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Lehmensiek, Anke. "Genetic mapping of gray leaf spot resistance genes in maize." Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51776.
Повний текст джерелаENGLISH ABSTRACT: Gray leaf spot (GLS) of maize, caused by the fungus Cercospora zeae-maydis, can reduce grain yields by up to 60% and it is now recognized as one of the most significant yield-limiting diseases of maize in many parts of the world. The most sustainable and long-term management strategy for GLS will rely heavily on the development of high-yielding, locally adapted GLS resistant hybrids. Molecular markers could be useful to plant breeders to indirectly select for genes affecting GLS resistance and to identify resistance genes without inoculation and at an early stage of plant development. Only two studies in the USA have examined quantitative trait loci (QTL) association with GLS resistance. The aim of this study was to map GLS resistance genes in a resistant Seed Co LTD, Zimbabwean inbred line. Molecular markers linked to the GLS resistance QTL were identified by using the amplified fragment length polymorphism (AFLP) technique together with bulked segregant analysis. Eleven polymorphic AFLP fragments were identified and converted to sequence-specific PCR (polymerase chain reaction) markers. Eight of the 11 converted AFLP markers were added to the maize marker database of the University of Stellenbosch. Five of the 8 converted AFLP markers were polymorphic between the resistant and the susceptible parent. They were amplified on the DNA of 230 plants of a segregating F2 population and linkage analysis was performed with MAPMAKER/EXP. Two linkage groups consisting of two markers each, with a linkage distance of 10.4 cM (LOD 22.83) and 8.2 cM (LOD 55.41) between the two markers, were identified. QTL mapping with MAPMAKER/QTL confirmed the presence of QTL in both linkage groups. Two publicly available recombinant inbred families (Burr et a/., 1988) were used to localize the converted AFLP markers on the genetic map of maize. The QTL, which were identified with the AFLP markers, were mapped to chromosomes 1 and 5. Another AFLP marker was mapped to chromosome 2 and a further to chromosome 3. To obtain more precise localizations of the QTL on chromosomes 1 and 5, sequence-tagged site markers and microsatellite markers were used. The markers were amplified on the DNA of the 230 plants of the F2 population and linkage analysis was performed with MAPMAKER/EXP. The order of the markers was in agreement with the UMC map of the Maize Genome Database. Interval mapping using MAPMAKERlQTL and composite interval mapping using QTL Cartographer were performed. The QTL on chromosome 1 had a LOD score of 21 and was localized in bin 1.05/06. A variance of 37% was explained by the QTL. Two peaks were visible for the QTL on chromosome 5, one was localized in bin 5.03/04 and the other in bin 5.05/06. Both peaks had a LOD score of 5 and 11% of the variance was explained by the QTL. To test the consistency of the detected QTL, the markers flanking each QTL were amplified on selected plants of two F2 populations planted in consecutive years and regression analysis was performed. Both the QTL on chromosome 1 and the QTL on chromosome 5 were detected in these populations. Furthermore, the presence of a QTL on chromosome 3 was confirmed with these populations. A variance of 8 -10% was explained by the QTL on chromosome 3. In this study, a major GLS resistance QTL was thus mapped on chromosomes 1 and two minor GLS resistance QTL were mapped on chromosomes 3 and 5 using a resistant Seed Co LTD, Zimbabwean inbred line. Markers were identified which could be used in a marker-assisted selection program to select for the GLS resistance QTL.
