Estimation of Pyrethrum Flower Number Using Digital Imagery

Flower number is the primary determinant of yield in pyrethrum (Tanacetum cineariifolium). Traditional estimates of flower numbers use physical harvesting of flowers, which is time consuming, destructive, and complicated. The precision of flower number estimates may be highly influenced by spatial heterogeneity of plant density and vigor. Here, we examined the potential for digital image analysis to enable rapid, nondestructive assessment of flower number. This technique involved removal of pixels with color profiles not typical of the disc florets of pyrethrum. Particle counting was then performed using defined size and shape parameters to estimate flower numbers. Estimates of flower number based on image analyses were correlated with physical harvests of flowers, with estimates representing about an average of 32% of total flower numbers present within a sampling unit. This relationship was consistent across all observed flower densities. Covariate analysis indicated that occurrences of crop lodging and over mature flower canopies had significant, detrimental effects on system predictions. Pyrethrum flowers were spatially aggregated within fields with the degree of aggregation greatest at the lowest flower densities. Based on modeled flower distributions, eight quadrats (0.49-m2 sampling unit) were sufficient to achieve a cv of 0.1 in a 600-m2 plot area in all but the lowest flower densities. The utility of this approach for biomass assessment in pyrethrum and other Compositae is discussed.

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Effect of High Temperatures on the Postharvest Flowering of Specialty Floral Crop Species

HortScience ◽

10.21273/hortsci.33.3.447f ◽

1998 ◽

Vol 33 (3) ◽

pp. 447f-448

Author(s):

Millie S. Williams ◽

Terri Woods Starman ◽

James E. Faust

Keyword(s):

United States ◽

Heat Tolerance ◽

Flower Development ◽

Consumer Satisfaction ◽

The United States ◽

Plant Canopy ◽

Flower Number ◽

Flower Bud ◽

Crop Species ◽

Mature Flower

Flower growers experience decreased consumer satisfaction with plant species that cease flowering during the summer. The objective of this experiment was to characterize the heat tolerance of four specialty floral crop species in order to predict their summer performance in the different climatalogical regions of the United States. The effect of increasing temperatures on the duration of postharvest flower development was determined for Ageranthemum frutescens `Butterfly' and `Sugar Baby', Brachycome hybrid `Ultra', and Sutera cordata `Snowflake'. Plants were grown in a 18 °C greenhouse until marketable with foliage covering the container and flowers distributed evenly across the plant canopy. Plants were then placed in a phytotron to determine their heat tolerance. Temperature set points of 18, 23, 28, and 33 °C were delivered serially at 2-week intervals, starting at 18 °C. Plants were then returned to 18 °C after the 33 °C treatment. Immature flower bud, mature flower bud, flower and senesced flower numbers were collected once per week. Sutera `Snowflake', and Brachycome `Ultra' had the greatest flower number at the 23 °C temperature, decreasing in the 28 °C environment. Argeranthemum `Butterfly' and `Sugar Baby' had greatest flower number at 28 °C, but flowers were smaller and of lower quality than at 23 °C. Flower development of all cultivars ceased at 33 °C, but when plants were returned to the 18 °C production greenhouse, flower development resumed. According to normal average daily temperatures in Knoxville, Tenn., Ageranthemum frutescens `Butterfly' and `Sugar Baby' would flower until mid-June, while Brachycome hybrid `Ultra' and Sutera cordata `Snowflake' would flower until mid-May.

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The key to successful second year white clover seed crops

NZGA: Research and Practice Series ◽

10.33584/rps.6.1995.3382 ◽

1996 ◽

Vol 6 ◽

pp. 40-40

Author(s):

B.L. Mccloy ◽

S.R. White

Keyword(s):

Seed Yield ◽

White Clover ◽

Block Design ◽

First Year ◽

Flower Number ◽

Mature Flower ◽

Second Year ◽

Clover Seed ◽

Seed Crops ◽

Rotary Type

In recent years there has been an increase in the number of white clover seed crops taken for a second harvest. Traditionally yields from second year crops are substantially lower than first year crops. A trial was established investigating techniques to increase yields in second year crops. The trial was located in a dryland crop of white clover (cv. Grasslands Demand) 4 km east of Methven, mid Canterbury. It involved 10 herbicide treatments and 8 'inter-row' treatments arranged in a split block design. Number of mature flower heads were recorded on all treatments at harvest as an indirect estimate of yield. Additionally, selected treatments were cut and collected using a rotary type mower, threshed, and machine dressed for direct estimates of seed yield. Flower number and machine dressed seed yield were significantly (P

