i don't think we have LB, but early blight which gradually progresses up the plant through the season. our heavy clay soil and all the fogs and dew we have is just a tough place to grow tomatoes. we have had some beautiful plants here or there for about the first month of the season. we plant late enough and only into warm soil so i've never tried starts outside in place. we have had a few volunteers show up from all the buckets of tomato processing we do. i bury everything to feed the worms in trenches and hope to get them down deep enough to not sprout, but after a few years i might move some of those seeds around. anyways, those starts are usually not where i want to grow tomatoes so i don't let them persist. since we usually are growing only one or two types of tomatoes i'm not sure what the chances are that any of the offspring are going to be much different. we are isolated a fair distance from all the neighbors (1/4 mile or more in almost all directions) and most of them do not garden that i can tell.
how much variation do you experience in an isolated population of tomatoes?
I found many segregating seedlings from seeds from irregular shaped fruits. Beef-like fruits on otherwise plants with perfectly round tomatos seem to be more likely to be crosspollinated. In the beginning I picked these fruits because I wanted to select towards beef type fruits. It turned out that these seedlings change shape colour and other features from year to year
Location: Lueneburg, Northern Germany, Europe Zone 7b