AFRIKAANSE OPSOMMING: Grys blaarvlek (GBV) van mielies, veroorsaak deur die swam Cercospora zeaemaydis, kan graanopbrengs met tot 60% verlaag en word beskou as een van die vernaamste opbrengs-beperkende siektes wêreldwyd. Die toepaslikste langtermyn stragtegie vir GBV beheer sal wees om plaaslike mieliebasters met hoë opbrengs en GBV weerstand te ontwikkel. Molekulêre merkers kan nuttig deur plantetelers gebruik word om weerstandsgene te selekteer. Seleksie is moontlik in die afwesigheid van inokolum en op 'n vroeë stadium van plant ontwikkeling. Slegs twee vorige studies (in die VSA) het kwantitatiewe-kenmerk-Iokusse (KKL), vir GBVweerstand ondersoek. Die doel van hierdie studie was om die GBV weerstandsgene in 'n weerstandbiedende ingeteelde lyn (Seed Co BPK, Zimbabwe) te karteer. Molekulêre merkers gekoppel aan die GBV weerstands KKL is geïdentifiseer deur gebruik te maak van die geamplifiseerde-fragmentlengte-polimorfisme- (AFLP-) tegniek en gebulkte-segregaat-analise. Elf polimorfiese merkers is geïdentifiseer en omgeskakel na volgorde-spesifieke PKR (polimerase kettingreaksie) merkers. Agt van die elf omgeskakelde AFLP-merkers is by die mieliemerker databasis van die Universiteit van Stellenbosch gevoeg. Vyf van die 8 omgeskakelde AFLP-merkers was polimorfies tussen die bestande en vatbare ouers. Hulle is geamplifiseer op die DNA van 230 plante van 'n segregerende F2-populasie en is gebruik in 'n koppelingstudie met MAPMAKER/EXP. Twee koppelingsgroepe, elk bestaande uit twee merkers, met onderskeidelik koppelingsafstande van 10.4 eM (LOD 22.83) en 8.2 eM (LOD 55.41) tussen die merkers, is geïdentifiseer. KKL-kartering het getoon dat KKL in albei koppelingsgroepe aanwesig is. Twee kommersieël beskikbare, rekombinant-ingeteelde families (Burr et aI., 1988) is gebruik om die omgeskakelde AFLP-merkers op die mielie genetiese kaart te plaas. Die KKL wat met die AFLP-merkers geïdentifiseer is, is gekarteer op chromosome 1 en 5. 'n Verdere AFLP-merker is op chromosoom 2 gekarteer en 'n ander op chromosoom 3. Ten einde die KKL op chromosome 1 en 5 meer akkuraat te karteer, is volgordege- etikeerde en mikrosatelliet merkers gebruik. Die merkers is geamplifiseer op die DNA van die 230 plante van die F2-populasie en koppelings-analises is uitgevoer. Die volgorde van die merkers was dieselfde as die van die UMC-kaart in die Mielie Genoom Databasis. Interval kartering met MAPMAKER/QTL en komposiet interval kartering met QTL Cartographer is uitgevoer. Die KKL op chromosoom 1 het 'n LOD-telling van 21 gehad en is in bin 1.05/06 geplaas. Die KKL was verantwoordelik vir 37% van die variansie. Twee pieke was onderskeibaar vir die KKL op chromosoom 5, een in bin 5.03/04 geleë en die ander in bin 5.05/06. Elke piek het 'n LOD-telling van 5 gehad en die twee KKL was verantwoordelik vir 11% van die variansie. Om die herhaalbaarheid van die effek van die KKL te toets is die merkers naaste aan elke KKL geamplifiseer op geselekteerde plante van twee F2-populasies wat in opeenvolgende jare geplant is. Regressie analise is op die data gedoen. Beide die KKL op chromosoom 1 en die KKL op chromosoom 5 kon in hierdie populasies geïdentifiseer word. Verder kon die aanwesigheid van 'n verdere KKL op chromosoom 3 in hierdie populasies bevestig word. Laasgenoemde KKL was verantwoordelik vir 8-10% van die totale variansie. In hierdie studie is daar dus 'n hoof GBV-weerstands KKL gekarteer op chromosoom 1 en twee kleiner GBV-weerstands KKL gekarteer op chromosome 3 en 5. Merkers is geïdentifiseer wat moontlik in merker-gebaseerdetelingsprogramme gebruik kan word om plante te selekteer wat die GBVweerstands KKL het.
