Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2016-10-21T11:16:35Z No. of bitstreams: 1 2016 - Fagner Jos? de Carvalho Louren?o.pdf: 722093 bytes, checksum: 3d1733623cf87f8f9db8063b46e336ca (MD5) / Made available in DSpace on 2016-10-21T11:16:35Z (GMT). No. of bitstreams: 1 2016 - Fagner Jos? de Carvalho Louren?o.pdf: 722093 bytes, checksum: 3d1733623cf87f8f9db8063b46e336ca (MD5) Previous issue date: 2016-03-18 / A fild plot was carried out in Rio Pomba, MG state, dealing with beans (Phaseolus vulgaris L.) from March to May 2015. Six cultivars were compared under organic farming from seeds inoculated or not inoculated (= control) with commercial biological products based upon N2 fixing bacteria (Rhizobium tropici) and plant growth promoting bacteria (Azospirillum brasilense). Two of the cultivars, ?Ouro Vermelho? and ?BRSMG Madrep?rola?, are recommended and have been developed for Minas Gerais bean growing regions. They are both characterized by a high grain yield potential and belong to ?vermelho? and ?carioca? groups, respectively, which are of known preference by state consumers. On the other hand the cultivars ?Bola?, ?Kaboon?, ?Constanza?, and ?Manteig?o? represent introduced genotypes producing grains considered of special types on account of tegument color, size (= mass) and / or shape differing from the most commonly planted beans in Brazil. Such differential traits have been associated to an aggregate value because of their higher prices in the organic market of Brazilian southeast large cities. The study aimed at evaluating the introduced cultivars in comparison with the regional cultivars relating agronomic performance under organic farming as well as the respective response to seed inoculation with the cited bacterial species having a potential for contributing to beans organic management system by favoring crop yields. The research concept was based on the perspective of agrobiodiversity gains in organic farming units and on the possibility to improve farmer?s family income by means of expanding foods variety offered to consumers, specially focusing on beans, a major daily component of Brazilian?s diet due to its high nutritional quality. The experiment followed a randomized block design in a six x two factorial scheme with four replicates. Results referring data on marketable grain yields pointed out the viability of beans organic farming under Rio Pomba soil and weather conditions. The special grains introduced cultivars yields were close or, in certain cases, comparable to those of the two Minas Gerais recommended cultivars. The overall average of cultivars yields, independently of seed treatments, in which co-inoculation did not differ from the control (= non treated seeds), widely surpassed regional and national mean yields reported for the bean crop. The N2 stock ready to be utilized by the plants present in the soil of the experimented plant and a possible significant contribution fron biological fixation were able to fulfill crop requirements since no inputs have been made as nitrogen fertilizers. Root nodulation otherwise indicated the relevant contribution of local soil bacterial communities already stablished in the experimental plot and responsible for beneficial interactions with the bean plants. On the basis of the average between seed treatments the highest nodulation rates in terms of total number of nodules per root dry matter linked to the cultivars ?Ouro Vermelho? and ?BRSMG Madrep?rola? which also had the higher grain yields. Statistical analysis of the agronomic attributes considered in the study demonstrated significant differences among cultivars, including: number of pods per plant, number of grains per pod, and weight (= mass) of 100 grains (approx. 