Estimated at approximately $43 billion annually, the cultivated soybean Glycine max (L.) Merr., is the second most valuable crop in the United States. Soybeans account for 57% of the world oil-seed production and are utilized as a protein source in products such as animal feed. The value of a soybean crop, measured in seed quality and quantity, is negatively affected by biotic and abiotic stresses. This research is focused on resistance to biotic disease stress in soybean. In particular, we are working on the Phytophthora soja (P. sojae) and Soybean Mosaic Virus (SMV) systems. For each of these diseases, we are working to develop superior soybean germplasm that is resistant to the devastating economic impacts of pathogens. The majority of this research is focused on screening for novel sources of P. sojae resistance with core effectors to identify resistance genes (R-genes) that will be durable under field conditions. Four segregating populations and two recombinant inbred line (RIL) populations have been screened with core effectors. Effector-based screening methods were combined with pathogen-based phenotyping in the form of a mycelium-based trifoliate screening assay. One RIL population has been screened with virulent P. sojae mycelium. Disease phenotyping has generated a preliminary genetic map for resistance in soybean accession PI408132. The identification of novel R-genes will allow for stacking of resistance loci into elite G. max cultivars. The second project covered in this dissertation describes the validation of the SMV resistance gene Rsv3. Utilizing a combination of transient expression and homology modeling; we provide evidence that Glyma14g38533 encodes Rsv3. / Ph. D. / Estimated at approximately $43 billion annually, the cultivated soybean <i>Glycine max</i> (L.) Merr., is the second most valuable crop in the United States. Soybeans account for 57% of the world oil-seed production and are utilized as a protein source in products such as animal feed. The value of a soybean crop, measured in seed quality and quantity, is negatively affected by pathogens and other stressors. This research is focused on resistance to pathogen disease stress in soybean. In particular, we are working on the <i>Phytophthora soja</i> (<i>P. sojae</i>) and <i>Soybean Mosaic Virus</i> (SMV) systems. For each of these diseases, we are working to develop superior soybean lines that are resistant to the devastating economic impacts of these pathogens. The majority of this research is focused on screening for new sources of <i>P. sojae</i> resistance, using certain pathogen virulence proteins called core effectors, to identify resistance genes (<i>R</i>-genes) that will be durable under field conditions. Four segregating populations and two recombinant inbred line (RIL) populations have been screened with core effectors. Effector-based screening methods were combined with pathogen-based phenotyping in the form of an assay that involved the use of <i>P. sojae</i> to infect detached soybean leaves. One RIL population has been screened with virulent <i>P. sojae</i>. Disease screening has generated a preliminary genetic map for resistance in soybean accession PI408132. The identification of novel <i>R</i>-genes will allow for stacking of resistance genes into elite <i>G. max</i> cultivars that can be grown by farmers. The second project covered in this dissertation describes the validation of the SMV resistance gene <i>Rsv3</i>. Utilizing a combination of a molecular assay and protein prediction software; we provide evidence that the soybean gene Glyma14g38533 encodes <i>Rsv3</i>.

