Talk:Centaurea cyanus

message: While reading Mein Kampf I came across a passage where Adolf Hitler described a symbol used by German pan-nationalist in Austria. He mentioned the corn-flower as that symbol. 168.16.141.62 18:32, 25 January 2007 (UTC)
thread_title: Comments

message: "The blue pigment is protocyanin, which in roses is red."  Does no one else find this comment to need a bit more explanation? ...  Chenel324 (talk) 03:05, 6 August 2008 (UTC)
thread_title: Untitled

message: Why is it named "cornflower" if it's not the flower of maize (corn)? Does it grow around maize plants? Badagnani (talk) 23:25, 31 December 2008 (UTC)
thread_title: Name

message: A recent Guardian article on the use of the cornflower as an ultra‑right symbol by the Aufbruch deutscher Patrioten – Mitteldeutschland (AdP) could be worked into a new section on symbolic use.
  The DE page also has a list of historical symbols too.  RobbieIanMorrison (talk) 14:07, 11 January 2019 (UTC)
replies: text: Hi,RobbieIanMorrison. What is meant by "the DE page"?--Quisqualis (talk) 18:15, 11 January 2019 (UTC)
thread_title:  Symbolic use 

message: I would like to suggest that the following sentence be added between the last and the-second-last sentence of the existing "Description" section:
Fruits are approx. 3.5 mm long with 2-3 mm long pappus bristles . 
Solanummelongena (talk) 11:50, 22 November 2020 (UTC)
thread_title:  Description 

message: I think that it may make sense to add a section about the ecology of Centaurea cyanus between the existing "Distribution" and "Cultivation" section. A major aim of this section should be to point out the difficult relationship of Centaurea cyanus to agriculture, which is already mentioned several times in the existing article, but not discussed in detail. Please find my draft of the new section below:
=== Weed in arable crops ===
Centaurea cyanus is considered a noxious weed in arable crops, especially cereals and rapeseed . In winter wheat, one plant per m2 can cause a yield loss of up to 30 kg / ha . Centaurea cyanus produces around 800 seed per plant, which are either shed shortly before the harvest of cereals, or they are threshed together with the cereal grains, contributing to the further spread of the species by the harvesting machinery and contaminated seed. The occurrence of Centaurea cyanus strongly decreased during the last decades due to improved seed cleaning, more intensive nitrogen fertilization and herbicide use. However, Centaurea cyanus has become more common in cropland due to an increase in crop rotations dominated by winter cereals and rapeseed and the use of more selective herbicides with a low effectiveness against Centaurea cyanus . In addition, the emergence of resistance against the herbicide class of sulfonylureas has been reported recently . Due to its strong roots, Centaurea cyanus is difficult to control mechanically in spring .
=== Fodder for insects and birds ===
The pollen of Centaurea cyanus is used by several different insect species. Insects of the orders Hymenoptera and Diptera are particularly attracted by the flower Carreck N., Williams I. (2002). "Food for insect pollinators on farmland: insect visits to flowers of annual seed mixtures". Journal of Insect Conservation 6:13–23.. As Centaurea cyanus is a self-incompatible species, it needs external pollination. The nectar of Centaurea cyanus is very sweet with a sugar content of 34 %. Due to its high sugar production of up to 0.2 mg sugar per day and flower, the species is highly appreciated by beekeepers Helmut Horn, Cord Lüllmann: Das große Honigbuch, Kosmos, Stuttgart, 3. Auflage, 2006, ISBN 3-440-10838-4, S. 31.
The seeds of Centaurea cyanus are one of the favourite foods of the European goldfinch. 
I think that it would make sense to relocate the information obout the European goldfinch from the "Uses" to the new "Ecology" section if the latter is created."
=== Control of insect pests ===
Centaurea cyanus was found to produce volatiles attracting Microplitis mediator , which is a major parasitoid of the cabbage moth (Mamestra brassicae), which is the most important pest of cabbage (Brassica oleracea) in central Europe. Planting "Centaurea cyanus" in cabbage fields was thus suggested as an alternative to the widespread use of insecticides for the control of Mamestra brassicae. Field experiments showed that planting "Centaurea cyanus" in cabbage filds at a density of 1 plant / m2 can result in a significant increase in parasitation of [Mamestra brassicae] larvae, predation of Mamestra brassicae eggs (e.g. by carabid beetles or spiders) and ultimately cabbage yield . 
Solanummelongena (talk) 11:50, 22 November 2020 (UTC)
thread_title:  Ecology 

message: Centaurea cyanus was found to produce volatiles attracting Microplitis mediator , which is a major parasitoid of the cabbage moth (Mamestra brassicae), which is the most important pest of cabbage (Brassica oleracea) in central Europe. Planting "Centaurea cyanus" in cabbage fields was thus suggested as an alternative to the widespread use of insecticides for the control of Mamestra brassicae. Field experiments showed that planting "Centaurea cyanus" in cabbage filds at a density of 1 plant / m2 can result in a significant increase in parasitation of [Mamestra brassicae] larvae, predation of Mamestra brassicae eggs (e.g. by carabid beetles or spiders) and ultimately cabbage yield . 
Solanummelongena (talk) 11:50, 22 November 2020 (UTC)
thread_title:  Control of insect pests 

