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  1. Article: Uromyces appendiculatus in Honduras: Pathogen Diversity and Host Resistance Screening.

    Acevedo, Maricelis / Steadman, James R / Rosas, Juan C

    Plant disease

    2019  Volume 97, Issue 5, Page(s) 652–661

    Abstract: Bean rust, caused by the fungus Uromyces appendiculatus, is a major constraint for common bean production worldwide. Virulence of U. appendiculatus collected from wild and cultivated Phaseolus spp. was examined in 28 locations across Honduras. Host ... ...

    Abstract Bean rust, caused by the fungus Uromyces appendiculatus, is a major constraint for common bean production worldwide. Virulence of U. appendiculatus collected from wild and cultivated Phaseolus spp. was examined in 28 locations across Honduras. Host accessions representing wild and domesticated Phaseolus spp. collected at the same sampling locations were evaluated for resistance against U. appendiculatus. In total, 91 pathotypes were identified from 385 U. appendiculatus isolates according to their virulence on each of the 12 host differentials. No significant difference in pathogen total virulence, measured as the mean disease score, was found between locations. However, significant differences were found in pathotype virulence among isolates collected from different Phaseolus spp. within a location. Moreover, when locations were compared on the basis of pathotype occurrence and frequency, differences among locations were evident. No two locations had the same pathotype composition. The most common pathotype was virulent on 9 of the 12 differential lines. A high number of resistant accessions were identified in Phaseolus coccineus and P. lunatus. Although most wild P. vulgaris accessions were highly susceptible, rust resistance was observed in P. vulgaris landraces collected from farmer's fields. Thirty-two (52%) of the accessions screened showed intermediate to high levels of resistance and, of those, 16% were P. coccineus accessions. Our findings support the hypothesis that interaction of U. appendiculatus in host populations composed of diverse Phaseolus spp. and genotypes has favored highly diverse and virulent pathotypes, creating a center for virulence diversity of the pathogen in Honduras. The high percentage of intermediate and highly resistant accessions identified in the present study supports the strategy of collecting plants from the center of diversity of a pathogen or in locations with high incidence of disease and pathogen diversity to maximize the probability of identifying new sources of resistance.
    Language English
    Publishing date 2019-02-05
    Publishing country United States
    Document type Journal Article
    ZDB-ID 754182-x
    ISSN 0191-2917
    ISSN 0191-2917
    DOI 10.1094/PDIS-02-12-0169-RE
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Root and crown rot pathogens found on dry beans grown in Mozambique

    Fernandes, Suzanna / Godoy-Lutz, Graciela / Jochua, Celestina / Urrea, Carlos / Eskridge, Kent / Steadman, James R / Herr, Joshua R

    Tropical plant pathology. 2021 June, v. 46, no. 3

    2021  

    Abstract: Dry edible beans are a vital food source in Mozambique, East Africa—one that alleviates hunger and malnutrition and adds value to the economy. In recent years, root/crown rot (RCR) pathogens have emerged as limiting constraints in dry bean production. ... ...

    Abstract Dry edible beans are a vital food source in Mozambique, East Africa—one that alleviates hunger and malnutrition and adds value to the economy. In recent years, root/crown rot (RCR) pathogens have emerged as limiting constraints in dry bean production. Not much has been characterized concerning the causal agents of RCR in Mozambique. The purpose of this study was to identify the primary pathogen(s) associated with RCR dry bean samples collected at breeder nursery sites and farmer fields in Mozambique using molecular sequencing and culture-based methods. Sequencing revealed, not surprisingly, an increased diversity of fungal/oomycete operational taxonomic units when compared to culture-based methods oof diversity. Species of Fusarium, mainly F. oxysporum, were the dominant taxa detected in RCR dry beans through sequencing the ITS rDNA region and partial EF-1α gene. Collectively, 333 fungi and/or Oomycetes were isolated in culture during the 2014–2015 growing seasons and tested for pathogenicity on healthy bean seedlings. Fusarium species were identified by both morphological and molecular characters. At least 60% of the isolates inoculated on common bean were recognized as potentially pathogenic. From both isolation frequency and pathogenicity testing, F. oxysporum and related species play an important role in the bean RCR complex. We found similar results from dry beans grown in the two main bean-growing regions of Mozambique. These findings will allow breeders to screen for resistance to F. oxysporum in greenhouse grown bean plants as well as within field grown bean cultivars.
    Keywords Oomycetes ; crown rot ; cultivars ; dry beans ; farmers ; fungi ; genes ; greenhouses ; hunger ; malnutrition ; pathogenicity ; pathogens ; plant pathology ; tropical plants ; Mozambique
    Language English
    Dates of publication 2021-06
    Size p. 294-310.
    Publishing place Springer International Publishing
    Document type Article
    Note NAL-AP-2-clean
    ZDB-ID 2519866-X
    ISSN 1983-2052 ; 1982-5676
    ISSN (online) 1983-2052
    ISSN 1982-5676
    DOI 10.1007/s40858-021-00422-8
    Database NAL-Catalogue (AGRICOLA)