Saito, Belisa Cristina [UNESP]. "Characterization of corn inbred lines for disease resistance." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/150400.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O milho é uma das culturas mais extensamente cultivadas em todo mundo. A incidência e a severidade de doenças têm aumentado significativamente nos últimos anos acarretando perdas no rendimento e afetando a qualidade dos grãos. Muitos trabalhos têm sido desenvolvidos na tentativa de identificar híbridos resistentes às principais doenças que acometem a cultura do milho, mas poucos são os relatos de estudos com linhagens. Dessa forma, o objetivo deste estudo foi: 1) identificar linhagens resistentes e susceptíveis com base na área abaixo da curva de progresso de doenças (AACPD) para os sintomas de ferrugem tropical (TR), ferrugem polissora (SR), cercosporiose (GLS), helmintosporiose (NLB), mancha marrom (PBS) e mancha branca (PLS); 2) identificar linhagens resistentes e suscetíveis com base nos parâmetros de adaptabilidade e estabilidade fenotípica para os sintomas de cercosporiose, helmintosporiose, mancha marrom e mancha branca; 3) identificar as melhores datas de semeadura, com a maior ocorrência das doenças, para fins de avaliação de linhagens e outros genótipos para resistência. Cinquenta linhagens, derivadas de populações com grãos flint e dent, foram avaliadas em blocos casualizados com três repetições, aos 45, 60, 75 e 90 dias após a semeadura em duas épocas, para medição da AACPD. Para a análise de adaptabilidade e estabilidade, 41 linhagens foram avaliadas em blocos casualizados com três repetições, 30 dias após o florescimento feminino, em onze épocas de semeadura, usando o método de análise de regressão. Foram atribuídas notas de 1, 2, 3, 4, 5, 6, 7, 8 e 9 correspondendo a 0, 1, 10, 20, 30, 40, 60, 80 e > 80% de área foliar com sintomas de doença. Para a AACPD, a análise de variância conjunta foi significativa para TR, SR, GLS e PLS e a interação linhagens x épocas foi significativa para ferrugem tropical e polissora. Para GLS e NLB as 41 linhagens foram classificadas como resistentes, sendo que as maiores severidades de doenças ocorreram nas semeaduras entre Junho e Setembro. As linhagens IVF1-3, IVF1-7, IVF1 -9, IVF1-10, IVF1 -11, IVF1 -25, IVF1-230, IVD1-2, IVD1 -2-1, IVD1-3, IVD1-9, IVD1 -12, 2F, 3F, 6F, 9F, 10F, 4C, 2D e 7D foram classificadas como resistentes para as doenças estudadas, sendo indicadas para o desenvolvimento de sintéticos. Para a mancha marrom e mancha branca, as semeaduras de Abril, Junho, Julho e Agosto apresentaram maiores severidades de doenças. As linhagens IVD1-9, IVD1-10, 7D, 10D e 2F podem ser indicadas no desenvolvimento de sintéticos resistentes.
Corn is one of the most widely cultivated crops in the worldwide. The incidence and severity of diseases affecting crops have increased significantly in the past years, leading to yield losses and affecting grain quality. Many studies have been carried out with the attempt to identify hybrids that are resistant to the main diseases, but few reports have studied inbred lines. Therefore, the objectives of this study were: 1) identify resistant and susceptible inbred lines based on the area under disease progress curve (AUDPC) for tropical rust, southern rust, gray leaf spot, northern leaf blight, physoderma brown spot and phaeosphaeria leaf spot; 2) identify resistant and susceptible inbred lines based on adaptability and stability parameters for symptoms of gray leaf spot (GLS), northern leaf blight (NLB), physoderma brown spot (PBS) and phaeosphaeria leaf spot (PLS); 3) identify the best planting dates, with the highest occurrence of diseases, for the purpose of evaluating inbred lines and other genotypes for resistance. For AUDPC, fifty inbred lines, derived from populations with flint and dent grains, were evaluated in randomized block designs with three replications, at 45, 60, 75 and 90 days after planting in two seasons. For the analysis of adaptability and stability, forty-one inbred lines were evaluated in randomized blocks with three replications, 30 days after silking, in eleven planting dates, using regression analysis method. The scale of scores from 1, 2, 3, 4, 5, 6, 7, 8 and 9 corresponding to 0, 1, 10, 20, 30, 40, 60, 80 and > 80% of leaf area with disease symptoms was used. For AUDPC, the joint analysis of variance was significant for TR, SR, GLS and PLS, while the interaction inbred lines x environments, was significant for TR and SR. For GLS and NLB, forty-one inbred lines were classified as resistant and the highest severities of diseases occurred in planting dates between June and September. The inbred lines IVF1-3, IVF1-7, IVF1 -9, IVF1-10, IVF1 -11, IVF1 -25, IVF1-230, IVD1-2, IVD1 -2-1, IVD1-3, IVD1-9, IVD1 -12, 2F, 3F, 6F, 9F, 10F, 4C, 2D and 7D were classified as resistant to the diseases studied and are indicated to produce synthetics. For PBS and PLS, the plating dates of April, June, July and August showed higher disease severity. The inbred lines IVD1-9, IVD1-10, 7D,10D and 2F may be indicated to produce synthetics.
