Not sure where to put this, but thought it might be interesting for some. All about saving seeds and what is available and the science of it all...
http://www.bbc.co.uk/iplayer/episode/b00qg0r4/Food_Programme_Seeds/
Quite interesting - especially the bit about heritage beans - mine did really brilliantly last year. I'm preety much only growing heritage peas and beans this year.
I don't grow anything but heritage peas and beans. For one thing, I'm not keen on short maincrop peas, I get far more off the tall ones, and they're all heirlooms.
Hierloom peas are so much easier to pick.... less bending ;D
It's ever so easy to save seed, so there's no need to keep buying the stuff either.