scholarly journals Evaluation of Resistance to Ergot, Caused by Claviceps purpurea, in Kentucky Bluegrass, Based on Incidence and Severity Estimates

Plant Disease ◽  
2003 ◽  
Vol 87 (9) ◽  
pp. 1043-1047 ◽  
Author(s):  
Steve C. Alderman ◽  
Reed E. Barker
Keyword(s):  
Large Scale ◽  
Disease Incidence ◽  
Kentucky Bluegrass ◽  
Disease Assessment ◽  
Flower Initiation ◽  
Claviceps Purpurea ◽  
Mean Values ◽  
Incidence Data ◽  
Maturity Period ◽  
Important Disease

Ergot, caused by Claviceps purpurea, is an important disease of Kentucky bluegrass grown for seed. Resistance is a preferred means of disease control, although approaches to evaluating ergot resistance in Kentucky bluegrass are not well established. A large scale disease assessment trial was established to compare within-year and year-to-year variability among measures of ergot incidence or severity in Kentucky bluegrass and to determine the most efficient approaches for cultivar evaluation. The susceptibility of 104 Kentucky bluegrass cultivars (78 commercial and 26 experimental) to ergot was assessed, based on percentage of panicles with sclerotia (incidence), sclerotia per panicle (severity), percentage of seeds replaced by sclerotia, or percentage of sclerotia among seed by weight. Cultivar ranking for susceptibility within years was similar for all methods of ergot assessment. Yearly mean incidence of ergot among cultivars ranged from 1.0 to 97.5% for susceptible cv. HV102 to 0.0 to 2.5% for resistant cv. Huntsville, with remaining cultivars distributed between the extremes. Yearly mean values of ergot incidence and severity differed among years. Much of this variability was due to days with rain during the period from flower initiation to maturity (period of susceptibility). Disease incidence was correlated (P ≤ 0.05) with days with rain in 22 of the cultivars. Duration of flowering was correlated (P ≤ 0.05) with ergot incidence in 11 cultivars. Results from this study suggest that variability in host and environment would likely offset any gain in precision of severity data. In large trials in particular, collection of incidence data (percentage of panicles with ergot) would provide the most timely and efficient means for ergot assessment.

scholarly journals Relationships Between Incidence and Severity of Fusarium Head Blight on Winter Wheat in Ohio

2005 ◽  
Vol 95 (9) ◽  
pp. 1049-1060 ◽  
Author(s):  
P. A. Paul ◽  
S. M. El-Allaf ◽  
P. E. Lipps ◽  
L. V. Madden
Keyword(s):  
Fusarium Head Blight ◽  
Prediction Interval ◽  
Disease Incidence ◽  
Disease Assessment ◽  
Data Sets ◽  
Head Blight ◽  
Incidence Data ◽  
Treatment Comparisons ◽  
Time Required ◽  
The Relationship

To determine the relationship between incidence (I; proportion of diseased spikes) and severity (S; mean proportion of diseased spikelets per spike) for Fusarium head blight of wheat and to determine if severity could be predicted reliably from incidence data, disease assessments were made visually at multiple sample sites in artificially and naturally inoculated research and production fields between 1999 and 2002. Ten distinct data sets were collected. Mean disease intensity ranged from 0.023 to 0.975 for incidence and from 0.0003 to 0.808 for severity. A model based on complementary log-log transformation of incidence and severity performed well for all data sets, based on calculated coefficients of determination and random residual plots. The I-S relationship was consistent among years and locations, with similar slopes for all data sets. For 7 of the 10 data sets and for the pooled data from all locations and years, the estimated slope from the fit of the model ranged from 1.03 to 1.26. Time of disease assessment affected the relationship between incidence and severity; however, the estimated slopes from each assessment time were also close to 1. Based on the width of the 95% prediction interval, severity was estimated more precisely at lower incidence values than at higher values. The number of sampling units and the index of dispersion of disease incidence had only minor effects on the precision with which S was predicted from I. The estimation of mean S from I would substantially reduce the time required to assess Fusarium head blight in field surveys and treatment comparisons, and the observed relationship between I and S could be used to identify genotypes with some types of disease resistance.