A soja tolerante ao herbicida glifosato é o vegetal geneticamente modificado mais cultivado. Entretanto, questões sobre a biossegurança dos alimentos GM são ainda levantadas, como as incertezas sobre a expressão das novas proteínas, mutações indesejadas, alterações de perfis nutricionais e aparecimento de compostos tóxicos. Apesar dos comprovados efeitos benéficos à saúde, a soja apresenta naturalmente, entre suas proteínas, fatores antinutricionais, que podem: provocar efeitos fisiológicos adversos; diminuir a biodisponibilidade de nutrientes; e induzir reações de hipersensibilidade. Paralelamente, a soja possui sabor e aroma desagradáveis por ação de enzimas lipoxigenases. Os fatores antinutricionais estão relacionados às aglutininas (lectinas) e aos inibidores de proteases (inibidor de tripsina, tipo Kunitz, e inibidor de tripsina e quimotripsina, tipo Bowman-Brik), enquanto as globulinas da soja respondem pelas reações de hipersensibilidade. Objetivou-se neste trabalho fazer a comparação dos mapas protéicos de soja GM, suas isolinhas convencionais e sojas orgânicas visando a detecção de alterações nos perfis protéicos destes diferentes tipos de cultivo, e também a análise da expressão dos fatores antinutricionais, como os inibidores de proteases e aglutininas, considerando a extensão das variações naturais existentes nas amostras. Para tanto, foram comparadas seis amostras de sementes de variedades comerciais de soja cultivadas em paralelo, sob as mesmas condições ambientais e de solo, compostas por três isolinhas genitoras e suas três correspondentes GMs e duas amostras orgânicas, sendo que uma delas é comercial e a outra ainda esta em campos de pesquisa, fornecidas pela Embrapa Soja. Foram analisados extratos protéicos de todas as amostras, após extração com ácido tricloroacético (TCA) e acetona, através de eletroforese unidimensional (1D) e bidimensional (2D). Nestas foi empregado gradiente de pH de 3-10 e as imagens avaliadas pelo software ImageMaster 2D Platinum. Diversos spots selecionados foram identificados por espectrometria de massas. Nas imagens dos géis 2D, foi possível identificar e quantificar os spots correspondentes às proteínas isoladas e não houve diferença estatística ao nível de significância de 5% entre os diferentes tipos de cultivo. Na verificação da sobreposição dos géis, obtivemos porcentagens de matchings superiores a 70% entre as amostras GMs e não GMs. As amostras orgânicas apresentaram % matchings menores que entre convencionais e GMs. Nos resultados da espectrometria de massas foi possível reconhecer os principais grupos protéicos da soja, como as frações e subunidades de &#946;-conglicinina e de glicinina, bem como os inibidores de proteases, aglutininas e lipoxigenases e não foi possível perceber alterações na expressão dos peptídeos identificados e analisados. Podemos concluir que as variações encontradas entre as três amostras convencionais e entre as amostras dos grupos convencionais e orgânicas foram maiores que a comparação das amostras GMs com suas genitoras correspondentes. / The glyphosate tolerant soybean is the most cultivated GM plant. However, questions about the bio-safety of GM foods are still rising, as there are uncertainty about the expression of new proteins, undesired mutations, changes in nutritional profile and the production of toxic compounds. Despite of the beneficial effects to human health, the soybean has anti-nutritional factors that can cause adverse physiological effects, reduce the bioavailability of nutrients, and induce hypersensitivity reactions. At the same time the soybean develop undesirable flavor due to the action of lipoxygenases. The anti-nutritional factors are related to agglutinins (lectins) and to the proteases inhibitors (Kunitz\'s Trypsin Inhibitor and Bowman-Birk\'s Inhibitor of Trypsin and Chymotrypsin) while the soybean globulins are responsible for hypersensitivity reactions. The objective of this work was to compare proteic maps of GM soybean, conventional isolines and organic soybean aiming to detect changes in protein profiles of the different types of cultivation and also analyze the expression of the anti-nutritional factors, such as protease inhibitors and agglutinins, taking into consideration the natural variation existing in the samples. For this, it was performed the comparisons between six seed samples of commercial varieties of soybeans, grown in parallel under the same environmental conditions and soil, composed of three parental isolines and their three corresponding GM and two organic sample, one of them is commercial and the other is still in search fields. The samples were provided by Embrapa Soja. Protein extracts were analyzed from the samples after extraction with trichloroacetic acid (TCA) and acetone using regular monodimensional electrophoresis (1D) and two-dimensional (2D) ones. For 2D were used strips of pH gradient 3-10 and the final images analyzed by ImageMaster 2D Platinum software. Several selected spots were identified by mass spectrometry. In the images of the 2D gels, we could identify and quantify the spots corresponding to proteins isolated and there was no statistical difference at 5% of significance between the different types of cultivation. Checking the overlap of the gels, we obtained matchings above 70% between GM and non GM sample. The organic sample had lower matching index between conventional and GM. It was possible to recognize the major groups of soy protein as a result of mass spectrometry such as¨&#946;-conglycinin fractions and glycinin as well as protease inhibitors, lipoxygenase, and agglutinins. We concluded that the variations found among the tree conventional samples and between samples of conventional and organic groups were higher than the comparison of sample GMs with their corresponding parentals.

