I know that Gigantomo are a F1 variety, but I'm loving the size and the taste, they are so good for burgers and BLT's. I'm saving seeds and I'm going to be interested in what two types of plants I get from the experiment.
Now I know that F1 saved seeds will not run true to the original, however I have done this before a couple of times. I did this with the Crimson Crush plant they sent me to trial when they first released plants only.
The result from saved seeds was two very different looking plants one with classic tomato leaves and the other with more potato looking leaves. I followed the more tomato looking plant into the second year as the fruit was more like the original, and now many years later have seeds that produce a tomato that look & taste the same as the Crimson Crush F1 but from my own seed stock so it cost me nothing to buy the seeds anymore.
I have 3 seed left over from the pack I bought this year so my plan is to grow a plant from the original F1 Seed and perhaps 4 from saved seeds and see how closely they follow the original F1.
I will save seeds from the first generation and sow them the following year and keep on going each year until I have a stable seed that gives me something closely resembling the original or perhaps better.