本世纪60年代以来,以改良混合选择法为基础的“三圃制”一直是我国良种繁育的主要技术。人们普遍认为,采用这一技术,在推广品种中“优中选优”,可以达到保持和提高品种种性的目的。然而,一些实践证明,采用“三圃制”进行原种生产,不仅周期长、费 Since the 1960s, the “Three-Pu system” based on the improved hybrid choice method has been the main technique of breeding and breeding in our country. It is generally believed that the adoption of this technology in the promotion of varieties of “excellent selection of superior”, you can achieve the purpose of maintaining and improving species variety. However, some practices have proved that adopting the “Three-Nu System” for the production of original species not only has long cycle fees