Yield and Seed Quality of Soybean Cultivars Infected with Sclerotinia sclerotiorum

Sclerotinia stem rot (SSR) is one of the most important diseases of soybean in the United States. Five maturity group III cultivars, Asgrow A3304 STS (A3304), Pioneer Brand 9342 (P9342), Pioneer Brand 9381 (P9381), Probst, and Yale, grown in fields in east-central Illinois, were used to determine the relationship of SSR incidence to yield, 100-seed weight, seed protein and oil content, visual seed quality, and seed germination. In addition, the number of sclerotia in seed samples and the seedborne incidence of Sclerotinia sclerotiorum were determined. For each cultivar, at least 23 two-row plots, 3 m long, that represented a range of SSR incidence from low to high, were used to count the number of plants with and without SSR stem symptoms and were used to estimate yields and evaluate seed quality. Disease incidence ranged from 2 to 45% for Probst, 0 to 65% for P9381, 0 to 68% for P9342, 1 to 93% for Yale, and 0 to 95% for A3304. Regression of yields on SSR incidences for each cultivar was significant (P < 0.05); for every 10% increase in SSR incidence, yields were reduced by 147, 194, 203, 254, and 263 kg/ha for Probst, A3304, P9342, Yale, and P9381, respectively. Disease incidence was negatively correlated (P < 0.05) with seed germination for all cultivars but Probst, and to oil content and seed weight for P9381 and Yale. Disease incidence was positively correlated (P < 0.05) with seed quality for all cultivars and to the number of sclerotia in harvested seeds for P9342, P9381, and Probst. The seedborne incidence of S. sclerotiorum was 0.3, 0.3, 0.3, 0.4 and 0.7% in A3304, P9381, Yale, Probst, and P9342, respectively, and represents a significant potential for further spread of this pathogen and disease.

Download Full-text

Soybean Varietal Response and Yield Loss Caused by Sclerotinia sclerotiorum

Plant Disease ◽

10.1094/pdis.1999.83.5.456 ◽

1999 ◽

Vol 83 (5) ◽

pp. 456-461 ◽

Cited By ~ 36

Author(s):

X. B. Yang ◽

P. Lundeen ◽

M. D. Uphoff

Keyword(s):

Regression Analysis ◽

Sclerotinia Sclerotiorum ◽

Disease Incidence ◽

Pearson Correlation ◽

The United States ◽

Yield Losses ◽

Linear Regression Models ◽

Sclerotinia Stem Rot ◽

Varietal Response ◽

Maturity Groups

Soybean Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, has recently emerged from being a minor problem in areas where soybeans of maturity groups 0 to I are grown to a significant cause of soybean yield losses in the north-central region, which produces 80% of soybean in the United States. Studies were conducted in Iowa to quantify varietal response to S. sclerotiorum for cultivars of maturity groups I to III in fields that had uniform infestation histories. Over the course of the study, disease incidence was generally high at the northern Iowa sites but low in central Iowa, with disease incidence of susceptible standards >60% and <30%, respectively. Regression analysis showed that maturity class significantly affected disease incidence, with greater effects in environments where susceptible standard cultivars had high disease incidences. Consistency of varietal response among the environments was quantified using Pearson correlation analysis. When disease incidence was high, varietal responses measured by disease ratings and yield were consistent among locations, but the responses were inconsistent when disease incidence was low. Pearson correlation coefficients ranged from 0.80 to 0.94 for disease incidence and 0.58 to 0.81 for yield among the experiments having high disease incidence in susceptible standards. The relationship between disease incidence and yield was well described by linear regression models with coefficients of determination (r2) ranging from 0.59 to 0.83. Based on regression slopes (significant at P < 0.0001), yield losses are estimated to range from 170 to 335 kg/ha for each 10 percentage points of disease incidence. Regression analysis also showed that maturity groups had a linear relationship with disease incidence (r2 = 0.18 to 0.39, P < 0.01).