Study of Biochemical and Clinical Markers in Steatohepatitis Related to Obesity

2018 ◽  
Vol 69 (6) ◽  
pp. 1501-1505
Author(s):  
Roxana Maria Livadariu ◽  
Radu Danila ◽  
Lidia Ionescu ◽  
Delia Ciobanu ◽  
Daniel Timofte
Keyword(s):  
Liver Disease ◽  
Liver Biopsy ◽  
Large Scale ◽  
Biological Data ◽  
Obese Patients ◽  
Clinical Markers ◽  
Mean Values ◽  
Nonalcoholic Fatty Liver ◽  
Obstructive Sleep ◽  
Increased Risk

Nonalcoholic fatty liver disease (NAFLD) is highly associated to obesity and comprises several liver diseases, from simple steatosis to steatohepatitis (NASH) with increased risk of developing progressive liver fibrosis, cirrhosis and hepatocellular carcinoma. Liver biopsy is the gold standard in diagnosing the disease, but it cannot be used in a large scale. The aim of the study was the assessment of some non-invasive clinical and biological markers in relation to the progressive forms of NAFLD. We performed a prospective study on 64 obese patients successively hospitalised for bariatric surgery in our Surgical Unit. Patients with history of alcohol consumption, chronic hepatitis B or C, other chronic liver disease or patients undergoing hepatotoxic drug use were excluded. All patients underwent liver biopsy during sleeve gastrectomy. NAFLD was present in 100% of the patients: hepatic steatosis (38%), NASH with the two forms: with fibrosis (31%) and without fibrosis (20%), cumulating 51%; 7 patients had NASH with vanished steatosis. NASH with fibrosis statistically correlated with metabolic syndrome (p = 0.036), DM II (p = 0.01) and obstructive sleep apnea (p = 0.02). Waist circumference was significantly higher in the steatohepatitis groups (both with and without fibrosis), each 10 cm increase increasing the risk of steatohepatitis (p = 0.007). The mean values of serum fibrinogen and CRP were significantly higher in patients having the progressive forms of NAFLD. Simple clinical and biological data available to the practitioner in medicine can be used to identify obese patients at high risk of NASH, aiming to direct them to specialized medical centers.

A Comparison of Disease Assessment Methods for Southern Stem Rot of Peanut

2002 ◽  
Vol 29 (1) ◽  
pp. 66-71 ◽  
Author(s):  
S. L. Rideout ◽  
T. B. Brenneman ◽  
K. L. Stevenson
Keyword(s):  
Alternative Assessment ◽  
Disease Incidence ◽  
Sclerotium Rolfsii ◽  
Correlation Coefficients ◽  
Assessment Method ◽  
Assessment Methods ◽  
Alternative Methods ◽  
Stem Rot ◽  
Disease Assessment ◽  
Time Required

Abstract Southern stem rot (caused by the soilborne fungus Sclerotium rolfsii Sacc.) of peanut (Arachis hypogaea L.) traditionally has been assessed based on the percentage of infected 30.5-cm row segments, commonly referred to as disease incidence. Several alternative disease assessment methods were evaluated in four fungicide trials during the growing season (aboveground ratings) and immediately after peanut inversion (belowground ratings). Pearson's correlation coefficients compared disease assessments and yields for all trials. Across all disease assessment methods, belowground assessments at inversion showed a stronger correlation with yield than in-season aboveground assessments. Several of the alternative assessment methods showed a stronger negative correlation with yield than did the traditional disease incidence rating. However, none of the alternative methods were consistently more precise across all assessment dates and trials. There was a significant positive correlation between many of the alternative methods and the traditional disease incidence method. Furthermore, none of the alternative methods was better than the traditional method for detecting differences among fungicide treatments when subjected to ANOVA and subsequent Waller-Duncan mean separation tests (k-ratio = 100). Based on comparisons of the time required to assess disease intensity, the traditional disease assessment method was found to be the most time efficient method of those tested in this study.

scholarly journals Spatial Heterogeneity of the Incidence of Powdery Mildew on Hop Cones

Plant Disease ◽  
2006 ◽  
Vol 90 (11) ◽  
pp. 1433-1440 ◽  
Author(s):  
David H. Gent ◽  
Walter F. Mahaffee ◽  
William W. Turechek
Keyword(s):  
Powdery Mildew ◽  
Spatial Heterogeneity ◽  
Power Law ◽  
Binomial Distribution ◽  
Disease Incidence ◽  
Disease Assessment ◽  
Cluster Sampling ◽  
Data Sets ◽  
Ratio Test ◽  
Frequency Distributions

