Application of Continuum Removal Method for Estimating Disease Severity Level of Wheat Powdery Mildew

2011 ◽  
Vol 396-398 ◽  
pp. 2012-2017
Author(s):  
Shi Zhou Du ◽  
Wen Jiang Huang ◽  
Rong Fu Wang ◽  
Ju Hua Luo ◽  
Jin Ling Zhao ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Disease Severity ◽  
Hyperspectral Data ◽  
Characteristic Parameters ◽  
Spectral Reflectivity ◽  
Wheat Powdery Mildew ◽  
Severity Levels ◽  
Wheat Leaves ◽  
The Right ◽  
Continuum Removal

The hyperspectral bands sensitive to the disease severity levels of wheat powdery mildew was elucidated in this study. The disease severity levels of wheat powdery mildew were also inverted by the extracting characteristic parameters, which provided a basis for detecting the wheat powdery mildew using hyperspectral data. The spectral data of single leaves was obtained at heading stage, the spectral characteristic parameters and sensitivity of wheat leaves were analyzed qualitatively and quantitatively. The result showed that spectral reflectivity within the visible wavebands (400—760 nm) was increased with the aggravating disease severity levels. The spectral sensitivity reached the maximum value within visible wavebands and the optimal sensitive bands for detecting disease severity levels was 630—680nm. After the spectrum was continuum removal-treated, the absorption position moved to longer wavelength with the aggravating disease severity levels and the disease severity levels showed extremely significant negative correlations with the absorption height, absorption width and absorption area. The linear regression equation has high determination coefficient and low root mean square error using the right AAI as independent variable to establish the model. Moreover, the precision verification test also showed that the model performed best in monitoring wheat powdery mildew. In conclusion, disease severity levels of wheat powdery mildew could be inverted effectively by hyperspectral technology, which provides the foundation for detecting wheat powdery mildew.

scholarly journals Detecting Wheat Powdery Mildew and Predicting Grain Yield Using Unmanned Aerial Photography

Plant Disease ◽  
2018 ◽  
Vol 102 (10) ◽  
pp. 1981-1988 ◽  
Author(s):  
Wei Liu ◽  
Xueren Cao ◽  
Jieru Fan ◽  
Zhenhua Wang ◽  
Zhengyuan Yan ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Grain Yield ◽  
Disease Severity ◽  
Flight Altitude ◽  
Imaging Data ◽  
Remote Imaging ◽  
Wheat Powdery Mildew ◽  
Imaging Tool ◽  
Random Coefficient Regression ◽  
Relationship Of

High-resolution aerial imaging with an unmanned aerial vehicle (UAV) was used to quantify wheat powdery mildew and estimate grain yield. Aerial digital images were acquired at Feekes growth stage (GS) 10.5.4 from flight altitudes of 200, 300, and 400 m during the 2009–10 and 2010–11 seasons; and 50, 100, 200, and 300 m during the 2011–12, 2012–13, and 2013–14 seasons. The image parameter lgR was consistently correlated positively with wheat powdery mildew severity and negatively with wheat grain yield for all combinations of flight altitude and year. Fitting the data with random coefficient regression models showed that the exact relationship of lgR with disease severity and grain yield varied considerably from year to year and to a lesser extent with flight altitude within the same year. The present results raise an important question about the consistency of using remote imaging information to estimate disease severity and grain yield. Further research is needed to understand the nature of interyear variability in the relationship of remote imaging data with disease or grain yield. Only then can we determine how the remote imaging tool can be used in commercial agriculture.

scholarly journals Virulence Structure of the Eastern U.S. Wheat Powdery Mildew Population

Plant Disease ◽  
2008 ◽  
Vol 92 (7) ◽  
pp. 1074-1082 ◽  
Author(s):  
Ryan Parks ◽  
Ignazio Carbone ◽  
J. Paul Murphy ◽  
David Marshall ◽  
Christina Cowger
Keyword(s):  
United States ◽  
Powdery Mildew ◽  
Geographic Distance ◽  
Restricted Gene Flow ◽  
Eastern United States ◽  
Phenotypic Differences ◽  
Wheat Powdery Mildew ◽  
Detached Leaves ◽  
Geographic Separation ◽  
Wheat Leaves

