I love tomatoes. I grow a variety of colours but I choose them for their flavour. The dark ones at the top of the picture are known to me as French Black. A friend from a gardening forum bought some on holiday in a French market, loved them and saved the seeds, which come true to type.
Underneath those are the classic red Alicante. This is an old variety our dads probably grew and has the old-fashioned tomato taste you don't get in the shop-bought. Again, if you save the seed, the resultant tomatoes are the same as their parents.
To their left are the fabulous Green Zebras. In my opinion this is the world's best grilling tomato with its balance of sweetness and acidity. Unripe, it's pale green and dark green. It's ripe when the pale green becomes yellow and the tomato feels soft. This also breeds true. These three are all pollinated by their own pollen so there's no genetic diversity.
At the bottom (there's a pound coin for scale) the oval yellow tomatoes are my own variety. I have one variety which I cross-pollinated but it's not in the picture as I didn't grow it this year. It'll be on next year's menu. The yellow is a selection from Sungold, a well-known orange cherry tomato famed for its flavour. It's also famed for its price - around £3 for 6 seeds! That's because it's a cross from two parents and has to be crossed each season.
People who know these things will tell you that you can't save seeds from a first generation cross of two varieties - known as an F1 hybrid - like Sungold. Don't be deterred if you want to do it. You can do anything! What you won't get if you do, is a Sungold tomato from your next generation. I did it about 7 years ago (it's called unhybriding or dehybridising) and from each generation of several plants, I saved seed from those with the best flavour. I no longer have a round orange tomato but an oval yellow one and each year I chose a flavour I like. I also select out the ones with the tough skins. This tomato is called Sweet Eleanor (after a grandchild). These Sweet Eleanors mostly come true from seed but there's still a little genetic 'settling down' going on. I've never had one that wasn't worth eating and the current line is producing a delightful tomato with a good balance of sweet/sharp flavours.
Incidentally, if anybody would like seeds of any of these, let me know before the season is over and I'll make sure I save enough.