The spatial heterogeneity of the incidence of hop cones with powdery mildew (Podosphaera macularis) was characterized from transect surveys of 41 commercial hop yards in Oregon and Washington from 2000 to 2005. The proportion of sampled cones with powdery mildew ( p) was recorded for each of 221 transects, where N = 60 sampling units of n = 25 cones assessed in each transect according to a cluster sampling strategy. Disease incidence ranged from 0 to 0.92 among all yards and dates. The binomial and beta-binomial frequency distributions were fit to the N sampling units in a transect using maximum likelihood. The estimation procedure converged for 74% of the data sets where p > 0, and a loglikelihood ratio test indicated that the beta-binomial distribution provided a better fit to the data than the binomial distribution for 46% of the data sets, indicating an aggregated pattern of disease. Similarly, the C(α) test indicated that 54% could be described by the beta-binomial distribution. The heterogeneity parameter of the beta-binomial distribution, θ, a measure of variation among sampling units, ranged from 0.01 to 0.20, with a mean of 0.037 and a median of 0.015. Estimates of the index of dispersion ranged from 0.79 to 7.78, with a mean of 1.81 and a median of 1.37, and were significantly greater than 1 for 54% of the data sets. The binary power law provided an excellent fit to the data, with slope and intercept parameters significantly greater than 1, which indicated that heterogeneity varied systematically with the incidence of infected cones. A covariance analysis indicated that the geographic location (region) of the yards and the type of hop cultivar had little effect on heterogeneity; however, the year of sampling significantly influenced the intercept and slope parameters of the binary power law. Significant spatial autocorrelation was detected in only 11% of the data sets, with estimates of first-order autocorrelation, r1, ranging from -0.30 to 0.70, with a mean of 0.06 and a median of 0.04; however, correlation was detected in only 20 and 16% of the data sets by median and ordinary runs analysis, respectively. Together, these analyses suggest that the incidence of powdery mildew on cones was slightly aggregated among plants, but patterns of aggregation larger than the sampling unit were rare (20% or less of data sets). Knowledge of the heterogeneity of diseased cones was used to construct fixed sampling curves to precisely estimate the incidence of powdery mildew on cones at varying disease intensities. Use of the sampling curves developed in this research should help to improve sampling methods for disease assessment and management decisions.

scholarly journals Morphological characterization and genetic diversity in lentil (Lens culinaris medikus ssp. Culinaris) germplasm

2014 ◽  
Vol 4 (1) ◽  
pp. 70-76
Author(s):  
KU Ahamed ◽  
B Akhter ◽  
MR Islam ◽  
MR Humaun ◽  
MJ Alam
Keyword(s):  
Seed Weight ◽  
Female Flower ◽  
Morphological Characterization ◽  
Flower Initiation ◽  
Mean Values ◽  
Maximum Value ◽  
Cluster Distance ◽  
The Mean ◽  
100 Seed Weight ◽  
Number Of Seeds

Genetic divergence of 110 lentil germplasm with checks was assessed based on morphological traits using multivariate analysis. Mahalanobis generalized distance (D2) analysis was used to group the lentil genotypes. Significant variations among lentil genotypes were observed in respect of days to 1st flowering, days to 50% flowering, days to maturity, plant height, and number of pods per peduncle, number of pods per plant, number of seeds per plant, 100 seed weight and yield per plant. Considering the mean values, the germplasm were grouped into ten clusters. The highest number of genotypes (17) was in cluster X and lowest (5) both in cluster II and IV. Cluster IV had the highest cluster mean for number of pods per plant (297.08), number of seeds per plant (594.16), 100 seed weight (1.44 g) and yield per plant (8.53 g). Among them, the highest inter-cluster distance was obtained between the cluster IV and I (24.61) followed by IV and III (22.33), while the lowest was between IX and II (1.63). The maximum value of inter-cluster distance indicated that genotypes belonging to cluster IV were far diverged from those of cluster I. The first female flower initiation was earlier in BD-3812 (49 days) in cluster I and cluster IV had highest grain yield per plant (8.53). BD-3807 produced significant maximum number of pods per plant (298.40) in cluster IV. DOI: http://dx.doi.org/10.3329/ijarit.v4i1.21095 Int. J. Agril. Res. Innov. & Tech. 4 (1): 70-76, June, 2014

scholarly journals Quantification of volumetric morphometry and optical property in the cortex of human cerebellum at micrometer resolution

