Spatial distribution of purple seed stain of soybean caused by Cercospora kikuchii in fields

Isolates of Cercospora kikuchii, a soybean (Glycine max) pathogen causing Cercospora leaf blight and purple seed stain, were tested to determine baseline sensitivities (n = 50) to selected quinone outside inhibitor (QoI) fungicides by conducting radial growth assays on fungicide-amended media. Baseline effective fungicide concentration to inhibit 50% of fungal radial growth (EC50) values were compared with EC50 values for isolates collected in 2011 (n = 50), 2012 (n = 50), and 2013 (n = 36) throughout soybean-producing areas in Louisiana. Median EC50 values for isolates subjected to QoI fungicides were significantly (P = 0.05) higher across all 3 years. Cross-resistance to QoI fungicides was observed in resistant isolates collected in 2011 to 2013. Discriminatory doses were developed for QoI fungicides to distinguish between sensitive and resistant isolates. On average, 89% of all isolates screened in 2011 to 2013 were resistant to QoI fungicides. At a discriminatory dose of thiophanate methyl (TM), a methyl benzimidazole carbamate (MBC) fungicide, at 5 μg/ml, resistance was detected in the 2000, 2011, 2012, and 2013 collections at 23, 38, 29, and 36%, respectively. Isolates exhibiting multiple resistance to QoI fungicides and TM also were detected in 2011, 2012, and 2013 at frequencies of 34, 26, and 31%, respectively. Based on these results, Cercospora leaf blight management strategies in Louisiana using solo applications of QoI or MBC fungicides in soybean should be reconsidered.

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Population Structure of Cercospora kikuchii, the Causal Agent of Cercospora Leaf Blight and Purple Seed Stain in Soybean

Phytopathology ◽

10.1094/phyto-98-7-0823 ◽

2008 ◽

Vol 98 (7) ◽

pp. 823-829 ◽

Cited By ~ 12

Author(s):

G. Cai ◽

R. W. Schneider

Keyword(s):

Genetic Relationships ◽

Random Amplified Polymorphic Dna ◽

Intergenic Spacer ◽

Chain Reaction ◽

Cercospora Kikuchii ◽

Vegetative Compatibility Groups ◽

Intergenic Spacer Region ◽

Group I ◽

Polymerase Chain ◽

Purple Seed Stain

Random amplified polymorphic DNA (RAPD) and microsatellite-primed polymerase chain reaction (MP-PCR) were used to characterize 164 isolates of Cercospora kikuchii, most of which were collected from Louisiana. Plant tissue (seeds versus leaves), but not host cultivar, had a significant impact on pathogen population differentiation. Cluster analysis showed that the Louisiana population was dominated by a primary lineage (group I) with only a few Louisiana isolates belonging to the minor lineage that also included the non-Louisiana isolates (group II). A previous study showed that isolates could be differentiated according to vegetative compatibility groups (VCGs). However, RAPD and MP-PCR data demonstrated that isolates of C. kikuchii were not generally clustered according to these VCGs. Furthermore, genetic relationships within and between VCGs were examined using sequences of the intergenic spacer region of rDNA. These analyses showed that VCG is not an indicator of evolutionary lineage in this fungus. Our results suggest the likely existence of a cryptically functioning sexual stage in some portion of the C. kikuchii population.

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Histological study on the resistance in soybean (Glycine max) and wild soybean (G. soja) to purple seed stain caused by Cercospora kikuchii.

Japanese Journal of Phytopathology ◽

10.3186/jjphytopath.54.151 ◽

1988 ◽

Vol 54 (2) ◽

pp. 151-157 ◽

Cited By ~ 1

Author(s):

Yoshikatsu FUJITA ◽

Hozumi SUZUKI

Keyword(s):

Glycine Max ◽

Histological Study ◽

Wild Soybean ◽

Cercospora Kikuchii ◽

Purple Seed Stain

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Screening a Diverse Soybean Germplasm Collection for Reaction to Purple Seed Stain Caused by Cercospora kikuchii

Plant Disease ◽

10.1094/pdis-09-14-0878-re ◽

2015 ◽

Vol 99 (8) ◽

pp. 1140-1146 ◽

Cited By ~ 2

Author(s):

Julieta Alloatti ◽

Shuxian Li ◽

Pengyin Chen ◽

Luciano Jaureguy ◽

S. Faye Smith ◽

...

