scholarly journals Analysis of Downy Mildew Infection of Field Pea Varieties Using the Logistic Model

2012 ◽  
Vol 52 (2) ◽  
pp. 240-246 ◽  
Author(s):  
Ewa Bakinowska ◽  
Wiesław Pilarczyk ◽  
Agnieszka Osiecka ◽  
Kazimierz Wiatr
Keyword(s):  
Downy Mildew ◽  
Logistic Model ◽  
Field Trials ◽  
Field Pea ◽  
Model Parameters ◽  
Scoring Method ◽  
Multinomial Data ◽  
Time Period ◽  
Resistant Varieties ◽  
Evaluation Of Data

Analysis of Downy Mildew Infection of Field Pea Varieties Using the Logistic ModelThe logistic model is commonly used for analysis of discrete, multinomial data. Such a model was used for the statistical evaluation of data concerning infection of field pea varieties by downy mildew, in two series of field trials. Each series consisted of experiments performed in locations spread over the whole of Poland in the time period from 2002 to 2005. Varieties cultivated on light soils were compared in the first series, and varieties cultivated on rich soils in the second. The most resistant varieties were identified (Sokolik - light soils, Terno - rich soils) and significant differences among varieties were detected. Estimators of model parameters were found using the Fisher scoring method implemented inlogistic glmprocedure of the SAS system.

Management strategies to reduce losses caused by fusarium seedling blight of field pea

2013 ◽  
Vol 93 (4) ◽  
pp. 619-625 ◽  
Author(s):  
K. F. Chang ◽  
S. F. Hwang ◽  
H. U. Ahmed ◽  
B. D. Gossen ◽  
G. D. Turnbull ◽  
...  
Keyword(s):  
Root Rot ◽  
Field Experiments ◽  
Management Strategies ◽  
Stand Density ◽  
Field Trials ◽  
Field Pea ◽  
Seedling Blight ◽  
Inoculum Level ◽  
Fusarium Seedling Blight ◽  
Disease Pressure

Chang, K. F., Hwang, S. F., Ahmed, H. U., Gossen, B. D., Turnbull, G. D. and Strelkov, S. E. 2013. Management strategies to reduce losses caused by fusarium seedling blight of field pea. Can. J. Plant Sci. 93: 619–625. Fusarium seedling blight can cause substantial reductions in the stand density of field pea in western Canada. In greenhouse experiments, emergence decreased and root rot severity rose with increasing inoculum density. In field trials in 2007 and 2008 near Edmonton, AB, seeding at different depths and seeding dates did not consistently affect emergence or yield in Fusarium-infested soils. In field experiments, emergence declined significantly with each increase in inoculum level. Also, seed yield were reduced at high levels of disease pressure. Treatment of seed with Apron Maxx improved emergence, nodulation and yield of treatments challenged with inoculum of F. avenaceum in both greenhouse and field experiments. This research demonstrates the need to prevent seedling blight and root rot through proper seed treatment.

Efficacy of Clonostachys rosea strain ACM941 and fungicide seed treatments for controlling the root rot complex of field pea

2003 ◽  
Vol 83 (3) ◽  
pp. 519-524 ◽  
Author(s):  
A. G. Xue
Keyword(s):  
Root Rot ◽  
Untreated Control ◽  
Seedling Emergence ◽  
Field Trials ◽  
Field Pea ◽  
Seed Treatments ◽  
Clonostachys Rosea ◽  
Pea Root ◽  
Pea Root Rot ◽  
Better Than