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  3. Article: Isolates of Uromyces appendiculatus with Specific Virulence to Landraces of Phaseolus vulgaris of Andean Origin.

    Sandlin, Craig M / Steadman, James R / Araya, Carlos M / Coyne, Dermot P

    Plant disease

    2019  Volume 83, Issue 2, Page(s) 108–113

    Abstract: Five isolates of the bean rust fungus Uromyces appendiculatus were shown to be specifically virulent on bean genotypes of Andean origin. This specificity was demonstrated by the virulence of five pairs of isolates on a differential set of 30 Phaseolus ... ...

    Abstract Five isolates of the bean rust fungus Uromyces appendiculatus were shown to be specifically virulent on bean genotypes of Andean origin. This specificity was demonstrated by the virulence of five pairs of isolates on a differential set of 30 Phaseolus vulgaris landraces. Each isolate pair was from a different country in the Americas and consisted of one Andean-specific isolate and one nonspecific isolate. Of the differential P. vulgaris landraces, 15 were of Middle American origin and 15 were of Andean origin. The Andean-specific rust isolates were highly virulent on Andean landraces but not on landraces of Middle American origin. Rust isolates with virulence to Middle American landraces were also generally virulent on Andean material; no truly Middle American-specific isolates were found. Random amplified polymorphic DNA (RAPD) analysis of the rust isolates also distinguished the two groups. Four of the Andean-specific rust isolates formed a distinct group compared to four of the nonspecific isolates. Two of the isolates, one from each of the two virulence groups, had intermediate RAPD banding patterns, suggesting that plasmagomy but not karyogamy occurred between isolates of the two groups.
    Language English
    Publishing date 2019-03-08
    Publishing country United States
    Document type Journal Article
    ZDB-ID 754182-x
    ISSN 0191-2917
    ISSN 0191-2917
    DOI 10.1094/PDIS.1999.83.2.108
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Variation in Sclerotinia sclerotiorum Bean Isolates from Multisite Resistance Screening Locations.

    Otto-Hanson, Lindsey / Steadman, James R / Higgins, Rebecca / Eskridge, Kent M

    Plant disease

    2019  Volume 95, Issue 11, Page(s) 1370–1377

    Abstract: There is no complete resistance to Sclerotinia sclerotiorum, cause of white mold in dry bean (Phaseolus vulgaris). Variable resistance expression is one problem in screening for improved white mold resistance. With no previous information in the ... ...

    Abstract There is no complete resistance to Sclerotinia sclerotiorum, cause of white mold in dry bean (Phaseolus vulgaris). Variable resistance expression is one problem in screening for improved white mold resistance. With no previous information in the literature, pathogen variation in multisite screening nurseries was evaluated as one cause of diverse resistance expression. In all, 10 isolates of S. sclerotiorum used in greenhouse screening and 146 isolates collected from nine white mold field screening nurseries in major bean production areas in the United States were compared using mycelial compatibility groupings (MCGs) and an aggressiveness test. These 10 greenhouse screening isolates formed six MCGs. Among 156 field and greenhouse isolates, 64 MCGs were identified and 36 of those were each composed of a single unique isolate. Significant differences in isolate aggressiveness were found between some isolates in different MCGs but the isolates within an MCG did not differ in aggressiveness. High isolate variation found within and between field locations could influence the disease phenotype of putative white mold resistant germplasm. We next compared genotype and phenotype of isolates from screening nurseries and those from producer fields. Variability found in and among screening locations did reflect variability found in the four producer fields sampled. White mold resistance screening can be improved by knowledge of isolate genotypic and phenotypic characteristics.
    Language English
    Publishing date 2019-02-07
    Publishing country United States
    Document type Journal Article
    ZDB-ID 754182-x
    ISSN 0191-2917
    ISSN 0191-2917
    DOI 10.1094/PDIS-11-10-0865
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: White mold

    Schwartz, Howard F. / Steadman, James R.