12% moisture). The first of such traits positively correlated with grain yield. Data also indicated that the number of grains per pod was inversely proportional to the 100 grains / mass. The last index (100 grains / mass weight) represented an estimative of the differences in grain sizes. With no exceptions, those introduced cultivars producing larger ? sized grains also revealed higher 100 grains mass values. The discarded levels of grains not reaching market standards again varied among cultivars and had influence on commercially suitable grain yields. This result leads to the need of adjusting bean organic farming in order to reduce yield losses. / Foi realizado em Rio Pomba, estado de Minas Gerais, um experimento de campo com o feijoeiro (Phaseolus vulgaris L.) correspondendo ? ?safra da seca` no per?odo de mar?o a maio do ano de 2015. Foram comparadas seis cultivares submetidas a sistema org?nico de produ??o, a partir de sementes co-inoculadas ou n?o (= controle) com produtos comerciais ? base de bact?rias fixadoras do nitrog?nio atmosf?rico (Rhizobium tropici) e de promotoras do crescimento vegetal (Azospirillum brasilense). Dessas seis cultivares, duas delas, ?Ouro Vermelho` e ?BRSMG Madrep?rola`, s?o recomendadas para plantio no estado e foram desenvolvidas e selecionadas para as regi?es mineiras produtoras de feij?o, sendo ambas caracterizadas pelo alto potencial de rendimento em gr?os dos grupos vermelho e carioca, respectivamente, de comprovada prefer?ncia dos consumidores de Minas Gerais. J?, as quatro outras cultivares, a saber: ?Bola`, ?Kaboon`, ?Constanza` e ?Manteig?o`, correspondem a gen?tipos introduzidos e que produzem gr?os considerados como especiais, por conta de colora??o, tamanho (massa) e/ou formato diferenciados. Tais atributos t?m sido associados a um valor agregado dessas cultivares, traduzido pelas cota??es mais elevadas de pre?os na comercializa??o em bancas e g?ndolas de produtos org?nicos encontradas em grandes metr?poles do Sudeste brasileiro. Os objetivos do estudo de Rio Pomba foram os de avaliar esses gen?tipos quanto a seu desempenho agron?mico sob manejo org?nico, al?m de suas respectivas respostas quando cultivados a partir da inocula??o, das sementes no pr?-plantio, com o cons?rcio mencionado de esp?cies bacterianas potencialmente capazes de contribuir para a viabiliza??o desse manejo, atrav?s de ganhos em produtividade. A concep??o da pesquisa fundamentou-se nas perspectivas de aumento da agrobiodiversidade em unidades de produ??o org?nica e da melhoria de renda familiar dos agricultores, por meio da diversifica??o da oferta de alimentos ? popula??o consumidora, especialmente com foco no feij?o, preponderante na dieta dos brasileiros e destacado por sua riqueza nutricional. O ensaio ficou delineado em blocos ao acaso com quatro repeti??es, constituindo um esquema fatorial 6 x 2. Os resultados obtidos, em termos de rendimento comercial das cultivares, apontaram para a viabilidade do manejo org?nico sob as condi??es edafoclim?ticas de Rio Pomba, com as cultivares de gr?os especiais introduzidas produzindo satisfatoriamente, aproximando-se ou mesmo, em alguns casos, alcan?ando valores compar?veis ?queles de cultivares recomendadas para Minas Gerais. A m?dia geral, calculada independentemente, dos tratamentos das sementes em que a co-inocula??o n?o diferiu do controle, suplantaram amplamente as m?dias regional e nacional de produ??o de feij?o por unidade de ?rea cultivada. O estoque de nitrog?nio assimil?vel presente no solo da ?rea experimental ? uma controbui??o possivelmente significativa da fixa??o biol?gica, foram suficientes para as necessidades da cultura, vez que n?o houve aporte do macronutriente na forma de aduba??o nitrogenada. A nodula??o radicular evidenciou atividade de comunidades de bact?rias j? estabelecidas no solo da ?rea experimental, respons?veis por intera??es ben?ficas com o feijoeiro. Tomando-se a m?dia entre os tratamentos de sementes (co-inocula??o e controle) os ?ndices superiores de nodula??o, com base no n?mero total de n?dulos por mat?ria seca das ra?zes, coincidiram com as cultivares mais produtivas (?Ouro Vermelho` e ?BRSMG Madrep?rola`). As an?lises estat?sticas das vari?veis fitot?cnicas consideradas no estudo revelaram diferen?as significativas entre as cultivares, incluindo: n?mero de vagens por planta, n?mero de gr?os por vagem e massa de 100 gr?os ( + ou ? 12% de umidade). A primeira delas correlacionou-se positivamente com a produtividade. Os dados indicaram, ainda, que o n?mero de gr?os por vagem ? inversamente proporcional ? massa de 100 gr?os (correla??o negativa). Este ?ltimo ?ndice representou uma estimativa das diferen?as no tamanho dos gr?os. Sem exce??es, aquelas cultivares introduzidas, caracterizadas pela produ??o de gr?os gra?dos, igualmente mostraram valores mais elevados das amostras dos 100 gr?os. Os n?veis de descarte de gr?os fora dos padr?es de mercado tamb?m variaram entre as cultivares testadas, influindo, em maior ou menor grau, no respectivo rendimento comercial, assim sinalizando para a conveni?ncia de ajustes no manejo org?nico do feijoeiro, objetivando contribuir para redu??o desse fator de perdas nas colheitas

