Today, we understand and appreciate the importance of plant genetic resources (PGR) as forming the building blocks for continuous crop improvement. Farmers may have little or no understanding of the scientific basis of genetic diversity, but they certainly understand its paramount importance to agriculture, and the need for promoting variability in agricultural practices. The autonomy that every farmer exercises in selecting, saving and maintaining seed for re-sowing has been fundamental for the agronomic transformation of plant species into crops, and their further selection. Any realistic valuation of PGR generated by farmers could well run into trillions of dollars, which is many times higher than the value that modern plant breeding has contributed.