scholarly journals Evaluation of Soybean Resistance to Sclerotinia Stem Rot Using Reciprocal Grafting

Plant Disease ◽  
2003 ◽  
Vol 87 (2) ◽  
pp. 154-158 ◽  
Author(s):  
T. D. Vuong ◽  
G. L. Hartman
Keyword(s):  
The United States ◽  
Stem Rot ◽  
Fungal Mycelium ◽  
Sclerotinia Stem Rot ◽  
Plant Survival ◽  
Plant Introductions ◽  
Inoculation Method ◽  
The North ◽  
Grafting Technique ◽  
Soybean Genotypes

Sclerotinia stem rot of soybean is one of the major soybean diseases in the north central region of the United States. One disease management option is to plant cultivars that have resistance. Some sources of partial resistance have been identified, but information pertaining to the nature of resistance is limited. The objective of this study was to determine if the expression of resistance is dictated by shoots of resistant plants and if this can be altered by using resistant and susceptible soybean genotypes grafted in different shoot and rootstock combinations of self-, single-, or double-shoot grafts. After successful grafts were made, several experiments were conducted using different inoculation techniques and soybean genotypes. In one experiment, cotyledons were inoculated with a plug of fungal mycelium, plants were incubated in a mist chamber for 23 h, and plant survival was recorded over time. Based on seven grafting combinations of cross- and self-grafted plants using two soybean cultivars, grafts with NKS19-90 (partially resistant) as shoots had greater (P ≤ 0.05) plant survival at 3, 4, and 5 days after inoculation than the other graft combinations. In another experiment, a total of 17 graft combinations were generated using resistant plant introductions and two susceptible cultivars. Resistant self-grafts of the plant introductions had greater (P ≤ 0.05) plant survival (mean = 75%) than self-grafts of the susceptible cultivars (mean = 15%) at 5 days after inoculation. Inter-genotypic grafts with resistant shoots had greater (P ≤ 0.05) plant survival (mean = 65%) than those in reciprocal combinations (mean = 8%) 5 days after inoculation. A cut stem inoculation method was used to test graft combinations of one resistant and two susceptible cultivars. Grafts with susceptible shoots of cvs. Williams 82 and Asgrow 2242 had greater (P < 0.05) lesion lengths (mean = 13.2 cm) than shoots of NKS19-90 (mean = 9.2 cm) regardless of the rootstock 15 days after inoculation. In a double-graft experiment, shoots of both NKS19-90 and Williams 82 were grafted to either NKS19-90 or Williams 82 rootstocks. Regardless of the rootstock, the shoots of Williams 82 died while shoots of NKS19-90 survived. For all the experiments, resistance was greater when the grafted shoot came from a resistant source on a susceptible rootstock compared with the reciprocal combination regardless of the type of grafting technique or inoculation method.

scholarly journals Impact of Management Practices on Prevalence of Soybean Sclerotinia Stem Rot in the North-Central United States and on Farmers' Decisions Under Uncertainty

Plant Disease ◽  
2003 ◽  
Vol 87 (9) ◽  
pp. 1048-1058 ◽  
Author(s):  
A. L. Mila ◽  
A. L. Carriquiry ◽  
J. Zhao ◽  
X. B. Yang
Keyword(s):  
United States ◽  
Seed Treatment ◽  
Management Practices ◽  
The United States ◽  
Stem Rot ◽  
Sclerotinia Stem Rot ◽  
Weather Variables ◽  
North Central ◽  
The North ◽  
Attainable Yield