Saito, Belisa Cristina. "Characterization of corn inbred lines for disease resistance /." Ilha Solteira, 2017. http://hdl.handle.net/11449/150400.
Повний текст джерелаResumo: O milho é uma das culturas mais extensamente cultivadas em todo mundo. A incidência e a severidade de doenças têm aumentado significativamente nos últimos anos acarretando perdas no rendimento e afetando a qualidade dos grãos. Muitos trabalhos têm sido desenvolvidos na tentativa de identificar híbridos resistentes às principais doenças que acometem a cultura do milho, mas poucos são os relatos de estudos com linhagens. Dessa forma, o objetivo deste estudo foi: 1) identificar linhagens resistentes e susceptíveis com base na área abaixo da curva de progresso de doenças (AACPD) para os sintomas de ferrugem tropical (TR), ferrugem polissora (SR), cercosporiose (GLS), helmintosporiose (NLB), mancha marrom (PBS) e mancha branca (PLS); 2) identificar linhagens resistentes e suscetíveis com base nos parâmetros de adaptabilidade e estabilidade fenotípica para os sintomas de cercosporiose, helmintosporiose, mancha marrom e mancha branca; 3) identificar as melhores datas de semeadura, com a maior ocorrência das doenças, para fins de avaliação de linhagens e outros genótipos para resistência. Cinquenta linhagens, derivadas de populações com grãos flint e dent, foram avaliadas em blocos casualizados com três repetições, aos 45, 60, 75 e 90 dias após a semeadura em duas épocas, para medição da AACPD. Para a análise de adaptabilidade e estabilidade, 41 linhagens foram avaliadas em blocos casualizados com três repetições, 30 dias após o florescimento feminino, em onze épocas de semeadura, us... (Resumo completo, clicar acesso eletrônico abaixo)
Doutor
Carter, Michele R. "Gray leaf spot of corn : yield loss and evaluation of germplasm for resistance /." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-10062009-020049/.
Повний текст джерелаNazareno, Nilceu Ricetti Xavier de. "Influence of infected corn residue as a source of primary inoculum of Cercospora zeae-maydis (Tehon and Daniels) the cause of gray leaf spot of corn /." The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487759914762668.
Повний текст джерелаDu, Min. "A greenhouse screening method for resistance to gray leaf spot in maize." Thesis, Virginia Tech, 1993. http://hdl.handle.net/10919/42953.
Повний текст джерелаWallhead, Matthew W. "Foliar Fungicide Effects on Gray Leaf Spot and Yield of Hybrid Corn as Influenced by Application Timing, Hybrid Characteristics and Production Practices." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1324573828.
Повний текст джерелаDonahue, Patrick J. "Inheritance of reactions to gray leaf spot and maize dwarf mosaic virus in maize and their associations with physiological traits." Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54518.
Повний текст джерелаPh. D.
Lewis, Aaron D. "Gasification of Biomass, Coal, and Petroleum Coke at High Heating Rates and Elevated Pressure." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/4373.
Повний текст джерелаLanza, Fabrício Eustáquio. "Mancha-branca do milho: etiologia e resistência de genótipos." Universidade Federal de Viçosa, 2009. http://locus.ufv.br/handle/123456789/4378.
