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DetecÃÃo da diversidade e associaÃÃo de Lasiodiplodia theobromae com o cajueiro utilizando marcadores microssatÃlites / Detection and diversity of Lasiodiploidia theobromae assiciated with cashew plants using microssatellites markersFÃbio Costa Farias 25 July 2008 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / The cashew crop is one of the most important agribusiness activity in northeastern Brazil, mainly due to its social and economic impact in that region. Nevertheless, severe outbreaks of gummosis and black branch dieback, both caused by the fungus Lasiodiplodia theobromae have imposed great losses under semi-arid conditions. Presently, these diseases are the most important ones over semi-arid conditions in Northeast Region. However, the limited amount of basic knowledge about population biology, genetic structure and pathogen, host and environment interaction are likely to hinder the efforts to manage this pathogen. This study was developed in order to establish a L. theobromae population associated with cashew plant from different ecological regions in the northeastern Brazil, to determine the survival endophytic ability of this fungus in cashew tissues and to characterize this population by using microsatellite markers. Initially, samples of cashew stems were gathered from three natural ecosystems in Brazil in order to isolate L. theobromae. A population of 41 isolates associated with cashew was obtained. Bioassays aiming to determine the surviving ability of this fungus in non infected tissues close to gummosis lesions were conducted using sampled stems. A subpopulation of 15 isolates of L. theobromae was used for DNA extraction followed by polimerase chain reaction (PCR) using 15 oligonucleotides primers designed to amplify microsatellites regions. PCR products were observed on agarose gel in ethidium bromide electrophoresis and analyzed by the unweighted pair-group method with arithmetic mean (UPGMA) by the Nei and Li similarity coefficient. L. theobromae was successfully isolated from cashew tissues as far as 90 cm from the border of the gummosis lesion in both up and down directions. This result confirms the endophytic behavior of this fungus in cashew plant. A great genetic variability of L. theobromae population was observed as determined by 16 similarities groups varying from 91% to 5%. None isolate achieved 100% similarity. The greatest similarity was found between pathogenic and endophytic isolates. / A cultura do cajueiro representa uma das mais importantes atividades agroindustriais do Nordeste do Brasil, sobretudo pelo seu carÃter social e econÃmico para esta regiÃo. Entretanto, a ocorrÃncia epifÃtica de doenÃas como a resinose e a podridÃo-preta-da-haste, ambas causadas pelo fungo Lasiodiplodia theobromae, tÃm produzido severas perdas principalmente nas regiÃes semi-Ãridas. Essas jà assumem a posiÃÃo de principais doenÃas em algumas regiÃes do semi-Ãrido nordestino. Entretanto, os conhecimentos bÃsicos sobre a biologia populacional, constituiÃÃo genÃtica e interaÃÃo do patÃgeno com as plantas hospedeiras, por exemplo, sÃo reduzidos e superficiais, nÃo permitindo significativos avanÃos no manejo dessas enfermidades. Este estudo teve como objetivos estabelecer uma populaÃÃo de isolados L. theobromae associados ao cajueiro em diferentes micro-regiÃes do nordeste brasileiro, determinar a capacidade deste fungo sobreviver endofiticamente em tecidos de cajueiro e caracterizar geneticamente essa populaÃÃo usando marcadores microssatÃlites. Inicialmente, foram coletadas amostras de caules de cajueiro em trÃs ecossistemas naturais brasileiros visando isolar o patÃgeno. Foi estabelecida uma populaÃÃo de 41 isolados de L. theobromae associados ao cajueiro. Bioensaios visando a determinaÃÃo da sobrevivÃncia do fungo em tecidos nÃo infectados, mas prÃximos Ãs lesÃes foram desenvolvidos a partir de amostras de caules com resinose. Uma sub-populaÃÃo de 15 isolados de L. theobromae foi usada na extraÃÃo de DNA e posterior submissÃo a reaÃÃes de polimerase (PCR) em cadeia usando 15 primers flanqueadores de regiÃes contendo seqÃÃncias simples repetidas (microssatÃlites). Os produtos amplificados do PCR foram observados em gel de eletroforese corados com brometo de etÃdio e analisados pelo mÃtodo de agrupamento nÃo balanceado baseado na mÃdia aritmÃtica (UPGMA), estimando-se as similaridades genÃticas pelo coeficiente de Nei e Li. L. theobromae foi isolado de tecidos do caule do cajueiro atà 90 cm de distÃncia da extremidade da lesÃo caracterÃstica de resinose nos dois sentidos (ascendente e descendente) em relaÃÃo à lesÃo, confirmando o comportamento endofÃtico desse fungo em cajueiro. Uma grande variabilidade genÃtica da populaÃÃo avaliada, representada por 16 grupos de similaridade variando de 91% a 5%, foi observada. Nenhum isolado foi igual (100% similaridade). As maiores similaridades (91%) foram observadas entre isolados comprovadamente patogÃnicos e supostamente endofÃticos.
