Unidentified tomatoes identified

I have mentioned a couple of times that last Autumn I rescued a few tiny self-seeded tomato plants from the shingle outside my kitchen window and grew them on indoors over the Winter...

Up till now I wasn't sure what variety they were, but I presumed they would be either "Maskotka" or "Montello", which were the two varieties I grew in that location last year. One of the plants produced a couple of fruit very early on:-

21 April 2019

From the shape of the fruit, I was able to determine that these were definitely NOT "Montello", which has plum-shaped fruit. This year I have one "Montello" plant out there, whose identity I'm sure of, because I grew it from seed. Its fruits are just turning colour now.

"Montello", 27 July 2019

Since the mystery plants were not "Montello" I jumped to the conclusion that they must be therefore be "Maskotka".  This would have suited me just fine, because this is my favourite variety of small-fruited tomato.

"Maskotka" 28 July 2019

Well, the plants in question have been growing away steadily in that spot below the kitchen window - a very good spot for growing tomatoes, by the way, since it gets most of the afternoon and evening sun.

"Montello" at the Left

All three of the mystery plants have set quite a lot of fruit, and it is now beginning to ripen. As it does so, it demonstrates that these are not "Maskotka" either. The way the clusters of fruit are arranged is different, and most obviously of all, the fruit have dark green shoulders before they ripen, which "Maskotka" does not.

So, realising that my original assumptions are completely wrong, I have been back through my records and I see that in 2017 I grew "Losetto" in this place, and the characteristics of both plant and fruit fit this variety. So the seeds that germinated in October 2018 had been there for at least a year!

This plant in the corner is definitely a "Losetto".

"Losetto"

I'm still not convinced that the other two plants are 100% "Losetto" though. Their fruits are much bigger - though they still have the distinct green shoulders - and to me they look a bit plum-shaped. Maybe they are a hybrid of "Losetto" and "Montello"?

None of the fruit from these plants is fully ripe yet, so I can't tell you what they taste like, but looking back in my records I see that I have grown them twice before and one time I thought they were good - "thin-skinned and very tasty" - but the other time my verdict was "unimpressive and with tough skins". It will be interesting to see what they are like this time round. I should also point out that "Losetto" has good blight-resistance, which was put to the test when I grew this variety back in 2012. The plant did develop blight, but it survived, produced new foliage even after being infected, and went on to produce a decent crop.

This has been an interesting experiment, but I still think I would rather know in advance what sort of plants I'm growing!