Download Full-text

Efficacy of Fungicides on Sclerotinia sclerotiorum and Their Potential for Control of Sclerotinia Stem Rot on Soybean

Plant Disease ◽

10.1094/pdis.2002.86.1.26 ◽

2002 ◽

Vol 86 (1) ◽

pp. 26-31 ◽

Cited By ~ 67

Author(s):

D. S. Mueller ◽

A. E. Dorrance ◽

R. C. Derksen ◽

E. Ozkan ◽

J. E. Kurle ◽

...

Keyword(s):

Sclerotinia Sclerotiorum ◽

Radial Growth ◽

Disease Incidence ◽

Leaf Tissue ◽

The United States ◽

Stem Rot ◽

Sclerotinia Stem Rot ◽

Thiophanate Methyl ◽

Application Systems

Sclerotinia stem rot of soybean, caused by Sclerotinia sclerotiorum, is a major disease in the north central region of the United States. One approach to managing Sclerotinia stem rot on soybean is the use of fungicides. S. sclerotiorum was assayed for sensitivity to benomyl, tebuconazole, thiophanate methyl, and vinclozolin in pure cultures on agar medium, inoculated soybean seedlings, detached inoculated leaves, and in experimental field plots. To evaluate the inhibitory effect of four fungicides on growth of S. sclerotiorum in vitro, potato dextrose agar (PDA) was amended with the fungicides at six concentrations. Based on measurements of fungal radial growth, vinclozolin was the most effective in inhibiting S. sclerotiorum mycelial growth at 1.0 μg a.i./ml of PDA. Ranges of reduction of radial growth of 91 isolates of S. sclerotiorum on PDA amended with thiophanate methyl and vinclozolin were 18 to 93% and 93 to 99%, respectively, when compared with the nonamended agar control. Benomyl, thiophanate methyl, and vinclozolin applied to greenhouse-grown seedlings prevented S. sclerotiorum from expressing symptoms or signs on leaf tissue. Detached leaves sprayed with thiophanate methyl and then inoculated with mycelial plugs of S. sclerotiorum did not express symptoms or signs. Of 13 different environments in Illinois, Indiana, Ohio, and Wisconsin from 1995 through 2000, six had low Sclerotinia stem rot incidence (<1%), three environments had low to moderate Sclerotinia stem rot incidence (5 to 25%), and four environments had high Sclerotinia stem rot incidence (>25%). When disease incidence was high, no consistent control of Sclerotinia stem rot was observed with benomyl or thiophanate methyl using different application systems. However, under low disease incidence, spray systems that were able to penetrate the canopy reduced the incidence of Sclerotinia stem rot an average of 50%.

Download Full-text

Occurrence of Sclerotinia sclerotiorum in Soybean Fields in East-Central Illinois and Enumeration of Inocula in Soybean Seed Lots

Plant Disease ◽

10.1094/pdis.1998.82.5.560 ◽

1998 ◽

Vol 82 (5) ◽

pp. 560-564 ◽

Cited By ~ 27

Author(s):

G. L. Hartman ◽

L. Kull ◽

Y. H. Huang

Keyword(s):