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Investigations into the Shear Strength Reduction method using distinct element modelsFournier, Mathew 11 1900 (has links)
This thesis reports a detailed investigation into the use of the Shear Strength Reduction (SSR) method to determine factor of safety values in discontinuum models using the Universal Distinct Element Code. The SSR method depends on the definition of failure within the model and two different criteria were compared: the numerical unbalanced force definition and a more qualitative displacement-monitoring based method. A parametric study was first undertaken, using a simple homogeneous rock slope, with three different joint networks representing common kinematic states. Lessons learned from this study were then applied to a more complex case history used for validation of the SSR method.
The discontinuum models allow for the failure surface to propagate based on constitutive models that better idealize the rockmass than simpler methods such as limit equilibrium (e.g. either method of slices or wedge solutions) and even numerical continuum models (e.g. finite difference, finite element). Joints are explicitly modelled and can exert a range of influences on the SSR result. Simple elasto-plastic models are used for both the intact rock and joint properties. Strain-softening models are also discussed with respect to the SSR method. The results presented highlight several important relationships to consider related to both numerical procedures and numerical input parameters.
The case history was modelled similar to how a typical forward analysis would be undertaken: i.e. simple models with complexities added incrementally. The results for this case generally depict a rotational failure mode with a reduced factor of safety due to the presence of joints within the rockmass when compared to a traditional limit equilibrium analysis. Some models with large persistence of steeply dipping joints were able to capture the actual failure surface. Softening models were employed in order to mimic the generation and propagation of joints through the rockmass in a continuum; however, only discontinuum models using explicitly defined joints in the model were able to capture the correct failure surface. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate
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A Highly Abstracted Method of FPGA-Based Development for Secondary Surveillance Radar Transpond DetectionWatt, James Penn 01 June 2009 (has links)
Traditional FPGA-based digital design is based on writing hardware definition language (HDL) code from scratch. Time to market, cost of development, and the level of training required for designers all can be reduced with a simplified and abstracted design strategy. This project intends to demonstrate a graphical user interface (GUI) layer of abstraction on top of existing commercially produced design aids including MATLAB, Simulink, and Xilinx System Generator. This project performs and demonstrates a specific implementation example of a Secondary Surveillance Radar (SSR) message decoder as proof-of-concept for the abstracted design method. The abstracted digital design methods shown in this project can be adapted for use in other areas of development and research including digital signal processing and communications.
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Testování genetické čistoty hybridního osiva zelí hlávkového pomocí molekulárních metodO'Shea, Denisa January 2017 (has links)
This diploma thesis deals with testing of hybrid seeds genetic purity in three varieties of head cabbage (Brassica oleracea var. capitata L.). The suitability of SSR primers chosen according to an earlier screening carried out as a part of a research project in the workplace of Mendeleum and hybrid seeds genetic purity in head cabbage by SSR molecular method was tested. Among the total of 8 SSR primers screened, only 5 could produce both parent specific markers and therefore they were able to differentiate hybrid offspring and its corresponding parental lines, by which crossbreeding they originated. For each variety, 70 samples of hybrid offspring and 2 samples of parental lines were tested always in two sets. By using these primers, the genetic purity of the variety D - F1 was determinated as 100% and of the varieties H - F1 and T - F1 as 98.57%. The results of this thesis have the potential to be used in practice by a commercial company that has provided the seed samples for testing.