message: I think that the existing "Cultivation" section would likely benefit from some expansion, as it contains little technical information about how to grow the cornflower. Furthermore, I saw that the user AlCropsCT suggested to make a new "Genetics" section. If this is approved of, I think that it would make sense to relocate the information on different cultivars to this section. Maybe the title should then be changed from "Genetics" to "Genetics and Breeding" or similar. As for the "Cultivation" section, I would suggest to delete the existing text, and replace it by the one below. I tried to integrate most of the information from the existing version into my draft, or, as already mentioned, relocate them elesewhere.
=== Soil and climate requirements ===
Centaurea cyanus requires full sun and neutral (6.6-7.5) to mildly alkaline (7.6-7.8), moist and well-drained soil. However, Centaurea cyanus is quite tolerant to drought once established . 
=== Sowing ===
For summer-blooming plants, sowing should be executed in late spring. In moderate climates, however, it is also possible to sow Centaurea cyanus in early fall. In this case, plants will already start to flower in the following spring. Recommended spacing between plants is approx. 20 to 30 cm . Centaurea cyanus can germinate from up to 10 cm depth, but the best result is obtained at 1 cm sowing depth . Germination occurs quickly after sowing. 
=== Fertilization and cultural practices ===
High phosphorus fertilization in mid-summer will increase flower production. Mulching is recommended to prevent drying out of the soil and exposure of the root system to the sun .
=== Pests and Diseases ===
In general, Centaurea cyanus is not very susceptible to pests and plant diseases. 
However, it may be affected by stem rot and stem rust if grown too tightly  or by powdery mildew (Best Plants 2020) . Furthermore, aphids and leafhoppers can cause relevant damage to Centaurea cyanus . 
Solanummelongena (talk) 11:50, 22 November 2020 (UTC)
thread_title:  Cultivation 

message: In general, Centaurea cyanus is not very susceptible to pests and plant diseases. 
However, it may be affected by stem rot and stem rust if grown too tightly  or by powdery mildew (Best Plants 2020) . Furthermore, aphids and leafhoppers can cause relevant damage to Centaurea cyanus . 
Solanummelongena (talk) 11:50, 22 November 2020 (UTC)
thread_title:  Pests and Diseases 

message: This is how I would change the "Genetics" section which AlCropsCT suggested to add to the existing article. Please note that it contains some information that should be relocated here from the existing "Cultivation" section (as mentioned above).
=== Genetics ===
Centaurea cyanus is a diploid flower (2n = 24)Martin E., Dinç M., Duran A. (2009). "Karyomorphological Study of Eight Centaurea L. Taxa (Asteraceae) from Turkey". Turkish Journal of Botany 33:97–104.. The genetic diversity within populations is high, although there could be a future decline in diversity due to fragmentation of population and intensive agricultureLe Corre V., Bellanger S., Guillemin J.-P., Darmency H. (2014). "Genetic diversity of the declining arable plant Centaurea cyanus: Population fragmentation within an agricultural landscape is not associated with enhanced spatial genetic structure". Weed Research 54:436–444.. In general, Centaurea cyanus is a self-incompatible species. However, selfing still occurs occassionally, but results in inbreeding depression .
=== Cultivars ===
The information contained in this section should be re-located here from the existing "Cultivation" section. Some sentences were slightly reformulated
Several cultivars of Centaurea cyanus with varying pastel colours, including pink and purple, have been selected for ornamental purposes. The species is also grown for the cutflower industry in Canada for use by florists. Doubled blue cultivars (such as 'Blue Boy' or 'Blue Diadem') are most commonly used for this purpose, but white, pink, lavender and black (actually a very dark maroon) cultivars are also used, albeit to a lesser extent.
=== Breeding goals ===
As for all ornamental plants, important goals of Centaurea cyanus breeding include the induction of phenotypic variation (e.g. in flower coloration, size and shape, foliage charcteristics or plant height), higher flower yield, resistance to pests and diseases as well as tolerance to abiotic stress (e.g. extreme temperatures, drought or salinity) .Solanummelongena (talk) 11:55, 22 November 2020 (UTC)
thread_title:  Genetics and Breeding 

message: As for all ornamental plants, important goals of Centaurea cyanus breeding include the induction of phenotypic variation (e.g. in flower coloration, size and shape, foliage charcteristics or plant height), higher flower yield, resistance to pests and diseases as well as tolerance to abiotic stress (e.g. extreme temperatures, drought or salinity) .Solanummelongena (talk) 11:55, 22 November 2020 (UTC)
thread_title:  Breeding goals 

message: I would suggest to add the following sub-section about phytoremediation to the end of the draft of the "Uses" chapter written by AlCropsCT:
=== Phytoremediation ===
Centaurea cyanus has been evaluated for phytoremediation of soils contaminated with lead. Inoculation of the contaminated soil with Glomus spp. (fungus) and Pseudomonas spp. (bacterium) would significantly enhance the biomass production and lead uptake of Centaurea cyanus .
Solanummelongena (talk) 12:12, 22 November 2020 (UTC)
thread_title:  Uses 

message: Centaurea cyanus has been evaluated for phytoremediation of soils contaminated with lead. Inoculation of the contaminated soil with Glomus spp. (fungus) and Pseudomonas spp. (bacterium) would significantly enhance the biomass production and lead uptake of Centaurea cyanus .
Solanummelongena (talk) 12:12, 22 November 2020 (UTC)
thread_title:  Phytoremediation 

message: Prussian uniforms are/were a much darker blue.  The flower is closer to French uniforms.  — Preceding unsigned comment added by 2A02:2788:1008:2C3:E2CB:4EFF:FE88:1A2C (talk) 00:01, 10 February 2021 (UTC)
thread_title:  Prussian uniforms mein arsch