Toxoplasma gondii é apontado como causa primária de doença congênita, abortamentos e natimortalidade em humanos e animais de produção. No Brasil, genótipos atípicos do parasita podem estar relacionados com ocorrência de enfermidade severa, inclusive em indivíduos imunocompetentes. Este estudo aplicou-se à reprodução experimental de infecções por T. gondii em ovinos, com vistas a estudar aspectos relacionados à ocorrência da transmissão congênita, avaliando reinfecções produzidas por diferentes genótipos de T. gondii isolados no Brasil. Treze ovelhas soronegativas para a infecção por T. gondii foram primo-infectadas com 2x103 oocistos esporulados via oral deste parasito, Grupo 1 (4 animais) com genótipo BrI e Grupos 2 e 3 (5 e 4 animais, respectivamente) com genótipo BrIII. Após a cronificação da infecção, os animais foram emprenhados. Da mesma forma, uma segunda infecção foi realizada após 2 meses de gestação, animais dos Grupos 1 e 3 receberam oocistos de T. gondii genótipo BrIII e o Grupo 2 recebeu BrI. Semanalmente foram observados os efeitos da reinfecção comparando com um grupo controle (5 animais) não infectado, através de exames físicos, ultrassonográficos, sorológicos, hematológicos e bioquímicos. Utilizando bioensaio em camundongos, análise molecular, exames histopatológicos e imunohistoquímica, avaliou-se a infecção experimental de ovelhas e cordeiros. Verificaram-se as diferenças entre as médias dos resultados dos grupos com ANOVA dois fatores para a sorologia e ANOVA um fator, post-hoc Bonferroni ou Kruskall-Wallys, post-hoc U de Mann-Withney para os outros parâmetros, sendo considerados significativos quando p<0,05. Não foram observados abortamentos, obtiveram-se 19 cordeiros dos grupos experimentais, todos soronegativos. As ovelhas infectadas apresentaram altos títulos de IgG e hipertermia após a primo-infecção e aumento moderado após a reinfecção, com diferença estatística somente no Grupo 1. Parâmetros clínicos alterados nos grupos experimentais foram observados principalmente nos dias 21 e 28 após o desafio. Houve significância estatística comparando-se resultados de patologia clínica em infecções por genótipos diferentes em vários pontos de tempo. À necropsia, observou-se fibrina nas placentas das ovelhas infectadas, um feto mumificado em uma das ovelhas do Grupo 2 e cordeiros e ovelhas com linfoadenomegalia. PCR realizado em amostras de tecido alterado confirmou presença de T. gondii em linfonodos e coração de cordeiros do grupo 2 e coração e placenta de ovelhas do Grupo 3. Nos bioensaios em camundongos dos tecidos de cordeiros foram observados cistos cerebrais em um animal do Grupo 2, confirmados por PCR. Análises histopatológicas confirmaram taxa de transmissão de 26% nos três grupos experimentais. Exceto por uma ovelha do Grupo 1, todos os ovinos, incluindo o cordeiro positivo, estavam infectados com o isolado utilizado na primo-infecção. Observou-se maior frequência de transmissão congênita endógena em ovelhas soropositivas após reinfecção com genótipos diferentes, com alterações fisiológicas significativas em ovelhas gestantes, porém não acarretando abortamento ou malformações. A primo-infecção proporcionou imunidade cruzada contra reinfecção subsequente na maioria dos animais, aparentando maior eficácia quando utilizado genótipo BrIII / Toxoplasma gondii is considered the primary cause of congenital disease, miscarriage and stillbirth in humans and farm animals. In Brazil, non-classical genotypes may be related with severe toxoplasmosis also in immunocompetent patients. This study evaluated infections and reinfections caused by two atypical field strains of T. gondii isolated in Brazil and their consequences over congenital transmission in sheep. Thirteen Santa Ines ewes seronegative for T. gondii were prime-infected orally with 2x103 sporulated oocysts, being Group 1 from genotype BrI (4 animals), whilst Groups 2 and 3 ewes received an inoculum from genotype BrIII (5 and 4 animals, respectively). After infection chronification all animals were mated. Likewise, a second inoculation was held at 2 months pregnancy, Group 1 and 3 receiving oocysts from genotype BrIII, while Group 2 was infected with genotype BrI. Blood samples for serology, CBC, biochemistry, vital signs evaluation and abdominal