    2017  

    Abstract: White mold, caused by the fungus Sclerotinia (Whetzelinia) sclerotiorum, is distributed worldwide and has more than 300 hosts. It infects flowers, cotyledons, seeds, leaves or injured plant tissue. The disease can be controlled by crop rotation, flooding, ...

    Abstract White mold, caused by the fungus Sclerotinia (Whetzelinia) sclerotiorum, is distributed worldwide and has more than 300 hosts. It infects flowers, cotyledons, seeds, leaves or injured plant tissue. The disease can be controlled by crop rotation, flooding, reduced seeding rates, application of chemical products in the middle of the flowering period, modifying plant architecture and the use of resistant var. Many soil microorganisms are associated with sclerotia and may cause them to degrade or fan to germinate. The symptoms and damage caused by the disease are illustrated in color. (CIAT)

    El moho blanco causado por el hongo Sclerotinia (Whetzelinia) sclerotiorum se halla presente en todo el mundo y mas de 300 plantas son hospedantes del patogeno; infecta las flores, cotiledones, semillas, hojas o tejido herido. El control de la enfermedad se puede hacer por: rotacion de cultivos, inundacion del terreno, utilizacion de menor cantidad de semilla en la siembra, aplicacion de productos quimicos a mediados de la floracion, modificando la arquitectura de la planta y utilizando var resistentes; muchos microorganismos del suelo estan asociados con los esclerosios y pueden causar degradacion e impedir que estos germinen. Se ilustran en color los sintomas y danos causados por la enfermedad. (CIAT)
    Keywords phaseolus vulgaris ; whetzelinia sclerotiorum ; etiology ; symptomatology ; host range ; cotyledons ; seed ; leaves ; plant injuries ; biological control ; chemical control ; cultural control ; resistance ; cultivars ; cultivation ; flowering
    Language English
    Publishing date 2017-06-20T08:51:40Z
    Publisher International Center for Tropical Agriculture
    Publishing country fr
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: El moho blanco

    Schwartz, Howard F. / Steadman, James R.

    2017  

    Abstract: White mold, caused by the fungus Sclerotinia (Whetzelinia) sclerotiorum, is distributed worldwide and has more than 300 hosts. It infects flowers, cotyledons, seeds, leaves or injured plant tissue. The disease can be controlled by crop rotation, flooding, ...

    Abstract White mold, caused by the fungus Sclerotinia (Whetzelinia) sclerotiorum, is distributed worldwide and has more than 300 hosts. It infects flowers, cotyledons, seeds, leaves or injured plant tissue. The disease can be controlled by crop rotation, flooding, reduced seeding rates, application of chemical products in the middle of the flowering period, modifying plant architecture and the use of resistant var. Many soil microorganisms are associated with sclerotia and may cause them to degrade or fan to germinate. The symptoms and damage caused by the disease are illustrated in color. (CIAT)

    El moho blanco causado por el hongo Sclerotinia (Whetzelinia) sclerotiorum se halla presente en todo el mundo y mas de 300 plantas son hospedantes del patogeno; infecta las flores, cotiledones, semillas, hojas o tejido herido. El control de la enfermedad se puede hacer por: rotacion de cultivos, inundacion del terreno, utilizacion de menor cantidad de semilla en la siembra, aplicacion de productos quimicos a mediados de la floracion, modificando la arquitectura de la planta y utilizando var resistentes; muchos microorganismos del suelo estan asociados con los esclerosios y pueden causar degradacion e impedir que estos germinen. Se ilustran en color los sintomas y danos causados por la enfermedad. (CIAT)
    Keywords phaseolus vulgaris ; whetzelinia sclerotiorum ; etiology ; symptomatology ; host range ; cotyledons ; seed ; leaves ; plant injuries ; biological control ; chemical control ; cultural control ; resistance ; cultivars ; cultivation ; flowering
    Language Spanish
    Publishing date 2017-06-20T08:50:59Z
    Publisher International Center for Tropical Agriculture
    Publishing country fr
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article ; Online: White mold

    Schwartz, Howard F. / Steadman, James R.

    2017  

    Abstract: White mold, caused by the fungus Sclerotinia (Whetzelinia) sclerotiorum, is distributed worldwide and has more than 300 hosts. It infects flowers, cotyledons, seeds, leaves, or injured plant tissue. The disease can be controlled by crop rotation, ... ...

