used the randomized block design with five replications and one plant per plot, being evaluated the diameter of stem above and below of grafting point, the crown diameter, plant height and volume crown. For the analysis of the fruits was used the randomized block design with four replications and four fruits per plot, being used twelve descriptors. In relation to maturation period, the Murcott, Kinnow and Fortune Iniasel tangerines were classified as mid-season, even as the Flame, Star Ruby and Henderson grapefruits. The Nova tangerine and the Flame grapefruit presented the smallest crown volume with 9.71 and 8.70 cubic meters respectively in the last measurement, positive feature in citrus breeding programs to obtain new crown varieties. Regarding fruit, the Robinson tangerine and the Henderson grapefruit presented the highest ratio mean with 20.83 and 5.93 respectively. All tangerines showed diameter within the established by standard classification of fresh citrus fruits, however, the Mexerica, Dancy and Swatow varieties had average fruit weight less than the main commercialized tangerines, even as the three grapefruits varieties studied. / O estudo de genótipos promissores de copa e porta-enxerto em regiões potenciais para a produção de citros de mesa é fundamental para a continuidade do desenvolvimento do setor citrícola nacional. A microrregião de Garanhuns no Agreste Meridional Pernambucano e outras áreas potenciais do Nordeste brasileiro, devido às condições edafoclimáticas favoráveis ao cultivo de citros, podem gerar produção que poderá atender tanto o mercado regional quanto internacional. Assim, objetivou-se avaliar genótipos de tangerineiras e pomeleiros nas condições edafoclimáticas da região do Agreste Meridional de Pernambuco, mediante avaliação dos parâmetros agronômicos e características físicas, físico-químicas e químicas dos frutos, visando à diversificação da fruticultura. O experimento foi realizado na Estação Experimental de Brejão (IPA), onde foram avaliadas treze variedades de tangerineiras e híbridos e três pomeleiros. A avaliação do período de maturação foi identificada com acompanhamento do desenvolvimento do ramo floral até a maturação dos frutos. Para a análise do desenvolvimento das plantas utilizou-se o delineamento em blocos casualisados, com cinco repetições e uma planta por parcela, sendo avaliado o diâmetro do caule acima e abaixo do ponto de enxertia, o diâmetro de copa, altura da planta e volume de copa. Para a análise dos frutos utilizou-se o delineamento em blocos casualisados, com quatro repetições e quatro frutos por parcela, sendo utilizados doze descritores. Quanto ao período de maturação, as tangerineiras Murcott, Kinnow e Fortune Iniasel se enquadraram como de meia-estação, assim como, os pomeleiros Flame, Star Ruby e Henderson. A tangerineira Nova e o pomeleiro Flame apresentaram o menor volume de copa com 9,71 e 8,70 m³ respectivamente na última medição, característica positiva em programas de melhoramento genético de citros para obtenção de novas variedades de copa. Em relação aos frutos, a tangerina Robinson e o pomelo Henderson apresentaram as maiores médias de ratio com 20,83 e 5,93 respectivamente. Todas as tangerinas apresentaram calibre dentro do estabelecido pela Norma de Classificação dos Citros de Mesa, porém, as variedades Mexerica, Dancy e Swatow apresentaram média da massa dos frutos inferior as principais variedades de tangerinas comercializadas, assim como, as três variedades de pomeleiros estudadas.

