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Curious

Posted by kwoods Cold z7 Long Is (My Page) on
Fri, Nov 1, 13 at 10:15

Odd blossom. Wondering if anyone has seen similar before... All other blossoms were yellow w/ red streaking like the left side of this one. Not certain the cultivar/variety.

Hybrid reverting to type?


Follow-Up Postings:

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RE: Curious

Which way is it going? To the red or to the variegated ?.


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RE: Curious

Cool!

Yes, kwoods, I've seen that happen often, with many variegated and bicolor varieties. It's still cool to see the different patterns that some blooms obtain, mixing the recessive varigated or bicolor traits with the dominant solid traits.

Sometimes the whole plant reverts to solid, and you have to buy/trade for new stock to get tubers with stronger variegation or bicolored genes. That happened to a Harvey Koop, Fuzzy Wuzzy and Ms. Zelda this season for me, and vendors rightfully will not replace tubers that revert to solid as it is a frequent occurrence out of their control.

There are some varieties that are known to 'mix it up' with every flower different. Hollyhill 6-in1 and Rebecca's World are two of the best, with plenty others. Problem is, often wildcard varieties settle into solid after a couple seasons and their DNA is 'shook up' to more dominant traits when making new tubers.

Here's Barbershop, a bicolored that likes to spin off some fun ones on occasion. Normally its pattern is very uniform on every petal. Look at the back row.


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RE: Curious

  • Posted by kwoods Cold z7 Long Is (My Page) on
    Fri, Nov 1, 13 at 14:41

Thanks very much for the info!

I've lifted this one and put it aside from the rest. Should be interesting to see what it does next year.


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RE: Curious

Here's a fairly new variety that is rare in that it has variegation and is bicolored. I have not heard if it has a tendency to revert, loosing either the variegation or two tone, or just going solid. Time will tell, but with double the recessive gene, this is a prime candidate to change.

Normally, seedlings or sports will be grown for four years or more with no change before named and introduced, to avoid an inferior plant from being put out there... but not everyone adheres to that standard.


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RE: Curious

Here's one that has not been introduced, and I am totally in love with... The hybridizer is hoping this one's tubers will perform as well next year, but it well may not.


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RE: Curious

Here's one that I forgot I had... The variegated side is what it is supposed to look like. This is the only bloom on two plants that did this.


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RE: Curious

CC, Nellie and WInnie is Way Cool!


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RE: Curious

All comments are more or less correct. Variegated and bicolor dahlias can be unstable and revert to solid colors. It is more common with variegated flowers. The variegations are caused by transposons otherwise called jumping genes. They were first discovered by Barbara McClintock who won a Nobel prize for genetic work in this area. The transposons cause dna strands to have missing pieces and that in turn causes the color formation to turn off, creating variegation. The red pigment is turned off in a random pattern of dots and streaks and the base color of the flower that is not affected by the transposon shows through. Sometimes the area that is affected by the transposon moves a bit and the flower is able to completely color the florets with the red pigment. It quite commonly reverts in either later flowers or in later years and become variegated again. The half red, half variegated flower shows how these jumping genes can jump around and in this case half of the flower was not affected by the transposon.
Bicolor flowers are said to be caused by transposons that do not move much. They turn off pigment for awhile and then allow pigment formation. The white tips are where the pigment was turned off.


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RE: Curious

So variegation and bicolor is not created from recessive genes, but from unstable genes... That's gotta sit a while on my skull before absorbing! Time to Google transposons and McClintock.

A very experienced dahlia grower has said that multiple attempts to grow Harvey Koop with variegation has failed, and the grower blames the soil for it. The grower claims that when the reverted Harvey Koop tubers are given to other growers with different soil, the variegation comes back. I suppose unstable genes makes more sense, if the theory about the soil is accurate. Your thoughts, Ted?


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RE: Curious

Transposons are DNA sequences within a gene that cause genes to to turn on and off in a somewhat random pattern. They cause the red pigment formation to turn on and off, creating variegation. Because they are unstable, they can sometimes "jump too far" or some such thing and affect another portion of the DNA and stay there for awhile. Later they may relocate back to the pigment producing area and again the flower would be variegated. I do not know what environmental factors affect transposons but have heard of this happening over and over to variegated flowers. Many times the variegation never again appears. I doubt that it is soil related but it may be related to excess heat.
And dahlias do not have "recessive genes" in the diploid sense because dahlias are octaploid, For a dahlia to be homozygous for a recessive trait 8 genes must be the same whereas in diploid plants only 2 are the same. It is nearly impossible to breed dahlias with all 8 genes being the same. If you know how to do it let me know.


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