ultrasound were performed weekly, comparing with a control group (5 animals). Experimental infection from ewes and lambs was evaluated thru mice bioassay, molecular analysis, histopathological and immunohistochemical tests. To analyze serology variation between groups their mean results were subjected to two-way ANOVA. The other parameters were tested using one-way ANOVA followed by Bonferroni or Kruskall-Wallys followed by Mann-Whitney U, where statistical significance was set at p<0,05. No abortion was observed and 19 lambs were born from ewes of the experimental groups presenting negative serology. Infected ewes showed high IgG titles and fever after prime-infection and moderate increase after reinfection, although only Group 1 presented statistical significance. Altered clinical values were observed from experimental groups mainly 21 and 28 days post challenge. Significant differences were detected when comparing infections from different genotypes. Post-mortem analysis revealed fibrin over placentas from ewes of all experimental groups; a mummified fetus inside an ewe from Group 2 and lymph nodes enlargement within ewes and lambs. PCR performed on altered tissues from necropsy confirmed presence of T. gondii on lymph nodes and heart of a Group 2 lamb and on placenta and heart of Group 3 ewes. Considering mice bioassays from lamb tissues, one animal from group 2 presented brain smear cysts, also PCR analysis positive. Histopathological tests corroborate a congenital transmission rate of 26% among experimental groups. Apart from one ewe from Group 1 all the other animals, including the positive lamb, were infected with the strain from the prime-infection. Therefore, it was more frequently observed endogenous congenital transmission in seropositive ewes after reinfections with different strains leading to significant physiological variations in pregnant ewes, abortion and congenital malformations absence notwithstanding. The prime-infection also provided cross protective immunity against a following reinfection for the majority of the animals, suggesting apparent better response when performed using genotype BrIII

Made available in DSpace on 2017-07-10T15:14:37Z (GMT). No. of bitstreams: 1 _Caroline_T_Echert.pdf: 2296815 bytes, checksum: bbff48fc695ec3d428d75a6cdb321beb (MD5) Previous issue date: 2016-02-05 / With the aim of find out what the best hybrid maize for ethanol production, according to characteristics of the state of Paraná Western region were evaluated 10 hybrids, and 9 have transgenic technology Bt and 1 conventional non-Bt . The experimental development, the field was conducted between February and October 2015, and used a randomized block with four replications, and the average test employee was Tukey test (&#8804;0,05), along with Correlation Matrix (&#8804;0,05) and Contrast Analysis (&#8804;0,05). The laboratory tests were conducted productivity and yield of die (kg ha-1 and L ethanol ha-1), the starch content, of soluble solids, and the percentage of ethanol in the wort produced. The hybrids were in accordance with literature by the fact that the amount of biomass produced per hectare was relevant to the yield of ethanol liters per hectare, in the same way that the quality of the grains had been indispensable for the good performance of hybrids. / Com o objetivo de averiguar qual o melhor híbrido de milho para a produção de etanol, de acordo com características da região Oeste do estado do Paraná, foram avaliados 10 híbridos, sendo que 9 possuem tecnologia transgênica Bt e 1 convencional não-Bt . O desenvolvimento experimental, a campo, foi realizado entre os meses de fevereiro a outubro de 2015, sendo utilizado o delineamento experimental em blocos casualizados com quatro repetições, e o teste de média empregado foi o Teste de Tukey (&#8804;0,05) juntamente com a Matriz de Correlação (&#8804;0,05) e a Análise de Contraste (&#8804;0,05). As análises laboratoriais realizadas foram de cunho de produtividade e rendimento (em kg ha-1 e L etanol ha-1), de conteúdo amiláceo, de sólidos solúveis e de percentual em etanol no mosto produzido. Os híbridos estiveram em conformidade com a literatura pelo fato de que a quantidade produzida de biomassa por hectare foi relevante para o rendimento em litros de etanol por hectare, da mesma forma que a qualidade dos grãos foi indispensável para que houvesse bom desempenho dos híbridos.