The efficacy of seed treatments with bioagent ACM941 (a strain of Clonostachys rosea), its formulated products GB116 and ACM941-Pro, and common fungicides for the control of pea root rot complex were examined in six field trials in western Canada from 1996 to 2000. The effects on seedling emergence, root rot severity, and yield varied among years. In trials 1 and 2 (1996–1997), none of the treatments significantly reduced root rot severity or increased yield. ACM941 + Thiram 75WP was the most effective treatment, increasing emergence by 17.4% and was significantly better than that of the untreated controls. In trials 3 and 4 (1997–1998), Apron FL alone and ACM941 + Apron FL were significantly better than the untreated control, increasing emergence by 6.2 and 7.7%, and yield by 10.8 and 11.5%, respectively. In trials 5 and 6 (1999–2000), AC M 941 and GB116 were equally the most effective treatments, increasing emergence by 11.5 and 12.2%, and yield by 8.2 and 6.3%, respectively. These effects were significantly greater than that of the untreated control, but not significantly different from those of Apron FL or Vitaflo-280. ACM941-Pro was developed and tested in 2000 only, and it increased emergence by 17.1% and reduced root rot severity by 29.6%. Key words: Bioagent, Clonostachys rosea, field pea, Pisum sativum, pea root rot complex (PRRC), seed treatment, fungicide

Field assessment of partial resistance to mycosphaerella blight in Pisum subspecies accessions

2012 ◽  
Vol 92 (2) ◽  
pp. 289-296 ◽  
Author(s):  
R. L. Conner ◽  
B. D. Gossen ◽  
S. F. Hwang ◽  
K. F. Chang ◽  
K. B. McRae ◽  
...  
Keyword(s):  
Partial Resistance ◽  
Field Trials ◽  
Field Pea ◽  
Mycosphaerella Pinodes ◽  
Detached Leaf ◽  
High Severity ◽  
Field Assessment ◽  
Ascochyta Pinodes ◽  
The Mean ◽  
Production Areas

Conner, R. L., Gossen, B. D., Hwang, S. F., Chang, K. F., McRae, K. B. and Penner, W. C. 2012. Field assessment of partial resistance to mycosphaerella blight in Pisum subspecies accessions. Can. J. Plant Sci. 92: 289–296. Mycosphaerella blight, caused by Mycosphaerella pinodes (Berk. & Bloxam) Vestergr., the teleomorph of Ascochyta pinodes Jones, is an important foliar disease of field pea in the major production areas of the world. Partial resistance to mycosphaerella blight has been reported in some field pea cultivars, but, at best, they are only moderately susceptible. A 3-yr field study was conducted to evaluate the mycosphaerella blight reactions of 28 accessions from a number of subspecies of Pisum sativum L. and one accession of P. fulvum Sibth. A few of the accessions carried mutations for the genes af, tl, and st that affect the morphology of the leaflets, stipules and tendrils. Reactions to mycosphaerella blight were characterized based on the mean of the severity ratings taken on the two final assessment dates before the crop matured and also on the change in mycosphaerella blight severity between these two dates. In many of the accessions, severity ratings were similar to that of the moderately susceptible check cultivar, CDC Peko, while a few had high severity ratings similar to those of the susceptible check cultivars. The accession PI 512079, which has small stipules, branched petioles with many leaflets but no tendrils, had the lowest ratings for mycosphaerella blight severity. Four other accessions exhibited the smallest change in mycosphaerella blight severity at the end of the growing season. Differences in leaf morphology likely influenced the change in disease severity, since all the semi-leafless and leafless accessions had smaller changes in mycosphaerella blight severity than the susceptible check cultivars. In a detached leaf assay with two isolates of Mycosphaerella pinodes (Berk. & Bloxam) Vestergr., the smallest lesions formed on PI 512079, but otherwise the results failed to show a relationship with the observed severity values in the field trials.

scholarly journals Unsupervised Learning in RSS-Based DFLT Using an EM Algorithm

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5549
Author(s):  
Ossi Kaltiokallio ◽  
Roland Hostettler ◽  
Hüseyin Yiğitler ◽  
Mikko Valkama
Keyword(s):  
Em Algorithm ◽  
Expectation Maximization ◽  
Tracking System ◽  
Model Parameters ◽  
Calibration Data ◽  
Tracking Accuracy ◽  
Time Period ◽  
The Em Algorithm ◽  
Device Free ◽  
Localization And Tracking

