Made available in DSpace on 2017-07-10T17:37:10Z (GMT). No. of bitstreams: 1 Hamilton Santana.pdf: 702139 bytes, checksum: d0ac4361cec105b090cd85a79db56ad3 (MD5) Previous issue date: 2007-08-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Cyst Nematode is one of the main soybean crop pathogens in the world levels. In Brazil, such nematode is spread throughout Brazilian regions in which soybean is grown and its damage for soybean crops is dependent on the infestation level on the field. In Paraná State, this species is widely distributed, and it has been reported in 11 counties in the western region. The physiological race determination in such species is fundamentally important for the recommendation of resistant soybean cultivars to H. glycines. This work aimed to study the genetic variability in H. glycines polycystic populations collected from infested areas, through the identification of physiological races in monocystic populations by tests in soybean differential plants. It was also aimed at testing the reaction of soybean commercial cultivars to H. glycines to race 3. Field population and monocystic isolates from H. glycines, collected in Cruz Alta (RS), Porto Mendes (PR) and Novo Horizonte (PR), were developed in CD 202 soybean plants. Soybean differentials and soybean commercial cultivars were seeded in tubes, inoculated in the V1 stage with 5.000 eggs and J2 and kept in a greenhouse under temperature ranging from 28 to 30oC. The greenhouse essays followed a completely randomized design with seven replications. The physiological race identification was carried out with two field populations and nine monocystic isolates whereas the resistance test was developed on 18 commercial cultivars. The evaluation procedure was accomplished at 28 days apart the inoculation and based on the Parasitism Index (PI). The PI was calculated on the number of females and cysts found on the differentials and the cultivars tested in relation to the check cultivar LEE . The tests in differential plants with monocystic isolates revealed the presence of the races 2, 5 and 6 to Porto Mendes, 3 and 6 to Cruz Alta and 5 and 6 to Novo Horizonte. Field populations showed the presence of race 6 in Porto Mendes and race 3 in Cruz Alta. Most of commercial cultivars tested were resistant to H. glycines race 3 while the cv. Liderança and the CD 217 presented susceptibility. The results showed that the race identification from monocystic isolates assists in the identification of genetic variability in field populations of H. glycines, what is not possible according to the race scheme based in polycystic populations extracted from the soybean crop fields / O nematóide de cisto é um dos principais patógenos da cultura da soja a nível mundial. No Brasil, este nematóide encontra-se disseminado em praticamente todas as regiões produtoras de soja, sendo responsável por perdas de produtividade variáveis, dependendo do nível de infestação a campo. No Paraná, esta espécie encontra-se amplamente distribuída, tendo sido relatada em 11 municípios somente da região oeste do estado. A determinação de raças fisiológicas de H. Glycines é de fundamental importância para a recomendação de cultivares de soja resistentes a este patógeno. Objetivou-se com o presente trabalho, estudar a variabilidade genética presente em populações policísticas de H. glycines coletadas a campo, através da identificação de raças fisiológicas de populações monocísticas, a partir de testes em plantas hospedeiro-diferenciadoras. Objetivou-se também testar a reação de cultivares comerciais de soja à raça 3 de H. glycines. Populações de campo e isolados monocísticos de H. glycines, provenientes dos municípios de Cruz Alta (RS), Porto Mendes (PR) e Novo Horizonte (PR), foram multiplicados em plantas de soja CD 202 . Plantas hospedeiro-diferenciadoras e cultivares comerciais de soja foram semeados em tubetes, inoculados no estádio V1 com 5.000 ovos e J2 e mantidos em casa-de-vegetação com temperatura variando de 28 a 30 oC. Os testes em casa-de-vegetação seguiram o delineamento inteiramente casualizados com sete repetições. A