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Analýza genetické variability konopí pomocí DNA markerůBalgová, Barbora January 2018 (has links)
This thesis is focused on analysis of genetic variability of Cannabis sativa L. and sequencing of the candidate genome sequences in selected varieties of Cannabis. In total there were 28 genotypes of hemp were analyzed with 23 microsatellite markers.107 alleles were found whose size ranged from 100 to 360 bp. Uniform marker was detected (CAN1660). The diversity index (DI), the polymorphic information content (PIC) and the probability of identity (PI) were calculated for every microsatellite marker. Similarity dendrogram was constructed on base of statistical evaluation. The specific primer for the patrial sequences of cannabidiolic acid synthase (CBDA) gene and the specific complete for the sequences of tethrahydrocannabinolic acid synthase (THCA) gene were used for the sequences study. Gained sequences were compared by BLAST. Most sequences had 100% match with sequences in the available databases. Single nucleotide polymorphisms were found in the sequences of CBDA synthase. One sequences that did not belong to the genus Cannabis was detected. All obtained sequences will be inserted into the NCBI database and access number will be assigned.
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Assessment of Chenopodium quinoa Willd. Genetic Diversity in the USDA and CIP-FAO Collections Using SSR?S and SNP?SChristensen, Shawn A. 23 November 2005 (has links) (PDF)
Quinoa (Chenopodium quinoa Willd.) is a staple grain for the indigenous people of the Andean region of South America with excellent nutritional qualities, including protein content. The objective of this study is to report on the development of fluorescence-tagged simple sequence repeats (SSRs) and single nucleotide polymorphisms (SNPs) to (1) genetically characterize the inherent diversity of 152 accessions of C. quinoa; (2) determine to what degree the CIP-FAO collection represents the range of genetic diversity in quinoa; and (3) test four hypotheses regarding quinoa?s center of diversity, Highland and Lowland clustering patterns, origin of Lowland varieties, and the origin of domestication. Thirty-five SSR loci comprising 432 alleles ranging from 5 (QAAT10) to 28 (QAAT50) alleles per locus (mean=13) were used to survey the 152 accessions of quinoa from the USDA and CIP-FAO collections. Heterozygosity was detected in 14.25% of the accessions for SNP loci and in at least one locus for 51% of the accessions. Both UPGMA and PCA analyses partitioned the quinoa accessions into two main clusters. The first major cluster consisted of accessions from the Andean highlands of Peru, Bolivia, Ecuador, Argentina, and extreme northeastern Chile. The other main cluster contained accessions from both the Lowlands of Chile and those collected by Emigdio Ballón The CIP-FAO collection appears to give a good representation of quinoa's genetic diversity within these two main clusters. The significance of patterns of genetic diversity within C. quinoa is discussed.
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Assisted GNSS Positioning using State Space CorrectionsPhilipsson, Oskar January 2023 (has links)
Classical GNSS based positioning has accuracy limitations due to many sources oferror. The error sources range from clock errors and orbit errors toerrors due to variations in atmospheric propagation delays. One way to improve GNSSpositioning is to generate real time corrections using a GNSS reference network.The corrections can then be distributed through the mobilenetwork and be delivered in real time to the device that should position itself. This thesis aims to develop a positioning engine utilizing statespace representation corrections (SSR). The thesis also has the goal to develop methods for combiningpseudorange measurements with carrier-phase measurements, in the case when SSR correctionsare used. The static and dynamic performance ofthe positioning engine will be evaluated. Also, the SSR correction format itself, willalso be evaluated and different levels of SSR corrections will be compared. The proposed combined positioning engine uses SSR correctionsand single-difference measurements. Through this, all majorerror sources on the satellite side, device side and in the atmosphere, are removedexcept for an integer ambiguity in the carrier phase measurement. This ambiguityis handled by tracking the GNSS receiver's position along with the integerambiguities in an extended Kalman filter (EKF). Experiments show that usingreal-time SSR corrections leads to a significant improvement in global absolutepositioning for simple GNSS receivers using only a single measurement frequencyand only using pseudorange measurements. For a more advanced receiver capable ofcarrier phase measurements, experiments together with simulation resultsshow that using the proposed combined positioning engine, improves the positioningperformance even further.
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Diversity and Management of Sclerotinia sclerotiorum in Brassica spp. in Bangladeshislam, Md. Mynul 11 September 2018 (has links)
No description available.