Sclerotinia Sclerotiorum ◽

Crop Improvement ◽

Central Area ◽

The United States ◽

Seed Infection ◽

Sclerotinia Stem Rot ◽

East Central ◽

Soybean Production ◽

Central Illinois ◽

Production Areas

Sclerotinia stem rot (SSR) of soybean is an important disease in the northern soybean-production areas of the United States. In Illinois, the occurrence of SSR has been limited to the northern-most soybean-production areas. In this study, soybean fields in east-central Illinois were surveyed for incidence of SSR. Of 68 fields surveyed, 31 contained SSR. Of the fields with SSR, 25 had between 1 and 5% SSR incidence, while 6 fields had more than 5% SSR incidence. The pattern of the disease in one field was mapped, and the spatial distribution of SSR was aggregated with a Lloyd's index of 1.4. In addition to field incidence of SSR, seed lots suspected of being contaminated with Sclerotinia sclerotiorum sclerotia were obtained from the Illinois Crop Improvement Association. Sclerotia and seeds were separated, and seeds were germinated to determine the level of seedborne infection by S. sclerotiorum. Sclerotia were recovered from 71 of 81 seed lots. Most of the seed lots were from the north-central area of Illinois, but one seed lot was from Madison County in the southwestern area of the state, and three and six seed lots contaminated with sclerotia were from Iowa and Wisconsin, respectively. Sclerotia counts ranged from 0 to 363 per seed lot. Normal-appearing seeds from the 81 seed lots (100 to 200 seeds per lot) were tested for germination and incidence of seedborne infection by S. sclerotiorum. Eight seed lots had at least one infected seed, and the incidence of seed infection ranged from 0.07 to 0.1%. From 10 randomly selected seed lots of the 81, discolored, shriveled seeds were selected and germinated to determine the incidence of seedborne infection. Seed infection rates ranged from 0 to 70%. The occurrence of SSR throughout Illinois and the importance of seedborne infection as a source of inoculum dispersal need further documentation.

Download Full-text

Effect of Sclerotinia Stem Rot on Yield of Soybean Inoculated at Different Growth Stages

Plant Disease ◽

10.1094/pdis.2004.88.3.297 ◽

2004 ◽

Vol 88 (3) ◽

pp. 297-300 ◽

Cited By ~ 23

Author(s):

G. A. Danielson ◽

B. D. Nelson ◽

T. C. Helms

Keyword(s):

Seed Weight ◽

Oil Content ◽

Field Experiments ◽

Seed Protein ◽

Disease Incidence ◽

Stem Rot ◽

Growth Stages ◽

Diseased Plant ◽

Sclerotinia Stem Rot ◽

Effect On Yield

The effects of Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, on yield of soybean were evaluated in the field with two cultivars in maturity group 0. Plants were inoculated at two growth stages, R3 and R5, using two inoculation methods. Seed weight, seed and pod numbers, seed protein, and oil content were measured. The effects of disease on yield were variable. Disease resulted in significant seed weight loss, with reductions per diseased plant ranging from 18.8 to 38.6%. The estimated yield loss per 10% disease incidence ranged from 83.2 to 229.0 kg/ha, with an average loss of 136.6 kg/ha for four field experiments. A reduction in the number of seeds and pods per plant and seed oil content occurred in some, but not all, experiments. Seed protein was not affected. When disease reduced seed weight, seed and pod numbers, or oil content, there was no growth stage × treatment interaction in the experiments, indicating that inoculation at R5 compared with R3 had a similar effect on yield.

Download Full-text

Favorable Bioactivity of the SDHI Fungicide Benzovindiflupyr Against Sclerotinia sclerotiorum Mycelial Growth, Sclerotial Production, and Myceliogenic and Carpogenic Germination of Sclerotia

Plant Disease ◽

10.1094/pdis-05-18-0729-re ◽

2019 ◽

Vol 103 (7) ◽

pp. 1613-1620 ◽

Cited By ~ 8

Author(s):

Xue-ping Huang ◽

Jian Luo ◽

Yu-fei Song ◽

Bei-xing Li ◽

Wei Mu ◽

...

Keyword(s):

