This is probably the most stupid question on here, but asked in innocence an an attempt to increase my knowledge. I understand that tomatoes are split into bush and cordon varieties - ie cordon are grown as a single stem through pinching out side shoots and bush varieties grow unhindered on multiple stems. My devil's advocate question is - why? What is it that determines whether a variety is best cultivated as a single or multi-stem plant? And what would be the outcome if the 'opposite' training method were used? (I anticipate you will all say poorer/fewer fruits but why is that?)
Taking the hypothetical a bit further, say I were given a healthy tomato plant but with no information about variety. Is there any way to tell if this is cordon or bush? If not, which should be assumed, to ensure most success? I am not in that position, but do have a few varieties of tomatoes all about the same size (and all labelled before you ask so this really IS hypothetical) and I can't see any obvious differences between them, hence my curiosity. Is there a clue in the way the flowers or trusses form perhaps? My feeling is that cordon varieties need lots of support so maybe they hold their fruit in a different way to bushes?
And lastly. is there any variety that falls in between the two types? I'm thinking maybe a hanging basket with two plants, one trained as a cordon up the chain and one left to hang, but both the same variety.
Thanks in anticipation of your answers. I'm new to gardening (it is probably obvious) but keen to understand things.