What kind of research have you done (other than inquiring on GW, which doesn't really count as research) to come up with possibilities? And exactly what do you mean by "yield per plant"? Bushels of fruit? Nutrient content per pound?

What exactly is the project for? Can you provide details?

The project is a science fiction book I am attempting to write, inspired by The Martian. Growing food in an artificial habitat, kind of thing.

Up to know, I've read several pages online including culinate.com and bonnieplants.com (to name two) which have helped me gather information about the easier and more "efficient" vegetable to grow in small spaces that also produce relatively high yields of fruit/vegetables (which I was referring to. Apologies for not specifying).

So far I've concluded that Tomatoes and leafy vegetables (such as Cabbage and Kale) are among the best options for what I need. However, although I can find plenty of information on the fruit/vegetables yields of a fruit/vegetable plants, I haven't found anything on how well fruit/vegetable plants produce oxygen.

If you still need more information, obviously let me know.

The production of oxygen by plants is a function of photosynthesis. Therefore theoretically, those plants that would release the most oxygen are those that photosynthesize easily, generally an indication of a lot of leaf surface. The terminology for this is called 'photosynthetic efficiency'. However even the most efficient plants don't produce much. Algae tends to lead the pack and the next strongest producer is sugar cane. I am not sure what other types of plants are high producers but you could certainly search under those key words of the specific plant type and 'photosynthetic efficiency'.

HTH and sounds like an interesting project :-) Have you published previously?

Thanks. That'll be my next
online search, for sure. also, no. I have never published before. TBH
"book" was probably an overstatement on my part, in hindsight. For
now, it's more just a story/writing project, but who knows; if/when I finish
it, I may try to publish it if it's good enough.

Anyway, thanks again