Phakopsora pachyrhizi H. Syd and P. Syd, the causal organism of soybean rust (SBR) was first reported in Japan in 1902. In 1934 the pathogen was found in several other Asian countries and as far south as Australia. In India, SBR was first reported on soybeans in 1951. There have been several early reports of SBR in equatorial Africa but the first confirmed report of P. pachyrhizi on the African continent was in 1996 from Kenya, Rwanda and Uganda. Since then, the pathogen has spread south with reports from Zambia and Zimbabwe in 1998 and in Mozambique in 2000. In February 2001, P. pachyrhizi was first detected on soybeans near Vryheid, in Northern KwaZulu-Natal, South Africa (SA). As the season progressed, the disease was observed in other parts of the province, and epidemic levels were found in the Cedara, Greytown, Howick and Karkloof production regions. Soybean rust subsequently spread to Amsterdam and Ermelo in the Highveld region of SA. The disease reappeared in SA in March 2002. It is now established that the pathogen is a threat to soybean production in the country with yield losses in the region of 10-80%. A literature review on SBR investigating the taxonomy of the pathogen, its morphology, symptoms, host range, infection process, epidemiology, control options and the economic importance of P. pachyrhizi was complied to provide the necessary background information to conduct research under local conditions and to assist in interpretation of results of experiments. Epidemiological trials were conducted at the University of KwaZulu-Natal under controlled environmental conditions in a dew chamber and conviron. Development of P. pachyrhizi on the susceptible cultivar (LS5995) was quantified in combinations of seven temperatures (15,19,21,24,26,28 and 30°C) and five leaf wetness durations (LWD) (6,9,12,14 and 16hrs) at three relative humidities (RH) (75%, 85% and 95%). Studies indicate that optimum temperature for uredospore infection is 21-24°C with a LWD greater than 12hrs and RH 85-95%. The number of pustules as well as lesion size on the abaxial and adaxial leaf surface increased with increasing LWD at all the RH values tested. Infection did not occur on plants incubated at 15°C and 30°C at 85% or 95%RH whereas at 75%RH infection did not occur on plants incubated at 15°C, 19°C and 30°C regardless of LWD. Number of pustules per lesion produced at 75%, 85% and 95%RH was highest at 24°C and showed a gradual increase with increasing LWD. Lesion size on both leaf surfaces increased after 12hrs LWD at 24°C at 75% and 85%RH whereas at 95%RH lesion size increased after 14hrs LWD at 24°C. Exposure of uredospores to ultraviolet light which is equivalent to ultraviolet C (sunlight) which is < 280nm, shows a decrease in germination (7%). Under continuous darkness, the germination percentage was found to range from 58% after 48 hrs. Germination was found to peak at 16hrs in darkness with a gradual decrease as time increased whereas germination under ultraviolet light was highest after 6hrs with a gradual decrease with increased exposure to light. Germ tube lengths were found to be shorter when exposed to ultraviolet light (107µm) compared to controls kept in the dark (181µm). Results obtained clearly show a negative effect of ultraviolet light on the germination and germ tube length of uredospores. A 0.1 ml suspension of uredospores on 1.25% water agar Petri dishes was exposed to cycles of 14h ultraviolet light and 10h darkness for 48h. Results indicate an increase in germination percentage of uredospores when exposed to 10h of darkness following a 14h period under ultraviolet light. Controlled environmental studies were conducted to determine alternative hosts of P. pachyrhizi in SA. The control used in this experiment was Prima 2000, a susceptible cultivar to soybean rust. Seven legume plants [Cajanus cajan (L.) Huth, Glycine max (L.) Merr, Lablab purpureus (L.) Sweet, Lupinus angustifolius (L.) Finnish, Phaseolus vulgaris (L.), Pueraria lobata (M&S) Wild and Vigna unguiculata (L.) Walp] and three dry bean lines (Bonus; OPS-RS2 and PAN 159) showed typical SBR symptoms when rated after 21 days post inoculation with uredospores for percentage disease severity. Disease severity was significantly different within the alternative hosts, but G. max, P. vulgaris and P. lobata were not significantly different from Prima 2000 (control). A uredospore suspension of 2.5 x 10(5) uredospores ml(-1) from plants that showed typical SBR symptoms was made and inoculated on to Prima 2000, a susceptible soybean cultivar. Uredospores from pustules on