scholarly journals Assessment of Severity of Powdery Mildew Infection of Sweet Cherry Leaves by Digital Image Analysis

HortScience ◽  
2001 ◽  
Vol 36 (1) ◽  
pp. 107-111 ◽  
Author(s):  
James W. Olmstead ◽  
Gregory A. Lang ◽  
Gary G. Grove
Keyword(s):  
Image Analysis ◽  
Powdery Mildew ◽  
Digital Image ◽  
Digital Image Analysis ◽  
Sweet Cherry ◽  
Prunus Avium ◽  
Leaf Tissue ◽  
Visual Assessment ◽  
Accurate Method ◽  
Leaf Disk

A personal computer-based method was compared with standard visual assessment for quantifying colonization of sweet cherry (Prunus avium L.) leaves by powdery mildew (PM) caused by Podosphaera clandestina (Wallr.:Fr.) Lev. Leaf disks from 14 cultivars were rated for PM severity (percentage of leaf area colonized) by three methods: 1) visual assessment; 2) digital image analysis; and 3) digital image analysis after painting PM colonies on the leaf disk. The third technique, in which PM colonies on each leaf disk were observed using a dissecting microscope and subsequently covered with white enamel paint, provided a standard for comparison of the first two methods. A digital image file for each leaf disk was created using a digital flatbed scanner. Image analysis was performed with a commercially available software package, which did not adequately detect slight differences in color between PM and sweet cherry leaf tissue. Consequently, two replicated experiments revealed a low correlation between PM image analysis and painted PM image analysis (r2 = 0.66 and 0.46, P ≤ 0.0001), whereas visual assessment was highly correlated with painted PM image analysis (r2 = 0.88 and 0.95, P ≤ 0.0001). Rank orders of the 14 cultivars differed significantly (P ≤ 0.05) when PM image analysis and painted PM image analysis were compared; however, rankings by visual assessment were not significantly different (P > 0.05) from those by painted PM image analysis. Thus, standard visual assessment is an accurate method for estimating disease severity in a leaf disk resistance assay for sweet cherry PM.

Inter-laboratory comparison of Ki-67 proliferating index detected by visual assessment and automated digital image analysis

2019 ◽  
Vol 38 (2) ◽  
pp. 73-79
Author(s):  
Snježana Tomić ◽  
Ivana Mrklić ◽  
Jasminka Jakić Razumović ◽  
Nives Jonjić ◽  
Božena Šarčević ◽  
...  
Keyword(s):  
Image Analysis ◽  
Digital Image ◽  
Digital Image Analysis ◽  
Visual Assessment ◽  
Ki 67

scholarly journals Nondestructive Measurement of Vegetative Cover Using Digital Image Analysis

HortScience ◽  
2004 ◽  
Vol 39 (1) ◽  
pp. 55-59 ◽  
Author(s):  
Mercy A. Olmstead ◽  
Robert Wample ◽  
Stephanie Greene ◽  
Julie Tarara
Keyword(s):  
Image Analysis ◽  
Digital Image ◽  
Cover Crops ◽  
Cover Crop ◽  
Digital Image Analysis ◽  
Ground Surface ◽  
Visual Assessment ◽  
Computer Assisted ◽  
Percent Cover ◽  
Vegetative Cover

Traditionally, vegetative cover has been subjectively assessed by visual assessment. However, visual assessment is thought to overestimate percent vegetative cover. Thus, a repeatable method to objectively quantify percent cover is desirable. In two vineyards near Prosser, Wash., the percentage of ground surface covered by up to 15 different cover crops was assessed both visually and by computer-assisted digital image analysis. Quadrats in the cover crop were photographed digitally and the images analyzed with commercially available software. Areas of green vegetation in each image were identified and measured. Weeds in some images were differentiated from the cover crop by user-defined thresholds. Subjective visual estimates of percent vegetative cover were generally higher than those digitally estimated. Values for the visual estimates ranged from 5% to 70% in 1998 (mean = 52.4%) and 7.5% to 55% in 1999 (mean = 30.7%), compared to digital readings ranging from 0.5% to 24% (mean = 11.1%) and 10.3% to 36.6% cover (mean = 20.1%), respectively. The visual assessments had lower coefficients of variability in 1998 (cv 28.1) than the digital image analysis (cv 52.3), but in 1999, the values for the two techniques were similar (cv 41.2 vs. cv 45.7). Despite initial variations between the two methods, the accuracy of digital image analysis for measuring percentage vegetative cover is superior.

scholarly journals Subcuticular-Intracellular Hemibiotrophic and Intercellular Necrotrophic Development of Colletotrichum acutatum on Almond

2005 ◽  
Vol 95 (7) ◽  
pp. 751-758 ◽  
Author(s):  
J. Diéguez-Uribeondo ◽  
H. Förster ◽  
A. Soto-Estrada ◽  
J. E. Adaskaveg
Keyword(s):  
Image Analysis ◽  
Digital Image ◽  
Digital Image Analysis ◽  
Leaf Tissue ◽  
Host Cells ◽  
Colletotrichum Acutatum ◽  
Fungal Colonization ◽  
Host Colonization ◽  
Tissue Samples ◽  
Histological Techniques