Received signal strength (RSS) changes of static wireless nodes can be used for device-free localization and tracking (DFLT). Most RSS-based DFLT systems require access to calibration data, either RSS measurements from a time period when the area was not occupied by people, or measurements while a person stands in known locations. Such calibration periods can be very expensive in terms of time and effort, making system deployment and maintenance challenging. This paper develops an Expectation-Maximization (EM) algorithm based on Gaussian smoothing for estimating the unknown RSS model parameters, liberating the system from supervised training and calibration periods. To fully use the EM algorithm’s potential, a novel localization-and-tracking system is presented to estimate a target’s arbitrary trajectory. To demonstrate the effectiveness of the proposed approach, it is shown that: (i) the system requires no calibration period; (ii) the EM algorithm improves the accuracy of existing DFLT methods; (iii) it is computationally very efficient; and (iv) the system outperforms a state-of-the-art adaptive DFLT system in terms of tracking accuracy.

scholarly journals Effect of mancozeb on the control of mycosphaerella blight of field pea

2000 ◽  
Vol 80 (2) ◽  
pp. 403-406 ◽  
Author(s):  
T. D. Warkentin ◽  
A. G. Xue ◽  
D. W. McAndrew
Keyword(s):  
Yield Loss ◽  
Foliar Application ◽  
Genetic Resistance ◽  
Similar Efficacy ◽  
Field Trials ◽  
Field Pea ◽  
Mycosphaerella Pinodes ◽  
Western Canada ◽  
Flowering Stage ◽  
Plot Design

Mycosphaerella blight (MB) [Mycosphaerella pinodes (Berk. & Blox.)Vestergr.] causes substantial yield loss to field pea in western Canada in most seasons and is a disease for which genetic resistance is lacking. The objective of this research was to evaluate the effectiveness of foliar application of mancozeb for the control of MB of field pea. Field trials of split-plot design were conducted at two sites per year from 1996 to 1998 in southern Manitoba, with cultivars as main-plots and fungicide treatments as sub-plots. In most site-years, a single application of mancozeb at the early flowering stage was effective in reducing MB severity and in increasing yield. Mancozeb had similar efficacy to chlorothalonil, the only currently registered fungicide for control of MB in field pea. The beneficial effect of both fungicides was greater for the highly MB susceptible cultivars AC Tamor and Carrera than the moderately MB susceptible cultivar Radley. Key words: Pisum sativum, field pea, mycosphaerella blight, mancozeb, chlorothalonil

scholarly journals Testing parallelism for the four-parameter logistic model with D-optimal design

2020 ◽  
Vol 15 (3) ◽  
pp. 273-284
Author(s):  
Lin Ying ◽  
Hyun Seung Won
Keyword(s):  
Optimal Design ◽  
Logistic Model ◽  
Test Preparation ◽  
Test Sample ◽  
Optimal Designs ◽  
Model Parameters ◽  
Reference Standard ◽  
Response Curves ◽  
Classical Design ◽  
Intersection Union Test

In order to determine the potency of the test preparation relative to the standard preparation, it is often important to test parallelism between a pair of dose-response curves of reference standard and test sample. Optimal designs are known to be more powerful in testing parallelism as compared to classical designs. In this study, D-optimal design was implemented to study the parallelism and compare+ its performance with a classical design. We modified D-optimal design to test the parallelism in the four-parameter logistic (4PL) model using Intersection-Union Test (IUT). IUT method is appropriate when the null hypothesis is expressed as a union of sets, and by using this method complicated tests involving several parameters are easily constructed. Since D-optimal design minimizes the variances of model parameters, it can bring more power to the IUT test. A simulation study will be presented to compare the empirical properties of the two different designs.

scholarly journals Challenges with Managing Disease Complexes during Application of Different Measures Against Foliar Diseases of Field Pea

Plant Disease ◽  
2020 ◽  
Author(s):  
Martin John BARBETTI ◽  
Tanveer N Khan ◽  
Ian Pritchard ◽  
Jay Ram Lamichhane ◽  
Jean-Noël Aubertot ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Seed Yield ◽  
Management Practices ◽  
Plant Density ◽  
Ascochyta Blight ◽  
Early Time ◽  
Field Pea ◽  
Foliar Disease ◽  
Foliar Pathogens ◽  
Disease Complexes