Trypanosamas de diversas espécies podem infectar mamíferos de interesse econômico em todo o mundo. Trypanosoma vivax, T. evansi, T. equiperdum, T. congolense, T. b. brucei e T. simiae geram importantes doenças em ungulados na África, Ásia e Américas Central e do Sul; enquanto T. theileri e espécies relacionadas são pouco patogênicas. Compreender a epidemiologia e as interações parasita-vector-hospedeiro requer estudos de estrutura populacional, filogeográficos e de diversidade e relações filogenéticas entre isolados. Sequências de microssatelites e dos genes SSUrRNA, gGAPDH, CatL, ITS, SL, 5S, Cytb e ESAG6 mostraram ampla diversidade biológica e diferenciaram genótipos com associação geográfica e restrição de hospedeiros em T. theileri e espécies relacionadas. T. evansi mostrou importante heterogeneidade de sequências no gene ESAG6, enquanto populações de T. vivax muito divergentes foram observadas em regiões preservadas e com transmissão cíclica quando comparadas com a microheterogeneidade biológica de áreas de transmissão mecânica. / Trypanosames can infect diverse species of mammals of economic interest worldwide. Trypanosoma vivax, T. evansi, T. equiperdum, T. congolense, T. brucei brucei and T. simiae cause important diseases in ungulates in Africa, Asia and Central and South America, while T. theileri and related species are of low pathogenicity. Understanding the epidemiology and host-parasite-vector interactions requires studies of population structure, phylogeography and diversity and phylogenetic relationships among isolates. Microsatellite loci and sequences from genes SSUrRNA, gGAPDH, CatL, ITS, SL, 5S, Cytb and ESAG6 revealed high biological diversity and allowed differentiation of genotypes with geographic structure and host-restriction event in T. theileri and related species. T. evansi showed significant heterogeneity in ESAG6 sequences, while populations of T. vivax widely divergent were observed in pristine regions and cyclical transmission compared to the microheterogeneity showed by isolates from mechanical transmission areas.

Dentre os desafios do cultivo de trigo, encontram-se as doenças fúngicas e a presença de micotoxinas. Estima-se que as perdas anuais nesse setor sejam bilionárias. Além dos prejuízos econômicos, há preocupações quanto a segurança alimentar humana e animal. Com o objetivo de avaliar a micobiota e a ocorrência de micotoxinas em diferentes estádios de maturação do trigo foram realizados estudos morfológicos, utilizando métodos morfológicos clássicos e moleculares, identificação do perfil genotípico dos fungos produtores de tricotecenos, por PCR em tempo real e determinação de deoxinivalenol (DON) e zearalenona (ZEA), utilizando a Cromatografia Líquida de Alta Eficiência acoplada à Espectrometria de Massas (LC-MS/MS). Os dados obtidos também foram correlacionados com os fatores climatológicos. Os resultados revelaram a predominância do gênero Fusarium nas amostras das duas safras, seguido de Alternaria e Epicoccum. A atividade de água média para os dois anos foram, 0,608 e 0,886, consecutivamente. Dentro do gênero Fusarium constatou-se predomínio do complexo de espécies Fusarium graminearum (CEFG), identificando F. graminearum sensu stricto, F. meridionale, F. cortaderiae e F. austroamericanum. Os genótipos dos isolados foram, na sua maioria, 15-ADON para F. graminearum s.s, seguido de NIV para as espécies F. meridionale, F. cortaderiae e F. austroamericanum