Orientador: Paula Rahal / Banca: João Renato Rebello Pinho / Banca: Maurício Lacerda Nogueira / Resumo: O HCV é uma das maiores causas de doença do fígado, sendo estimado que mais de 2% da população mundial está infectada. Este vírus possui um genoma de RNA (+) fita simples, que devido à falta de atividade corretiva da polimerase viral apresenta variabilidade genética em vários níveis: genótipos, subtipos e quasispecies. O genótipo 1 é o mais prevalente no Brasil e no mundo, sendo preditivo de uma baixa resposta à terapia antiviral, que atualmente é baseada na administração de PEG-IFN e ribavirina. A variabilidade genética da região viral NS5A tem sido relacionada à sensibilidade ou resistência ao IFN. Este estudo teve como objetivo investigar se a possível relação entre a composição de quasispecies da NS5A e a resposta ao tratamento. Foram selecionados 12 pacientes, sendo 4 respondedores (R), 4 não respondedores (NR) e 4 respondedores ao final do tratamento (RFT). As amostras pré-tratamento destes pacientes foram amplificadas, clonadas e seqüenciadas, resultando em 165 seqüências da NS5A completa. Estas seqüências foram alinhadas, editadas e a construção da topologia da árvore filogenética foi realizada. A NS5A e suas regiões específicas CRS, PKR-binding, ISDR, NLS e V3 foram analisadas quanto às substituições e o grau de variabilidade genético. O grupo de pacientes RFT apresentou uma maior taxa de substituições sinônimas em relação aos demais grupos. Uma maior quantidade de mutações foi observada na região downstream à ISDR, principalmente na região V3. Nenhum sítio específico de mutação foi relacionado a um tipo particular de resposta, e não houve agrupamento filogenético das quasispecies de acordo com o tipo de resposta. Estes resultados sugerem que o número de mutações não é suficiente para predizer a sensibilidade ou resistência à terapia baseada em IFN, sendo necessário avaliar se estas mutações conservaram ou não as propriedades químicas dos aminoácidos. / Abstract: Hepatitis C virus (HCV) is major causes of liver desease and about 2% of world s population are infected. This virus is a single strain RNA genome of approximately 9.6 kb. Genetics variability of HCV exists at several different levels: genotypes, subtypes and quasispecies. The high mutation rates are related to the low fidelity of viral RNA polymerase. Genotype 1 HCV is the most prevalent in Brazil, as well as worldwide. Genotypes 1a and 1b are predictive of lower sustained virological response in peginterferon (PEG-IFN) plus ribavirin combination therapy. Genetic variability of viral NS5A has been related to IFN sensibility or resistance. To evaluate whether HCV NS5A quasispecies composition are related to responsiveness to combined PEG-IFN and ribavirin therapy, this study analyzed before treatment sample of 12 treated patients (4 sustained responders - SR, 4 non responders - NR and 4 end of treatment responder - ETR). Samples were amplified, cloned and sequenced, resulting in 165 sequences of complete NS5A. Sequences were aligned, edited and phylogenetical tree was constructed. Mutations and mean of genetic distance were analyzed to NS5A and specific regions CRS, PKR-binding, ISDR, NLS and V3. The number of synonymous substitutions per synonymous sites was higher in ETR patients than in other patient groups. Mutations were more common downstream ISDR, mainly concentrated in V3 domain. No single amino acid position or motif was associated with different responses to therapy in any NS5A regions analyzed and phylogenetic analysis did not show clustering of nucleotide sequences of viral isolates from SR, NR or ETR. These results suggest that number of mutations is not sufficient to predict sensibility or resistance to IFN based therapy. Other studies are necessary to evaluate whether chemical characteristics of amino acids were altered for the mutations. / Mestre

Introduction: The purpose of this study was to examine phenotypic expression of craniofacial form, shape, and size as it relates to the genotype of an individual. Shape analyses were completed on 3-D images of each subject's craniofacial structure by landmarking 45 points of interest on the cranial base, facial bones, and upper and lower jaws. A candidate gene analysis was undertaken focusing on specific genes in the Hippo Signaling Pathway to examine genotype-phenotype correlations that play a role in craniofacial development. This study is a continuation of a larger project aimed at the identification of candidate genes associated with human dento-skeletal bite problems led by Dr. Lina Moreno-Uribe. Methods: The sample size for our study included 166 individuals who had never been treated orthodontically at the time of records. Each individual was genotyped and a CBCT of the craniofacial complex was captured. Each CBCT image was landmarked by a single observer using 45 points to mark points on the cranial base and facial bones including the maxilla and mandible. General Procrustes superimposition was used to find correlations with phenotype and genotype. Size analysis was completed with average Euclidean Distances and ANOVA analysis. Results: 2 SNP's from the FOX03 gene had significant associations with size. The AA genotyped individuals appeared larger in overall size than AB genotyped individuals. 3 SNP's had statistically significant associations with facial form. The FOX06 SNPs had significant associations with increased anterior-posterior growth of the maxilla. The AJUBA SNP had significant associations with increased overall craniofacial breadth. Conclusion: Genes in the Hippo signaling pathway have specific roles in the development of facial form and size.