Studies were undertaken across five field locations in Western Australia to determine the relative changes in disease severity and subsequent field pea yield from up to four foliar pathogens associated with a field pea foliar disease complex (viz. Didymella, Phoma, Peronospora, Septoria), across four different pea varieties sown at three different times and at three different densities. Delaying sowing of field pea significantly (P<0.05) reduced severity of Ascochyta blight (all five locations) and Septoria blight (1 location), increased severity of downy mildew (4 locations), but had no effect on seed yield. In relation to Ascochyta blight severity at 80 days after sowing, at all locations the early time of sowing had significantly (P<0.05) more severe Ascochyta blight than the mid and late times of sowing. Increasing actual plant density from 20-25 plants m-2 to 58-78 plants m-2 significantly (P<0.05) increased the severity of the Ascochyta blight (4 locations) and downy mildew (1 location), and increased seed yield at four locations irrespective of sowing date and three locations irrespective of variety. Compared with varieties Dundale, Wirrega and Pennant, variety Alma showed significantly (P<0.05) less severe Ascochyta blight (1 location), downy mildew (1 location) and Septoria blight (1 location). Grain yield was highest for the early time of sowing at three locations. Varieties Alma, Dundale and Wirrega significantly (P<0.05) out yielded Pennant at four locations. The percentage of isolations of individual Ascochyta blight pathogens at 80 days after the first time of sowing varied greatly, with Didymella ranging 25-93% and Phoma from 6- 23% across the five field locations. This fluctuating nature of individual pathogen types and proportions within the Ascochyta blight complex, along with variation in occurrence of Peronospora and Septoria, highlights the challenges to understand and manage the complexities of co-occurring different foliar pathogens of field pea. While the search for more effective host resistance continues, there is a need for and opportunities from further exploring and exploiting cultural management approaches focussing on crop sequence diversification, intercropping, manipulating time of sowing and stand density, and application of improved seed sanitation and residue/inoculum management practices. We discuss the constraints and opportunities towards overcoming the challenges associated with managing foliar disease complexes in field pea.

Yield loss and management of downy mildew on field pea in Alberta, Canada

2013 ◽  
Vol 46 ◽  
pp. 23-28 ◽  
Author(s):  
K.F. Chang ◽  
S.F. Hwang ◽  
H.U. Ahmed ◽  
S.E. Strelkov ◽  
R.L. Conner ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Yield Loss ◽  
Field Pea

Corroboration That Highly Resistant Impatiens Cultivars Are Not Immune to Downy Mildew Disease: A Report of Crop Losses from Two California Producers

2020 ◽  
Vol 21 (3) ◽  
pp. 214-216
Author(s):  
Margery Daughtrey ◽  
Janna Beckerman ◽  
William J. Davis ◽  
Karen Rane ◽  
Jo Anne Crouch
Keyword(s):  
United States ◽  
Downy Mildew ◽  
Genetic Resistance ◽  
Disease Outbreaks ◽  
The United States ◽  
Field Trials ◽  
Commercial Production ◽  
Impatiens Walleriana ◽  
Action Groups ◽  
Downy Mildew Disease

Two new series of Impatiens walleriana (impatiens) cultivars, Beacon and Imara XDR, were released to commercial growers in the United States in 2019 to 2020. Field trials show these new cultivar series are highly resistant to impatiens downy mildew (IDM). However, neither of these two impatiens series are completely immune to the disease, and preventive fungicide programs are still recommended for use throughout production to maintain plant health. Here we report two destructive outbreaks of IDM from Imara XDR in two commercial production facilities in California, one in 2019 and one in 2020. The disease outbreaks were caused by a known rDNA genotype of Plasmopara destructor (synonym = P. obducens). Modified Koch’s postulates showed that the pathogen could infect and cause disease in both Beacon and Imara XDR plants. Mefenoxam applied by both growers may have been ineffective due to resistance in P. destructor populations, which has been demonstrated on several previous occasions. Given these findings, fungicide programs intended to supplement genetic resistance should not be overly reliant upon application of mefenoxam and should utilize effective materials from different mode of action groups, in rotation. Fungicides to supplement genetic resistance are particularly appropriate in frost-free areas or in any circumstances that provide a potential inoculum source.

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