And some of it will need to be learned by trial an error but I’m thankful for people on this site willing to share information to a beginner 
Breeding: For Color
Dahlia Breeding on Facebook has over 4,000 members.
If I were on Facebook or instagram id totally check sites like that out but since we decided to stay off of them I guess that’s out for me.
I post most things on Facebook and have never had a negative experience on Facebook. The breeding site was started by person who has a PhD in genetics and the members were over 4500 last time I looked. Lots of information on all subjects related to breeding dahlias. Names of potential seed parents is a subject that few people share and even my wife and I are very reluctant to share something that took us many years to find out by personal experience. . We also use specialized breeding varieties that we never share or sell and are going more and more in that direction. We have bred a seed parent that is a B IC Lavender that produced 122 seeds in one pod. Most of them sprouted too and the seedlings have been good.
That is lovely to hear Ted... I love the incurved cactus ones. particularly the smaller ones for my garden. I got one of those from you this year and am excited to grow it.
3 months later
- Edited
Picking up the conversation from Dahlia Seedling Pictures 2024
Teddahlia Using the chemical basis for color: F. Copper has a yellow towards orange base pigment that is overlaid with some version of red to give it the so called copper color. Your F. Copper seeding is lavender and some would say light purple. In order to be that color , a flower cannot have the base pigment of F. Copper and it needs to get a different lighter white pigment that allows purple to appear.
I was curious and did a tiny bit of online research. Based on the theory of orange pigment inheritance in dahlias, do the color of the seedlings produced by SB's Fiesta dahlia follow the orange rules you describe? Birch Bay website information:
Another example of an orange seed parent:
A dahlia can be orange two different ways: The underlying pigment has different versions that range from white to yellow to orange. The second way is for a flower that has a yellow base acquire a small amount of anthocyanin and red and yellow make orange.
SB's Fiesta lost the yellow pigment that is now white and it always had some anthocyanin and the seedlings are anthocyanin on top of white.
Poppet: Underlying orange pigment changed to yellow and Irish Glow has anthocyanin on top of yellow and that makes red. The yellow flower is just the underlying yellow color and no anthocyanin. The third one lost the yellow that is now white and the anthocyanin overlays the white base and this version of white pigment does not change the anthocyanin to red and it is it's native color that is lavender or purple.
Am I correct? My answers are what I think happened but I could be wrong.
14 days later
- Edited
Old picture of Hollyhill Fireball, the flower that is unbelievably nice for the first blooms but as the days of sunlight decline, it's red pigment declines too and by October it is a yellow flower. It is an example of a flower with a yellow base pigment that is covered with red pigment. And it is a flower with the fairly common trait that the formation of it's version of red pigment is dependent on sunlight during the maturation of the flower. Picture taken with the best camera lens I own, a 1.7 aperture lens. I no longer use it but should drag it out once in awhile. And we no longer grow HH Fireball and should because it is a good seed parent and has Odyssey genes.
I did not ask Gordie about Fireball when I talked to him. I doubt he used Odyssey in his breeding.
14 days later
This thread is interesting to me and color is both the pigments and the pattern of the pigments. One hot new "color" is picotee where the edges of the petals are outlined with pigment, usually a darker pigment. Whenever we see it n our seedlings we tend to keep that flower around despite borderline form. 
As a cut flower grower and user, this is what I really like. The solid color show dahlias are lovely. But one that this...the mix of colors that can be played off with other colors...the way it changes as it opens, or closes up for the night...I find it far more exciting than perfect form! It's like the difference between a photo and live action...
5 months later
- Edited
In my Google News feed this morning there is an excellent article on a genetics research paper that I found interesting. As I was reading it, it reminded me of some of the discussions on genetics @Teddahlia has eluded to. As I understand what the article summary states is that the actual genes are separated from the "enhancer" switch genetics. The article is about fruit flies, but I can envision how it relates to Dahlias.