e 3-ADON para as duas últimas. Por PCR em tempo real, a determinação do genótipo nos grãos de trigo nas safras 2014/15 e 2015/16 demonstraram predomínio de 100% e 93% para 15-ADON, respectivamente. A quantificação de DNA dos isolados do CEFG demostrou que o perfil 15-ADON foi responsável por mais de 95% nas duas safras, com valores irrisórios, menores que 3% para 3-ADON e NIV. Os níveis de contaminação pela micotoxina DON nas amostras foi de 100% nas duas safras, com valores variando entre 24,3 a 5530 &#956g/kg. Para ZEA os valores foram 30% e 96%, nas duas coletas consecutivas, variação entre 26,0 a 4360 &#956g/kg. Ambas as micotoxinas foram detectadas em concentrações acima do limite estabelecido pela legislação brasileira, 3000 &#956g/kg para DON e 400 &#956g/kg para ZEA. Os fatores climáticos obtiveram uma correlação positiva tanto na contaminação fúngica quanto no acúmulo de micotoxinas. Este estudo forneceu novas informações sobre a micobiota natural do trigo brasileiro, em diferentes etapas do cultivo, demonstrando a contaminação por DON e alta frequência de ZEA em amostras do provindas do Paraná. / The fungal diseases and the presence of mycotoxins in cereals cause annually, billionaire losses. In addition, there are concerns about human and animal food safety. Due to the wheat culture relevance in feed and foodstuff, the present work aimed to evaluate mycobiota and the occurrence of mycotoxins in different wheat maturation stages. In order to achieve these objectives, morphologic studies using classic and molecular methods, genotype profile and DNA quantification from trichothecene producers, by real-time PCR and determination of deoxynivalenol (DON) and zearalenone (ZEA), using High Performance Liquid Chromatography coupled to Mass Spectrometry (LC-MS/MS), were done. The obtained data were also correlated with the climatic factors. The results showed the predominance of the genus Fusarium followed by Alternaria and Epicoccum. The average water activity over two years were 0.608 and 0.886, consecutively. Within the genus Fusarium, it was identified a predominance of the Fusarium graminearum species complex (FGSC), identifying F. graminearum sensu stricto, F. meridionale, F. cortaderiae and F. austroamericanum. The genotypes of the isolates were 15-ADON for F. graminearum s.s, followed by NIV for the F. meridionale, F. cortaderiae and F. austroamericanum and 3-ADON for F. cortaderiae and F. austroamericanum. In real-time PCR, the determination of genotype in wheat grains in the 2014/15 and 2015/16 harvests showed a predominance of 100% and 93% for 15-ADON, respectively. The DNA quantification of the FGSC isolates showed that the 15-ADON profile was responsible for more than 95% in both harvests. The levels of DON mycotoxin contamination in the samples were 100%, with values ranging from 24.3 to 5530 &#956g/kg. For ZEA the values were 30% and 96%, in the two consecutive collections, ranging from 26,0 to 4360 &#956g/kg. Both mycotoxins were detected in concentrations above the limit established by Brazilian legislation, 3000 &#956g / kg for DON and 400 &#956g/kg for ZEA. The climatic factors obtained a positive correlation both in the fungal contamination and in the accumulation of mycotoxins. This study provided new information on the Brazilian native mycobiota to different stages of cultivation, demonstrating contamination by DON and high frequency of ZEA in samples from Paraná.