The early infection and colonization processes of Colletotrichum acutatum on leaves and petals of two almond cultivars with different susceptibility to anthracnose (i.e., cvs. Carmel and Nonpareil) were examined using digital image analysis of light micrographs and histological techniques. Inoculated tissue surfaces were evaluated at selected times after inoculation and incubation at 20°C. Depth maps and line profiles of the digital image analysis allowed rapid depth quantification of fungal colonization in numerous tissue samples. The results showed that the early development of C. acutatum on petals was different from that on leaf tissue. On petals, conidia germinated more rapidly, germ tubes were longer, and fewer appressoria developed than on leaves. On both tissues, penetration by the pathogen occurred from appressoria and host colonization was first subcuticular and then intracellular. On petals, colonizing hyphae were first observed 24 h after inoculation and incubation at 20°C, whereas on leaves they were seen 48 to 72 h after inoculation. Intercellular hyphae were formed before host cells became necrotic and macroscopic lesions developed on petals ≥48 h and on leaves ≥96 h after inoculation. Histological studies complemented data obtained by digital image analysis and showed that the fungus produced infection vesicles and broad hyphae below the cuticle and in epidermal cells. In both tissues, during the first 24 to 48 h after penetration fungal colonization was biotrophic based on the presence of healthy host cells adjacent to fungal hyphae. Later, during intercellular growth, the host-pathogen interaction became necrotrophic with collapsed host cells. Quantitative differences in appressorium formation and host colonization were found between the two almond cultivars studied. Thus, on the less susceptible cv. Nonpareil fewer appressoria developed and host colonization was reduced compared with that on cv. Carmel.

Comparison between digital image analysis and visual assessment of immunohistochemical HER2 expression in breast cancer

2018 ◽  
Vol 214 (12) ◽  
pp. 2087-2092 ◽  
Author(s):  
Morten Ragn Jakobsen ◽  
Chinachote Teerapakpinyo ◽  
Shanop Shuangshoti ◽  
Somboon Keelawat
Keyword(s):  
Breast Cancer ◽  
Image Analysis ◽  
Digital Image ◽  
Digital Image Analysis ◽  
Visual Assessment ◽  
Her2 Expression

scholarly journals Practical approaches to automated digital image analysis of Ki-67 labeling index in 997 breast carcinomas and causes of discordance with visual assessment

PLoS ONE ◽  
2019 ◽  
Vol 14 (2) ◽  
pp. e0212309 ◽  
Author(s):  
Ah-Young Kwon ◽  
Ha Young Park ◽  
Jiyeon Hyeon ◽  
Seok Jin Nam ◽  
Seok Won Kim ◽  
...  
Keyword(s):  
Image Analysis ◽  
Digital Image ◽  
Digital Image Analysis ◽  
Visual Assessment ◽  
Labeling Index ◽  
Breast Carcinomas ◽  
Ki 67

scholarly journals A Comparison of Visual Assessment and Automated Digital Image Analysis of Ki67 Labeling Index in Breast Cancer

PLoS ONE ◽  
2016 ◽  
Vol 11 (2) ◽  
pp. e0150505 ◽  
Author(s):  
Fangfang Zhong ◽  
Rui Bi ◽  
Baohua Yu ◽  
Fei Yang ◽  
Wentao Yang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Image Analysis ◽  
Digital Image ◽  
Digital Image Analysis ◽  
Visual Assessment ◽  
Labeling Index ◽  
Ki67 Labeling Index

scholarly journals A Leaf Disk Assay for Screening Sweet Cherry Genotypes for Susceptibility to Powdery Mildew

HortScience ◽  
2000 ◽  
Vol 35 (2) ◽  
pp. 274-277 ◽  
Author(s):  
James W. Olmstead ◽  
Gregory A. Lang ◽  
Gary G. Grove
Keyword(s):  
Powdery Mildew ◽  
Sweet Cherry ◽  
Prunus Avium ◽  
Leaf Age ◽  
Nutrient Content ◽  
Field Resistance ◽  
Leaf Disk ◽  
Detached Leaf ◽  
Breeding Populations ◽  
Sweet Cherry Cultivars

A detached leaf disk assay for screening sweet cherry (Prunus avium L.) genotypes for susceptibility to powdery mildew (PM) [Podosphaera clandestina (Wallr.:Fr.) Lev.] was developed by evaluating the effects of photoperiod (24 hours light, 0 hours light, 14 hours light/10 hours dark), substrate nutrient content (sterile distilled water, 1% sucrose), leaf age (old, young, emergent), and leaf explant size (intact leaf, 30 mm, 20 mm) on PM growth on leaves from the susceptible cultivar Bing. The only parameter described that had a significant (P ≤ 0.001) effect on PM growth was leaf age. Old leaves, designated as the third fully expanded leaf from the basal end of current-year's shoot growth, were never infected with PM under controlled inoculations. In the absence of significant differences between treatments, those parameters with the highest treatment means were selected for subsequent evaluation. To test the leaf disk assay, 14 sweet cherry cultivars were screened in two experiments, and rated according to level of PM susceptibility. Rank sum comparison of results from cultivars used for leaf disk screening agreed with earlier field rankings of the same cultivars. The developed leaf disk assay greatly reduced the space required to screen sweet cherry cultivars, and was a repeatable and objective predictor of field resistance that may be useful for screening germplasm or breeding populations.

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