I've spent a great deal of time this summer trying to get the citandarins US 1279, Us1281, and US 1282. These are relatively unrelated citandarins, each with lmore than 95% zygotic seedlings. Together with US 852, these are enough variation that I don't need to worry about inbreeding
Other unrelated breeding material I have are;
Seedless Kishu mandarin, with a dominant gene for seedless.
Citrus medica, which is reported as quite precocious and zygotic.
Finger lime, which I've read mixed reports as being precocious. All zygotic.
P. trifoliata+ seedlings. Unproven as breeders, but should lack the Ponciris taste and be zygotic.
Still to get are;
F, hindsii, Hong Kong kumquat, which I've read is quite precocious, and zygotic.
Laaz's precocious P, trifoliata. I had it and it died, but I lost a lot of stuff that winter, so I'm not blaming the plants. It is not zygotic, as far as I know. And it has not produced precocioous seedlings nor grandchildren. But it hasn't been tested enough for me to be sure it won't produce precocious grandchildren.