    Abstract White mold, caused by the fungus Sclerotinia (Whetzelinia) sclerotiorum, is distributed worldwide and has more than 300 hosts. It infects flowers, cotyledons, seeds, leaves, or injured plant tissue. The disease can be controlled by crop rotation, flooding, reduced seeding rates, fewer irrigations, and destruction of bean- cull screenings containing sclerotia. Other control measures include chemical products in the middle of the flowering period, modifying plant architecture, and using resistant var. Many soil microorganisms are associated with sclerotia and may cause them to degrade or fail to germinate. The symptoms and damage caused by the disease are illustrated in color. (CIAT)

    El moho blanco causado por el hongo Sclerotinia (Whetzelinia) sclerotiorum se halla presente en todo el mundo, con mas de 300 plantas hospedantes del patogeno; infecta las flores, cotiledones, semillas, hojas o tejido lesionado. El control de la enfermedad se puede hacer por rotacion de cultivos, inundacion del terreno, menos riego y destruccion de residuos con esclerocios y utilizacion de menor cantidad de semilla en la siembra. Otras medidas de control incluyen la aplicacion de productos quimicos a mediados de la floracion, la modificacion de la arquitectura de la planta y la utilizacion de var. resistentes. Muchos microorganismos del suelo se asocian con los esclerocios y pueden causar degradacion e impedir que estos germinen. Se ilustran a color los sintomas y danos causados por la enfermedad. (CIAT)
    Keywords phaseolus vulgaris ; whetzelinia sclerotiorum ; etiology ; symptomatology ; host range ; plant injuries ; biological control ; chemical control ; cultural control ; resistance ; cultivars ; cultivation ; flowering ; epidemiology ; crop losses ; developmental stages ; diseases and pathogens ; mycoses ; pests ; etiologia ; sintomatologia ; rango de hospedantes ; danos a la planta ; control biologico ; control químico ; control cultural ; resistencia ; variedades ; cultivo ; floración ; epidemiologia
    Language English
    Publishing date 2017-06-20T08:59:31Z
    Publisher International Center for Tropical Agriculture
    Publishing country fr
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  8. Article ; Online: Rust and halo blight epidemics, and the first report of bacterial brown spot in western Nebraska and eastern Colorado

    Steadman, James R. / Schwartz, Howard F.

    2017  

    Abstract: High incidence of Uromyces phaseoli and Pseudomonas syringae pv. phaseolicola was reported in Pinto and Great Northern bean fields in SW Nebraska and NE Colorado (USA) in 1981. Pinto beans showed other symptoms that, after isolation and tests, were found ...

    Abstract High incidence of Uromyces phaseoli and Pseudomonas syringae pv. phaseolicola was reported in Pinto and Great Northern bean fields in SW Nebraska and NE Colorado (USA) in 1981. Pinto beans showed other symptoms that, after isolation and tests, were found to be caused by P. syringae pv. syringae. (CIAT)
    Keywords phaseolus vulgaris ; uromyces phaseoli ; pseudomonas syringae pv. syringae ; pseudomonas syringae ; symptomatology ; usa ; mycoses ; diseases and pathogens ; pests ; bacterial diseases ; north america
    Language English
    Publishing date 2017-10-12T08:03:15Z
    Publishing country fr
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  9. Article: Registration of Great Northern Common Bean Cultivar ‘Panhandle Pride’ with Enhanced Disease Resistance to Bean Rust and Common Bacterial Blight

    Urrea, Carlos A / Hurtado-Gonzales, Oscar P / Pastor-Corrales, Marcial A / Steadman, James R

    Journal of plant registrations. 2019 Sept., v. 13, no. 3

    2019  

    Abstract: Panhandle Pride’ (Reg. no. CV-325, PI 691461) great northern common bean (Phaseolus vulgaris L.) cultivar was developed by the dry bean breeding program at the University of Nebraska and released in 2016. It was bred specifically for adaptation to ... ...

