Efeito de Fusarium graminearum schwabe na qualidade fisiológica de sementes de soja e cariopse de trigo na Argentina

F. graminearum is the main causal agent of Head blight in cereals in Argentina. This is a disease that develops during the host floral state. When the reproductive structures in the host are invaded, grains may be shriveled and reduced in weight, causing a decrease in yield. Physiological diagnostic techniques on seeds detect the damages produced by this fungus could be used to take decisions related to the quality of seed lots. The objective of this study was to evaluate the possible physiological damage caused by F. graminearum isolates in soybean seeds and wheat caryopsis. Seeds and caryopsis were obtained from plants exposed to fungal infection and were evaluated under two situations: artificial inoculations under greenhouse conditions and natural infection from fields of Santa Fe Province (33°43'22''S; 62°14'46''W). Seed weight, topographical tetrazolium test, standard germination test, electrical conductivity test and X-ray test were performed in soybean seeds and wheat caryopsis from each treatment. Differential behaviors of F. graminearum strains in susceptible soybean and wheat cultivars under greenhouse conditions revealed specific interactions among soybean and wheat genotypes with this fungus. F. graminearum infection in susceptible cultivars under greenhouse conditions produced a significant decrease in the physiological quality of soybean seed and wheat caryopsis. These behaviors were not detected under field conditions in the evaluated locations. All seed quality tests used in this experiment were useful to show differences in infection in soybean and wheat independently of F. graminearum infection.F. graminearum é o principal agente causal da giberela em cereais na Argentina. É uma doença que se desenvolve durante o estado floral de hospedeiro. Quando as estruturas reprodutivas no hospedeiro são colonizadas, os grãos podem ser enrugados e mostrar reduções de peso, causando diminuição no rendimento. Técnicas de diagnóstico fisiológico em sementes podem detectar os danos produzidos por este fungo e pode ser usada para tomar decisões sobre a qualidade dos lotes. O objetivo deste estudo foi avaliar possíveis danos fisiológicos causados por F. graminearum em sementes de soja e cariopses de trigo. As sementes e cariopses foram obtidas a partir de plantas expostas a infecção fúngica e foram avaliadas em duas situações: inoculação artificial em casa de vegetação e infecção natural em campos da Província de Santa Fé (33°43'22''S; 62°14'46''O). Determinou-se o peso da semente e realizou-se os testes de tetrazólio, germinação, condutividade elétrica e raios-X em sementes de soja e cariopses de trigo para cada tratamento. Comportamentos diferenciais de cepas de F. graminearum em cultivares suscetíveis de soja e trigo sob condições de casa de vegetação revelou interações específicas entre cultivares de soja e trigo com este fungo. As interações produziram uma redução significativa na qualidade fisiológica de sementes de soja e cariopses trigo. Esses comportamentos não foram detectados em condições de campo nos locais avaliados. Todos os testes de qualidade das sementes utilizados neste experimento foram úteis para mostrar as diferenças de infecção em sementes de soja e cariopses de trigo, independentemente da infecção por F. graminearum.Fil: Peruzzo, Alejandra María. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pioli, Rosanna Nora. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Salinas, A.. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; Argentin