<p>The current research is directed towards dissection of host genetic factors involved in host immune response and the malaria disease outcome. A possible association between FcγRIIa polymorphism and anti-malarial antibody (A.M.A) responses were investigated in Sudanese patients in relation to clinical outcome of falciparum malaria. The frequency of the R/R131 genotype was significantly higher in patients with severe malaria as compared with mild malaria. A.M.A IgG3 was shown to be associated with reduced risk of clinical malaria in individuals carrying the H/H131 genotype. Low levels of IgG2 reactive with the Pf332-C231 antigen were associated with lower risk of severe malaria in individuals carrying the H131 allele. </p><p>Fulani and Masaleit, two sympatric ethnic groups in Sudan, are characterized by marked differences in susceptibility to falciparum malaria. We investigated whether the two populations differ in the frequency of GM/KM allotypes. The distribution of GM/KM phenotypes differed significantly among the two groups, with Gm 6 being significantly lower among the Fulani, and the combined frequency of Km 1,3 and Gm 1,17 5,6,13,14 phenotypes was found to be higher among Masaleit.</p><p> In interethnic study we investigated whether the two groups differ in the frequency of FcγRIIa and HbAS genotypes. The frequency of the H/H131, R/R13 and HbAS genotypes differed significantly among the two groups. Moreover, the Fulani showed higher levels of A.M.A IgG2 and lower IgG1 and IgG3 when compared to their sympatric non-Fulani neighbours.</p><p>A tri-allelic SNP (C/T/A) in the CRP gene was investigated for possible ethnic associations. The A allele, which is associated with higher basal CRP levels, was found to be less frequent in the Fulani compared with non-Fulani ethnic groups both in Sudan and Mali. </p><p>In conclusion, our results suggest possible associations between FcγRIIa, CRP genotypes, GM/KM allotypes, and anti-malarial antibody responses and the clinical outcome of falciparum malaria.</p>

The current research is directed towards dissection of host genetic factors involved in host immune response and the malaria disease outcome. A possible association between FcγRIIa polymorphism and anti-malarial antibody (A.M.A) responses were investigated in Sudanese patients in relation to clinical outcome of falciparum malaria. The frequency of the R/R131 genotype was significantly higher in patients with severe malaria as compared with mild malaria. A.M.A IgG3 was shown to be associated with reduced risk of clinical malaria in individuals carrying the H/H131 genotype. Low levels of IgG2 reactive with the Pf332-C231 antigen were associated with lower risk of severe malaria in individuals carrying the H131 allele. Fulani and Masaleit, two sympatric ethnic groups in Sudan, are characterized by marked differences in susceptibility to falciparum malaria. We investigated whether the two populations differ in the frequency of GM/KM allotypes. The distribution of GM/KM phenotypes differed significantly among the two groups, with Gm 6 being significantly lower among the Fulani, and the combined frequency of Km 1,3 and Gm 1,17 5,6,13,14 phenotypes was found to be higher among Masaleit. In interethnic study we investigated whether the two groups differ in the frequency of FcγRIIa and HbAS genotypes. The frequency of the H/H131, R/R13 and HbAS genotypes differed significantly among the two groups. Moreover, the Fulani showed higher levels of A.M.A IgG2 and lower IgG1 and IgG3 when compared to their sympatric non-Fulani neighbours. A tri-allelic SNP (C/T/A) in the CRP gene was investigated for possible ethnic associations. The A allele, which is associated with higher basal CRP levels, was found to be less frequent in the Fulani compared with non-Fulani ethnic groups both in Sudan and Mali. In conclusion, our results suggest possible associations between FcγRIIa, CRP genotypes, GM/KM allotypes, and anti-malarial antibody responses and the clinical outcome of falciparum malaria.