Little is known about the population structure of wheat powdery mildew in the eastern United States, and the most recent report on virulence in this population involved isolates collected in 1993–94. In the present study, wheat leaves naturally infected with powdery mildew were collected from 10 locations in the southeastern United States in 2003 and 2005 and a collection of 207 isolates was derived from single ascospores. Frequencies of virulence to 16 mildew resistance (Pm) genes were determined by inoculating the isolates individually on replicated plates of detached leaves of differential wheat lines. These virulence frequencies were used to infer local effectiveness of Pm genes, estimate virulence complexity, detect significant associations between pairs of pathogen avirulence loci, and assess whether phenotypic differences between pathogen subpopulations increased with geographic distance. In both years, virulence to Pm3a, Pm3c, Pm5a, and Pm7 was present in more than 90% of sampled isolates and virulence to Pm1a, Pm16, Pm17, and Pm25 was present in fewer than 10% of isolates. In each year, 71 to 88% of all sampled isolates possessed one of a few multilocus virulence phenotypes, although there were significant differences among locations in frequencies of virulence to individual Pm genes. Several significant associations were detected between alleles for avirulence to pairs of Pm genes. Genetic (phenotypic) distance between isolate subpopulations increased significantly (R2 = 0.40, P < 0.001) with increasing geographic separation; possible explanations include different commercial deployment of Pm genes and restricted gene flow in the pathogen population.

scholarly journals An important role for secreted esterase in disease establishment of the wheat powdery mildew fungus Blumeria graminis f. sp.tritici

2011 ◽  
Vol 57 (3) ◽  
pp. 211-216 ◽  
Author(s):  
Jie Feng ◽  
Feng Wang ◽  
Geoff R. Hughes ◽  
Susan Kaminskyj ◽  
Yangdou Wei
Keyword(s):  
Powdery Mildew ◽  
Blumeria Graminis ◽  
Powdery Mildew Fungus ◽  
Diisopropyl Fluorophosphate ◽  
Wheat Powdery Mildew ◽  
Leaf Surfaces ◽  
Indigo Blue ◽  
Serine Esterases ◽  
Wheat Leaves

The activity of esterase secreted by conidia of wheat powdery mildew fungus, Blumeria graminis f. sp. tritici, was assayed using indoxyl acetate hydrolysis, which generates indigo blue crystals. Mature, ungerminated, and germinating conidia secrete esterase(s) on artificial media and on plant leaf surfaces. The activity of these esterases was inhibited by diisopropyl fluorophosphate, which is selective for serine esterases. When conidia were inoculated on wheat leaves pretreated with diisopropyl fluorophosphate, both appressorial germ tube differentiation and symptom development were significantly impaired, indicating an important role of secreted serine esterases in wheat powdery mildew disease establishment.

Identification of wheat powdery mildew using in-situ hyperspectral data and linear regression and support vector machines

2019 ◽  
Vol 101 (4) ◽  
pp. 1035-1045 ◽  
Author(s):  
Linsheng Huang ◽  
Wenjuan Ding ◽  
Wenjing Liu ◽  
Jinling Zhao ◽  
Wenjiang Huang ◽  
...  
Keyword(s):  
Support Vector Machines ◽  
Powdery Mildew ◽  
Linear Regression ◽  
Hyperspectral Data ◽  
Support Vector ◽  
Wheat Powdery Mildew ◽  
Vector Machines

scholarly journals Silencing of a Wheat Ortholog of Glucan Synthase-Like Gene Reduced Resistance to Blumeria graminis f. sp. tritici

2021 ◽  
Vol 12 ◽  
Author(s):  
Peng Cheng ◽  
Zihao Wang ◽  
Yanyan Ren ◽  
Pengfei Jin ◽  
Kangjie Ma ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Infection Type ◽  
Plant Immunity ◽  
Transcript Level ◽  
Blumeria Graminis ◽  
Virus Induced Gene Silencing ◽  
Crop Species ◽  
Glucan Synthase ◽  
Wheat Powdery Mildew ◽  
Wheat Leaves