Regional prevalence of soybean Sclerotinia stem rot (SSR), caused by Sclerotinia sclerotiorum, was modeled using management practices (tillage, herbicide, manure and fertilizer application, and seed treatment with fungicide) and summer weather variables (mean monthly air temperature and precipitation for the months of June, July, August, and September) as inputs. Logistic regression analysis was used to estimate the probability of stem rot prevalence with disease data from four states in the north-central region of the United States (Illinois, Iowa, Minnesota, and Ohio). Goodness-of-fit criteria indicated that the resulting model explained well the observed frequency of occurrence. The relationship of management practices and weather variables with soybean yield was examined using multiple linear regression (R 2 = 0.27). Variables significant to SSR prevalence, including average air temperature during July and August, precipitation during July, tillage, seed treatment, liquid manure, fertilizer, and herbicide applications, were also associated with high attainable yield. The results suggested that SSR occurrence in the north-central region of the United States was associated with environments of high potential yield. Farmers' decisions about SSR management, when the effect of management practices on disease prevalence and expected attainable yield was taken into account, were examined. Bayesian decision procedures were used to combine information from our model (prediction) with farmers' subjective estimation of SSR incidence (personal estimate, based on farmers' previous experience with SSR incidence). MAXIMIN and MAXIMAX criteria were used to incorporate farmers' site-specific past experience with SSR incidence, and optimum actions were derived using the criterion of profit maximization. Our results suggest that management practices should be applied to increase attainable yield despite their association with high disease risk.

scholarly journals Selected Soybean Plant Introductions with Partial Resistance to Sclerotinia sclerotiorum

Plant Disease ◽  
2002 ◽  
Vol 86 (9) ◽  
pp. 971-980 ◽  
Author(s):  
D. D. Hoffman ◽  
B. W. Diers ◽  
G. L. Hartman ◽  
C. D. Nickell ◽  
R. L. Nelson ◽  
...  
Keyword(s):  
United States ◽  
Disease Severity ◽  
Partial Resistance ◽  
Germ Plasm ◽  
Agronomic Traits ◽  
Field Tests ◽  
The United States ◽  
Stem Rot ◽  
Sclerotinia Stem Rot ◽  
Plant Introductions

Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, is a major soybean (Glycine max) disease in north-central regions of the United States and throughout the world. Current sources of resistance to Sclerotinia stem rot express partial resistance, and are limited in number within soybean germ plasm. A total of 6,520 maturity group (MG) 0 to IV plant introductions (PIs) were evaluated for Sclerotinia stem rot resistance in the United States and Canada in small plots or in the greenhouse from 1995 to 1997. Selected PIs with the most resistance were evaluated for resistance in the United States and Canada in replicated large plots from 1998 to 2000. The PIs in the MG I to III tests in Urbana, IL were evaluated for agronomic traits from 1998 to 2000. The selected PIs also were evaluated with an excised leaf inoculation and petiole inoculation technique. After the 1995 to 1997 evaluations, all but 68 PIs were eliminated because of their susceptibility to Sclerotinia stem rot. In field tests in Urbana, higher disease severity in selected MG I to III PIs was significantly (P< 0.05) associated with taller plant heights and greater canopy closure. All other agronomic traits evaluated were not associated or were inconsistently associated with disease severity. MG I to III PIs 153.282, 189.931, 196.157, 398.637, 417.201, 423.818, and 561.331 had high levels of resistance and had canopies similar to the resistant checks. The resistance ratings from the petiole inoculation technique had a high and significant (P< 0.01) correlation with disease severity in the MG I and II field tests. The partially resistant PIs identified in this study can be valuable in incorporating Sclerotinia stem rot resistance into elite germ plasm.

Identification of Soybean (Glycine max) Check Lines for Evaluating Genetic Resistance to Sclerotinia Stem Rot

Plant Disease ◽  
2020 ◽  
Author(s):  
Richard Wade Webster ◽  
Mitchell Roth ◽  
Hannah Reed ◽  
Brian Mueller ◽  
Carol Groves ◽  
...  
Keyword(s):  
Management Strategy ◽  
Genetic Resistance ◽  
Field Studies ◽  
The United States ◽  
Stem Rot ◽  
Sclerotinia Stem Rot ◽  
Upper Midwest ◽  
Soybean Genotypes ◽  
Moderately Resistant ◽  
Disease Present