Mycotoxins in flours derived from wheat and soybean detected by the Elisa test

El objetivo de este trabajo fue evaluar la presencia de micotoxinas en las harinas derivadas de trigo y soja expuestos a la infección de Fusarium graminearum y detectadas por prueba de Elisa. La contaminación fue evaluada durante 2010 y 2012, en condiciones de invernadero, a través de inoculaciones artificiales, y en lotes de producción en campo, expuestos a infecciones naturales. Se utilizaron 26 muestras de harinas derivadas de cariopsis de trigo y semillas de soja. La detección de micotoxinas deoxinivalenol y zearalenona se realizó por kit de Elisa. En harinas de trigo de diversos ambientes, se detectaron ambas micotoxinas – deoxinivalenol y zearalenona –, mientras que en harinas de soja sólo se detectó zearalenona. Las concentraciones de esas micotoxinas observadas en las harinas no son admisibles para el consumo humano y animal. El kit de Elisa constituyó una herramienta biotecnológica efectiva para la detección de la contaminación predominante de zearalenona, producida por F. graminearum, en harinas de trigo y soja de diferentes ambientes semicontrolados y naturales.The objective of this work was to evaluate the presence of mycotoxins in flours derived from wheat caryopses and soybean seed exposed to Fusarium graminearum infection and detected by the Elisa test. Contamination was evaluated during 2010 and 2012, in greenhouse conditions, by artificial inoculation, and on field‑production batches exposed to natural infections. Twenty‑six samples of flours derived from wheat caryopses and soybean seeds were used. Detection of the mycotoxins deoxynivalenol and zearalenone was performed by an Elisa kit. In wheat flour of different environments both mycotoxins – deoxynivalenol and zearalenone – were detected, while in soybean flour only zearalenone was detected. Mycotoxins concentrations observed in these flours are inappropriate for human and animal consumption. Elisa kit constituted an effective biotechnological tool for the detection of prevailing contamination by zearalenone, caused by F. graminearum in wheat and soybean flours of different, semicontrolled and natural environments.The objective of this work was to evaluate the presence of mycotoxins in flours derived from wheat caryopses and soybean seed exposed to Fusarium graminearum infection and detected by the Elisa test. Contamination was evaluated during 2010 and 2012, in greenhouse conditions, by artificial inoculation, and on field‑production batches exposed to natural infections. Twenty‑six samples of flours derived from wheat caryopses and soybean seeds were used. Detection of the mycotoxins deoxynivalenol and zearalenone was performed by an Elisa kit. In wheat flour of different environments both mycotoxins – deoxynivalenol and zearalenone – were detected, while in soybean flour only zearalenone was detected. Mycotoxins concentrations observed in these flours are inappropriate for human and animal consumption. Elisa kit constituted an effective biotechnological tool for the detection of prevailing contamination by zearalenone, caused by F. graminearum in wheat and soybean flours of different, semicontrolled and natural environments

Study of plant origin compounds with potential antifungal action against pathogens of cultivated plants

Los hongos patógenos generan enfermedades en distintos cultivos y afectan el rendimiento y producción de alimentos. El control mediante fitosanitarios puede implicar un riesgo para la salud humana y el ambiente. En este contexto la utilización de los metabolitos vegetales como potenciales bio-controles de patógenos son una alternativa sustentable. El objetivo de este estudio fue evaluar la acción antifúngica de seis compuestos de origen vegetal, daidzeína, genisteína, dos chalconas, vainillina e iso-vainillina, sobre el crecimiento in vitro de patógenos que actúan en cultivos de interés alimentario. Se evaluó la Concentración Inhibitoria Mínima (CIM) y la Concentración Fungicida Mínima (CFM) de cada compuesto químico mediante el método de microdilución en caldo frente a cinco géneros fúngicos: Alternaria sp., Cladosporium sp., Fusarium (F. graminearum, F. subglutinans, F. proliferatum, F. oxysporum), Phomopsis longicolla, y Rhizopus stolonifer. Los resultados indicaron que daidzeína, genisteína, iso-vainillina y CH1 no presentaron acción inhibitoria y/o fungicida en concentraciones menores a 250 µg mL-1. CH2 se caracterizó por inhibir a cuatro aislamientos pertenecientes a tres géneros en diferentes concentraciones y presentar actividad fungicida sobre dos de los mismos. La vainillina demostró ser efectiva para inhibir y/o eliminar la totalidad de los aislamientos (nueve) incluidos en los cinco géneros fúngicos evaluados con concentraciones menores a 250 µg mL-1. Se concluyó que los metabolitos de origen vegetal como la vainillina y CH2 presentaron capacidad antifúngica en diferente grado y especificidad sobre los aislamientos.Pathogenic fungi generate crop diseases, and affect yield and food production. The use of phytosanitary products to control fungal diseases can pose a risk to human health and the environment. In this context, the use of plant metabolites as potential bio-controls for pathogens turns out to be a sustainable alternative. The objective of this study was to evaluate the anti-fungal action of six compounds of plant origin: daidzein, genistein, two chalcones, vanillin and isovanillin, on the in vitro growth of pathogens. The Minimum Inhibitory Concentration (MIC) and the Minimum Fungicidal Concentration (CFM) of each chemical compound were evaluated by the broth micro-dilution method against five fungal genera: Alternaria sp., Cladosporium sp., Fusarium (F. graminearum, F. subglutinans, F. proliferatum, F. oxysporum), Phomopsis longicolla, and Rhizopus stolonifer. The results indicated that daidzein, genistein, iso-vanillin and CH1 did not show an inhibitory and / or fungicidal action at concentrations lower that 250 µg mL-1. CH2 was characterized by inhibiting four isolates belonging to three genera in different concentrations, and presenting fungicidal activity on two of them. Vanillin proved to be effective to inhibit and / or eliminate all of the isolates (nine) included in the five fungal genera evaluated at concentrations below 250 µg mL-1. It is concluded that metabolites of plant origin such as vanillin and CH2 presented antifungal capacity in different degrees and specificity on the isolates.Fil: Badaracco, Paula. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Departamento de Sistema de Producción Vegetal. Laboratorio Biodiversidad Vegetal y Microbiana Fitopatología; ArgentinaFil: Sortino, Maximiliano Andrés. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química Orgánica. Área Farmacognosia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; ArgentinaFil: Pioli, Rosanna Nora. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Departamento de Sistema de Producción Vegetal. Laboratorio Biodiversidad Vegetal y Microbiana Fitopatología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; Argentin