Повний текст джерелаConselho Nacional de Desenvolvimento Científico e Tecnológico
The main objectives of this work were to identify the causal agent of the maize White Spot, to obtain preliminary information on the disease dispersal in the field and to characterize the reaction of maize hybrids and inbreds to the disease. For the etiological studies, isolations were performed from white spot lesions the anasarca phase, resulting in the development of bacterial colonies. Maize hybrids BRS2022, BRS1010, 1D2195, BRS1040, BRS1035, BRS1031, BRS3025, BRS1030, 2B710 e P30F35 and inbred lines L3, L228-3, 521274, 521236 e 262841-1-4-1 were evaluated under natural epidemic in a randomized block design with three replications. Cultivars were planted in single row plots, separated by two rows of the resistant hybrid BRS1010. Spreader rows were formed by planting the susceptible genotype DAS657 0,5 m apart and in front of each block. Disease severity was evaluated at a weekly internal starting 60 days after planting, through a 1 to 9 scale of disease severity where 1= no disease and 9= 100% of leaf area affected. Ratings were taken at three different locations within each plot: 1, 2, 3, 4, 5 and 6 meters inoculum source. Data were used for the calculation of the area under disease progress curve (AUDPC), disease severity at 50% of epidemic development (Y50), disease severity at the end of the epidemic, and the rate of disease progress. Inoculations on the susceptible hybrid DAS657, in the greenhouse, reproduced the typical symptoms of the disease. Re-isolations from theses lesions confirmed the presence of the same bacteria isolated from the field, which identified as Pantoea ananatis, confirming previous reports on the involvement of this bacteria in the initial lesions of this disease. No disease gradient was observed based on the disease severity observed in each point of evaluation within each plot. A better distinction between the level of resistance of maize genotypes was obtained through AUDPC and Ymáx values. Maize hybrids BRS1030, BRS1035 and BRS1010 and inbreds L3, and L228-3 were the most resistant genotypes. These inbred lines may be useful in breeding programs for resistance to maize white spot.
Este trabalho objetivou confrimar o agente causal da mancha-branca do milho, obter informações preliminares sobre a dispersão do patógeno e caracterizar a reação de genótipos de milho a doença. Para o estudo etiológico, isolados foram obtidos de lesões de manchabranca em fase de anasarca, resultando em desenvolvimento de colônias bacterianas. Híbridos de milho, BRS2022, BRS1010, 1D2195, BRS1040, BRS1035, BRS1031, BRS3025, BRS1030, 2B710 e P30F35 e as linhagens L3, L228-3, 521274, 521236 e 262841-1-4-1 foram avaliados sob epidemia natural em delineamento de blocos ao acaso e três repetições. Os cultivares foram plantados em fileiras de cinco metros, separadas por uma linha do híbrido resistente BRS1010. A cortina suscetível (fonte de inóculo) formada pelo híbrido DAS657, foi plantada na parte frontal de cada bloco, afastada 0,5 m. A severidade da doença foi avaliada em intervalos semanais a partir dos 60 dias do plantio, utilizando uma escala de 1 a 9, onde: 1= sem doença e 9= 100% de área foliar afetada. As avaliações foram realizadas em 6 pontos dentro da parcela afastados 1, 2, 3, 4, 5 e 6 metros da fonte de inóculo. Os dados de severidade foram usados para o calculo da área abaixo da curva de progresso da doença (AACPD), severidade da doença na metade da epidemia (Y50), severidade da doença no final da epidemia (Ymáx), e taxa de progresso da doença. Com inoculações em híbrido suscetível DAS657, em casa de vegetação, foi possível reproduzir os sintomas típicos da doença. Reisolamento a partir dessas lesões confirmou a presença da mesma bactéria isolada do campo, identificada como Pantoea ananatis, corroborando relatos do envolvimento desta bactéria nos sintomas iniciais da doença. Não foi observada a formação de um gradiente de dispersão baseado na severidade da doença observada em cada ponto de avaliação dentro da parcela. A melhor distinção entre os níveis de resistência de genótipos de milho foi obtida pelos valores de AACPD e Ymáx. Os híbridos de milho BRS1030, BRS1035 e BRS1010 e as linhagens L3, e L228-3 foram os genótipos mais resistentes. Essas linhagens podem ser usadas em programas de melhoramento visando resistência a mancha-branca.
