Since this has been brought up from the depths, I will report a distinct lack of success in producing cauliflower seed.
Pusa Meghna produced loonie-sized heads (tiny, in other words) then flowered and produced seed. It would have been self fertilized.
Everything else flowered much, much later. I was quite hopeful for a while nevertheless. However, plants kept turning sllimy and dying just as they got going. Somebody mentioned Swede Midge and I am inclined to say we have it. (Our broccoli was also pretty much a complete failure this year, which is unusual. Certain varieties grew to be nice lush plants that produced... nothing.)
Haven't decided what we are going to do this year.
Sorry to hear about the lack of success. Have you tried growing them under row cover to keep out insects?
Growing in a coastal zone 7a in the Northern Hemisphere. Hot humid summers and cold snowy winters. Plenty of rain. Sandy loam topsoil over clay subsoil, whatever the glacier left behind when it made Long Island.
In about 2014 I received lots of seeds from Ilex. He did a mass cross of six old varieties from Mallorca with the aim of having cauliflowers that will ripen from November to April. He found that they tolerated drought and poor soil - just what I needed! He then started crossing them with some of the new coloured cauliflowers.
I grow a row of plants each year, and still have enough seeds for a small farm. They are all different, of course. The one that is producing right now is like a Romanesco- the kind like a fractal.
Would you like some of his seeds?
Victoria, British Columbia, Canada a cool mediterranean climate - rainy winter, dry summer