Sclerotinia Sclerotiorum ◽

Mycelial Growth ◽

Disease Incidence ◽

Stem Rot ◽

Sclerotinia Stem Rot ◽

Baseline Sensitivity ◽

Carpogenic Germination ◽

Alternative Product ◽

Application Potential ◽

New Generation

Sclerotinia sclerotiorum, which can cause Sclerotinia stem rot, is a prevalent plant pathogen. This study aims to evaluate the application potential of benzovindiflupyr, a new generation of succinate dehydrogenase inhibitor (SDHI), against S. sclerotiorum. In our study, 181 isolates collected from different crops (including eggplant [n = 34], cucumber [n = 27], tomato [n = 29], pepper [n = 35], pumpkin [n = 32], and kidney bean [n = 25]) in China were used to establish baseline sensitivity to benzovindiflupyr. The frequency distribution of the 50% effective concentration (EC50) values of benzovindiflupyr was a unimodal curve, with mean EC50 values of 0.0260 ± 0.011 μg/ml, and no significant differences in mean EC50 existed among the various crops (P > 0.99). Benzovindiflupyr can effectively inhibit mycelial growth, sclerotial production, sclerotial shape, and myceliogenic and carpogenic germination of the sclerotia of S. sclerotiorum. In addition, benzovindiflupyr showed good systemic translocation in eggplant. Using benzovindiflupyr at 100 μg/ml yielded efficacies of 71.3 and 80.5% for transverse activity and cross-layer activity, respectively, which were higher than those of acropetal and basipetal treatments (43.6 and 44.7%, respectively). Greenhouse experiments were then carried out at two experimental sites for verification. Applying benzovindiflupyr at 200 g a.i. ha−1 significantly reduced the disease incidence and severity of Sclerotinia stem rot. Overall, the results demonstrated that benzovindiflupyr is a potential alternative product to control Sclerotinia stem rot.

Download Full-text

Effect of Three Desiccant Herbicides on Soybean (Glycine max) Seed Quality

Weed Science ◽

10.1017/s0043174500041023 ◽

1982 ◽

Vol 30 (5) ◽

pp. 484-490 ◽

Cited By ~ 13

Author(s):

Raymond F. Cerkauskas ◽

Onkar D. Dhingra ◽

James B. Sinclair ◽

Stephen R. Foor

Keyword(s):

Glycine Max ◽

Seed Germination ◽

Seed Weight ◽

Seed Quality ◽

Sodium Chlorate ◽

Sodium Borate ◽

Growth Stages ◽

Seed Infection ◽

Herbicide Application ◽

Combined Data

Soybean [Glycine max(L.) Merr.] cultivars ‘UFV1’ and ‘UFV2’ grown at Viçosa and Florestal, Brazil, and ‘Bonus' and ‘Wells' at Urbana, Illinois, were sprayed at growth stages R5.5to R6(full-pod) or R7(50% defoliation) with the desiccant/herbicides glyphosate [N-(phosphonomethyl)glycine], paraquat (1,1′-dimethyl-4,4′-bipyridinium ion), or sodium chlorate:sodium borate (50:50, w/v). Desiccation of plants by paraquat significantly reduced seed weight and germination at all locations and increased the incidence ofAlternariaandPhomopsisspp. at Urbana. Analysis of the combined data from the Brazilian locations showed a significant decrease in seed germination for all treatments except paraquat sprayed on the UFV2at R7and sodium chlorate: sodium borate sprayed on UFV1at R7. Herbicide application at R7did not result in consistent increases in seedborneFusariumorPhomopsisspp. at any Brazilian location. Rainfall and temperature at seed maturation were more important variables in pod-to-seed infection by these fungi than increased rates of tissue senescence caused by the desiccants.

Download Full-text

Evaluation of disease forecasting variables for sclerotinia stem rot (Sclerotinia sclerotiorum) of canola

Canadian Journal of Plant Science ◽

10.4141/p99-071 ◽

2000 ◽

Vol 80 (4) ◽

pp. 889-898 ◽

Cited By ~ 33

Author(s):

M. Bom ◽

G. J. Boland

Keyword(s):

Soil Moisture ◽

Disease Severity ◽

Sclerotinia Sclerotiorum ◽

Prediction Models ◽

Disease Incidence ◽

Stem Rot ◽

Disease Prediction ◽

Strong Correlations ◽

Sclerotinia Stem Rot ◽

Spring Canola

Selected environmental, crop and pathogen variables were sampled weekly from winter and spring canola crops before and during flowering and evaluated for the ability to predict sclerotinia stem rot, caused by Sclertinia sclerotirum. Linear and nonlinear relationships were examined among variables but, because no strong correlations were observed between final disease incidence and any of the variables tested, a categorical approach (e.g., disease severity) was used instead. Disease severity in individual crops was categorized as low (< 20% diseased plants) or high (> 20% disease), and differences in weekly rainfall, soil moisture, crop height, percentage of petal infestation, and number of apothecia m−2 and clumps of apothecia m−2 were significantly associated with differences in disease severity within or between years. Two disease prediction models were compared for the ability to predict low or high disease severities using petal infestation alone, or petal infestation in combination with soil moisture. The model that included petal infestation and soil moisture predicted more fields correctly than the model using petal infestation alone, but the accuracy of both was affected by the timing of soil moisture measurements in relation to petal infestation, and threshold values used in discriminating categories of soil moisture and petal infestation. Key words: Brassica rapa, Brassica napus, Sclerotinia sclerotiorum, disease prediction

