seed gathering?

[Oscgrr]

I tried to gather seeds from a supermarket tomato (just to see if it could be done) this past Spring and they never sprouted. Over the Summer, I researched and learned that the seeds needed to be fermented. Okay, that explained that but I read on and the article recommended that any seeds that I wish to save should be taken from one of the best tomatoes on the plant. At the start of the season, I bought several plants from a big hardware/lumber/garden store and on a whim I picked up a yellow tomato plant that claimed to be an heirloom (I didn't know what "heirloom" was, I do now) and it gave me a bunch of very nice deep yellow, fist sized tomatoes that tasted awesome. I ate just about all of them before I decided that I would like to start all my plants from seed next year but the only one left was a smallish tomato with several surface cracked looking scars. I put the seeds in a jar with some flesh and a little water and covered it with cheesecloth. It looks fermented and smells nasty, like I believe it's supposed too. My question is this, because I saved the seeds from a smaller fruit, will that mean that my tomatoes next year may trend smaller? I understand that there's no guarantee and genetics is a tricky thing to predict but more specifically, do tomatoes really differ, genetically, from fruit to fruit on the same plant? If I wanted larger fruit, should I have taken seeds from the largest one on the plant?

[remy]

Hi Oscar,
No need to worry, you'll get bigger fruit next year even though you saved from a smaller one. All the same genetic material is in the fruits(once in a blue moon there's a mutation but that's for another time.) The size differences in the fruit is normal on plants.
Oh and yes, the fermented seeds smell nasty!
Remy

[Oscgrr]

Remy,
Thanks for the response. Since discovering what exactly heirlooms are I'm kinda excited at the prospect of perpetuating a particular tomato (accidental alliteration). Is it possible that the seeds I gathered may be the product of cross-germination from another variety that lives in my garden (or, unlikely, across town for that matter)? I wouldn't mind so much as long as the result were interesting.
Oscgrr

[remy]

There's a small chance you could have crossing, but the rate is fairly low so you should be ok. It would occur from in your garden and not across town. Tomato plants don't have to be very far apart like some other types of plants to come true. If you've got lots of other types of plant in bloom, this will even lower your chances of crossing. Bees much prefer other types of blossoms if they are available.
It is always best to save seeds from a few fruits so in case you had some crossing occur, you'll still have many plants that come true. I wouldn't worry about the fact you only saved seeds from one fruit though as I said the rate is fairly low.
Remy

[pinakbet]

Oscgrr -> Just recently, I was still able to germinate air-dried, un-fermented seeds from last year coz I only recently that I found out about the fermenting method.

[RinTinTin]

The key, is not to pick the largest fruit in your garden, but to pick the fruit from the healthiest plant in your garden. Fruit size is not a gene, but health/vigor will be passed throughout future generations.