2021 ◽  
Author(s):  
Chao J. Liu ◽  
William Ammon ◽  
Viviana Siless ◽  
Morgan Fogarty ◽  
Ruopeng Wang ◽  
...  
Keyword(s):  
Optical Property ◽  
Cerebellar Cortex ◽  
Large Scale ◽  
Granular Layer ◽  
Ex Vivo ◽  
Volumetric Analysis ◽  
Disease Assessment ◽  
Subject Variability ◽  
Human Cerebellum ◽  
Human Cerebellar Cortex

AbstractThe surface of the human cerebellar cortex is much more tightly folded than the cerebral cortex. Volumetric analysis of cerebellar morphometry in magnetic resonance imaging studies suffers from insufficient resolution, and therefore has had limited impact on disease assessment. Automatic serial polarization-sensitive optical coherence tomography (as-PSOCT) is an emerging technique that offers the advantages of microscopic resolution and volumetric reconstruction of large-scale samples. In this study, we reconstructed multiple cubic centimeters of ex vivo human cerebellum tissue using as-PSOCT. The morphometric and optical properties of the cerebellar cortex across five subjects were quantified. While the molecular and granular layers exhibited similar mean thickness in the five subjects, the thickness varied greatly between the crown of the folium and the depth of the fissure in the granular layer within subjects. Layer-specific optical property remained homogenous within individual subjects but showed higher cross-subject variability than layer thickness. High-resolution volumetric morphometry and optical property maps of human cerebellar cortex revealed by as-PSOCT have great potential to advance our understanding of cerebellar function and diseases.HighlightsWe reconstructed cubic centimeters of human cerebellar samples at micrometer resolution in five subjects.Thickness of the granular layer varies greatly between the crowns and depths of cerebellar fissures.Cross-subject variability is higher in optical property than cortical morphology.Our results suggest homogenous cell and myelin density in the cortical layers of human cerebellum despite the highly convoluted folding patterns.

Regional Spatial-Temporal Spread of Citrus Huanglongbing Is Affected by Rain in Florida

2018 ◽  
Vol 108 (12) ◽  
pp. 1420-1428 ◽  
Author(s):  
M. M. Shimwela ◽  
T. S. Schubert ◽  
M. Albritton ◽  
S. E. Halbert ◽  
D. J. Jones ◽  
...  
Keyword(s):  
Large Scale ◽  
Disease Incidence ◽  
Kernel Density ◽  
Candidatus Liberibacter Asiaticus ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Density Analysis ◽  
Liberibacter Asiaticus ◽  
Kernel Density Analysis ◽  
Temporal Spread

Citrus huanglongbing (HLB), associated with ‘Candidatus Liberibacter asiaticus’ (Las), disseminated by Asian citrus psyllid (ACP), has devastated citrus in Florida since 2005. Data on HLB occurrence were stored in databases (2005 to 2012). Cumulative HLB-positive citrus blocks were subjected to kernel density analysis and kriging. Relative disease incidence per county was calculated by dividing HLB numbers by relative tree numbers and maximum incidence. Spatiotemporal HLB distributions were correlated with weather. Relative HLB incidence correlated positively with rainfall. The focus expansion rate was 1626 m month−1, similar to that in Brazil. Relative HLB incidence in counties with primarily large groves increased at a lower rate (0.24 year−1) than in counties with smaller groves in hotspot areas (0.67 year−1), confirming reports that large-scale HLB management may slow epidemic progress.

scholarly journals Effects of Temperature and Duration of Preconditioning Cold Treatment on Sclerotial Germination of Claviceps purpurea

Plant Disease ◽  
2016 ◽  
Vol 100 (10) ◽  
pp. 2080-2086 ◽  
Author(s):  
Sai Sree Uppala ◽  
B. M. Wu ◽  
S. C. Alderman
Keyword(s):  
Incubation Temperature ◽  
Cold Treatment ◽  
Kentucky Bluegrass ◽  
Claviceps Purpurea ◽  
Willamette Valley ◽  
Spore Trap ◽  
C Cycle ◽  
Incubation Temperatures ◽  
Ascospore Production ◽  
Sclerotial Germination