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The effect of quadrat shape and placement on the accuracy of yield and density estimates for crops seeded in narrow rows

Canadian Journal of Plant Science ◽

10.4141/cjps95-147 ◽

1995 ◽

Vol 75 (4) ◽

pp. 889-892

Author(s):

Larry Hume ◽

Scott Shirriff

Keyword(s):

Key Words ◽

Plant Density ◽

Sampling Unit ◽

Plant Populations ◽

Density Estimates ◽

Plot Size ◽

Row Width

Small quadrats (commonly 1-m2 or less) have been used extensively as the sampling unit in studies examining crops seeded in narrow rows. The effects of sampling unit shape and orientation on yield and plant density estimates was examined. When small quadrats are required for sampling crops seeded in narrow rows, sampling would best be done using rectangular quadrats with sides parallel to crop rows and having some multiple of row width. In seventy seven published papers from 1988 to 1994, the quadrat shape used in sampling plant populations was appropriate in only fourteen instances. Inappropriately shaped quadrats could result in errors of up to 25% in estimates of crop related variables, such as yield. Key words: sampling unit, quadrat shape, plot size, plot shape

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Foraging behaviour of the Scale-throated Hermit Phaethornis eurynome Lesson, 1832 (Aves, Trochilidae) in Vriesea incurvata Gaudich (Bromeliaceae)

Brazilian Journal of Biology ◽

10.1590/1519-6984.15512 ◽

2014 ◽

Vol 74 (2) ◽

pp. 311-314 ◽

Cited By ~ 3

Author(s):

BG. Silva ◽

AJ. Piratelli

Keyword(s):

Foraging Behaviour ◽

Plant Density ◽

Local Density ◽

Local Scale ◽

The Other ◽

Flower Number ◽

Heterogeneous Distribution ◽

Density Dependent ◽

Visitation Rates ◽

Number Of Visits

In this study we tested for density-dependent relationships between visitation rates of the Scale-throated Hermit (Phaethornis eurynome) and the plant density and flower number of the bromeliad Vriesea incurvata, by comparing plots with varying densities of this bromeliad. Eight 100 m2 plots were established at least 200 m from each other; four plots contained 10-15 individuals of V. incurvata each, whereas the other four contained 4-5 individuals each. The visitors, number of visits, behaviour (nectar thief or potential pollinator) and the height of foraging were recorded during focal observations on the plants. The number of visits of P. eurynome varied according to the local density of V. incurvata, showing that the heterogeneous distribution of this bromeliad species may promote adjustments in the pollinator populations, through resource variation at a local scale.

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Sampling Unit, Spatial Distribution of Trees, and Precision

Northern Journal of Applied Forestry ◽

10.1093/njaf/9.1.3 ◽

1992 ◽

Vol 9 (1) ◽

pp. 3-6 ◽

Cited By ~ 7

Author(s):

Robin M. Reich ◽

Loukas G. Arvanitis

Keyword(s):

Spatial Distribution ◽

Sample Size ◽

Spatial Patterns ◽

Basal Area ◽

Sampling Unit ◽

Sample Variance ◽

Plot Size ◽

Plot Area ◽

The Relationship

Abstract The relationship between plot size and sample variance as affected by the spatial patterns of trees, volume, and basal area is reported. This information is useful for practicing foresters in determining the best combination of sample size, plot area, or basal area factor in forest surveys. North. J. Appl. For. 9(1):3-6.

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Ecological approach in the adapted breeding system of mid-late maize hybrids (FAO 300-399) in the Lower Volga region

The Agrarian Scientific Journal ◽

10.28983/asj.y2021i3pp19-24 ◽

2021 ◽

pp. 19-24

Author(s):

Sergey Aleksandrovich Zaytsev ◽

Valeriy Ivanovich Zhuzhukin ◽

Lyudmila Aleksandrovna Gudova ◽

Dmitriy Petrovich Volkov ◽

Svetlana Aleksandrovna Guseva ◽

...