    Abstract ‘Panhandle Pride’ (Reg. no. CV-325, PI 691461) great northern common bean (Phaseolus vulgaris L.) cultivar was developed by the dry bean breeding program at the University of Nebraska and released in 2016. It was bred specifically for adaptation to western Nebraska growing conditions and for enhanced resistance to bean rust and common bacterial blight (CBB). Seed yield of Panhandle Pride was comparable to the other cultivars in the on-station and on-farm trials conducted in Nebraska and was greater than ‘Orion’ and lower than ‘Matterhorn’ in regional trials. Seed size (100-seed weight) for Panhandle Pride was larger than Marquis and Beryl-R in trials grown in Nebraska, and larger than Orion and Matterhorn in regional trials. Panhandle Pride carries the sequence characterized amplified region (SCAR) markers SAP6 and SU91 linked to a major CBB resistance quantitative trait locus, and its reaction to the CBB pathogen under field conditions was consistent across 3 yr at the West Central Research and Extension Center, North Platte, NE, with disease ratings of 6.0, 4.3, and 5.2. Panhandle Pride has the Ur-3 and Ur-6 genes for resistance to bean rust and carries the SS68 Kompetitive Allele Specific polymerase chain reaction (KASP) and SK14 SCAR markers linked the Ur-3 bean rust resistance locus. It also carries the single dominant hypersensitive I gene that provides resistance to all non-necrotic strains of the Bean common mosaic virus (BCMV) and the SW13 SCAR marker linked to the I gene for resistance to BCMV. Panhandle Pride has bright white seed, blooms 44 d after planting, and is a midseason bean, maturing 87 d after planting.
    Keywords Bean common mosaic virus ; Phaseolus vulgaris ; alleles ; bean rust ; blight ; cultivars ; disease resistance ; dry beans ; pathogens ; polymerase chain reaction ; quantitative trait loci ; resistance genes ; seed size ; seed yield ; Nebraska
    Language English
    Dates of publication 2019-09
    Size p. 311-315.
    Publishing place The Crop Science Society of America, Inc.
    Document type Article
    Note epub
    ZDB-ID 2381569-3
    ISSN 1940-3496 ; 1936-5209
    ISSN (online) 1940-3496
    ISSN 1936-5209
    DOI 10.3198/jpr2019.02.0006crc
    Database NAL-Catalogue (AGRICOLA)

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  10. Article: Genetic variation and structure of Sclerotinia sclerotiorum populations from soybean in Brazil

    Pannullo, Anthony / Everhart, Sydney E / Kamvar, Zhian N / Miorini, Thomas J. J / Steadman, James R

    Tropical plant pathology. 2019 Feb., v. 44, no. 1

    2019  

    Abstract: The clonal, necrotrophic plant pathogen, Sclerotinia sclerotiorum is the causal agent of white mold on soybean, which causes significant losses for Brazilian farmers each year. While assessments of population structure and clonal dynamics can be ... ...

    Abstract The clonal, necrotrophic plant pathogen, Sclerotinia sclerotiorum is the causal agent of white mold on soybean, which causes significant losses for Brazilian farmers each year. While assessments of population structure and clonal dynamics can be beneficial for determining effective management strategies, few studies have been performed. In this paper, we present a population genetic analysis with 11 microsatellite loci of 94 isolates of S. sclerotiorum from soybean fields in six Brazilian states (Goiás, N = 18; Rio Grande do Sul, N = 16; Paraná, N = 15; Bahia, N = 13; Minas Gerais, N = 7; Mato Grosso do Sul, N = 5) with Argentina (N = 5) and the U.S. (N = 15) as outgroups. Genotyping identified 87 multilocus genotypes with 81 represented by a single isolate. The pattern of genetic diversity observed suggested populations were not strongly differentiated because despite the high genetic diversity, there were few private alleles/genotypes. In addition, no multilocus genotypes were identified in both South and North America while one multilocus genotype was shared between Argentina and Brazil. Pairwise analysis of molecular variance between populations in Brazil revealed nine out of 15 pairs significantly different (P > 0.05). The population from the U.S. was most strongly differentiated in across all measures of population differentiation. Overall, our results found evidence for gene flow across populations with a moderate amount of population structure within states in Brazil. We additionally found shared genotypes across populations in Brazil and Argentina that suggests sclerotia may be transferred across states either through seeds or shared equipment. This represents the first population genetic study of S. sclerotiorum to cover a wide geographic area in Brazil.
    Keywords alleles ; equipment ; farmers ; gene flow ; genetic analysis ; genetic variation ; genotype ; genotyping ; microsatellite repeats ; plant pathogens ; population structure ; sclerotia ; Sclerotinia sclerotiorum ; seeds ; soybeans ; variance ; Argentina ; Brazil ; United States
    Language English
    Dates of publication 2019-02
    Size p. 53-64.
    Publishing place Springer International Publishing
    Document type Article
    ZDB-ID 2519866-X
    ISSN 1983-2052 ; 1982-5676
    ISSN (online) 1983-2052
    ISSN 1982-5676
    DOI 10.1007/s40858-018-0266-5
    Database NAL-Catalogue (AGRICOLA)

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