Open pollination of a group of genotypes (generally selected) in isolation in such a way to promote random mating inter se is called

Open pollination of a group of genotypes (generally selected) in isolation in such a way as to promote random mating is called Polycross.
It is a cross in which the female parent is known but the male may belong to any of several available strains and which is used in the production of new lines of some economic plants.
It refers to an initial step in the development of a synthetic variety where you are working with a crop that displays heterosis but its breeding system requires too many of our resources to market it as a hybrid as with maize.