Keyword(s):

Grain Yield ◽

Plant Density ◽

Corn Hybrids ◽

Hydrothermal Coefficient ◽

Lower Volga Region ◽

Maize Hybrids ◽

Grain Moisture ◽

Cultivation Technique ◽

Plot Area ◽

Harvest Moisture

The article examines the results of the ecological testing of maize hybrids (FAO 300-399), created in different selective centers of Russia. The volume of nursery ecological testing of hybrids varied in the range of 15-30 titles. Plot area 14.8 m2. The plant density for harvesting in the Saratov region is 45 thousand plants / ha. Repetition three times. The cultivation technique is zonal. The hydrothermal coefficient during the growing season varied from 0.32 to 1.1. The amplitude of variation of the parameters of maize hybrids in the years of research was: plant height - 149.1 ... 268.1 cm; the height of the cob is 37.8 ... 106.0 cm; grain yield - 1.13 ... 8.69 t / ha; harvest moisture content of grain - 9.21 ... 46.85%; the protein content in the grain is 7.16 ... 13.83%. Insignificant coefficients of skewness (As) and kurtosis in most years of research characterize the samples of hybrids as corresponding to the normal distribution. As a result of the research, it has been established that, in terms of grain yield of corn hybrids, hybrids created at the FGBNU «NСZ im. P.P. Lukyanenko», which also feature increased grain moisture during harvesting. Lower costs for drying grain will be required for the cultivation of hybrids Ak – OOO «Agroplasma», OOO «Pioneer Hi-Brad Rus», FGBNU «NСZ im. P.P. Lukyanenko»

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Spatiotemporal Characterization of Sclerotinia Crown Rot Epidemics in Pyrethrum

Plant Disease ◽

10.1094/pdis-07-13-0692-re ◽

2014 ◽

Vol 98 (2) ◽

pp. 267-274 ◽

Cited By ~ 6

Author(s):

Jason B. Scott ◽

David H. Gent ◽

Sarah J. Pethybridge ◽

Frank S. Hay

Keyword(s):

Plant Density ◽

Disease Incidence ◽

Severe Disease ◽

Disease Outbreaks ◽

Spatial Aggregation ◽

Crown Rot ◽

Sampling Unit ◽

Small Scale ◽

Unit Scale ◽

Substantial Decline

Sclerotinia crown rot, caused by Sclerotinia minor and S. sclerotiorum, is a disease of pyrethrum in Australia that may cause substantial decline in plant density. The spatiotemporal characteristics of the disease were quantified in 14 fields during three growing seasons. Fitting the binary power law to disease incidence provided slope (b = 1.063) and intercept (ln(Ap) = 0.669) estimates significantly (P ≤ 0.0001) greater than 1 and 0, respectively, indicating spatial aggregation at the sampling unit scale that was dependent upon disease incidence. Covariate analyses indicated that application of fungicides did not significantly influence these estimates. Spatial autocorrelation and spatial analysis by distance indices indicated that spatial aggregation above the sampling unit scale was limited to 20 and 17% of transects analyzed, respectively. The range of significant aggregation was limited primarily to neighboring sampling units only. Simple temporal disease models failed to adequately describe disease progress, due to a decline in disease incidence in spring. The relationships between disease incidence at the scales of individual plants within quadrats and quadrats within a field was modeled using four predictors of sample size. The choice of the specific incidence–incidence relationship influenced the classification of disease incidence as greater than or less than 2% of plants, a provisional commercial threshold for fungicide application. Together, these studies indicated that epidemics of Sclerotinia crown rot were dominated by small-scale aggregation of disease. Larger scale patterns of diseased plants, when present, were associated with severe disease outbreaks. The spatial and temporal analyses were suggestive of disease epidemics being associated with localized primary inoculum and other factors that favor disease development at a small scale.

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Morphometric analysis of cellular interactions with the endothelium during the development of arterial lesions using Scanning Electron Microscopy and digital image analysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100128870 ◽

1987 ◽

Vol 45 ◽

pp. 918-919

Author(s):

M.E. Rosenfeld ◽

C. Karboski ◽

M.F. Prescott ◽

P. Goodwin ◽

R. Ross

Keyword(s):

Electron Microscopy ◽

Image Analysis ◽

Quantitative Data ◽

Digital Image Analysis ◽

Lower Cost ◽

Matched Control ◽

Digital Analysis ◽

Cellular Interactions ◽

Arterial Lesions ◽

Scanning Electron

Previous research documenting the chronology of the cellular interactions that occur on or below the surface of the endothelium during the initiation and progression of arterial lesions, primarily consisted of descriptive studies. The recent development of lower cost image analysis hardware and software has facilitated the collection of high resolution quantitative data from microscopic images. In this report we present preliminary quantitative data on the sequence of cellular interactions that occur on the endothelium during the initiation of atherosclerosis or vasculitis utilizing digital analysis of images obtained directly from the scanning electron microscope. Segments of both atherosclerotic and normal arteries were obtained from either diet-induced or endogenously (WHHL) hypercholesterolemic rabbits following 1-4 months duration of hypercholesterolemia and age matched control rabbits. Vasculitis was induced in rats following placement of an endotoxin soaked thread adjacent to the adventitial surface of arteries.

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