I don't grow very many vegetables. This year all I grew were sugar snap peas, lettuce, kale and tomatoes. In 2007 I bought a number of heirloom tomatoes from Project Grow's annual plant sale. My favorite was 'New Brooks', a pinkish beefsteak. I liked it well enough to try saving the seed, something I have never done before. All I did was take some of the seeds and wipe them across a paper towel with my fingertip to remove the pulp and then let them dry for a day or two on the paper towel. Then I removed them from the paper towel and put them in a ziplock bag to be planted this spring.
I planted the seed expecting to get tomatoes like the parent, and some of the 'New Brooks' plants did produce large pinkish beefsteaks similar to the 'New Brooks' I had last year. However, some some produced golden yellow beefsteaks. They are both good but I actually like the gold better.
Something similar happened with cherry tomatoes. I have grown a number of cherry tomatoes over the years, usually hybrids like'Sun Sugar' or 'Sun Gold'. After awhile I started seeing volunteer tomato plants that produced small cherry tomatoes about the size of a grape. They tasted pretty good so last year when I saved the 'New Brooks' seed I saved some seed from the volunteer cherry tomatoes, too. Surprisingly, these seed gave me plants producing two very distinct cherry tomatoes.
The smaller one is about the size of a small grape and is a pale orangey-pink. The larger one is bigger around than a quarter, but smaller than a golf ball and is classic, deep tomato red. They taste very different, too. The larger one is sweet and tastes...well, like a cherry tomato. The smaller one is a little more tart and more fruity or citrusy. I keep eating one and then the other and trying to figure out what is different.
I asked Royer, Project Grow's heirloom seed guru, how he could explain this since he had told me a few years ago that tomatoes typically do not naturally cross pollinate. Royer said that 'New Brooks' is not a very pure strain and he had also seen some of the following generation turn up yellow.
At any rate, these unexpected results have made the whole idea of saving tomato seeds much more fun! I've already saved the seed from all 4 varieties but will have to wait until next year to see what they produce.