identificação de raças fisiológicas foi realizada em duas populações de campo e nove isolados monocísticos e o teste de resistência em 18 cultivares. comerciais. As avaliações foram feitas aos 28 dias após a inoculação com base no Índice de Parasitismo (IP). O IP foi calculado em função do número de fêmeas e cistos encontrados nas diferenciadoras e cultivares testados em relação ao padrão de suscetibilidade e multiplicado por 100. Os testes em plantas diferenciadoras com isolados monocísticos revelou a presença das raças 2, 5 e 6 para Porto Mendes, 3 e 6 para Cruz Alta e 5 e 6 para Novo Horizonte. Populações de campo revelaram a presença da raça 6 para Porto Mendes e da raça 3 para Cruz Alta. A maioria dos cultivares comerciais testados foram resistentes à H. glycines raça 3, enquanto que a cv. Liderança e a CD 217 apresentaram-se suscetíveis. Os resultados mostraram que a identificação de raças a partir de isolados monocísticos de H. glycines auxilia na identificação da variabilidade genética presente em populações de campo, o que não é possível mediante a determinação de raças com base em populações policísticas obtidas a campo

Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2014-10-14T14:34:16Z No. of bitstreams: 2 Tese - Fernando Godinho de Araujo - Agronomia.pdf: 1300550 bytes, checksum: 2fcb22f0659c2649971101a837569973 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2014-10-17T21:38:21Z (GMT) No. of bitstreams: 2 Tese - Fernando Godinho de Araujo - Agronomia.pdf: 1300550 bytes, checksum: 2fcb22f0659c2649971101a837569973 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-10-17T21:38:21Z (GMT). No. of bitstreams: 2 Tese - Fernando Godinho de Araujo - Agronomia.pdf: 1300550 bytes, checksum: 2fcb22f0659c2649971101a837569973 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-07-04 / Soybean is the most important oilseed crop grown in the world and Brazil is the second largest producer. Many pest problems can affect soybean, including the soybean cyst nematode, Heterodera glycines. The search for efficient management alternatives of this nematode and understanding of their biology have been largely studied, but still lacking information. Experiments were conducted under greenhouse conditions and naturally infested field aiming to better understand the behavior of H. glycines and to propose management alternatives. The first study had the purpose to evaluate the penetration and life cycle of H. glycines, race 3 (HG Type 0 -) in soybean cultivars resistant (BRSGO 8860RR) and susceptible (BRS Valiosa RR) under greenhouse conditions. Evaluations in stained roots were made at 2, 4, 6, 9, 12, 15, 18, 21, 24 and 30 days after inoculation (DAI). The penetration of H glycines occurred throughout the period of evaluation in both cultivars. The H. glycines life cycle was completed in 15 days, both in the susceptible and resistant cultivars. Resistant cultivar had the peak period of formation of J3, J4 and females delayed in comparison with the susceptible cultivar. The second study aimed to evaluate effectiveness of the resistance to H. glycines under high inoculum concentration, and the effect of increasing inoculum rates on the penetration of juveniles and H. glycines survival. Two experiments were conducted using three soybean cultivars (BRS Valiosa RR, susceptible to H. glycines; BRSGO Chapadoes and BRSGO 8860RR, both resistant to H. glycines) under four inoculum concentrations (1.000, 2.500, 5.000 and 10.000 eggs and J2 per plant). The increase in the H. glycines inoculum concentration increased the final nematode population in the susceptible cultivar. The cultivar resistance was not affected by high inoculum concentration. The root penetration of J2 increased as the inoculum concentration increased regardless the cultivar. The survival rate was higher in the susceptible cultivar decreasing with increasing of inoculum concentration. The third study evaluated the effect of seed treatment two soybean cultivars (resistant BRSGO 8860RR and susceptible BRS Valiosa RR). Two experiments were conducted, one in a naturally infested field and other under