Wheat powdery mildew, caused by the obligate biotrophic ascomycete fungal pathogen Blumeria graminis f. sp. tritici (Bgt), is a major threat to wheat production worldwide. It is known that Arabidopsis thaliana glucan synthase-like 5 (AtGSL5) improves the resistance of wheat to powdery mildew by increasing its anti-penetration abilities. However, the function of glucan synthase-like (GSL) orthologs in crop species remains largely unknown. In this study, TaGSL22, a novel functional ortholog of AtGSL5, was isolated as the only Bgt-induced GSL gene in wheat. Phylogenetic analysis indicated that TaGSL22 was conserved within the group of Gramineae and showed a closer relationship to GSL orthologs from monocots than to those from dicots. The TaGSL22 transcript was highest in the wheat leaves, followed by stems then roots. TaGSL22 was localized in the cell membrane and cytoplasm of wheat protoplasts, as predicted by transmembrane structure analysis. In addition, expression of TaGSL22 was induced by the plant hormones ethylene (ETH) and salicylic acid (SA), but down-regulated by jasmonate (JA) and abscisic acid (ABA). The transcript level of TaGSL22 was up-regulated in the incompatible interaction between Bgt and wheat, whereas it remained relatively unchanged in the compatible interaction. Knocking down of TaGSL22 by virus-induced gene silencing (VIGS) induced a higher infection type in the wheat–Bgt interaction. The TaGSL22-silenced plants exhibited reduced resistance to Bgt, accompanied by decreased callose accumulation. Our study shows a conserved function of GSL genes in plant immunity associated with penetration resistance, and it indicates that TaGSL22 can be used to improve papilla composition and enhance resistance to wheat powdery mildew.

scholarly journals Monitoring of Wheat Powdery Mildew under Different Nitrogen Input Levels Using Hyperspectral Remote Sensing

2021 ◽  
Vol 13 (18) ◽  
pp. 3753
Author(s):  
Wei Liu ◽  
Chaofei Sun ◽  
Yanan Zhao ◽  
Fei Xu ◽  
Yuli Song ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Powdery Mildew ◽  
Grain Yield ◽  
Disease Severity ◽  
Spectral Reflectance ◽  
Growth Stage ◽  
Hyperspectral Remote Sensing ◽  
Nitrogen Input ◽  
Wheat Powdery Mildew ◽  
Reflectance Data

Both wheat powdery mildew severities and nitrogen input levels can lead to changes in spectral reflectance, but they have been rarely studied simultaneously for their effect on spectral reflectance. To determine the effects and influences of different nitrogen input levels on monitoring wheat powdery mildew and estimating yield by near-ground hyperspectral remote sensing, Canopy hyperspectral reflectance data acquired at Feekes growth stage (GS) 10.5.3, 10.5.4, and 11.1 were used to monitor wheat powdery mildew and estimate grain yield under different nitrogen input levels during the 2016–2017, 2017–2018, 2018–2019 and 2019–2020 seasons. The relationships of powdery mildew and grain yield with vegetation indices (VIs) derived from spectral reflectance data across the visible (VIS) and near-infrared (NIR) regions of the spectrum were studied. The relationships of canopy spectral reflectance or first derivative spectral reflectance with powdery mildew did not differ under different nitrogen input levels. However, the dynamics of VIs differed in their sensitivities to nitrogen input levels, disease severity, grain yield, The area of the red edge peak (Σdr680–760 nm) was a better overall predictor for both disease severity and grain yield through linear regression models. The slope parameter estimates did not differ between the two nitrogen input levels at each GSs. Hyperspectral indices can be used to monitor wheat powdery mildew and estimate grain yield under different nitrogen input levels, but such models are dependent on GS and year, further research is needed to consider how to incorporate the growth stage and year-to-year variation into future applications.