G. max, L. purpureus, L. angustifolius, P. vulgaris, P. lobata, V. unguiculata, Bonus and PAN 159 produced viable uredospores on PRIMA 2000. These plants are considered alternative hosts of P. pachyrhizi. Effect of leaf age on susceptibility of soybean to SBR was tested under controlled environmental conditions. Mean number of lesions as well as lesion size were greater on younger leaves than on older leaves of plants at the same physiological age. Plants at the early vegetative and reproductive stages had a significantly lower number of lesions as well as a smaller lesion size. Plants at the V6 and R1 growth stages were significantly more susceptible to P. pachyrhizi than plants at other developmental stages. Trichoderma harzianum Rifai, Eco-77® a commercial biological control product, was evaluated for its efficacy as a biological control agent of P. pachyrhizi. Trichoderma harzianum sprayed at the standard concentration on infected soybean plants was significantly more effective in controlling P. pachyrhizi than plants sprayed at 1/2X and 2x the standard concentration. This was noted in both Trial 1 and 2. Data indicate that spraying the filtrate two days after inoculation produces less disease. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

A soja tolerante ao herbicida glifosato é o vegetal geneticamente modificado mais cultivado. Entretanto, questões sobre a biossegurança dos alimentos GM são ainda levantadas, como as incertezas sobre a expressão das novas proteínas, mutações indesejadas, alterações de perfis nutricionais e aparecimento de compostos tóxicos. Apesar dos comprovados efeitos benéficos à saúde, a soja apresenta naturalmente, entre suas proteínas, fatores antinutricionais, que podem: provocar efeitos fisiológicos adversos; diminuir a biodisponibilidade de nutrientes; e induzir reações de hipersensibilidade. Paralelamente, a soja possui sabor e aroma desagradáveis por ação de enzimas lipoxigenases. Os fatores antinutricionais estão relacionados às aglutininas (lectinas) e aos inibidores de proteases (inibidor de tripsina, tipo Kunitz, e inibidor de tripsina e quimotripsina, tipo Bowman-Brik), enquanto as globulinas da soja respondem pelas reações de hipersensibilidade. Objetivou-se neste trabalho fazer a comparação dos mapas protéicos de soja GM, suas isolinhas convencionais e sojas orgânicas visando a detecção de alterações nos perfis protéicos destes diferentes tipos de cultivo, e também a análise da expressão dos fatores antinutricionais, como os inibidores de proteases e aglutininas, considerando a extensão das variações naturais existentes nas amostras. Para tanto, foram comparadas seis amostras de sementes de variedades comerciais de soja cultivadas em paralelo, sob as mesmas condições ambientais e de solo, compostas por três isolinhas genitoras e suas três correspondentes GMs e duas amostras orgânicas, sendo que uma delas é comercial e a outra ainda esta em campos de pesquisa, fornecidas pela Embrapa Soja. Foram analisados extratos protéicos de todas as amostras, após extração com ácido tricloroacético (TCA) e acetona, através de eletroforese unidimensional (1D) e bidimensional (2D). Nestas foi empregado gradiente de pH de 3-10 e as imagens avaliadas pelo software ImageMaster 2D Platinum. Diversos spots selecionados foram identificados por espectrometria de massas. Nas imagens dos géis 2D, foi possível identificar e quantificar os spots correspondentes às proteínas isoladas e não houve diferença estatística ao nível de significância de 5% entre os diferentes tipos de cultivo. Na verificação da sobreposição dos géis, obtivemos porcentagens de matchings superiores a 70% entre as amostras GMs e não GMs. As amostras orgânicas apresentaram % matchings menores que entre convencionais e GMs. Nos resultados da espectrometria de massas foi possível reconhecer os principais grupos protéicos da soja, como as frações e subunidades de &#946;-conglicinina e de glicinina, bem como os inibidores de proteases, aglutininas e lipoxigenases e não foi possível perceber alterações na expressão dos peptídeos identificados e analisados. Podemos concluir que as variações encontradas entre as três amostras convencionais e entre as amostras dos grupos convencionais e orgânicas foram maiores que a comparação das amostras GMs com suas genitoras correspondentes. / The glyphosate tolerant soybean is the most cultivated GM plant. However, questions about the bio-safety of GM foods are still rising, as there are uncertainty about the expression of new proteins, undesired mutations, changes in nutritional profile and the production of toxic compounds. Despite of the beneficial effects to human