greenhouse conditions. The seed treatments did not affect the stand and the plant height of the resistant soybean cultivar. There was no effect of seed treatments on the nematode population in the field experiment. Under greenhouse, seeds treated with abamectin (50 and 75 mL a.i. 100 kg seed-1) + thiamethoxam (70 mL a.i.), imidacloprid + thiodicarb (105+315 mL a.i.) and thiodicarb + imidacloprid with carbendazim + thiram (75+225 e 30+70 mL a.i.) reduced the number of females per gram of roots on the susceptible cultivar. Seed treatment with imidacloprid + thiodicarb (75+225 mL a.i.) also reduced the number of eggs per female on the resistant cultivar BRSGO 8860RR. / A soja é a mais importante oleaginosa cultivada no mundo sendo o Brasil o segundo maior produtor. Diversos problemas fitossanitários afetam a cultura da soja, dentre eles o nematoide de cisto da soja, Heterodera glycines. A busca por alternativas de manejo eficiente desse nematoide e a compreensão de sua biologia têm sido temas muito difundidos, mas ainda carente de estudos. Dessa forma, foram conduzidos experimentos em condições de casa de vegetação e campo naturalmente infestado visando conhecer melhor o comportamento de H. glycines e propor alternativas para seu manejo. O primeiro estudo teve como objetivo avaliar a penetração e a duração do ciclo de H. glycines, raça 3 (HG tipo 0-), em cultivares de soja resistente (BRSGO 8860RR) e suscetível (BRS Valiosa RR) em condições controladas de casa de vegetação. Foram realizadas avaliações de coloração de raiz aos 2, 4, 6, 9, 12, 15, 18, 21, 24 e 30 dias após a inoculação (DAI). A penetração do H. glycines ocorreu durante todo o período de avaliação nas duas cultivares. O ciclo do H. glycines se completou em 15 dias, tanto na cultivar suscetível como na cultivar resistente. Na cultivar resistente o período de pico de formação de J3, J4 e fêmeas foi atrasado em relação a cultivar suscetível. O segundo estudo teve como objetivo avaliar se a resistência ao H. glycines é eficiente na redução do desenvolvimento do nematoide, mesmo sob elevada concentração de inóculo, bem como se esse aumento na concentração de inóculo e a resistência afetam a penetração de juvenis e a taxa de sobrevivência do H. glycines. Foram conduzidos dois ensaios utilizando-se três cultivares de soja, uma suscetível (BRS Valiosa RR) e duas resistentes (BRSGO Chapadões e BRSGO 8860RR), submetidas a quatro concentrações de inóculo (1.000, 2.500, 5.000 e 10.000 ovos e J2 por vaso). O aumento na concentração inicial de inóculo de H. glycines resultou no aumento da população final do nematoide na cultivar suscetível. A reação de resistência das cultivares não foi afetada por altas concentrações de inóculo e a penetração de J2 nas raízes aumentou com o aumento da concentração de inóculo independentemente da cultivar. A taxa de sobrevivência do nematoide foi maior na cultivar suscetível diminuindo com o aumento da concentração do inóculo, não sendo influenciada pela concentração de inóculo para cultivares resistentes. O terceiro estudo teve como objetivo avaliar o efeito do tratamento de sementes de duas cultivares de soja resistente (BRSGO 8860RR) e suscetível (BRS Valiosa RR), com produtos a base de abamectina e tiodicarbe no manejo de H. glycines. Foram conduzidos dois experimentos, sendo um em campo naturalmente infestado e outro em condições de casa de vegetação. Os tratamentos de sementes não afetaram o estande e a altura das plantas de soja. Não foi observado efeito dos tratamentos de sementes sobre o nematoide no experimento conduzido em campo. Em condições de casa de vegetação os tratamentos de sementes com produtos a base de abamectina, nas dosagens de 50 e 75 mL i.a. 100 kg sementes-1 acrescido de tiametoxam (70 mL i.a.) e os tratamentos imidacloprido + tiodicarbe (105+315 mL i.a.) e imidacloprido + tiodicarbe e carbendazim + tiram (75+225 e 30+70 mL i.a.) reduziram o número de fêmeas por grama de raiz na cultivar suscetível. O tratamento de sementes com imidacloprido + tiodicarbe (75+225 mL i.a.) também reduziu o número de ovos por fêmea na cultivar resistente, BRSGO 8860RR.

