many years ago I was reading this website
http://jandlgardens.com/and he had a peanut that he adapted to cold weather.
I loved the idea and wanted the seeds, but california has a restriction on importing peanuts... (not the same as my issue sending things out of the USA)
anyway, I just recreated the project.
started with raw peanuts I got at an indian grocery store,
took about 4 years to get production every year
now I get reliable production
and last harvest was the largest yet, and it was from every plant as well.
but each root system was totally different, so there is still lots of variation in them even now.
so, it seems to me that they are capable of doing quite a bit, just that most people have not bothered to do much breeding with them before.