If you grow the different types separated from each other, the seeds will be pure and close to the parent plant. Of you grow several plants of each type, test the peppers from each plant and whichever one you think is the best, use that one for seed. If heat is your criteria, you take the plant that makes the hottest peppers to use for the next generation. By selecting the best plants to use for breeding, you can possibly even increase the heat in future generations. That is the way the Red Brain Strain was made.

To answer your question, click here.> Saving chilli pepper seeds to grow again

Thanks guys, great help

You're welcome!