Download Full-text

Protein, weight, and oil prediction by single-seed near-infrared spectroscopy for selection of seed quality and yield traits in pea (Pisum sativum).

10.31220/osf.io/7j9cy ◽

2020 ◽

Author(s):

Gokhan Hacisalihoglu ◽

Jelani Freeman ◽

Paul R. Armstrong ◽

Brad W. Seabourn ◽

Lyndon D. Porter ◽

...

Keyword(s):

Infrared Spectroscopy ◽

Pisum Sativum ◽

Protein Content ◽

Near Infrared Spectroscopy ◽

Seed Weight ◽

Oil Content ◽

Near Infrared ◽

Seed Quality ◽

Single Seed ◽

Selection Of

Abstract Background: Pea (Pisum sativum) is a prevalent cool season crop that produces seeds valued for high protein content. Modern cultivars have incorporated several traits that improved harvested yield. However, progress toward improving seed quality has received less emphasis, in part due to the lack of tools for easily and rapidly measuring seed traits. In this study we evaluated the accuracy of single-seed near-infrared spectroscopy (NIRS) for measuring pea seed weight, protein, and oil content. A total of 96 diverse pea accessions were analyzed using both single-seed NIRS and wet chemistry methods. To demonstrate field relevance, the single-seed NIRS protein prediction model was used to determine the impact of seed treatments and foliar fungicides on protein content of harvested dry peas in a field trial. Results: External validation of Partial Least Squares (PLS) regression models showed high prediction accuracy for protein and weight (R2 = 0.94 for both) and less accuracy for oil (R2 = 0.75). Single seed weight was not significantly correlated with protein or oil content in contrast to previous reports. In the field study, the single-seed NIRS predicted protein values were within 1% of an independent analytical reference measurement and were sufficiently precise to detect small treatment effects. Conclusion: The high accuracy of protein and weight estimation show that single-seed NIRS could be used in the dual selection of high protein, high weight peas early in the breeding cycle allowing for faster genetic advancement toward improved pea nutritional quality.

Download Full-text

Occurrence of Stem Rot on Canola Caused by Sclerotinia sclerotiorum in Argentina

Plant Disease ◽

10.1094/pd-89-0530b ◽

2005 ◽

Vol 89 (5) ◽

pp. 530-530 ◽

Cited By ~ 1

Author(s):

S. Gaetán ◽

M. Madia

Keyword(s):