Claviceps purpurea is an important ovary-infecting pathogen that replaces seed with sclerotia in Kentucky bluegrass grown for seed. Sclerotia overwinter in the soil and germinate in the spring to produce ascospores that infect grass seed ovaries. To better understand environmental conditions affecting ascospore production, the effects of preconditioning cold treatment and subsequent incubation temperature on germination of sclerotia were determined in growth chambers under controlled conditions. Preconditioning cold treatment was essential for germination only in treatments where the incubation temperature was high (at least higher than 20°C). At lower incubation temperatures (10 to 20°C), preconditioning also played a role in improving sclerotial germination. Preconditioning at 4°C (in darkness) for 4 to 8 weeks followed by incubation at 10 and 20°C (cycle of 12 h each of darkness and light), or constant 15°C (cycle of 12 h each of darkness and light), was optimal for ergot germination. When sclerotia were preconditioned for 4 weeks or longer, number of incubation days required for initiation of germination was not affected by temperature in the range from 10 to 25°C (cycle of 12 h each of darkness and light), although the duration of germination (or the progress speed of germination) was still affected by temperature. A simple model was developed based on laboratory results and validated with historic spore trap data collected from various Kentucky bluegrass fields in Oregon (Willamette Valley, central Oregon, and Grande Ronde Valley). The prediction model could predict ascospore onset well and explained 55% of variation in the data.

scholarly journals In vitro Mass Propagation of Artemisia (Artemisia annua L.) cv: Anamed

2014 ◽  
Vol 23 (2) ◽  
pp. 165-176 ◽  
Author(s):  
Tilahun Hailu ◽  
Balcha Abera ◽  
Gabra Mariam
Keyword(s):  
Large Scale ◽  
Artemisia Annua ◽  
Shoot Tip ◽  
Nodal Explants ◽  
Mass Propagation ◽  
Mean Values ◽  
Coffee Husk ◽  
Soil Mix ◽  
Shoot Tip Explants

An efficient in vitro propagation protocol was developed for anamed (A-3) cultivar of Artemisia annua. Two and 1.5% concentration of NaOCl treatment for 10 and 20 min were found to be optimum for sterilization of shoot tip and nodal explants, respectively. Maximum percentage (98.75 ± 2.50) shoot induction was observed from nodal explants cultured on MS supplemented with 0.8 mg/l BAP + 0.1 mg/l IBA  followed by 82.50 ± 2.88% from shoot tip explants on the same medium with 0.8 mg/l TDZ for shoot tip explants. The highest number of shoots (8.05 ± 0.66/explant) was regenerated on MS + 1 mg/l BAP + 0.1 mg/l IBA. Best rooting with mean values of 18.25 ± 0.95/explant root number and root length (6.35 ± 0.10 cm) was recorded on 1/2 MS + 0.5 mg/l IBA. Up on acclimation and transplanting, 80% survival efficiency was observed on the soil mix ratio of  2 : 1 : 1 (decomposed coffee husk, forest soil and sand, respectively). The developed regeneration protocol enables a large scale commercial production and a possible system towards the genetic improvement of this crop. D. O. I. http://dx.doi.org/10.3329/ptcb.v23i2.17518 Plant Tissue Cult. & Biotech. 23(2): 165-176, 2013  (December)

scholarly journals Thymic involution and rising disease incidence with age

2018 ◽  
Vol 115 (8) ◽  
pp. 1883-1888 ◽  
Author(s):  
Sam Palmer ◽  
Luca Albergante ◽  
Clare C. Blackburn ◽  
T. J. Newman
Keyword(s):  
T Cell ◽  
Power Law ◽  
Wide Spectrum ◽  
Disease Incidence ◽  
Thymic Involution ◽  
Incidence Data ◽  
Age Related ◽  
Exponential Decline ◽  
Combining Data ◽  
Cancer Types

For many cancer types, incidence rises rapidly with age as an apparent power law, supporting the idea that cancer is caused by a gradual accumulation of genetic mutations. Similarly, the incidence of many infectious diseases strongly increases with age. Here, combining data from immunology and epidemiology, we show that many of these dramatic age-related increases in incidence can be modeled based on immune system decline, rather than mutation accumulation. In humans, the thymus atrophies from infancy, resulting in an exponential decline in T cell production with a half-life of ∼16 years, which we use as the basis for a minimal mathematical model of disease incidence. Our model outperforms the power law model with the same number of fitting parameters in describing cancer incidence data across a wide spectrum of different cancers, and provides excellent fits to infectious disease data. This framework provides mechanistic insight into cancer emergence, suggesting that age-related decline in T cell output is a major risk factor.

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