Made available in DSpace on 2014-07-29T14:52:07Z (GMT). No. of bitstreams: 1 Agnelo Jose Vitti.pdf: 640233 bytes, checksum: ecfaee175905565f39d3d5a461af0b91 (MD5) Previous issue date: 2009-06-06 / Despite its presence in many soybean production regions in Brazil and its high damage potential, soybean cyst nematode (Heterodera glycines), has been efficiently controlled by crop rotation and the use of soybean cultivars resistant to the main nematode races in the country. However, the continuous use of those cultivars can change the nematode populations leading to resistance break down. Few resistance genes availability, associated to the difficulties of inserting multiple races resitance to high productivity cultivares without yield drag tends to worsen the long-term perspectives of nematode anagement. Thus, auxiliary control measures, aiming at minimizing the selection pressure effects, exercised by the resistant varieties on nematode of detection frequency in number of areas and populational density of root-lesion nematode (Pratylenchus brachyurus), has been related in soybean main growing regions in Brazil. Although its potential of damage to soybean crop is still controversial, its poliphagous behavior leaves few options for crop rotation with soybean, and can increase their populations to the economic damage levels in the near future. With the objective of testing the nematicide effect of abamectin as seed treatment, and its interaction with other products on population management of these nematode species, it was carried out greenhouse and field trials, testing three doses of abamectin with or without thiabendazol or acibenzolar-S-methyl addition, for H. glycines and P. brachyurus control, respectively. Although not showing effect on soybean yield, in field tests, the dose of 50 g of abamectin.ha-¹ reduced significantly the number of eggs produced by H. glycines at 30 days after planting, the number of females in the plants roots at 45 days, with reduction in the number of females and cysts recovered from the soil at root zone at 60 days, in the susceptible cultivar. Thiabendazole addition reduced the number of eggs per female at 60 days, but not in other assessments carried out 30 and 45 days after planting. However, the same was not observed for the soybean cultivar resistant to race 14. In all assessment date, that cultivar produced a number of females significantly smaller in the roots and soil and higher yield than the susceptible cultivar. In pot tests under greenhouse conditions, it was observed significant differences between cultivars, besides the treatments made in the seeds, in assessments carried out 30 days after planting. It was not observed significant differences to seed treatments with abamectin or acibenzolar-S-methyl on P. brachyurus populations recovered from soybean roots, neither among the cultivars tested in field nor in greenhouse conditions. It was concluded that seed treatment with abamectin at 50 g. ha-¹ as seed treatment is effective at reducing the H. glycines population and can be used as one more option against the directional selection imposed by the use of soybean resistant cultivars. / O nematóide de cisto da soja (Heterodera glycines), apesar de sua presença em solos das principais regiões produtoras de soja do Brasil e de seu potencial de dano, tem sido eficientemente controlado com a rotação de culturas e utilização de cultivares resistentes às principais raças presentes no país. Entretanto, a utilização contínua destas cultivares, pode levar a mudanças populacionais que venham quebrar estas resistências. A pouca disponibilidade de gens de resistência, vinculado à dificuldade de inserção de resistência a múltiplas raças às cultivares elite de soja, sem decréscimo de produtividade, tende a agravar as perspectivas a longo prazo. Assim, medidas de controle auxiliares, visando minimizar os efeitos da pressão de seleção exercida pelas cultivares resistentes são recomendadas para o manejo populacional de H. glycines. O aumento das detecções do nematóide das lesões radiculares (Pratylenchus brachyurus), tanto em número de áreas, como na densidade populacional por área, tem sido relatado nas principais regiões de cultivo de soja no Brasil. Apesar do seu potencial de dano à cultura ainda ser controverso, seu comportamento polífago, deixa poucas opções para rotação de cultivos com a soja, podendo elevar as suas populações a níveis de dano econômico em futuro próximo. Visando testar o efeito do nematicida abamectina, via tratamento de sementes, e sua interação com outros produtos, no manejo populacional destes nematóides, foram conduzidos experimentos de campo e casa de vegetação, sendo testadas três doses de abamectina com ou sem a adição de tiabendazol ou acibenzolar-S-metil, para o controle de H. glycines, ou P. brachyurus, respectivamente. Apesar de não ter demonstrado efeito sobre a produtividade da cultura nos testes de campo a dose de 50 g de abamectina.ha-¹ reduziu significativamente o número de ovos produzidos por fêmea de H. glycines aos 30 dias após a semeadura (DAS), o número de fêmeas nas raízes das plantas aos 45 DAS, com consequente redução no número de cistos recuperados no solo aos 60 DAS, na cultivar suscetível à raça 14, BRSGO Luziânia. A adição de tiabendazol, reduziu o número de ovos por fêmea aos 60 DAS, mas não nas demais avaliações. Entretanto, estas diferenças não foram observadas para a cultivar resistente, BRSGO Ipameri. Em todas as avaliações, esta cultivar apresentou número significativamente menor de fêmeas nas raízes e no solo, e produtividade de grãos superior ao observado em BRSGO Luziânia. Em testes em vasos, conduzidos em casa de vegetação, houve diferença significativa entre cultivares, mas não entre os tratamentos com fungicidas efetuados nas sementes, nas avaliações conduzidas ao 30 DAS. Não foram observadas diferenças significativas dos tratamentos com abamectina ou acibenzolar-S-metil nas populações de P. brachyurus, recuperados das raízes de plantas de soja, nem entre as cultivares testadas em campo ou casa de vegetação. Frente aos resultados obtidos conclui-se que o tratamento com abamectina a 50 g.ha-¹, via tratamento de sementes, é efetivo na redução populacional de H. glycines e pode ser utilizado como mais uma ferramenta contra a seleção direcional imposta pelo uso de cultivares de soja resistentes.