United States ◽

Sclerotinia Sclerotiorum ◽

Buenos Aires ◽

Disease Incidence ◽

Fungal Growth ◽

Ground Level ◽

The United States ◽

Stem Rot ◽

Buenos Aires Province ◽

Rot Disease

Canola (Brassica napus) was introduced as an alternative crop for wheat in Argentina. During 2003, typical symptoms of stem rot disease were observed on canola plants in two commercial fields located at Bragado, in northern Buenos Aires Province in Argentina. Average disease incidence across four canola cultivars was 21% (range = 13 to 29%). Symptoms included chlorosis and wilting of foliage and necrosis of basal stems. The disease appeared singly or in patches consisting of 4- to 5-month-old plants. The first visible symptom noticed was chlorosis and wilting of the foliage beginning from the basal leaves. Infection of the main stem at ground level typically was followed by a grayish white discoloration that progressed above the soil line to the apex. In advanced stages of the disease, stems and branches became bleached and eventually died. Black and irregularly shaped sclerotia (average size 5.5 × 2.8 mm) inside necrotic stem tissue were the typical signs of the pathogen. From September to October 2003, four samples consisting of six affected plants per sample were arbitrarily collected from two commercial fields located at Bragado. Sclerotia were taken from diseased stems, dipped in 70% ethanol, surface sterilized with 1% sodium hypochlorite for 1 min, and rinsed in sterile water. Each sclerotium was blotted dry on sterile Whatman's filter paper and placed on potato dextrose agar. Plates were incubated in the dark at 25°C for 2 to 3 days, followed by incubation under 12-h NUV light/12-h dark for 6 to 8 days. Six resulting colonies were identified as Sclerotinia sclerotiorum (Lib.) de Bary on the basis of taxonomic characteristics of the plant pathogenic species of Sclerotinia (3). Koch's postulates for three fungal isolates from infected plants were carried out on 6-week-old canola plants (cvs. Eclipse, Impulse, Master, and Mistral) by placing a colonized agar disk into wounds made in the basal stem region with a sterile scalpel. Pathogenicity tests, which included five inoculated and three control plants potted in a sterilized soil mix (soil/sand, 3:1), were conducted in a greenhouse at 23 to 26°C and 75% relative humidity with no supplemental light. Characteristic symptoms identical to the original observations developed within 12 days after inoculation on 100% of the inoculated plants for three isolates. Symptoms included wilted foliage, collapsed plants, and plant death. White mycelium and sclerotia developed on infected tissues, and the pathogen was successfully reisolated from symptomatic plants in all instances. Control plants, which were treated similarly except that the agar disk did not contain fungal growth, remained healthy. The experiment was repeated, and the results were identical to the first inoculations. Canola stem rot disease incited by S. sclerotiorum was first reported in Argentina during 1995 at experimental field plots in Buenos Aires. S. sclerotiorum, which has been reported to cause disease in canola in Canada (2) and the United States (1,4), currently represents a serious problem to the main canola cultivars grown in Argentina. To our knowledge, this is the first report of the occurrence of S. sclerotiorum causing a high incidence of stem rot in commercial crops of canola in Argentina. References: (1) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN, 1989. (2) L. B. Jamaux et al. Plant Pathol. 44:22, 1995. (3) L. M. Kohn. Phytopathology 69:881, 1979. (4) D. V. Phillips et al. Phytopathology 92:785, 2002.

Download Full-text

Effect of sunflower head rot [Sclerotinia sclerotiorum (Lib.) de Bary] on impurities in harvested product, and oil content and acidity.

The Journal of Agriculture of the University of Puerto Rico ◽

10.46429/jaupr.v85i3-4.3071 ◽

1969 ◽

Vol 85 (3-4) ◽

pp. 177-186

Author(s):

María Eugenia Agüero ◽

Víctor R. Pereyra ◽

Alberto R. Escande

Keyword(s):

Key Words ◽

Sclerotinia Sclerotiorum ◽

Oil Content ◽

Disease Incidence ◽

Head Rot

The effect of sunflower head rot on impurities in the harvested product (HP), oil content (OC) and oil acidity (OA) was studied. Levels of 0,10, 20, 30, 40, 50,80 and 100% of disease incidence (Dl) were analyzed. The HP was either weighed and left untouched or it was divided into three fractions: seeds, sclerotia and other impurities. For OC and OA measurement, we analyzed samples from each Dl level composed of seeds (S), seeds and scleratia (S+Sci), seeds and other impurities (S+Ol), and untouched original samples (S+Sct+Ol). Disease incidence significantly affected the composition of the harvested product. At greater Dl levels, seed percentage went down and impurities rose. Sclerotia were the most abundant impurities. With 100% Dl, seed represented 65% and sclerotia 25% of the HP. At greater Dl ievels, OC went down and OA rose. Content of seeds in the HP defined OC. Sclerotia content was the main reason for the increase in OA. At 100% Dl, S+Scl samples yielded 31% Jess OC and 53% more OA than the S samples. Key words: sunflower, Sclerotinia sclerotiorum, oil content, oil acidity

Download Full-text