Plant diversity

The uniformity of most modern crops is due to three genetic bottlenecks that took place during centuries of plant domestication. The first occurred at the start of sedentary, agricultural life, and could best be described as the domestication bottleneck. Early farmers only used a limited number of individuals as the progenitor species for their crop, resulting in a landrace. Thus, all of the subsequent crop plants came from the few those farmers had picked out, narrowing genetic variation in that plant. The second occurred during the first migratory phases of human civilization. When people migrated to new lands they would bring with them only a select number of plants from the landraces, which would once again reduce the genetic variation in the resulting crops. Finally, the third occurred many centuries later with the advent of modern genetic technology. Through the use of gene editing technology it became possible to create homogeneity for entire crop fields. Plants could now be edited to include genes of choice such as herbicide resistance, pest resistance, disease resistance, and many other traits, some of which allowed for the complete mechanization of farming. The final bottleneck has resulted in single plant genotypes propagated across entire fields, random variations becoming a thing of the past.