EFFECT OF Fusarium graminearum Schwabe ON PHYSIOLOGICAL QUALITY OF SOYBEAN SEEDS AND WHEAT CARYOPSIS IN ARGENTINA

F. graminearum is the main causal agent of Head blight in cereals in Argentina. This is a disease that develops during the host floral state. When the reproductive structures in the host are invaded, grains may be shriveled and reduced in weight, causing a decrease in yield. Physiological diagnostic techniques on seeds detect the damages produced by this fungus could be used to take decisions related to the quality of seed lots. The objective of this study was to evaluate the possible physiological damage caused by F. graminearum isolates in soybean seeds and wheat caryopsis. Seeds and caryopsis were obtained from plants exposed to fungal infection and were evaluated under two situations: artificial inoculations under greenhouse conditions and natural infection from fields of Santa Fe Province (33°43’22’’S; 62°14’46’’W). Seed weight, topographical tetrazolium test, standard germination test, electrical conductivity test and X-ray test were performed in soybean seeds and wheat caryopsis from each treatment. Differential behaviors of F. graminearum strains in susceptible soybean and wheat cultivars under greenhouse conditions revealed specific interactions among soybean and wheat genotypes with this fungus. F. graminearum infection in susceptible cultivars under greenhouse conditions produced a significant decrease in the physiological quality of soybean seed and wheat caryopsis. These behaviors were not detected under field conditions in the evaluated locations. All seed quality tests used in this experiment were useful to show differences in infection in soybean and wheat independently of F. graminearum infecti

Fungal abundance and distribution as influenced by clearing and land use in a vertic soil of Argentina

The influence of native vegetation clearing and different further soil managements on fungal propagule population diversity was studied in the present work. In each of the 3 years (1998, 1999, and 2000), soil samples were collected at the depth of 0-7.5 cm from sites under native vegetation (V0); naturalized prairie, cleared in 1982 (P16); conventional tillage, cleared in 1972 (T26); and direct drilling, cleared in 1958 (D40). Fungal population size and relative abundance of fungal genera were studied by plate counts and further identification of isolates on potato dextrose agar. The undisturbed site and the other sites with increasing time elapsed since native vegetation clearing and different management history showed a distinctive distribution of fungal genera. There were significant differences (p<0.05) among the sites in the abundance of fungal genera analyzed in all the 3 years. Principal component analysis based on relative fungal genus abundance differentiated the sites with 75% variance explained by the first and second components. Diversity and abundance of isolated fungal genera were increased as density of Penicillium spp. decreased, suggesting a competitive effect of this fungal genus. The largest diversity was found in the site under no-till management. The different distribution and relative abundance of the fungal genera studied seemed to be influenced strongly by the management and the presence of surface residue in the no-tilled site. © 2006 Springer-Verlag.Fil: Gomez, Elena del Valle. Universidad Nacional de Rosario; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; ArgentinaFil: Pioli, Rosanna Nora. Universidad Nacional de Rosario; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; ArgentinaFil: Conti, Marta Elvira. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Molecular mapping of the genomic region conferring resistance to soybean stem canker in Hutcheson soybean

