Both are polyantha species. Pacific Giants have been around forever and are open pollinated. Super Nova are bred by the same company (Sakata) and are an F1 hybrid. They will have larger flowers and more uniformity, but should still perform like the Pacific Giants

Does this means I can get seeds from the Pacific Giants? I bought three. I never had reseeding before with primroses.

Absolutely.

Here in California this is the time we put the primulas in the garden. Pacific Giants make wonderful color through the winter. Yesterday I found flats of 10 four inch Pacific Giants from a Gilroy grower in wonderful condition for less than $10 at Costco. I was able to get them planted before the next full week of rain. Sometimes you get lucky. Al

That right Al, you have a big garden. I got three planted, that's all I have space for, but they already taking off like gang busters.