Posted: 26/07/2013 at 07:38
Saving seeds from F1 plants gives you F2 seeds. F2 seeds won't produce true to the F1 parent plants because, in simple terms, you're starting to unravel the gene combinations created and stabilised in the breeding of the F1 plant.
F2 seeds will usually produce fruit recognisably similar to the F1 fruit but with variations. The further you go down this road - F3 seeds, etc - the greater the variations you'll see.
I know some tomato growers with too much time on their hands who delight in trying to grow out F1 tomato plants to try to determine the original varieties used in the F1 creation. Most seed companies who create F1 varieties decline to reveal the varieties they use.
The more varieties used in the creation of the F1 plant, the longer it takes to trace its origins. I know one chap who spent 10 years on one plant. As I say, too much time on his hands.