Dhau, Inos. "Detection, identification, and mapping of maize streak virus and grey leaf spot diseases of maize using different remote sensing techniques." Thesis, University of Limpopo, 2019. http://hdl.handle.net/10386/2866.
Повний текст джерелаOf late climate change and consequently, the spread of crop diseases has been identified as one of the major threat to crop production and food security in subSaharan Africa. This research, therefore, aims to evaluate the role of in situ hyperspectral and new generation multispectral data in detecting maize crop viral and fungal diseases, that is maize streak virus and grey leaf spot respectively. To accomplish this objective; a comparison of two variable selection techniques (Random Forest’s Forward Variable, (FVS) and Guided Regularized Random Forest: (GRRF) was done in selecting the optimal variables that can be used in detecting maize streak virus disease using in-situ resampled hyperspectral data. The findings indicated that the GRRF model produced high classification accuracy (91.67%) whereas the FVS had a slightly lower accuracy (87.60%) based on Hymap when compared to the AISA. The results have shown that the GRRF algorithm has the potential to select compact feature sub sets, and the accuracy performance is better than that of RF’s variable selection method. Secondly, the utility of remote sensing techniques in detecting the geminivirus infected maize was evaluated in this study based on experiments in Ofcolaco, Tzaneen in South Africa. Specifically, the potential of hyperspectral data in detecting different levels of maize infected by maize streak virus (MSV) was tested based on Guided Regularized Random Forest (GRRF). The findings illustrate the strength of hyperspectral data in detecting different levels of MSV infections. Specifically, the GRRF model was able to identify the optimal bands for detecting different levels of maize streak disease in maize. These bands were allocated at 552 nm, 603 nm, 683 nm, 881 nm, and 2338 nm. This study underscores the potential of using remotely sensed data in the accurate detection of maize crop diseases such as MSV and its severity which is critical in crop monitoring to foster food security, especially in the resource-limited subSaharan Africa. The study then investigated the possibility to upscale the previous findings to space borne sensor. RapidEye data and derived vegetation indices were tested in detecting and mapping the maize streak virus. The results revealed that the use of RapidEye spectral bands in detection and mapping of maize streak virus disease yielded good classification results with an overall accuracy of 82.75%. The inclusion of RapidEye derived vegetation indices improved the classification accuracies by 3.4%. Due to the cost involved in acquiring commercial images, like xviii RapidEye, a freely available Landsat-8 data can offer a new data source that is useful for maize diseases estimation, in environments which have limited resources. This study investigated the use of Landsat 8 and vegetation indices in estimating and predicting maize infected with maize streak virus. Landsat 8 data produced an overall accuracy of 50.32%. The inclusion of vegetation indices computed from Landsat 8 sensor improved the classification accuracies by 1.29%. Overally, the findings of this study provide the necessary insight and motivation to the remote sensing community, particularly in resource-constrained regions, to shift towards embracing various indices obtained from the readily-available and affordable multispectral Landsat-8 OLI sensor. The results of the study show that the mediumresolution multispectral Landsat 8-OLI data set can be used to detect and map maize streak virus disease. This study demonstrates the invaluable potential and strength of applying the readily-available medium-resolution, Landsat-8 OLI data set, with a large swath width (185 km) in precisely detecting and mapping maize streak virus disease. The study then examined the influence of climatic, environmental and remotely sensed variables on the spread of MSV disease on the Ofcolaco maize farms in Tzaneen, South Africa. Environmental and climatic variables were integrated together with Landsat 8 derived vegetation indices to predict the probability of MSV occurrence within the Ofcolaco maize farms in Limpopo, South Africa. Correlation analysis was used to relate vegetation indices, environmental and climatic variables to incidences of maize streak virus disease. The variables used to predict the distribution of MSV were elevation, rainfall, slope, temperature, and vegetation indices. It was found that MSV disease infestation is more likely to occur on low-lying altitudes and areas with high Normalised Difference Vegetation Index (NDVI) located at an altitude ranging of 350 and 450 m.a.s.l. The suitable areas are characterized by temperatures ranging from 24°C to 25°C. The results indicate the potential of integrating Landsat 8 derived vegetation indices, environmental and climatic