Abstract Ecological based weed management strategies are imperative in cropping systems when herbicide use is limited or prohibited. Herbicides are not applicable in controlling wild oat (Avena fatua L.) in oat (Avena sativa L.) cropping systems, as they are closely related. Moreover, herbicide use is prohibited in organic oat cultivation, resulting in a need for developing alternative weed management strategies. Enhancing the crop competitive ability (CA) can be an essential strategy in managing weeds in such instances. Two studies were carried with the objectives to: 1) evaluate newly developed oat genotypes for their CA against wild oat; and 2) develop a competitive organic oat cropping system integrating mechanical and cultural weed control practices. In the first study, seven oat lines deliberately bred for enhanced CA and their two parental cultivars were evaluated for the CA with wild oat. The genotypes yielded similarly in the presence and in the absence of wild oat competition. The tall oat line SA050479 with greater seedling leaf size was more wild oat suppressive among all lines. Moreover, SA050479 had greater yield potential and grain quality; thus, it has the potential to be developed as a commercial wild oat suppressive cultivar. The second study used two contrasting levels of genotype, row spacing, crop density and a post-emergence harrowing and a non-harrowed control in two organic oat fields to develop an integrated weed management system. High crop density and harrowing increased the grain yield by 11% and 13% respectively. The competitive cultivar CDC Baler and high crop density (500 plants m-2) reduced weed biomass by 22% and 52% respectively. Harrowing reduced weed density by more than 50% in three site-years. The cultural and mechanical weed control practices when combined were additive in increasing grain yield and reducing weed biomass. Oat seed yields were increased by 25% when high crop density planting and harrowing were combined. Similarly, the combined effect of competitive cultivar, high crop density, and post-emergence harrowing were greater as weed biomass was reduced by 71%. The outcome of this project implies the importance of enhancing the crop CA by means of crop breeding and integrating cultural and mechanical weed control strategies. Furthermore, this study was able to identify the importance of ecological based weed management strategies in order to overcome the constraints in weed management in present oat cropping systems.

Abstract Ecological based weed management strategies are imperative in cropping systems when herbicide use is limited or prohibited. Herbicides are not applicable in controlling wild oat (Avena fatua L.) in oat (Avena sativa L.) cropping systems, as they are closely related. Moreover, herbicide use is prohibited in organic oat cultivation, resulting in a need for developing alternative weed management strategies. Enhancing the crop competitive ability (CA) can be an essential strategy in managing weeds in such instances. Two studies were carried with the objectives to: 1) evaluate newly developed oat genotypes for their CA against wild oat; and 2) develop a competitive organic oat cropping system integrating mechanical and cultural weed control practices. In the first study, seven oat lines deliberately bred for enhanced CA and their two parental cultivars were evaluated for the CA with wild oat. The genotypes yielded similarly in the presence and in the absence of wild oat competition. The tall oat line SA050479 with greater seedling leaf size was more wild oat suppressive among all lines. Moreover, SA050479 had greater yield potential and grain quality; thus, it has the potential to be developed as a commercial wild oat suppressive cultivar. The second study used two contrasting levels of genotype, row spacing, crop density and a post-emergence harrowing and a non-harrowed control in two organic oat fields to develop an integrated weed management system. High crop density and harrowing increased the grain yield by 11% and 13% respectively. The competitive cultivar CDC Baler and high crop density (500 plants m-2) reduced weed biomass by 22% and 52% respectively. Harrowing reduced weed density by more than 50% in three site-years. The cultural and mechanical weed control practices when combined were additive in increasing grain yield and reducing weed biomass. Oat seed yields were increased by 25% when high crop density planting and harrowing were combined. Similarly, the combined effect of competitive cultivar, high crop density, and post-emergence harrowing were greater as weed biomass was reduced by 71%. The outcome of this project implies the importance of enhancing the crop CA by means of crop breeding and integrating cultural and mechanical weed control strategies. Furthermore, this study was able to identify the importance of ecological based weed management strategies in order to overcome the constraints in weed management in present oat cropping systems.

Field pea (Pisum sativum L.) is an important grain legume in western Canada. Growers can, however, be reluctant to include pulse crops such as field pea in their rotation because they are poor competitors with weeds. This thesis research was conducted to determine whether competitive differences exist among semi-leafless field pea cultivars and to determine the mechanism(s) driving competitive differences. Cultivars included in the studies were chosen on the basis of varying seed size and vine length, which are traits known to confer competitive ability. Differences in competitive ability were identified among cultivars as yield loss ranged from 9% to 31% and 14% to 31% for model weed seed return. However, cultivars were inconsistent in their competitive ranking as cultivars typically performed well for one metric, but not both. None of the traits measured in this study correlated with competitive ability. The greenhouse research was unable to identify the mechanism responsible for these competitive differences. Focal pea plants generally responded to the presence of below-ground neighbours by allocating more resources to shoot production. Therefore, semi-leafless field pea cultivars exhibit differences in below-ground responses to neighbours and it may be useful to include this as part of the selection criteria in breeding programs.