Hemlady said:I can tell you that Pastel Classic which is a single bloom has produced double blooming seedlings for me.
Under simple ideas for the inheritance of doubling (for example one gene with a recessive allele for doubles) some single flowered cultivars would be able to produce double-flowered offspring in crosses with some other single flowered cultivars. Those would be single-flowered cultivars that were heterozygous for double flowering. Under more complex ideas for the inheritance of doubling (for example one gene with many modifying genes or more simply many genes involved) then single-flowered cultivars would be expected to sometimes produce double-flowered offspring when crossed with certain other single-flowered cultivars. The difference between the two scenarios would be that under simple ideas a specific proportion of the seedlings from such crosses would be double-flowered (one quarter) but under complex ideas there would be no way to guess what proportion of the seedlings from such crosses would be double-flowered.
In both cases there is no simple way to predict how many single x single crosses would be expected to produce any seedlings that flowered double. One could do so if one knew the frequency of the doubling alleles (commonly genes) in the entire daylily gene pool (diploids separate from tetraploids).
We may be able to get a better idea of the genetic possibilities from crosses by looking at the AHS registration database.
It may be interesting if we look at the parentage of Pastel Classic which is Mysterious Veil X Becky Lynn. Both are registered as singles. Mysterious Veil has nine diploids registered as its offspring and none are doubles. Becky Lynn has 121 diploids registered as its offspring and four are registered as doubles. Of those two have simple parentage involving Becky Lynn (only one generation) - Prairie Canary (Becky Lynn x Lacy Dawn) and Pretend My Love (Elijah x Becky Lynn). Both Lacy Dawn and Elijah are registered as singles. Neither produced any other double offspring. We could assume that Becky Lynn carries some of the genetics for doubling and that some of those were passed on to its offspring Pastel Classic.
We could then expect that if Pastel Classic was crossed with Lacy Dawn (single x single) some of the seedlings would be double-flowered. Or if it was crossed with Elijah (single x single) some of the seedlings would be double-flowered. We should also expect that if Pastel Classic was crossed with a registered double that a larger proportion of such seedlings should be double-flowered (than from its crosses with registered single-flowered cultivars). We should expect that in crosses of Pastel Classic with some single-flowered daylilies some of the offspring would be double-flowered and in crosses with other single-flowered daylilies none of the offspring would be double-flowered.
