Teddahlia You always hear me saying, breed like to like to get like. If you are going to outcross between forms, you need several generations of breeding to get back to either of the starting forms
That is why, if I ever decided to breed WLs for show I would use Hollyhill or Boley WLs as the seed parents rather than a random WL found on social media or from a new grower/breeder. Both the Hollyhill and Boley lines of WLs have removed most of the bad genes via several generation of breeding. So, if I cross a Hollyhill (or Boley) WL with a Hollyhill (or Boley) WL I will have a very good chance of getting a WL seedling.
Another thing to consider is the dominance of genes. Usually, the wild(species) genotype of a plant will be the gene that is dominant. In dahlias the wild "petal count gene(s)" produces a single row of ray florets. To simplify and generalize, that means I don't want even one copy of the gene mixed in with the other 7 genes for that trait even when the other 7 genes have a "fully double" genotype. For one breeding project I crossed a single variety with an established double variety. The resulting seedlings were all singles with a few partial doubles. When I crossed these siblings with each other all of the 150 seedlings were single except for 1 fully double and 3 partially double seedlings. This tells me the gene for a single row of florets is dominant and probably the reason serious show breeders (for double blooms) do not allow open-centered dahlias in their garden.