variables to improve the prediction of areas that are likely to be affected by MSV disease outbreaks in maize fields in semi-arid environments. After realizing the potential of remote sensing in detecting and predicting the occurrence of maize streak virus disease, the study further examined its potential in mapping the most complex disease; Grey Leaf Spot (GLS) in maize fields using WorldView-2, Quickbird, RapidEye, and Sentinel-2 resampled from hyperspectral data. To accomplish this objective, field spectra were acquired from healthy, moderate and xix severely infected maize leaves during the 2013 and 2014 growing seasons. The spectra were then resampled to four sensor spectral resolutions – namely WorldView-2, Quickbird, RapidEye, and Sentinel-2. In each case, the Random Forest algorithm was used to classify the 2013 resampled spectra to represent the three identified disease severity categories. Classification accuracy was evaluated using an independent test dataset obtained during the 2014 growing season. Results showed that Sentinel-2 achieved the highest overall accuracy (84%) and kappa value (0.76), while the WorldView-2, produced slightly lower accuracies. The 608 nm and 705nm were selected as the most valuable bands in detecting the GLS for Worldview 2, and Sentinel-2. Overall, the results imply that opportunities exist for developing operational remote sensing systems for detection of maize disease. Adoption of such remote sensing techniques is particularly valuable for minimizing crop damage, improving yield and ensuring food security.
Gordon, Stuart G. "Genetic Mapping and Components of Resistance to Cercospora Zeae-Maydis in Maize." The Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1041605948.
Повний текст джерелаMoreira, José Ubirajara Vieira. "Mapeamento de QTLs para reação à doença mancha de Phaeosphaeria em milho." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/11/11137/tde-09062005-153756/.
Повний текст джерелаPhaeosphaeria leaf spot disease in maize (Zea mays L.) has becoming a concern in Brazil in the last years because of its increase spreading in maize growing areas. Inheritance studies of the reaction of maize genotypes to this foliar disease are necessary to support plant breeding programs. Thus, the objective of this research was to map QTLs to study the inheritance and to identify favorable alleles for reaction to the Phaeosphaeria leaf spot in a tropical maize population. Inbred lines L 14-04B and L 08-05F, highly susceptible and highly resistant to Phaeosphaeria leaf spot, respectively, were used to develop an F2 reference population. Two-hundred and fifty-six F2 plants were genotyped with 143 microsatellites markers, and their F2:3 progenies were evaluated in 16 x 16 simple lattice designs at three locations in the 2002/2003 growing season, and at four locations in the 2003/2004 growing season. Artificial infection was not used, but plots of the highly susceptible parental inbred L 14-04B were allocated at the beginning and at the end of each replication, at each set of sixteen progenies, and as a border all around the experiments, to provide the spread of P. maydis spores. Ten plants were evaluated per plot, 30 days after silk emergence, following a note scale; i.e., from 1 (highly resistant) to 9 (highly susceptible). The plot means were used for the analyses of variance, and the least squares means across environments were used to map QTLs. The multiple intervals mapping (MIM) was used for QTL mapping. The joint analysis of variance showed highly significance for progenies and for progenies by environment interaction, but the estimate of genetic variance was significantly greater than the estimate of the genetic by environment interaction, and the broad sense coefficient of heritability was high (91.37%). Six QTLs were mapped, one at each of the following chromosomes: 1 (Ph1), 3 (Ph3), 4 (Ph4), and 6 (Ph6); and two at chromosome 8 (Ph8a and Ph8b). The average level of dominance was partial dominance, but the gene action of the QTLs ranged from additive to partial dominance, and dominance x dominance epistasis was also detected between the QTLs mapped at chromosome 8. The phenotypic variance explained by the QTLs ( 2 R ) ranged from 2.91% (Ph8b) to 11.86% (Ph8a), and the joint QTLs effects explained 41.62% of the phenotypic variance. All the favorable alleles to reaction to Phaeosphaeria leaf spot; i.e., resistance alleles, were in the resistant parental line L- 08-05F. The correlation between mean phenotypic values and the predicted genotypic values based on QTLs effects of the progenies was 70 , 0 = r ; and the selection based under both criteria (phenotypic means and predicted values) at 10% selection intensity (26 progenies) showed an agreement of only 46.15% (12 progenies). Nonetheless, the favorable alleles of the QTLs mapped in the parental line L 08-05F could be transferred to other inbred lines by marker-assisted backcross breeding programs, which could make them useful for breeding purposes.
