I have been a strict 'heirloom only' gardener for my whole life. However, the other day I was reading about tomato hybridization and it said that in F1 hybrids there is often the characteristic of 'hybrid vigor'. This article said that F1 exhibits a stronger and more productive plant, but it fades away by F2 and by F3 it is non-existent. This caused me to think of a possibility. I have some tomato seeds and herb seeds that are from different countries, but they are the same variety.
For instance, I have seeds for the Brandywine tomato from Canada, Germany, South Carolina, and Oregon. They are all the same variety, but they have been selectively bred in different climates and have been totally isolated from each other for untold decades; in all probability. It would stand to reason that they are not precisely the same genetics, although they should be very close.
So, the question is: if I crossed the Canadian version with the German version, would the resulting seeds exhibit increased vigor?
A second question is: since these are not technically hybrids, would the vigor remain in the next generations F2, F3, etc instead of diminishing as hybrids will?