You are correct, dahlias do NOT come true from seed. However, if you have a great looking dahlia flower, you can duplicate that plant with the tubers that form below that particular plant. How commercial growers duplicate dahlias in quantity I can not tell you, possibly by taking cuttings as the dahlia grows, plus the tubers from the new plant, etc. but that is only a supposition on my part. Hopefully someone else will post a more valuable answer.

Thats what I thought too, however, a site listed on here, had a tutorial about growing Dahlias from seed, and since they sell them, I was wondering how its done.

Not a dumb question at all---the "secret" to getting good dahlias from seed is 30 years of trial & error, a hybridizing program with copious note-taking & evaluation reports & lots of plain old work!
I have to laugh when someone tells me they are sooo happy because they bought seeds to grow, for instance-- pink cactus dahlias-- & then I get angry because someone has taken advantage of them & taken their money under false pretenses. Chances are there won't be a pink cactus in the lot & most of them will be very poor dahlias.
For every 1000 planted you're lucky to get a few really good ones. We only grow fully double, AA & A sized dahlias in our seed parent garden, do hand-crossing of the ones that our records show to be good parents with a good rate of success. We don't grow any open centered dahlias anywhere on the farm.
We start with really good show quality dahlias, & cull ruthlessly any seedlings that aren't up to snuff. It's better to start with good ones than to try to breed out flaws.
We do breeding back- using the seed parents with the seedlings from them when doing hand pollinating.
The first year you get, maybe 3-4 tubers from the seedling. Then you have to keep the tubers over & grow the dahlias for 4 years before you can send them to the trial gardens. After that you can introduce them -- so every dahlia that we have introduced we have grown for at least 5 years, entered it in shows to see how it does, sent some to trials-- some we even send to other countries to see how they do there. We have a couple of friends around the US & Canada & England that we let grow some of our seedlings to see how they do in regular gardens-- not just in the trials.
It's a lot of work but like Christmas every day in the summer when a brand new seedling baby opens up & we get to see something that no one has ever see before-- & quite a few that no one will ever see again, too :)

Hi there,
I think it is in the nature of Dahlias to form tubers in order to survive in dormancy till next season. The size and number of tubers actually produced varies from plant to plant (well, genetics+ enviroment). In a book on breeding Dahlias was said that one criteria should be that a seedling produces a couple/ plenty of tubers.
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Dahlias seedlings form tubers in their first growing season. You can enhance the number of tubers by planting the seedling stem slanted/angular and covering some pairs of leaves (nodes) with soil. At every node should grow aditional tubers, provided the growing conditions are ok.

I hope that helps, if you have lots of space I would grow some from seed just for fun, have a nice summer, cheers, Lin

Thanks soo much, Plantlady, and Lunaria. I knew there was a complicated process to it, and than it can be done,( not that I want to.
I'm afraid I dont have enough years left to start such a process, but I'm so grateful to those of you who do, and let us enjoy your successes.
I would also imagine its like having a new baby, waiting to see what comes up!