I do kind of wonder if it's possible to hybridize each with some intermediate relative, and then hybridize the result. Not sure if that's how things work.
Tomatoes are Solanum lycopersicum. Potatoes (the type you eat) are Solanum tuberosum.
According to this, modern tomatoes were probably the result of hybridization between a wild tomato ancestor and a wild potato plant that doesn't grow tubers:
And potatoes and tomatoes are each other’s closest living relatives.
Zhang and his team found that wild tomato plants bred with a potato-like plant called Etuberosum around nine million years ago. Alone, neither plant had the genes to make tubers—but together, they could grow the feature. That’s because the gene that switches on tuber growth, called SP6A, comes from tomatoes, while the gene controls the growth of the underground stems that turn into tubers, called IT1, comes from Etuberosum.
That fateful hybridization, the authors suggest, occurred in the Andes mountains. At the time the plants developed the ability to make tubers, the Andes mountains were rapidly rising. The tubers allowed the potato to survive in this unforgiving habitat—and spread across the world. Tubers enable plants to reproduce without pollinators or seeds, making them adaptable.
Genetic family tree with all three species:
https://lemmy.today/pictrs/image/ca1edae2-11a4-468f-b501-9bceb1338b8f.png
It looks like Solanum etuberosum (well, modern forms of it) is still around:
https://en.wikipedia.org/wiki/Solanum_etuberosum
Solanum etuberosum is a species of wild potato in the family Solanaceae, endemic to central Chile.
So I wonder if maybe it'd be possible to grow a fertile Solanum etuberosum x Solanum tuberosum hybrid and cross it with a fertile Solanum etuberosum x Solanum lycopersicum hybrid.



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