Years ago I crossed a bell pepper with a variegated hot pepper (bought unlabeled). Among the F2 (grandchildren) I found a few mild offspring which became the foundation for all of my mild lines of pepper.
Along the way, I've selected for purplish foliage and general productiveness. In recent years, I've started outcrossing to various hot peppers to bring certain traits into my lines. I wanted the fuzzy stems and foliage of 'Serrano', and the general vigor and growth habit of 'Habanero'. Both of these could add some interesting fruit characteristics also.
These peppers are from: one of my mild peppers crossed with 'Habanero' pollen and then the resulting hot F1 were backcrossed using pollen of my milds. The ones pictured are a few of milds (2 yellows and a red). They are 1/4 'Habanero'. Since 'Habanero' is Capsicum chinense, the original cross with my Capsicum anuum milds was not especially easy, and there are still some lingering issues with fertility. Many of these backcross offspring have a reduced number of seeds inside - sometimes only 2 or 3. So I'm hoping to keep all the milds alive over the winter (indoors) and plant them out next year for seed production (with no hots around to pollinate them). There's so much to select for with these guys that it's not easy to make progress. In addition to growth and production characteristics, there's flavor, size of fruit and thickness of fruit wall. I'll need to have a lot of seeds in order to be able to grow a big enough population to get what I want all combined into one plant.