Soybean production in the Upper Midwest of the United States is affected by Sclerotinia stem rot (SSR) caused by the fungal pathogen Sclerotinia sclerotiorum, and genetic resistance is an important management strategy for this disease. However, assessing genetic resistance to S. sclerotiorum is challenging, because a standardized method to examine resistance across genotypes is lacking. Using a panel of nine diverse S. sclerotiorum isolates, four soybean lines were assessed for reproducible responses to S. sclerotiorum infection. Significant differences in SSR severity were found across isolates (P < 0.01) and soybean lines (P < 0.01), including one susceptible, two moderately resistant, and one highly resistant line. These four validated lines were used to screen 11 other soybean genotypes to evaluate their resistance levels, and significant differences were found across genotypes (P < 0.01). Among these 11 genotypes, five commercial and public cultivars displayed high resistance and were assessed in field studies across the Upper Midwest growing region for their response to SSR and yield. These five cultivars resulted in low disease levels (P < 0.01) in the field which were consistent with greenhouse experiments. Yield was significantly different in fields with disease present (P < 0.01) and disease absent (P < 0.01), and the order of cultivar performance was consistent between environments where disease was present or absent suggesting resistance prevented yield loss to disease. This study suggests the use of a soybean check panel can accurately assess SSR resistance in soybean germplasm and aid in breeding and commercial soybean development.

scholarly journals Logistic Regression Modeling of Prevalence of Soybean Sclerotinia Stem Rot in the North-Central Region of the United States

2004 ◽  
Vol 94 (1) ◽  
pp. 102-110 ◽  
Author(s):  
A. L. Mila ◽  
A. L. Carriquiry ◽  
X. B. Yang
Keyword(s):  
Regression Analysis ◽  
Explanatory Power ◽  
Weather Conditions ◽  
The United States ◽  
Stem Rot ◽  
North Central Region ◽  
Sclerotinia Stem Rot ◽  
North Central ◽  
The North ◽  
Input Variables

Regional prevalence of soybean Sclerotinia stem rot (SSR), caused by Sclerotinia sclerotiorum, was modeled using tillage practices, soil texture, and weather variables (monthly air temperature and monthly precipitation from April to August) as inputs. Logistic regression was used to estimate the probability of stem rot prevalence with historical disease data from four states of the north-central region of the United States. Potential differences in disease prevalence between states in the region were addressed using regional indicator variables. Two models were developed: model I used spring (April) weather conditions and model II used summer (July and August) weather conditions as input variables. Both models had high explanatory power (78.5 and 77.8% for models I and II, respectively). To investigate the explanatory power of the models, each of the four states was divided into small geographic areas, and disease prevalence in each area was estimated using both models. The R2 value of the regression analysis between observed and estimated SSR prevalence was 0.65 and 0.71 for models I and II, respectively. The same input variables were tested for their significance to explain the within-field SSR incidence by using Poisson regression analysis. Although all input variables were significant, only a small amount of variation of SSR incidence was explained, because R2 of the regression analysis between observed and estimated SSR incidence was 0.065. Incorporation of available site-specific information (i.e., fungicide seed treatment, weed cultivation, and manure and fertilizer applications in a field) improved slightly the explained amount of SSR incidence (R2 = 0.076). Predicted values of field incidence generally were overestimated in both models compared with the observed incidence. Our results suggest that preseason prediction of regional prevalence would be feasible. However, prediction of field incidence would not, and a different site-specific approach should be followed.

Integration of Row Spacing, Seeding Rates, and Fungicide Application for Control of Sclerotinia Stem Rot in Glycine max

Plant Disease ◽  
2021 ◽  
Author(s):  
Richard Wade Webster ◽  
Mitchell Roth ◽  
Brian Mueller ◽  
Daren S. Mueller ◽  
Martin I Chilvers ◽  
...  
Keyword(s):  
Glycine Max ◽  
The United States ◽  
Stem Rot ◽  
Row Spacing ◽  
Sclerotinia Stem Rot ◽  
Upper Midwest ◽  
Multiple Control ◽  
Economic Implications ◽  
Increased Risk ◽  
History Of