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Molecular marker analysis of a segregating monoploid potato familyChani, Eduard 13 February 1998 (has links)
Anther culture experiments were conducted to construct a monoploid family. The donor plants used were hybrids between high leptine producing selections of Solanum chacoense Bitt. and anther culture responsive selections of Solanum phureja Juz. et Buk. Several steps of the anther culture process were studied. The results indicated that genotype remains the main factor affecting anther culture response. Growing anther-donor plants in higher greenhouse temperatures (30 degrees C day/20 degrees C night) increased the number of embryos per anther by 40 percent. A heat shock given to anthers in culture for 12h at 35 degrees C was also found to be beneficial resulting in an increase of the anther culture response by 40 percent. However the effect of the high temperature shock resulted in lower regeneration rates. In all experiments a highly significant "date" effect was observed with one or two days differing from the others by showing higher response rates in all hybrids tested. The majority of the regenerated plants was diploid, probably resulting from unreduced gametes. Simple sequence repeat analysis with eight polymorphic primer pairs was used successfully to identify the homozygous diploid plants that were added to the monoploids. In total 34 monoploid plants and 14 homozugous diploids were obtained. The degree of heterozygosity revealed by SSR analysis indicated that the diploid plants originated from unreduced gametes formed by first division restitution (FDR) mechanism. The SSR marker data were used to map the genes with respect to the centromeres by half tetrad analysis. SSR-containing sequences from the public databases, as well as sequences obtained from a genomic library enriched for SSRs, were used to generate 48 primer pairs. Only 12 of them were found to be polymorphic in the monoploid family. Ten primer pairs did not amplify any specific fragment. The monoploid population showed distorted segregation at four of the polymorphic loci, showing overrepresentation of the chacoense alleles in three of them. One of the loci showing distorted segregation (STSTP, amplified by primer pair RV 11+12) is most probably linked to lethal alleles, whereas another one (ST13ST, amplified by primer pair RV 21+22) could be linked to genes affecting anther-culture response. The location of the SSR loci on the potato chromosomes is not known except for one (waxy, primer pair 3+4), but statistical analysis on the segregation data obtained from 70 heterozygous anther-derived diploids showed no linkage between them. The SSR primer pairs developed in this study might be useful in studying genetic relationships among cultivars and accessions in breeding programs. Randomly amplified polymorphic DNA (RAPD) analysis was used in association with bulked segregant analysis to detect linkage with genes controlling leptine biosynthesis. With all the limitations imposed by the population size and contamination from foreign pollen, a band amplified by primer OPA-16 could differentiate the bulks contrasting for leptine content. It is possible that this band is linked to genes suppressing leptine biosynthesis, since it appears only in the plants that do not synthesize leptines. Further investigation with larger populations is needed to confirm this possibility. / Ph. D.
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Development of New and Alternative Resources for Breeding Low Phytate SoybeansBurleson, Sarah Ann 12 May 2011 (has links)
Soybean (Glycine max (L.) Merr) cultivars with genetic reduction in seed phytate concentration will be a valuable resource to livestock producers both nutritionally and economically, as well as in the preservation of the environment. However, due to association with reduced seed germination and field emergence potential, low phytate (LP) soybean cultivars are not being advanced to commercialization. Soybean breeders of LP lines must adjust their techniques and resources in order to efficiently select LP germplasm. Reduced seed germination and field emergence potential associated with LP germplasm eliminates many individuals with the desired LP trait during early generation population development, making improvement of agronomic performance among LP lines difficult. Thus, development of resources for improved phenotyping, genotyping, and early generation population development will facilitate the commercialization of LP cultivars.
Discovery of variation for field emergence potential among F2-derived LP families suggests the potential for using a pedigree method for early generation population development in LP germplasm, as it preserves diversity and allows selection for improved field emergence. Integration of markers into a pedigree method will be useful to breeder. An example is BARCSOYSSR_11_1495 with 90-93% selection efficiency in various V99-5089-derived populations. Another resource for improved LP selection is a time-efficient, high-throughput modified iron (Fe) colorimetric phytate assay that does not suffer from inorganic phosphorus (P) concentration interference. Together these tools will provide breeders more accurate selection of LP lines. / Master of Science
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