TomTato

The BBC wrote about somebody who had successfully grafted a tomato plant onto potatoes, so you can get two crops from one space.

Bit of a problem though:

"It has been very difficult to achieve because the tomato stem and the potato stem have to be the same thickness for the graft to work," he said...

The firm said the plants last for one season and by the time the tomatoes are ready for picking, the potatoes can be dug up.

Well a fat lot of good that is then, if they only last one season. The extra hassle of the trial and error grafting them is probably not worth those few extra potatoes/tomatoes.

But this reminds us that tomatoes and potatoes are from the same plant family and are native to Central/South America, so sooner or later, they'll be able to splice the DNA together and make plants which will grow again and again or from seeds. (You'd have to be careful which up you plant the seeds though, if you put them in the wrong way up, you'll get potato flowers growing on tomato roots, which is worse than useless.)

The list of useful plants in that family is very long:

Perhaps the most economically important genus of the family is Solanum, which contains the potato (Solanum tuberosum, in fact, another common name of the family is the "potato family"), the tomato (Solanum lycopersicum), and the aubergine or eggplant (Solanum melongena). Another important genus Capsicum produce both chilli peppers and bell peppers...

Nicotiana contains, among other species, the plant that produces tobacco.

So in a perfect world, you'd have a plant which produces potatoes under the ground and tomatoes above it, with leaves which you can dry and smoke. Result!

Other useful plants which are native to Central/South America, although not in the same family, are cocoa/chocolate and coca.

Which all makes me think that life in Europe must have been pretty grim until they started importing these plants/products a few hundred years ago.

Europe/the Middle East actually only has one major useful native plant, wheat (and rye, barley and so on), which you need to make beer and pizzas.

The other plant which make life worth living is from Ethiopia (coffee), which is a bit closer to home, but they didn't even work out how to make it until a few hundred years ago.