Hello again, Loretta,
You have made your point that those follow-on blooms are inferior in appearance. Why that is the case is a bit of a mystery to me. It seems counter-intuitive that so many blooms would be "bud sport mutations", and it is hard for me to accept that they are genetically different from the original bloom. No question that they are inferior, but it seems improbable to me that they are genetically inferior.
For the most part, I don't see inferior secondary blooms on my zinnias. My secondary blooms are, and have been over the years, quite comparable to my primary bloom on the plant. And I see that with commercial zinnias that I grow, as well as my breeders. At this moment, I have to admit that I simply don't know why you and other zinnia growers are seeing this effect in the secondary blooms.
For the moment, I will speculate that the explanation could be differences in plant nutrition
. My indoor zinnia project has forced me to take total responsibility for supplying the elements that my zinnias need, because I grow them in Premier ProMix, which, by design, has very little nutritional content. There are a few bits of limestone that prevent a Calcium deficiency for a couple of weeks, but unless you supply Calcium, you will very quickly see a serious Calcium deficiency. My culture of zinnias in ProMix is essentially a form of hydroponics, in which I supply a nutrient solution and the ProMix simply supplies a structure to hold the plant, its roots, and soluble nutrients in a favorable relation to each other. A different form of hydroponics uses gravel instead of ProMix.
My initial attempts to grow plants indoors under fluorescent lighting in ProMix watered with Orchid nutrients resulted in the catastrophic death of all of the plants within a few weeks, with obvious symptoms of a severe fatal Calcium deficiency. My so-called "complete" orchid nutrients contained zero Calcium. So I purchased some Calcium Nitrate from a hydroponics supply company and, surprise surprise, my indoor plant project became successful. However, my older zinnias showed puckering and folding of the upper leaves, a symptom of Boron deficiency. The orchid nutrients contained trace Boron, but apparently not enough for my zinnias, which tend to act like little Boron pigs. So I added a little extra Boric Acid to my nutrient formula to solve that problem. I also add trace amounts of Nickel, Cobalt, and Silicon
because those are not included in the Orchid formulas that I use.
So it is possible that the differences in zinnia bloom development that we are seeing are due to differences in zinnia nutrition. But that is not proven at this point in time. I just can't think of an alternative at the moment.