I broke a rather large piece of the main stem on one of my tomato seedlings today. I put the broken piece into a small bottle of water and will wait for roots to grow. My question is will my cloned plant be less productive than a plant grown from seed?

What kind of lighting should I give the clone in the water?

The clone is from a JD's Special C-Tex plant started from seed.

I would think this early in the season it should perform about as well as if it were grown from seed. I've done that before. Later in the season rootlings didn't do as well, though. Especially in the extreme heat and drought we went though late last summer.

The same lighting as any other plant.
To be true you can start the thing in mud or really wet potting soil and it will be a better transition to being put out in real soil.

No, it will not be less productive.

The clones will probably flower before the mother.
I usually start clones if the mothers get to big (started seeds too early) just as a backup.
I'll also clone plants when i only have a couple seeds.
I ordered seeds from a company and they sent 10 seeds.
I didn't want to use all my seeds so I planted a couple then cloned the mother.

You'll have faster and better cloning if you put the stems in a nutrient solution. This could be just a weak fertilizer, or a specialized cloning solution, with some hormones it it, which will speed things up. Clonex is my favorite brand to use in my cloner. Only 5 tsp is needed for a gallon of water, so very little is needed in a cup.

I would cut that bottom large leaf in half or even cut it. You can plant it directly now in a small pot with well draining medium away from direct sunlight till roots form. Like Worth mentioned it's best to root in wet mix since it'll transition to soil later anyways. I then put the pot in a plastic bowl, tupperware, whatever, with a small amount of water at all times. You can root rose cuttings this way too except I learned it's best to put a loose plastic bag over it but I don't do that for tomatoes. I've cloned many this way esp if I only have 1 plant that grew from seed but is popular, like Sungold for example. Or other expensive hybrids. Amazingly quick & easy.

I would trim off more leaves, dip it in rooting hormone and stick it in something like a wad of pro mix, wet sand, or perlite. Your stem might rot in the stagnant water.

Remove more leaves and put it in some sort of grow medium. You will form weak roots growing it in water and you will set the plant back when you move it to soil.

Agree on all above. Rooting in water is not a good idea, it's so easy to do directly in a pot that fits the cutting, keep moist & transplant. Good luck on whatever you choose to do!

The internet is full of people rooting tomato cuttings in water, but I trust my tomato buds more than I trust the internet. I trimmed the cut, dipped it in root stimulating hormone, and placed it in seed starting mix. I'll see what happens.

Just keep it good and wet till roots start to grow then ease off the wetness.