See FAQ below. There is also a FAQ on pruning and many, many discussions here about it - both pros and cons - that the search will pull up.

Pruning is strictly optional. It is not required in any way, and what you call "suckers" are actually fruit producing lateral branches. By doing it you have reduced the plant's production substantially.

But it is your choice.

Dave

Here is a link that might be useful: Tomato forum FAQs - How to prevent cross pollination?

Some people "bag blossoms" to ensure no cross-pollination.

Right, I know it's optional, so I probably won't prune the ones I'm growing for consumption. I just know that pruning will make for bigger fruit, even if it means a smaller overall yield. I just figured it may be a smart thing to do for my "seeder" plants, from which I won't eat any of the fruit. It'll still be possible to produce a decent amount of fruit, and therefore seeds, from the pruned plants, right?

Thanks for the link, I'm going to read up after I hit submit for this post.

It'll still be possible to produce a decent amount of fruit, and therefore seeds, from the pruned plants, right?

Not sure what the relevance of fewer and/or bigger fruit is to seed saving since you want to save the seed from a wide selection of fruits anyway and preferably from more than one plant and at different times of production. Are you assuming bigger fruit will yield more seeds? That may or may not be true depending on growing conditions. But lots of seed savers routinely save seeds from unpruned plants with no issues. Or is your goal increasing the size if the variety if possible?

And I assume you know that the size increase that might result is only marginally bigger. But yes, assuming the plant is not overly pruned or overly stressed by pruning and so more inclined toward disease you can still get sufficient fruit for seed saving.

Dave

Well, I know the brandywine variety has potential to produce massive fruits, which is one reason I chose that variety, so I wanna do everything I can to make that possible.

As for the health of the plants, nothing seems negative at all after the pruning, and I baby the hell out of them anyway. So I assume I can still expect a good number of fruits / seed?

Also, I realize that about saving seed from different plants, different stages of maturity, etc. I just figured this one plant would be enough, since I'm not going to consume any of the fruits, and since I selected the single most healthy seedling for this.

Also, I know it will vary from fruit to fruit, but what is a rough estimate of how many seeds could possibly be found in one Brandywine tomato? Will there be very few, a decent amount, an abundance, what?

Agree with edweather, that said:

" Some people "bag blossoms" to ensure no cross-pollination"

You can bag (cover with fine netted french tulle) a cluster before flowering untill fruits are set. Then tag that cluster and remove the bag. Let the fruits ripen to perfection an then collect the seeds from it .