health, the soybean has anti-nutritional factors that can cause adverse physiological effects, reduce the bioavailability of nutrients, and induce hypersensitivity reactions. At the same time the soybean develop undesirable flavor due to the action of lipoxygenases. The anti-nutritional factors are related to agglutinins (lectins) and to the proteases inhibitors (Kunitz\'s Trypsin Inhibitor and Bowman-Birk\'s Inhibitor of Trypsin and Chymotrypsin) while the soybean globulins are responsible for hypersensitivity reactions. The objective of this work was to compare proteic maps of GM soybean, conventional isolines and organic soybean aiming to detect changes in protein profiles of the different types of cultivation and also analyze the expression of the anti-nutritional factors, such as protease inhibitors and agglutinins, taking into consideration the natural variation existing in the samples. For this, it was performed the comparisons between six seed samples of commercial varieties of soybeans, grown in parallel under the same environmental conditions and soil, composed of three parental isolines and their three corresponding GM and two organic sample, one of them is commercial and the other is still in search fields. The samples were provided by Embrapa Soja. Protein extracts were analyzed from the samples after extraction with trichloroacetic acid (TCA) and acetone using regular monodimensional electrophoresis (1D) and two-dimensional (2D) ones. For 2D were used strips of pH gradient 3-10 and the final images analyzed by ImageMaster 2D Platinum software. Several selected spots were identified by mass spectrometry. In the images of the 2D gels, we could identify and quantify the spots corresponding to proteins isolated and there was no statistical difference at 5% of significance between the different types of cultivation. Checking the overlap of the gels, we obtained matchings above 70% between GM and non GM sample. The organic sample had lower matching index between conventional and GM. It was possible to recognize the major groups of soy protein as a result of mass spectrometry such as¨&#946;-conglycinin fractions and glycinin as well as protease inhibitors, lipoxygenase, and agglutinins. We concluded that the variations found among the tree conventional samples and between samples of conventional and organic groups were higher than the comparison of sample GMs with their corresponding parentals.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / The research was carried out between July and December 2009 using tropical soya bean (Glycine max (L.) Merril) cultivars irrigated by center pivots in the irrigation district of Jaguaribe-Apodi, belonging to the agribusiness Faedo Sementes situated at the Apodi plateau, Limoeiro do Norte, CearÃ, Brazil. The study aimed to investigate the use of Apis mellifera L. for pollination and productivity increment in the soya bean cultivars Monsoy 9144RR, BRS-CarnaÃba, BRS-SambaÃba, adapted for the tropical conditions of N and NE Brazil. The following aspects were investigated: floral biology, pollination requirements, pollination efficiency of A. mellifera ; behavior and pattern of foraging; use of A. mellifera to augment productivity per Ãrea, per plant, in oil and protein content; and potential for honey production in soya bean crops and risks of pesticide contamination of the honey. Results showed that the cultivars are attractive to honey bees and they concentrate their foraging for nectar collection in the morning shift. The varieties were capable of autopollination, however there were significant (p<0.05) increments of productivity when flowers were visited by biotic agents. A single honey bee visit raised productivity to equivalent (p>0.05) levels of those flowers open for pollination. Regarding absolute production, it differed significantly (p<0.05) from the areas where honey bees were introduced in the center or along the sideline of the plantation to that where flowers did not receive flower visits. The mean number of pods per plant was 49.64  2.64, 57.16  2.41 and 59.60  2.71; the mean number of seeds per plant was 104.68  5.13, 121.46  3.98 and 127.42  5.95; and the percentage of pods bearing three seeds was 18.65%, 20.43% and 23.72% for the caged, open and open + honey bees treatments, respectively. Oil and protein contents of seeds did not differ (p>0.05) among treatments. All colonies produced honey and by the end of the blooming period (30 days) total production reached 81.7 kg, with a mean production of 10.1  0.86 kg per hive and no pesticide residue was found. It was concluded that the soya bean cultivars