This is one of the reasons I took the Online Seed Course. "All agricultural crops have continuously changed with the selection pressures applied from both farmers and the environments in which they were cultivated. When farmers and the environment changed, the crop changed. Many of our crops continue to change and adapt to new challenges.
The number of environments that crops are bred in, and the number of breeders, have both shrunk over the past 100 years. This is because farmers in most agricultural regions of the globe do little or no plant breeding anymore, and the number of regionalized seed companies doing breeding has also drastically shrunk in the past 40 to 60 years."
source: Introduction to On-farm Organic Plant Breeding