Hi Teresa,
First of all, welcome to this message thread on breeding your own zinnias. You have covered a lot with your first message, made many good comments, and posed many relevant questions. I will address at least some of them, in no particular order. Your red Benary picture is a somewhat light rose red, which is a delicate cool red. Zinnias are capable of many subtly different colors, including many subtly different reds.
" For the last four years I've grown the Giant Cactus mix, but have yet to see a red of that color, or any red for that matter. ... I would love to breed into the Cactus mix a red. "
You are right that commercial cactus mixes seem to be predominately oranges and pinks. Bees pollinate randomly, and orange and pinks seem to be dominate zinnia colors.
" ...but I haven't seen the Giant Cactus in individual colors. "
Hazzards sells Giant Cactus zinnias in the separate colors red, orange, purple, pink, white, and yellow.
http://www.hazzardsgreenhouse....
Unfortunately they have the wrong picture at that link (I just emailed them about that), and the actual picture of a red cactus zinnia seems to be at their listing for an orange cactus zinnia.
http://www.hazzardsgreenhouse....
Despite the picture mix-ups, red cactus flowered seed is available commercially, and would be a good starting point to select out and perfect a good strain of red cactus flowered zinnias. As you have already discovered, many (perhaps all) commercial zinnia strains are in serious need of purification and selection for better on-type specimens.
" So then also, which, in your opinion, gives most to the flower form, the seed producer plant; or the pollen donor? "
I don't think it matters. What does matter is which genes are dominant and which genes are recessive. Dominant genes can come from either the seed producer or pollen donor, as can recessive genes.
" ...you don't always isolate, nor save specifically, your seeds in recording individual plants and colors, etc. But from what you can recall, do you have any knowledge input about resultant seedling color? "
I do keep a detailed journal of my zinnia breeding, and each breeder zinnia receives a unique "code" consisting of a letter denoting the year of the designation (my designations for 2016 all begin with the the letter "J") and a number starting at 1 and incrementing for each new selected breeder specimen that year. Each breeder specimen gets a page in the journal, telling several details about that breeder, including the code for its maternal (seed) parent, the date it was planted, physical properties of the plant and bloom including petal color(s), petal form, bloom form, plant habit, and which breeder or breeders it was pollinated with. So when I plant a bunch of breeder seedlings I do know the color of their seed parent. The colors of the seedlings will certainly be influenced by the maternal color, but recombinations of the maternal genes and recombinations of the paternal genes have the potential for creating a variety of colors in the seedlings.
Their is really a lot of "meat" to this zinnia color subject, including the nature of the organic chemicals that produce the zinnia colors, and recombinations of genes that occur in the cellular processes of meiosis that produce the egg cell and the pollen grain that united to form the embryo of the seedling.
There are many points in your message that I haven't gotten to here, but this is starting to become rather long, so I will pause for the time being. More later.
ZM