scholarly journals The dynamics of powdery mildew development on pumpkins

2019 ◽  
pp. 111-123
Author(s):  
S. Mykhailenko ◽  
O. Melnyk
Keyword(s):  
Powdery Mildew ◽  
Disease Severity ◽  
Weather Conditions ◽  
Disease Spread ◽  
Forest Steppe ◽  
Erysiphe Cichoracearum ◽  
Significant Difference ◽  
Severity Of The Disease ◽  
The Right ◽  
Powdery Mildew Infection

Goal. To determine the spread and development of powdery mildew on pumpkins in the Forest-Steppe of Ukraine. Methods of investigation. The experiments were carried out in 2016—2018 biennium in the Right-Bank Forest Steppe of Ukraine (Khmelnytsky region) on the following varieties: common pumpkins — Ukrainskyi bahatoplidnyi, hull-less — Shtyriiskyi. Assessment of severity and spread of powdery mildew was carried out by conventional methods. The records were taken by visual method at 51, 73 and 89 stages (BBCH scale). Ten plants per plot were selected and spread and severity of the disease in percentage were determined. Results of investigation. During the period of investigation, powdery mildew was observed on the pumpkins of both varieties annually. Its first sympthoms were noted at the 15—17 stage. According to the morphological and biometric features, the pathogen identified as Erysiphe cichoracearum (DC.) V.P. Heluta. In the varieties studied, powdery mildew was found with a non-significant difference in severity and spread. In 2016, the severity of powdery mildew on pumpkins of variety Ukrainskyi bahatoplidnyi varied in the range of 15.4—19.5%, disease spread — 45.1—49.6%, on variety Shtyriiskyi development was 13.3—17.5%, distribution — 46.2—48.1%. In 2017, we obtained the following results: the disease severity for common pumpkins was in the range 13.2—17.4%, disease spread — 42.8—46.7%, for hull-less pumpkins disease severity was 12.2—16.8%, disease spread — 41.7—45.3%. In 2018, severity of powdery mildew was higher than in previous years, accounting for 21.2—26.7% with spread 50.4—55.2% on common pumpkins, and 19.4—25.3% with spread 48.8—54.2% on hull-less pumpkins. The correlation analysis of the data showed that the closest correlation between the spread and the development of the disease was observed with the precipitation and GTC in June. Conclusions. Dynamics of severity of powdery mildew during 2016—2018 years on common and hull-less pumpkins were studied. At stage of full ripening, the maximum rates of spread and severity of the disease were noted, which averaged 49.2—50.5% and 19.9—21.2% over the three years, respectively. No significant difference in the powdery mildew infection between common pumpkins (variety Ukrainskyi bahatoplidnyi) and hull-less pumpkins (variety Shtyriiskyi) was found. The defining conditions for the development of powdery mildew on pumpkins are the weather conditions in June, most notably the presence of increased moisture during this period.

scholarly journals Development of Weather- and Airborne Inoculum-Based Models to Describe Disease Severity of Wheat Powdery Mildew

Plant Disease ◽  
2015 ◽  
Vol 99 (3) ◽  
pp. 395-400 ◽  
Author(s):  
Xueren Cao ◽  
Dongming Yao ◽  
Xiangming Xu ◽  
Yilin Zhou ◽  
Kejian Ding ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Disease Severity ◽  
Meteorological Data ◽  
Free Field ◽  
Model Performance ◽  
Model Parameters ◽  
Weather Variables ◽  
Wheat Powdery Mildew ◽  
Airborne Inoculum ◽  
Airborne Conidia

Disease severity of wheat powdery mildew, caused by Blumeria graminis f. sp. tritici, was recorded weekly in fungicide-free field plots for three successive seasons from 2009 to 2012 in Langfang City, Hebei Province, China. Airborne conidia of B. graminis f. sp. tritici were trapped using a volumetric spore sampler, and meteorological data were collected using an automatic weather station. Cumulative logit models were used to relate the development of wheat powdery mildew to weather variables and airborne conidia density. Density of airborne conidia was the most important variate; further addition of weather variables, although statistically significant, increased model performance only slightly. A model based on variables derived from temperature and humidity had a generalized R2 of 72.4%. Although there were significant differences in model parameters among seasons, fine adjustment did not increase model performance significantly.

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