Article in phys.org: link Excerpt below.
The blueprint of plant and animal forms is encoded in their DNA. But only a small part of the genome—about two percent in mammals—contains genes, the instructions for making proteins. The rest largely controls when and where these genes are active: how many of their transcripts are produced, and thus how many proteins are made from these transcripts.
Some of these regulatory sequences, called "enhancers," work like dimmer switches used to modulate the light in our living room. Indeed, they specifically increase the expression of a particular gene, where and when this gene is required. Genes controlling morphology often respond to several independent enhancers, each determining the expression of the gene in a different body part.
Research Paper in science.org: link
Let me know what you think...
I just had a startling idea, what if some of the categories/forms of decorative plants we now grow, exhibit, attempt to hybridize, and collectively call "dahlias" are unique subspecies? This idea came to me when I thought about the incompatibility of some Dahlia crosses. One of the many criteria for uniqueness of a subspecies is:
- Reproductive Isolation: If two plants cannot interbreed or produce viable offspring, they are considered different species.
I watched short video on Mendelian genetics and the blue eye, brown eye example was said to be only partially true. As you say other genes or genetic material influence the formation of specific traits. In the big picture, breeding like things to get like things, works and not just because of the alleles(better word for genes in this case) but because you are preserving the "other genetic material" that influences your creation. 
Margaret keeps a record of hand crosses that do not take. I am inputting onto a spreadsheet her results of hand crossing this year. We only started doing the spreadsheet in 2022 although she had paper records from previous years. She does not hand cross every year and skipped 2023 for example. Several years ago there were very few breeders who hand crossed and the late Ken Stock of Bournemouth England was a staunch advocate of doing so. We communicated by email and he was a very interesting person. Around this time, most breeders converted from their attempts at hand crossing to what the late Mike Iler called "isolation breeding" . The Ilers and the Boleys are good examples of it. Iler planted a cactus-incurved cactus bed with known seed makers and several only pollen makers in an area 100 feet away from his main dahlia garden. The bees did the pollinating and he was very successful. He had been a hand crosser but said that it took way too much time. There has been a minor resurgence of hand crossing since Kristine Albrecht wrote the book on hand crossing. There is just enough information in the book to get started but really you need to actually learn by doing. Margaret explained how she hand crossed to Kristine several years before the book was written. Amazing Fact: Margaret liked her best first year seedling so well this year that she used it's pollen to hand cross some reliable seed parents and got lots of seeds. No sense waiting until next year. That first year seedling did have 11 flowers on it at the same time and 5 or 6 of them were them were ripe for picking. Hopefully, it will pass on it's florescent pink color to some seedlings. 
Another good system for controlled crosses is a method my father used quite often: He would give two varieties that he wanted crossed to a friend who didn't grow dahlias. He asked that they quit picking the blooms (I think sometime in August) so that the bees would have time to pollinate and the cross to set/mature seed before frost.
This method is much more productive than hand crosses but it doesn't allow for crosses with a first year seedling. Hand crosses are a real pain but will always have a place in dahlia breeding.
People have a tough time understanding how to breed dahlia colors. I will repeat again that the easiest strategy is to breed like colors together. However, there are exceptions and white to white often fails to yield many whites. If you by chance or on purpose have white flowers that are white for the same genetic reason, you will get lots of white. When I judged with the Stanford student now at OSU, he said there are at least 5 versions of white and they each have chemical causes. That is, if a chemical fails to be formed the flower is white. There are at least 5 times in the chemical formation of pigment where this can happen and the result is a white flower.
SteveM so funny this comes up because I just talked to my mom last week about doing this next year. My parents live in a condo and she likes to grow 1 dahlia in a pot but is willing to do 2 for my "project". She likes pompons and MBs the best so I'm deciding which to try out. I think Winkie Lambrusco or Bowen will be one as they both have made seed for me before and they both have some qualities I like a lot. 