Soybean (Glycine max) farmers in the Upper Midwest region of the United States frequently experience severe yield losses due to Sclerotinia stem rot (SSR). Previous studies have revealed benefits of individual management practices on SSR. This study examined the integration of multiple control practices on the development of SSR, yield, and the economic implications of these practices. Combinations of row spacings, seeding rates, and fungicide applications were examined in multi-site field trials across the Upper Midwest from 2017-2019. These trials revealed that wide row spacing and low seeding rates individually reduced SSR levels but also reduced yields. Yields were similar across the three higher seeding rates examined. However, site-years where SSR developed showed the highest partial profits in the intermediate seeding rates. This indicates that partial profits in diseased fields were negatively impacted by high seeding rates, but this trend was not observed when SSR did not develop. Fungicides strongly reduced the development of SSR, while also increasing yields. However, there was a reduction in partial profits due to their use at a low soybean sale price, but at higher sale prices fungicide use was similar to not treating. Additionally, the production of new inoculum was predicted from disease incidence, serving as an indicator of increased risk for SSR development in future years. Overall, this study suggests the use of wide rows and low seeding rates could be useful in fields with a history of SSR, while reserving narrow rows and higher seeding rates for fields without a history of SSR.

Suppression of Soybean Yield Potential in the Continental United States by Plant Diseases from 2006 to 2009

2010 ◽  
Vol 11 (1) ◽  
pp. 5 ◽  
Author(s):  
Stephen R. Koenning ◽  
J. Allen Wrather
Keyword(s):  
United States ◽  
The United States ◽  
Plant Diseases ◽  
Soybean Rust ◽  
Yield Potential ◽  
Stem Rot ◽  
Yield Losses ◽  
Sclerotinia Stem Rot ◽  
Soybean Yield ◽  
The Impact

Research must focus on management of diseases that cause extensive losses, especially when funds for research are limited. Knowledge of the losses caused by various soybean diseases is essential when prioritizing research budgets. The objective of this project was to compile estimates of soybean yield potential losses caused by diseases for each soybean producing state in the United States from 2006 to 2009. This data is of special interest since the 4-year period summarized in this report, permits an examination of the impact of soybean rust that was first reported in the United States in 2004. Thus, in addition to the goal of providing this information to aid funding agencies and scientists in prioritizing research objectives and budgets, an examination of the impact of soybean rust on soybean yield losses relative to other diseases is warranted. Yield losses caused by individual diseases varied among states and years. Soybean cyst nematode caused more yield losses than any other disease during 2006 to 2009. Seedling diseases, Phytophthora root and stem rot, sudden death syndrome, Sclerotinia stem rot, and charcoal rot ranked in the top six of diseases that caused yield loss during these years. Soybean yield losses due to soybean rust and Sclerotinia stem rot varied greatly over years, especially when compared to other diseases. Accepted for publication 21 October 2010. Published 22 November 2010.

scholarly journals Evaluation of Soybean for Resistance to Neohyadatothrips variabilis (Thysanoptera: Thripidae) Noninfected and Infected With Soybean Vein Necrosis Virus

2019 ◽  
Vol 113 (2) ◽  
pp. 949-955 ◽  
Author(s):  
D Lagos-Kutz ◽  
M L Pawlowski ◽  
J Haudenshield ◽  
J Han ◽  
L L Domier ◽  
...  
Keyword(s):  
Choice Experiments ◽  
The United States ◽  
Necrosis Virus ◽  
Plant Introductions ◽  
Soybean Genotypes ◽  
Efficient Vector ◽  
Vein Necrosis ◽  
Neohydatothrips Variabilis ◽  
Multiple Species ◽  
Soybean Thrips

Abstract Soybean vein necrosis virus (SVNV) was first identified in Arkansas and Tennessee in 2008 and is now known to be widespread in the United States and Canada. Multiple species of thrips transmit this and other tospoviruses with Neohydatothrips variabilis (Beach) (soybean thrips) cited as the most efficient vector for SVNV. In this study, 18 soybean, Glycine max (L.) Merr., genotypes were evaluated in four experiments by infesting plants with noninfected and SVNV-infected thrips using choice and no-choice assays. In both choice experiments with noninfected and SVNV-infected thrips, the lowest number of immature soybean thrips occurred on plant introductions (PIs) 229358 and 604464 while cultivars Williams 82 and Williamsfield Illini 3590N supported higher counts of mature thrips. The counts between the two assays (noninfected and SVNV-infected thrips) were positively correlated. In both no-choice experiments with noninfected and SVNV-infected thrips, counts of thrips did not differ by soybean genotypes. Further studies are needed to characterize the inheritance and mechanisms involved in the resistance found in the choice assay.