Keyword(s):

Germplasm Collection ◽

The United States ◽

United States Department ◽

Seed Infection ◽

Department Of Agriculture ◽

Cercospora Kikuchii ◽

Plant Introductions ◽

Seed Decay ◽

Positive Correlations ◽

Purple Seed Stain

Purple seed stain (PSS), caused by Cercospora kikuchii, is a prevalent soybean disease that causes latent seed infection, seed decay, purple seed discoloration, and overall quality deterioration. The objective of this research was to screen soybean accessions from the United States Department of Agriculture germplasm collection for resistance to PSS. In total, 123 plant introductions (PI) from 28 different countries, representing maturity groups (MG) III, IV, and V, were screened. Incidence of Cercospora leaf blight (% CLB), visual PSS (% PSS), and seed infected by C. kikuchii (% C. kikuchii) in harvested seed were determined. In 2007, % C. kikuchii was 2 to 51% for MG III, 2 to 35% for MG IV, and 0 to 33% for MG V. In 2008, % C. kikuchii was 0 to 45% for MG III, 1 to 71% for MG IV, and 0 to 15% for MG V. In total, four and ten PI from MG III and IV, respectively, were identified as resistant to PSS in both years. Highly positive correlations were found for inoculated versus noninoculated treatments and for % PSS versus % C. kikuchii infection. The PSS-resistant PI identified in this study will be valuable to breeders in developing resistant cultivars.

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Phenological Traits Of Soybean In Correlation With Seed Infection By Cercospora Kikuchii (Matsumoto And Tomoyasu) Gardner

Zuriat ◽

10.24198/zuriat.v12i2.6690 ◽

2015 ◽

Vol 12 (2) ◽

Author(s):

D. Ruswandi ◽

R. M. Lantican ◽

R. A. Hautea ◽

M. P. Natural

Keyword(s):

Field Experiment ◽

Plant Breeding ◽

Selection Criteria ◽

Seed Infection ◽

Cercospora Kikuchii ◽

Natural Field ◽

Natural Field Experiment ◽

Study Results ◽

Purple Seed Stain ◽

Different Levels

A study was conducted at Institute of Plant Breeding (IPB), University of thePhilippines at Los Ba~nos (UPLB) from February to July 1997 to determine any relationship among various phonological traits with purple seed stain on soybean caused by C. kikuchii. Thirty genotypes that showed different levels of resistance and susceptibility under the 1996 natural field experiment were used in the study. Results suggest that phonological traits in R7-1-R7-2, R7-1-R7-3, R7-1-R8, R7-2-R8 and R7-3-R8 can serve as selection criteria for developing resistance to C. kikuchii.

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Inheritance of Resistance to Purple Seed Stain Caused by Cercospora kikuchii in PI 80837 Soybean

Crop Science ◽

10.2135/cropsci2004.0621 ◽

2006 ◽

Vol 46 (4) ◽

pp. 1462-1466 ◽

Cited By ~ 13

Author(s):

Eric W. Jackson ◽

Patrick Fenn ◽

Pengyin Chen

Keyword(s):

Inheritance Of Resistance ◽

Cercospora Kikuchii ◽

Purple Seed Stain

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Cercospora kikuchii. [Descriptions of Fungi and Bacteria].

IMI Descriptions of Fungi and Bacteria ◽

10.1079/dfb/20056400466 ◽

1975 ◽

Author(s):

J. L. Mulder

Keyword(s):

Glycine Max ◽

Seed Germination ◽

Geographical Distribution ◽

Cyamopsis Tetragonoloba ◽

Seed Infection ◽

Flowering Period ◽

Purple Colour ◽

Cercospora Kikuchii ◽

Characteristic Symptom ◽

Purple Seed Stain

Abstract A description is provided for Cercospora kikuchii. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Glycine max, Phaseolus spp., Cyamopsis tetragonoloba, Vigna. DISEASE: Purple seed stain (also purple blotch, purple stain or purple speck) of soyabean Infection has also been reported on other legumes, including bean (cowpea) and cluster bean or guar (35, 861; 42, 69). The most characteristic symptom is the light to dark purple colour of the seed coat, the whole of which can be affected, and which shows cracking. Other species of Cercospora cause this purple staining of soyabean seed when pods are inoculated (35, 861; 39, 68) but these are not apparently of importance in the field. Seed germination may not be greatly reduced but infected seeds develop into weak seedlings (sometimes there is a slow death) and less productive plants. Reddish-purple spots, becoming angular to irregular, up to 1 cm diam., occur on the leaves; stems are also infected (4, 714; 29, 489; 30, 503). GEOGRAPHICAL DISTRIBUTION: Widespread with host. TRANSMISSION: Through seed; infection of seed is lowest before maturity and can rise to 50% at maturity and to higher levels thereafter (36, 569). Plants whose maturity is delayed (and where the flowering period is longer) tend to show more seed infection (45, 3447). Infection of the seed reduced germination in a blotter test and in the field; the fungus can occur in seeds that show no purple staining (52, 1735).

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