A process for breeding plants which comprises growing plants of a species in an array of containers charged with growing medium of uniform characteristics in an environment of controlled climatic conditions with controlled supply of nutrients and feed water and changing the positions of the containers within the environment as required to ensure at least substantially uniform exposure of all plants in the containers to conditions in the environment. A process for the breeding of open pollinating plants in a greenhouse environment is also provided. A process for breeding plants which comprises identifying trait leads.