Genetic resistance to soybean stem canker, caused by the fungus Diaporthe phaseolorum var. meridionalis (Dpm), is controlled by five major, dominant, nonallelic genes Rdm1 to Rdm5. A genomic region containing the Rdm4 and Rdm5 genes was first described in Hutcheson soybean, where they were found to confer specific resistance to Argentinean physiological races of Dpm. Here, we report the genetic mapping of Rdm4 and Rdm5 loci using two pheno- and genotypically characterized F2:3 populations derived from Hutcheson cultivar. The mapping populations were screened with amplified fragment length polymorphism (AFLP) markers using bulk segregant analysis, and with simple sequence repeat (SSR) markers. Linkage analysis indicated that the Rdm4 and Rdm5 resistance loci were located in a genomic region collinear with the molecular linkage group (MLG) A2 (chromosome 8) of the soybean genetic map. The linkage group contains two SSR markers, Sat_162 and Satt233, flanking the Rdm4 and Rdm5 loci. These SSR will be useful to increase the efficiency of selection in breeding programs aimed to incorporate Rdm4 and Rdm5 genes into soybean elite germplasm.Fil: Chiesa, Maria Amalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Departamento de Biologia. Cátedra de Fisiología Vegetal; ArgentinaFil: Cambursano, Mariana Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Departamento de Biologia. Cátedra de Fisiología Vegetal; ArgentinaFil: Pioli, Rosanna Nora. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Departamento de Sistema de Producción Vegetal. Laboratorio Biodiversidad Vegetal y Microbiana Fitopatología; ArgentinaFil: Morandi, Eligio Natalio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Departamento de Biologia. Cátedra de Fisiología Vegetal; Argentin

Differential expression of distinct soybean resistance genes interacting with Argentinean isolates of Diaporthe phaseolorum var. meridionalis

Soybean Stem Canker (SSC), caused by Diaporthe phaseolorum var. meridionalis (Dpm), is an important disease of soybean in Argentina. There are five known dominant genes that confer resistance to SSC, Rdm1 to Rdm5. Particularly, Rdm2 was identified in cv. Tracy-M and then it was stabilized in the breeding line T2. The Rdm4 gene was first identified in cv. Hutcheson. More recently it was found that this gene was linked to the Rdm5 gene, defining the Rdm4-5 resistance region in Hutcheson. The objective of this work was to analyze the behaviour of the dominant Rdm2, Rdm4 and Rdm5 genes interacting with the CE109 and CE112 local physiological races of Dpm, in different susceptible backgrounds (genotypes RA702 and J77-339). Rdm4 and Rdm5 segregated phenotypically as completely dominant genes in the specific interactions with the CE109 and CE112 isolates, respectively, in both susceptible backgrounds. Similarly, Rdm2 segregated as expected for a complete dominant gene in the specific interaction with the CE109 isolate, in both susceptible backgrounds. However, when interacting with the CE112 isolate, the Rdm2 gene did not segregate as expected for a completely dominant gene, neither in RA702 nor in J77-339 susceptible background. The distorted segregation of the Rdm2 gene was due to incomplete penetrance. To the best of our knowledge this is the first report documenting changes in the degree of penetrance of a soybean resistance gene (Rdm2) depending upon the physiological race of Dpm which interacts with and the genetic background in which the Rdm gene is being expressed.Fil: Chiesa, Maria Amalia. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pioli, Rosanna Nora. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; ArgentinaFil: Cambursano, Mariana Virginia. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Morandi, Eligio Natalio. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Identificação e herança do primeiro gene (Rdc1) de resistência ao cancro da haste da soja (Diaporthe phaseolorum var. caulivora)