Meta-Analytic and Economic Approaches for Evaluation of Pesticide Impact on Sclerotinia Stem Rot Control and Soybean Yield in the North Central United States

2019 ◽  
Vol 109 (7) ◽  
pp. 1157-1170 ◽  
Author(s):  
Jaime F. Willbur ◽  
Paul D. Mitchell ◽  
Mamadou L. Fall ◽  
Adam M. Byrne ◽  
Scott A. Chapman ◽  
...  
Keyword(s):  
Disease Severity ◽  
Yield Loss ◽  
Severity Index ◽  
Stem Rot ◽  
Sclerotinia Stem Rot ◽  
Soybean Yield ◽  
The North ◽  
Central United States ◽  
Meta Analyses ◽  
The Impact

As complete host resistance in soybean has not been achieved, Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum continues to be of major economic concern for farmers. Thus, chemical control remains a prevalent disease management strategy. Pesticide evaluations were conducted in Illinois, Iowa, Michigan, Minnesota, New Jersey, and Wisconsin from 2009 to 2016, for a total of 25 site-years (n = 2,057 plot-level data points). These studies were used in network meta-analyses to evaluate the impact of 10 popular pesticide active ingredients, and seven common application timings on SSR control and yield benefit, compared with not treating with a pesticide. Boscalid and picoxystrobin frequently offered the best reductions in disease severity and best yield benefit (P < 0.0001). Pesticide applications (one- or two-spray programs) made during the bloom period provided significant reductions in disease severity index (DIX) (P < 0.0001) and led to significant yield benefits (P = 0.0009). Data from these studies were also used in nonlinear regression analyses to determine the effect of DIX on soybean yield. A three-parameter logistic model was found to best describe soybean yield loss (pseudo-R2 = 0.309). In modern soybean cultivars, yield loss due to SSR does not occur until 20 to 25% DIX, and considerable yield loss (−697 kg ha−1 or −10 bu acre−1) is observed at 68% DIX. Further analyses identified several pesticides and programs that resulted in greater than 60% probability for return on investment under high disease levels.

scholarly journals Impact of Sclerotinia Stem Rot on Yield of Canola

Plant Disease ◽  
2007 ◽  
Vol 91 (2) ◽  
pp. 191-194 ◽  
Author(s):  
L. E. del Río ◽  
C. A. Bradley ◽  
R. A. Henson ◽  
G. J. Endres ◽  
B. K. Hanson ◽  
...  
Keyword(s):  
North Dakota ◽  
Field Experiments ◽  
Disease Incidence ◽  
The United States ◽  
Stem Rot ◽  
Sclerotinia Stem Rot ◽  
Potential Yield ◽  
Naturally Occurring ◽  
The Cost ◽  
The Impact

Sclerotinia sclerotiorum is the causal agent of Sclerotinia stem rot (SSR) of canola (Brassica napus). In North Dakota, the leading canola producer in the United States, SSR is an endemic disease. In order to estimate the impact of this disease on canola yield, field experiments were conducted from 2000 to 2004 at several locations in North Dakota and Minnesota. Experimental plots were either inoculated with laboratory-produced ascospores or infected by naturally occurring inoculum in commercial fields. Applying fungicides at different concentrations and timings during the flowering period created epiphytotics of diverse intensities. Disease incidence was measured once prior to harvesting the crop on 50 to 100 plants per plot. Results of the study indicated that 0.5% of the potential yield (equivalent to 12.75 kg/ha) was lost for every unit percentage of SSR incidence (range of 0.18 to 0.96%). Considering the current cost of fungicide applications and the market value of this commodity, a 17% SSR incidence could cause losses similar to the cost of a fungicide application. Additional efforts are required to improve current levels of tolerance of canola plants to this pathogen.

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