Master of Science / Department of Agronomy / William T. Schapaugh Jr / Fusarium virguliforme, the soilborne fungus which causes sudden death syndrome (SDS) of soybean, and Heterodera glycines Ichinohe, soybean cyst nematode (SCN), are two economically important pathogens in the Midwest. The pathogens are often found together in soybean (Glycine max (L.) Merr.) fields. This study was conducted to determine the effect of soybean genotype, F. virguliforme populations, and H. glycines populations have upon yield and to examine the interaction between the two pathogens. In 2008 and 2009, four genotypes with different levels of resistance to SDS and H. glycines were planted at seven environments. F. virguliforme and H. glycines soil populations were quantified at planting, midseason, and harvest. At the end of the growing season, area under the disease progress curves of SDS, F. virguliforme root populations, and H. glycines reproductive indices were determined and plots harvested for seed yield. Soil populations of F. virguliforme and H. glycines at planting, midseason, and harvest varied across environments. Within environments, generally, they were not significantly different. Seed yield varied within and across environments. As disease pressure increased, the performance of resistant genotypes increased compared to susceptible genotypes. Genotypes resistant to SDS yielded higher than susceptible genotypes. There were negative correlations between yield and disease rating and F. virguliforme root populations. F. virguliforme soil populations and H. glycines populations at planting were positively correlated. It is important to manage both SDS and H. glycines in fields with a history of the two diseases. This can be achieved through genetic resistance. Information in this study will improve decisions regarding genotype selection to minimize losses to SDS and H. glycines.

Master of Science / Department of Plant Pathology / Harold Trick / The object of this study was to find a target sequence for the known Heterodera glycines Y25 sequence that contained no homology to any known Glycine max genes so homologous endogenous soybean gene expression will not be effected. In addition, in attempt to improve the accuracy of SCN bioassays performed in greenhouse settings, applications of a variety of insecticides with differing modes of action were applied to screen for any detectable effects on the SCN populations. The full-length sequence of the Y25 gene was blasted against the G. max genome using the National Center for Biotechnology Information blast database and a portion of the gene was found to contained no homology to the G. max genome. A rapid hairy root assay was used to screen for resistance to H. glycines. The sequence was transformed into Agrobacterium rhizogenes using a modified heat shock method. The transformed A. rhizogenes were used to inoculate soybean seedlings. The inoculated seedlings developed hairy roots expressing the target sequence. Upon finishing the hairy root assay it was discovered that there were no detectable differences across any of the treatments or the controls. It was neither proved nor disproved that the new target sequence containing no homology to the G. max genome was as effective as the original target. Further investigation will need to be conducted to show the level of control for the new target sequence.

Master of Science / Department of Statistics / Perla Reyes / Heterodera glycines, or the soybean cyst nematode (SCN), is a parasite that targets and damages the roots of soybean plants. It is the most yield-limiting pathogen of soybean in the U.S. and the reliable detection and accurate estimation of population densities is crucial to research and management of this pathogen. A study was performed to understand the effects of crop rotation on the prevalence of SCN. Standard sampling procedures in the plant pathology community dictate taking soil samples from potentially infected fields, processing them and counting the number of eggs in one 1 mL subsample via microscope. Suspecting the traditional procedure may lead to invalid results, false negatives in particular, the researcher created and implemented a sampling procedure based on his knowledge of sampling methods and constraints of sampling in the field. Using the data collected, we will discuss the strengths and limitations of the procedure in estimating the population density of SCN in the field. In addition, a simulation study informed by the data will be conducted to determine a sampling strategy that will yield accurate results while still considering the conditions in the field. Knowledge on how the different stages of the sampling procedure for SCN affect the accurate detection of the pathogen would extend to experimental designs and sampling methodologies for other soil dwelling organisms.