Soybean stem canker (SSC) is caused by two varieties of the fungus Diaporthe phaseolorum: var. meridionalis (Dpm) and var. caulivora (Dpc). The objective was to identify and characterize the mode of inheritance of Rdc genes through a classical Mendelian analysis. Resistant (R) and susceptible (S) genotypes were used to make 288 RxS and 132 RxR crosses, including their reciprocals. Segregating F2 generations were obtained by self-fertilization of the respective F1. The incorporation of codominant molecular markers (Single Nucleotide Polymorphism, SNP) allowed the molecular validation of 48.75% of F1 heterozygous individuals. Parents (R and S), F1 individuals, and F2:3 families (Progeny Test, PT) from COD 1–258-2 population were inoculated with an isolate of Dpc (Dpc16), previously identified morphologically and molecularly. The assay showed 21 F2:3 families categorized as R, 42 segregated R and S, and 11 as S. Particularly, this F3 population showed 466 individuals R and 274 S. The chi-square goodness of fit test verified that phenotypic segregation for individual plants in F3 adjusted to a 5:3 ratio (R:S) and the PT results corresponded to the genotypic ratios (1RR: 2Rr: 1rr) of F2 individuals. Results allowed the identification of a major resistance gene of simple Mendelian inheritance to SSC that was named Rdc1. Also, independent segregation 9:3:3:1 was verified between this Rdc1 gene and the gene that regulates flower colour, a typical phenotypic marker in soybean. Based on literature review, this is the first report on resistance genes (Rdc) identified for SSC caused by Dpc.O cancro da haste da soja (CHS) é causado por duas variedades do fungo Diaporthe phaseolorum: var. meridionalis (Dpm) e var. caulivora (Dpc). O objetivo foi identificar e caracterizar o modo de herança dos genes Rdc por meio de uma análise Mendeliana clássica. Genótipos resistentes (R) e suscetíveis (S) foram usados para fazer 288 cruzamentos RxS e 132 RxR, incluindo seus recíprocos. As gerações F2 segregadas foram obtidas por autofecundação do respectivo F1 . A incorporação de marcadores moleculares codominantes (Single Nucleotide Polymorphism, SNP) permitiu a validação molecular de 48,75% dos indivíduos heterozigotos F1 . Pais (R e S), indivíduos F1 e famílias F2:3 (Teste de Progênie, TP) da população COD 1-258-2 foram inoculados com um isolado de Dpc (Dpc16), previamente identificado morfologicamente e molecularmente. O ensaio mostrou 21 famílias F2:3 categorizadas como R, 42 segregadas R e S e 11 como S. Particularmente, esta população F3 mostrou 466 indivíduos R e 274 S. O teste de qualidade de ajuste do qui-quadrado verificou que a segregação fenotípica para o indivíduo plantas em F3 ajustadas a uma proporção de 5:3 (R:S) e os resultados de TP corresponderam às razões genotípicas (1RR: 2Rr: 1rr) de indivíduos F2. Os resultados permitiram a identificação de um importante gene de resistência de herança simples de Mendel ao CHS, denominado Rdc1. Além disso, foi verificada segregação 9:3:3:1 independente entre este gene Rdc1 e o gene que regula a cor das flores, um marcador fenotípico típico da soja. Com base na revisão da literatura, este é o primeiro relato sobre genes de resistência (Rdc) identificados para CHS causada por Dpc.Fil: Peruzzo, Alejandra María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; ArgentinaFil: Pioli, Rosanna Nora. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; ArgentinaFil: Hernández, Facundo Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; ArgentinaFil: Ploper, Leonardo Daniel. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; ArgentinaFil: Pratta, Guillermo Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; Argentin

Identification and inheritance of an Rdc gene resistance to soybean stem canker (Diaporthe phaseolorum var. caulivora)

Soybean stem canker (SSC) is caused by two varieties of the fungus Diaporthe phaseolorum: var. meridionalis (Dpm) and var. caulivora (Dpc). The objective was to identify and characterize the mode of inheritance of Rdc genes through a classical Mendelian analysis. Resistant (R) and susceptible (S) genotypes were used to make 288 RxS and 132 RxR crosses, including their reciprocals. Segregating F2 generations were obtained by self-fertilization of the respective F1. The incorporation of codominant molecular markers (Single Nucleotide Polymorphism, SNP) allowed the molecular validation of 48.75% of F1 heterozygous individuals. Parents (R and S), F1 individuals, and F2:3 families (Progeny Test, PT) from COD 1–258-2 population were inoculated with an isolate of Dpc (Dpc16), previously identified morphologically and molecularly. The assay showed 21 F2:3 families categorized as R, 42 segregated R and S, and 11 as S. Particularly, this F3 population showed 466 individuals R and 274 S. The chi-square goodness of fit test verified that phenotypic segregation for individual plants in F3 adjusted to a 5:3 ratio (R:S) and the PT results corresponded to the genotypic ratios (1RR: 2Rr: 1rr) of F2 individuals. Results allowed the identification of a major resistance gene of simple Mendelian inheritance to SSC that was named Rdc1. Also, independent segregation 9:3:3:1 was verified between this Rdc1 gene and the gene that regulates flower colour, a typical phenotypic marker in soybean. Based on literature review, this is the first report on resistance genes (Rdc) identified for SSC caused by Dpc.Fil: Peruzzo, Alejandra María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; ArgentinaFil: Hernández, Facundo Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; ArgentinaFil: Pratta, Guillermo Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; ArgentinaFil: Ploper, Leonardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto de Tecnología Agroindustrial del Noroeste Argentino; ArgentinaFil: Pioli, Rosanna Nora. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; Argentin