adapted to N and NE Brazil can be used for honey production and the foraging behavior of A. mellifera visiting flowers only in the morning allows to recommend spraying the crop only in the late afternoon and early evening when bees are no longer in the crop to produce residue-free honey and prevent poisioning risks to the bees; also, introducing A. mellifera for pollination purpose can increase production over 25% especially due to augment in the percentage of three-seeded pods. / A pesquisa foi conduzida entre julho e dezembro de 2009 usando cultivares tropicais de soja (Glycine max (L.) Merril) irrigadas por pivà central no distrito de irrigaÃÃo Jaguaribe-Apodi, sendo o plantio pertencente à agroempresa Faedo Sementes situada na Chapada do Apodi, Limoeiro do Norte, CearÃ. O estudo teve por objetivo investigar o uso de Apis mellifera L. para polinizaÃÃo e incrementos de produtividade nas cultivares de soja Monsoy 9144RR, BRS-CarnaÃba, BRS-SambaÃba, adaptadas Ãs condiÃÃes tropicais do Norte e Nordeste brasileiro. Os seguintes aspectos foram investigados: biologia floral, requerimentos de polinizaÃÃo, eficiÃncia de polinizaÃÃo de A. mellifera; comportamento e padrÃo de forrageamento; uso de A. mellifera para elevar a produtividade por Ãrea, por planta, em conteÃdo de Ãleo e proteÃna dos grÃos; potencial para a produÃÃo de mel e os riscos de contaminaÃÃo deste mel. Os resultados mostraram que as cultivares estudadas sÃo atrativas para as abelhas melÃferas e elas concentram seu forrageio na coleta de nÃctar no turno da manhÃ. As variedades sÃo capazes de se autopolinizarem, contudo houve incrementos de produtividade significativos (p<0,05) quando as flores foram visitadas por agentes biÃticos. Uma Ãnica visita da abelha melÃfera elevou a produtividade para nÃveis equivalentes (p>0.05) ao das flores abertas para polinizaÃÃo. No que se refere à produÃÃo total, observou-se diferenÃas significativas (p<0,05) das Ãreas onde as abelhas foram introduzidas no centro ou ao longo da linha lateral do plantio para a Ãrea cujas flores nÃo receberam visitas. O nÃmero mÃdio de vagens por planta foi 49,64  2,64, 57,16  2,41 e 59,60  2,71; o nÃmero mÃdio de grÃos por planta foi 104,68  5,13, 121,46  3,98 e 127,42  5,95; e o percentual de vagens com trÃs grÃos foi 18,65%, 20,43% e 23,72% para os tratamentos onde as plantas foram engaioladas para nÃo receberem visitantes florais, deixadas abertas para receberem visitantes florais e aberta + a introduÃÃo de colÃnias de abelhas melÃferas, respectivamente. Os conteÃdos de Ãleo e proteÃna nÃo diferiram (p>0,05) entre os tratamentos. Todas as colÃnias produziram mel e ao final do florescimento (30 dias) a produÃÃo total alcanÃou 81,7 kg, com uma produÃÃo mÃdia por colmÃia de 10,1  0,86 kg e nenhum resÃduo de pesticida foi identificado no mel. Concluiu-se que as cultivares de soja adaptadas ao Norte e Nordeste do Brasil podem ser usadas para a produÃÃo de mel e o comportamento de forrageio de A. mellifera visitando flores somente no perÃodo da manhà permite recomendar a aplicaÃÃo de defensivos apenas no final da tarde ou cedo da noite, quando as abelhas nÃo se encontram no plantio para produzir mel livre de resÃduos de pesticidas e prevenir riscos de envenenamento das abelhas; tambÃm, a introduÃÃo de A. mellifera para polinizaÃÃo pode elevar a produtividade em mais de 25%, principalmente devido ao aumento no percentual de vagens com trÃs grÃos.

Master of Science / Department of Agricultural Economics / Michael W. Woolverton / Globally, the majority of countries now use genetically modified (GM) soybeans to produce oil and meal for livestock and human consumption. Japan, however, uses only Non-GM soybeans for direct human consumption of which more than 80% are imported from the U.S., Canada, and China. This research used the inverse residual demand model to estimate a two-country partial equilibrium trade model to test the existence of market power in the Japanese Non-GM soybean import market. The two-country partial equilibrium trade model incorporated the U.S. residual Non-GM soybean supply for Japan, the Japanese residual demand for U.S. Non-GM soybeans, and the equilibrium condition, where the U.S. residual Non-GM soybean supply equals the Japanese residual Non-GM soybean demand. Monthly data from January 2003 to December 2007 were used for the analysis. Empirical results indicated that U.S. Non-GM soybean exporters have stronger market power than Japanese Non-GM soybean importers. The results also indicate that Japanese consumers are willing to pay higher prices for soybeans, tofu, natto, miso, and other all soy food products.

