Strategies_for_the_development_of_unique_flower_forms_in_orn

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jbergeson
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Re: Strategies_for_the_development_of_unique_flower_forms_in

Post: # 66798Post jbergeson
Thu Jan 11, 2018 1:06 pm

I'm interested in induced mutations in roses. Possibly through the application of ethyl methanesulfonate. I have a friend who does that with corn, immersing the pollen in a solution of the mutagen mixed in mineral oil. The first question - would rose pollen still be able to take if it was applied in a mineral oil slurry?

Unfortunately mutations are always recessive, my friend claims, so the changes wouldn't even manifest until the treated seedlings were inbred to the next generation.

It seems like Art Nouveau is an rose that could be used to develop unique flower forms via conventional breeding.

Karl K
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Re: Strategies_for_the_development_of_unique_flower_forms_in

Post: # 66807Post Karl K
Thu Jan 11, 2018 8:44 pm

'Art Nouveau' puts me in mind of Rosa humilis var triloba.
http://rosebreeders.org/forum/viewtopic ... oba#p65012
Meehan (1889) presented the latter as evidence that rose petals are modified stipules, rather than leaves. In 'Triloba', and to a lesser degree in 'Art Nouveal', the dilated petiole is expressed.

Another possibility for a new form is 'Permanent Wave'. The crisped petal edges would be particularly effective combined with picotee, or with a bicolor such as red/yellow or purple/white.
http://bulbnrose.x10.mx/Roses/Rose_Pict ... twave.html

Jwindha
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Re: Strategies_for_the_development_of_unique_flower_forms_in

Post: # 66812Post Jwindha
Fri Jan 12, 2018 8:49 am

Mutations are not always recessive, necessarily.

Gain-of-function mutations tend to be dominant while loss-of-function mutations tend to be recessive. Exposing plants to mutagens will *most likely* result in a recessive trait, but not always.

philip_la
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Re: Strategies_for_the_development_of_unique_flower_forms_in

Post: # 66820Post philip_la
Sun Jan 14, 2018 11:56 am

Does gain-of-function really correlate with dominance, or do you mean to say that gain-of-function mutations, when they occur, are often passed on to future generation whereas the others are less likely to be reflected in future generations?

For the most part, the generalization about mutations rarely getting passed on seems to hold, based on my limited understanding. I'm not aware, for instance, of a case where fimbriated or heavily lobed petals were inherited -- those are traits that would, IMO, be interesting to be able to breed into a line.

Karl, I thought the consensus was that petals anthers and stamens were all considered analagous, as evidenced by the mutation of doubles, in which the sex organs are reduced or absent.
Philip F.
[size=small][color=#669966]Zone 8 / Sunset Zn 30 (Austin, TX -- formerly New Orleans, LA)[/color][/size]

Jwindha
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Re: Strategies_for_the_development_of_unique_flower_forms_in

Post: # 66828Post Jwindha
Sun Jan 14, 2018 10:22 pm

Being passed on to future generations more frequently IS what makes gain-of-function mutations dominant.

Gain-of-function mutations often confer a selective advantage. The plants with the advantage out-compete those which don't have it and thus the trait is passed on more frequently. As time goes by, the gain-of-function mutation becomes the dominant trait in the population because it's the most efficient.

Loss-of-function mutations often confer a *disadvantage to survival* and thus the mutation isn't passed on as often.

If the mutation doesn't confer some sort of advantage to survival, it's often eliminated in a wild population or hides in heterozygous carriers. In our artificial breeding programs, however, a plant can afford a loss-of-function mutation because it's being provided with water and nutrients rather than competing in the wild for resources.

philip_la
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Re: Strategies_for_the_development_of_unique_flower_forms_in

Post: # 66831Post philip_la
Mon Jan 15, 2018 10:14 am

Okay. So, to be clear, you are talking "selection" and not "heritability."
Philip F.
[size=small][color=#669966]Zone 8 / Sunset Zn 30 (Austin, TX -- formerly New Orleans, LA)[/color][/size]

Karl K
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Re: Strategies_for_the_development_of_unique_flower_forms_in

Post: # 66852Post Karl K
Fri Jan 19, 2018 8:27 pm

philip_la wrote:Karl, I thought the consensus was that petals anthers and stamens were all considered analagous, as evidenced by the mutation of doubles, in which the sex organs are reduced or absent.
Yes, that's right. Goethe deserves credit for bringing attention to the metamers.
http://bulbnrose.x10.mx/Heredity/Goethe ... e1849.html

Cook expanded on the concept with further examples.
http://bulbnrose.x10.mx/Heredity/Cook/C ... taphan.htm
Take a look at Figure 13, which shows the reduction of the leaf blade, and enlargement of the stipular region in the production of bracts on a rose bush.

The Botanical Register illustration of Rosa ferox (rugosa) shows how the leaves nearest the flower have greatly enlarged stipules that take on some of the floral color.
http://bulbnrose.x10.mx/Roses/Rose_Pict ... ferox.html

Cook (1816) also reviewed various evidence about the evolution of leaves in general.
http://bulbnrose.x10.mx/Heredity/Cook/C ... s1916.html

If you want to go even further, check out Lubbock's ' On Buds and Stipules' (1899).
https://archive.org/stream/onbudsstipul ... 1/mode/2up

And TYLER, A. A. The nature and origin of stipules. Ann. N. Y. Acad. Sci., 10: 1-49, pls. 1-111. 1897.
https://www.biodiversitylibrary.org/ite ... 3/mode/1up

philip_la
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Re: Strategies_for_the_development_of_unique_flower_forms_in

Post: # 66865Post philip_la
Tue Jan 23, 2018 12:14 am

Would it be fair to say, Karl, that these metamers have a hierarchy, such that petals and sex organs might be on the same tier or branch, and stipules on another, and leaves, yet another? I suppose the green rose is an example whereby the petals mutated to sepals, but did the sex organs as well? These are questions of total ignorance, admittedly, and I ask merely as a matter of academic curiosity. Dunno if my questions are logical.
Philip F.
[size=small][color=#669966]Zone 8 / Sunset Zn 30 (Austin, TX -- formerly New Orleans, LA)[/color][/size]

Karl K
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Re: Strategies_for_the_development_of_unique_flower_forms_in

Post: # 66867Post Karl K
Tue Jan 23, 2018 7:06 am

There does seem to be a hierarchy. Certainly we are more likely to see confusion of traits between organs that are produced in sequence. Goethe illustrated a tulip with an organ on its stem that was too high to be a leaf, but too low to be a tepal. I found an example of my own.
http://bulbnrose.x10.mx/Heredity/Freaky ... /Tulip.jpg

Here's a shoot growing from an ovule (apparently).
http://bulbnrose.x10.mx/Heredity/Cook/C ... tshoot.jpg

Petaloid stamens on a single-flowered Azalea.
http://bulbnrose.x10.mx/Heredity/Freaky ... aloids.jpg

And leaves replacing sepals.
http://bulbnrose.x10.mx/Heredity/Cook/C ... metsep.jpg

Here are some leaves growing from the center of a waterlily.
http://bulbnrose.x10.mx/Heredity/Waterl ... rlily.html

And some lily bulbils that have formed some tepals and reproductive parts.
http://bulbnrose.x10.mx/Heredity/Bulbils/Bulbils.html

However, sometimes the genetic program "jumps ship" and turns up where it is not expected. A classic example is the Begonia "Phyllomaniaca" that managed to transform trichomes (cellular hairs) into tiny leaves.
http://bulbnrose.x10.mx/Heredity/Begoni ... a1919.html

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