Selfing to achieve 4N breeders

[GirlGoneWild]

I am in the beginning stages of developing a breeding program (meaning the planning stage, really), and as I collect plants to be eventual breeders, I am wondering how to deal with the issue of ploidity.

I've read that 4N plants generally produce better results than diploids, and that tetraploid plants can be achieved by "selfing" the original diploid.

So, say I want to turn my diploid species plant into a tetraploid to make it a stronger specimen for breeding, with the desired result being hybridizing with another 4N plant to achieve 4N offspring.

Since some of the offspring of the selfing may mutate back to diploid and I wouldn't know it, I run the risk of breeding another diploid with a tetraploid and ending up with a sterile triploid. I definitely don't want that.

So would it make more sense to cross the two intended plants first, then self the offspring of the cross to get 4N (since the offspring would be the desired plant and would be sold as the end product) rather than selfing each parent and then crossing the (hopefully) 4N offspring?

I hope I'm making sense here. I'm not sure I'm explaining this properly. Basically I want to know this: If I want to create a tetraploid hybrid with plant A and plant B (which are diploid currently), should I self A and B first to create the 4N parents, then cross those? Or should I create a diploid hybrid from the two parents and then self the hybrid to get the final 4N result?

I'm really not looking for a debate on the pros and cons of tetraploids here...I'm more looking for an answer on the best way to go about achieving tetraploid offspring.

Thanks for your help, friends!