Messina, Frédéric. "Équilibre concurrentiel et sport professionnel : l'exemple du football européen." Thesis, Montpellier 1, 2011. http://www.theses.fr/2011MON10066.
Повний текст джерелаThe competitive analysis of the relevant market of the European professional football highlights the striking contrast between the strength of the requirement of a “free” and “undistorted” competition and the relativity of its existence on the market.Since the “Bosman” decision and the recognition by the European Court of Justice of the freedom of movement for professional sportsmen, the competitive economy of the relevant market is non-egalitarian and the result of economic competition is predictable. By suppressing the nationality clauses which limited the transnational flows of the players and the impact of heterogeneity of tax systems on the competitive process, the judges of Luxembourg structurally altered the competitive conditions into the market. Indeed, football clubs at “the wedge between labour costs and net wages” saw their competitive freedom being affected and their chance to succeed in the economic competition considerably reduced. Their tax incapacity to propose, at equal cost, attractive and competitive payments to the competition factors that are the players, has translated, in the context of the liberalization of the market, by a “structural inferiority state”. This situation at once went against the objectives of the Treaties causing an inefficient allowance of the wealth in the market, as well as an ill-assorted quality of the sport entertainment offer within the Common Market
Kwena, Philip Onyimbo. "Recurrent selection for gray leaf spot (GLS) and phaeosphaeria leaf spot (PLS) resistance in four maize populations and heterotic classification of maize germplasm from western Kenya." Thesis, 2007. http://hdl.handle.net/10413/747.
Повний текст джерелаYeh, Yi-Chun, and 葉怡君. "The Relationship Between Natural Gas Price and Corn Price - Evidence From Spot Market and Future Market." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/zttkq5.
Повний текст джерела國立高雄應用科技大學
國際企業研究所
101
As a clean and pure energy, natural gas has become a valuable product to the industries around the world. This study discusses the multiple relationships (both in a long run and a short run) of natural gas price and corn price, opposed to the fluent studies on the price of oil, and the agricultural commodity price. This paper employs a multivariate E-GARCH model to analyze the price spill-over effect between the natural gas market and corn market based on monthly price ranging from January 1997 to February 2013. Several major results stand out from the research. First, we find there is no long run equilibrium relationship between these two market prices. Second, evidence shows that there is a volatility spillover between natural gas market and corn market. Third, we demonstrate that there is an asymmetric effect between these market prices.
Boudreau, Mark Alan 1958. "Effects of intercropping beans with maize on angular leaf spot and rust of beans." Thesis, 1991. http://hdl.handle.net/1957/36577.
Повний текст джерелаGraduation date: 1992
Duffie, Laura Elizabeth. "Effects of intercropping corn and peanut on peanut leaf spot management and the spatial and temporal epidemiology of Cercospora arachidicola." 2003. http://www.lib.ncsu.edu/theses/available/etd-02062003-231506/unrestricted/etd.pdf.
Повний текст джерелаLapointe, Marie. "Les facteurs écologiques influençant la dynamique d'une espèce exotique envahissante, Acer platanoides, et d'un congénère indigène, A. saccharum, dans une forêt urbaine du sud du Québec." Thèse, 2009. http://hdl.handle.net/1866/8136.
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