Soybean (Glycine max) yield is significantly affected by soybean cyst nematode (SCN), Heterodera glycines, and causes an annual loss of billions of US dollars. In this study, Glycine max xyloglucan endotransglycosylase/hydrolase gene (Gm-XTH52) was transformed into a nematode susceptible G. max [Williams 82/PI 518671] variety of soybean to test whether the protein expression has a role in resistance to H. glycines, and possible chemical changes the expression may cause in the plant composition. Expression level of the Gm-XTH52 gene was three times higher than in controls. Significant reduction in the number of SCN cysts suggested suppression of H. glycines parasitism upon transformation. While total sugar amounts did not significantly differ between the transformed and control plants, xyloglucan amounts of loosely bound sugars of genetically mosaic plants were significantly lower in comparison to controls. Control plants showed lower molecular weight sugars than the transformed plants not subjected to H. glycines infection.

No description available.

No description available.

Le nématode à kyste du soya (NKS), Heterodera glycines, est la principale cause de pertes économiques chez le soya aux États-Unis. Au Canada, on le retrouve en Ontario depuis 1988 et il continue à gagner du terrain chaque année. Il a été répertorié pour la première fois au Québec en 2013, et les producteurs de soya québécois ont déjà commencé à déployer des outils pour sa répression. La méthode de lutte la plus utilisée contre cet organisme est l’utilisation de gènes de résistance quantitative combiné à la rotation des cultures. Par contre, l’organisme causant le plus de dommages chez le soya à l’heure actuelle au Québec est la pourriture phytophthoréenne, causée par l’oomycète, Phytophthora sojae. Cette maladie racinaire peut, elle aussi, être réprimée grâce à des cultivars génétiquement résistants (résistance qualitative à gènes Rps). Sachant que le NKS se retrouve déjà dans certaines régions du Québec où sévit également P. sojae, il devient urgent de déterminer si les cultivars de soya présentement utilisés exprimeront une résistance satisfaisante contre ces agents pathogènes majeurs. Dans ce contexte, l’objectif principal de ce projet était d’évaluer l’interaction entre ces deux agents pathogènes du soya en fonction de la résistance (qualitative à gènes Rps / résistance quantitative au NKS) des cultivars utilisés. L’étude, réalisée en système hydroponique, a permis de démontrer qu’en présence d’un cultivar sensible aux deux organismes, P. sojae a un impact négatif sur la capacité du NKS à produire des kystes. Cela suggère que P. sojae pourrait influencer le développement du NKS. La présence du nématode, quant à elle, n’a pas influencé l’efficacité de la résistance qualitative à gènes Rps contre P. sojae. En conséquence, les cultivars résistants aux deux agents pathogènes représentent une bonne option pour prévenir et lutter contre ces affections. / The soybean cyst nematode (SCN), Heterodera glycines, is the leading cause of economic losses in soybean in the United States. In Canada, it has been found in Ontario in 1988 and continues to spread every year. It was identified for the first time in Quebec in 2013 and soybean growers have already begun to deploy management tools. The most commonly used control method against SCN is the use of quantitative resistance genes and crop rotation. However, the most damaging organism in soybean in Quebec currently is Phytophthora root rot, caused by Phytophthora sojae. This root disease can also be controlled by genetically resistant cultivars (qualitative resistance with Rps genes). Because SCN is now present in regions struggling with P. sojae, it is important to determine if the cultivars will express sufficient resistance against these two major pathogens. In this context, the main objective of this project was to evaluate the interaction between these two organisms on soybean, according to the resistance (qualitative Rps genes/ or quantitative resistance to SCN) of the cultivars used. This study, in a hydroponic system, demonstrated that P. sojae has a negative impact on SCN capacity to produce cysts produced. This suggests that P. sojae might influence SCN development. On the other hand, resistant cultivars were not affected by the presence of both pathogens and the presence of the nematode did not influence the efficacy of qualitative Rps resistance gene against P. sojae. As a result, cultivars resistant to both pathogens are a good option for preventing and controlling these diseases.