I am curious as to why no one has suggested Corn, as a grain, I know corn is a heavy feeder, but in a system where nothing goes to waste, nothing gets wasted. Native
Americans were able to grow corn sustainably for 1000s of years, and it would seem to me that given all the things you could get from it, ( corn on the cob
, flour, animal feed
, etc. ) that it would be on most peoples list.
Here in the tropics, we have a squash the locals call "Auyama" this thing grows easily all over, and taste great, they look similar to the Seminole squash and wonder if they are related.
With these squash you can basically just plant them and walk away. some get huge.