Open and Closed Breeding of Crops

Mutual suiting relationship between breeding way and widening germplasm was first analyzed. Source of utilization germplasm was the more the widener from only using variation in a variety to among family even bigger scope, especially transformation gene breeding could use superfine gene of living things in the world and create germplasm resources that could not obtain in conventional breeding. Secondly contradiction and its movement between ecological and yield ability character, among yield ability characters or ecological characters exist all; this verified that explaining all of phenomenon was “net system of character composition of yield performance”, “theoretical genetics and breeding science of crops” theory system setting up by author. Thirdly new concepts, closed breeding and open breeding were put forward on basis of relationship of unity of opposition among above characters (genes) and supplying way of necessary energy in character express. Theory of closed and open breeding was a generalization of most essential distinction for different breeding way, also theory basis of correct evaluation these. It made people abandon tradition concept that only had variation and also emergence of new variety, and also made people refute mythology on basis of theory that depending on closed breeding could obtain higher yield variety. Openness of sexual cross breeding etc. decided that it will forever be foothold in an invincible position, develop always and any breeding way will not all replace it.