Tomato trunk question?

[materhater]

I have a 2 tomato plants where the trunks looks like 2 trunks are fused together, what causes this?

[peppereater]

hey dld, how goes it?
Since no one has taken a stab at this, I will.
I think I know what you're describing, I've seen it quite a bit if it's basically sort of a broad, flat stem with maybe a crease down the middle or even several ridges. I think it's related in some way to the gene's of 'maters that also make fused fruit and especially large fruit, as I seem to remember seeing it more on things like Brandywine. It could be environmentally triggered while also predisposed to some specific gene or set of genes.
In some cases environmental factors alone, like herbicide drift or a virus, or even hormone mimicking chemicals injected from certain insect's bites could certainly cause it, but I think typically it's from natural growth regulators in the plant itself either just displaying natural tendencies or exaggerated by growing conditions or soil characteristics.