No description available.

Master of Science / Department of Agronomy / William T. Schapaugh Jr / The soybean cyst nematode (Heterodera glycines) (SCN) is an important pathogen of soybean in the United States. Annual yield losses from SCN are estimated to be over $2 billion worldwide. However, SCN virulence or the ability of a nematode to grow on resistant soybean genotypes varies widely among SCN populations. Fortunately there are several genetic sources of resistance to decrease the virulence of the pathogen on soybean. The objectives of this research were to: 1) characterize the genetic diversity of soybean cyst nematode populations in Kansas, 2) determine the frequency of Kansas SCN populations virulent on PI88788, 3) determine which plant introductions used in the HG Type Test provide the best level resistance, and 4) compare the performance of commercial soybean cultivars to the plant introduction from which their SCN resistance was derived. Soil samples were collected from SCN-infested fields across the state. Each soil sample was taken to the greenhouse and planted to a susceptible soybean cultivar to increase SCN population. Following an SCN population increase, a HG Type Test was planted. H. glycines field populations were highly variable, not only in population densities, but also in their abilities to develop on soybean genotypes. Collected from a diverse range of environments, ten HG types were identified. About 50% of the H. glycines populations were virulent on PI 88788, and most of the populations were virulent on commercial SCN resistant lines which derived their resistance from PI 88788. The commercial lines tended to be more susceptible to SCN than the lines from which they derived their resistance, but few HG populations were virulent on PI 437654 or the commercial line that derived its resistance from PI 437654. These results suggest that sources other than PI 88788 should be used in the development of H. glycines resistant cultivars for Kansas. One possible source of resistance is PI 437654. Information about SCN diversity in Kansas will improve decisions regarding cultivar development and selection for SCN management.

Doctor of Philosophy / Department of Agronomy / Dave Mengel / The Kansas State University Soil Testing Laboratory currently uses the Walkley-Black (WB) method for soil organic matter (SOM) estimations, the Shoemaker-Mclean-Pratt (SMP) buffer for lime recommendations, and bases the soybean phosphorus (P) critical value for P fertilizer recommendations off other crops. Hazardous waste is produced from WB and SMP creating a health hazard for workers, and substantial cost for handling and disposal. The substantial increase in land area devoted to soybean creates the need to validate currently assumed soil test P critical value and check the current P recommendations for that crop. Overarching objectives of this dissertation are to find suitable non-hazardous replacements for WB and SMP, and to find the soybean P critical value in Kansas. Three common methods used to estimate SOM are WB, dry combustion (DC), and loss on ignition (LOI). An experiment was set up using 98 Kansas soils to compare WB, scooped and weighed, LOI scooped, and DC weighed. All methods correlated well to each other with LOI to weighed WB, LOI to DC, and WB weighed to DC, having correlation coefficients of 0.97, 0.98, and 0.98, respectively. The lowest variability was observed with DC, followed by WB weighed, LOI, and then WB scooped with average standard deviations of 0.04, 0.13, 0.17, and 0.24, respectively. Two non-hazardous alternatives to the SMP buffer to determine soil lime requirement are the Sikora buffer, and the modified-Mehlich buffer. Sikora’s buffer is designed to mimic SMP. Buffer values alone or Mehlich’s equation may be used to calculate lime requirements. Thirty seven soils with a pH less than 5.8 were incubated at lime rates 0, 2240, 4480, 8960, and 17920 kg ECC ha[superscript]-1. Amount of lime required to reach pHs 6.0, 6.3, and 6.6 was calculated. Mehlich’s equation better predicted lime requirements for all target pHs and buffers than buffer pH alone. The Sikora buffer with Mehlich’s equation provided a better lime estimation than the Mehlich buffer using Mehlich’s equation. A P correlation and calibration study was conducted with soybeans at 23 sites in Eastern Kansas from 2011 to 2014. Soil Mehlich-3 P available P was compared to relative soybean yield at these sites. Soybean P critical value was found to be between 10 and 15 or 11.6 mg kg[superscript]-1 using Cate-Nelson, and linear-plateau models, respectively. A linear response to P and relative yield was observed on soils testing between 3 and 8 mg kg[superscript]-1, but not on higher testing soils.

Typescript (photocopy). / Digitized by Kansas Correctional Industries