My plant biology is firmly rooted in high school lessons of many years ago, and my understanding of such is rudimentary. I have often wondered how strains are developed and maintained with a consistency that remains year in and year out, particularly for growers who buy seeds, out there
Sure, there are dodgy seedbanks who will sell seeds and call them whatever we expect them to be, and then be disappointed with the results.
I came across this interesting link and it is inspiring, in that there are still gardeners who are passionate, to the point of obsession, about consistency of the seed, which is the key to it all, really.
Check it out, it is great history/biology/botany lesson, if nothing else.
http://blog.humboldtseeds.net/en/the-spice-of-life/