First of all, it is never necessary to prune suckers. Old wives' tales about suckers include that they don't bear fruit, that they aren't "real" branches, and that they steal energy from the rest of the plant so that the plant is better off without them. None of those are true.

As far as not being "real" branches goes: tomatoes have a main stem, leaves, flower trusses, and branches. All tomato branches start out as suckers.

The only reason to prune to one stem (i.e. remove all suckers) is lack of space for a wider plant. Those interested in growing particularly huge tomatoes usually prune to one stem -- but it's unclear how much of a role such pruning plays in giant fruit.

Disadvantages of pruning to one stem include a greatly reduced fruit crop, the risk of sunscalded fruit due to reduced leaf cover ... I think I'm forgetting some others. Okay, pruning takes time: but then, the more time you spend with your plants, the quicker you'll notice diseases, aphids, and hornworms, so that's a toss-up.

Now, I'm saying this as someone who was raised to prune to one stem. I realized it was a disadvantage. I wanted more tomatoes than that! (And being 5'2", I thought that perhaps with multiple stems, the plant would be shorter and the top easier to reach.)

[Whether or not you prune suckers on indeterminate (or "vine") varieties, determinate (or "bush") varieties should never be pruned, since determinate plants naturally terminate their stems and stop growing after a certain amount of flower clusters. Pruning a determinate means losing the majority of the crop of a naturally shorter-lived plant.]

About your forking stem: sometimes unpruned suckers stretch out so it's not obvious they originated in the crotch between a leaf and the main stem. And sometimes -- rarely -- a growing point does actually fork into two stems. But your main stem looks unnaturally widened in that area ... kind of double, as if two stems were stuck together.

That happens sometimes with plants, either the result of a mutation in a single cell, or occasionally a mutation that affects the entire plant and can be passed on to its offspring. The technical term in at least some cases (I am not a botanist) is fasciation. Sometimes when I'm pruning my apple trees I find a branch that turns into a fan of branches, very similar to the fingers on a hand. I've also found weird dandelions with 1" wide stems below rectangular flowers.

You can prune it if it makes you feel better. But why? Although raised to prune to one stem, I feel better having more tomatoes to eat (and inflict on family and neighbors and friends)....

First you don't have either tomato leaf roll or tomato leaf curl and no curly top virus. There is no evidence of any problems at all. Your plants in the pics are normal. Large leaves will often hyper-extend like that in response to their size and to varying environmental factors, primarily humidity or early injury.

Don't try to compare the appearance of different varieties. It is an apples to oranges comparison and only misleads you.

As to the pruning issue I agree 100% with all that missingtheobvious already posted. Prune if you wish but there is nothing in any of those pics that needs to be pruned. The one plant in the last pic clearly has a fused stem where the branch (the so-called 'sucker') first fused to the main stem and has now branched off.

Dave

I appreciate your responses! everything I read here seems to contradict what I've read before so I'm glad I feel like I'm finally learning something useful :)

everything I read here seems to contradict what I've read before

Hmmmm, since most of what we talk about here is fairly common knowledge, that makes me want to ask where you have been reading before?

But then sometimes what seems like a contradiction is really just a misunderstanding.

Dave

It seems like pruning suckers is a practice that is pretty commonly recommended for indeterminate vines.. Another example is a post i was reading the other day about BER not being caused by a calcium deficiency in the soil, but instead by the way calcium circulates through the plant. I was just trying to say I've learned a lot here. This is my first season to grow tomatoes (or anything really), and from seed, so I'm just a little green, my bad.