Barley is the second largest grain crop produced in Australia and has two primary end uses. The first use is the premium market for malt and beer production. The second use is animal consumption. The quality of barley for the range of end uses is influenced by the cultivar itself as well as the growing environment. A detailed understanding of these factors at the genetic and biochemical levels was required to enable breeding program to select for quality improvement. A number of grain and end product quality traits were assessed for genetic and environmental affects as well as their interaction.Grain size has an important impact on quality and large plump grain is desirable for malt and feed quality. The results from the research conducted in this study clearly show that grain size was affected by cultivar and environmental conditions. Using screenings (< 2.2 mm) and retention (> 2.5mm) data provided information on how cultivars performed under a range of environmental conditions, which included irrigated (water unlimited) to terminal moisture stress (no in crop rain). The results showed a strong genetic component in the variation in grain size and it would be possible to select for increased grain size but also stable grain size when considering cultivars grown under adverse environmental conditions.The husk content in barley impacts on malt and feed quality. The results in this studied showed there were significant genetic effects as well as environments effects on the level of husk. In addition, it was identified that the genetic regions controlled husk expression were associated with two other quality traits, namely, resistance to kernel discolouration and resistance to pre-harvest sprouting (dormancy). These regions on chromosome 4H and 6H are also associated with previously identified dormancy genes.Hardness is a trait not usually considered when assessing barley quality but the results from this study showed there are differences in the level of barley hardness, as measured by three methods, as well as differences in the hardness gene sequence. The three hardness methods used showed that barley hardness could be measured independently of the method used, but also that there were significant genetic and environmental effects on hardness. However, the results from sequencing for allelic variation in the hardness genes showed that while there was polymorphism, and hance the transcribed protein had little effect on variation in quality. The cultivars used were malting and feed cultivars and a set of iv breeding lines targeted at malt quality. It may be possible to identify diverse haplotypes from the use of wild relatives or landraces.This study also investigated the variation in barley for cattle feed quality. Feed quality was determined using an in-sacco dry matter digestibility (ISDMD) assay in fistulated cows as well as three other laboratory assays, namely acid detergent fibre, starch and particle size. These four traits are then used to calculate Net Energy (NE) and Average Daily Gain (ADG). The results show that there were genetic and environmental effects on feed quality. The key trait was the ISDMD assay and there were significant differences between the cultivars tested. The data suggested feed quality was a measurable and definable attribute that could be used in breeding selection.The final aspect of this study compared the feed data obtained with routine malt quality traits, of friability and hot water extract. There were strong genetic and environmental effects. The malting cultivars generally had the highest level of ADG and NE. The results also showed that there were negative correlations between extract and husk, ISDMD and ADG. Positive correlations were shown between friability and hardness, extract and test weight, and there was only a slight correlation between average daily gain and extract.An important aspect of this study was the calculation of the genetic component for each trait. This was carried using spatial analysis of mixed models. It was necessary to use this approach so a true estimation of the genetic component could be calculated which would then allow for the calculation of heritability. In plant breeding, the cultivar is not a fixed effect but rather a random variable, hence it was not possible to use normal analysis of variation (ANOVA) models. Rather models were written with cultivars, like environment and field position, as random effects which will allow the effect of each random variable to be accounted for in the analysis. Best Linear Unbiased Predictions (BLUPs) are calculated and presented for all traits.For all the traits measured in this study, heritability values were calculated to ascertain the level of success in improving these traits through breeding. The range in heritability for grain size was 40 to 90%, husk 30 to 60%, hardness, 40 to 90%, feed quality traits 20 to 80% and malt quality traits 40 to 90%. Generally most traits exhibited a moderate to high level of heritability which indicated genetic improvement was possible through the use of appropriate genetic material.

Extensive research has been devoted to evaluating potential genotype-environment interactions. However, plant breeders are still in need of a simple way to describe how genotypes respond to different locations and years. In an environmentally diverse state like Oregon, significant genotype-environment interactions do occur The resulting lack of association between actual and genotypic potential yield performance makes it difficult to select genotypically superior lines. This study was prompted to evaluate the extent of such an interaction and compare various yield stability models. A significant genotype-environment interaction encompassing lines, environments, and years was discovered for each individual year analyzed and for the combined analysis of 1992, 1994 and 1995, and 1989 through 1994. Most lines evaluated during 1992, 1994 and 1995 were adapted to low yielding environments. However, two genotypes (OR880172 and OR880525) exhibited broad adaptation. Stephens and Mac Vicar were less adapted to the relatively high yielding Chambers site than the other genotypes tested during 1992, 1994 and 1995 due to Septoria tritici infections. The most stable genotypes during the combined 1992, 1994 and 1995 and 1989-1994 seasons were OR870831, Madsen and OR8500933H. Gene was the most desirable genotype based on stability and yield for both the combined 1992, 1994 and 1995 and 1989-1994 seasons. Due to an inability to adapt to higher yielding environments, the cultivar Rohde was the least stable genotype during the same combined periods. High and low temperatures and precipitation had minor yet significant effects on yield responses at all three sites during various periods identified. Advanced winter wheat selections and cultivars were grown in three diverse environments and compared over different time periods. Due to trial design and the objective of identifying superior genotypes from a set tested in target environments a combination of two methods, stability variance and a selection index, emerged as the most appropriate techniques. These approaches are considered the most appropriate because they use the mean of the trial as a gauge for measuring stability. / Graduation date: 1997

No description available.