植物 育種技術의 推移

Transition in the plant breeding technology

Breeding, which was primitive and based rather on the art than on the scientific knowledges until the last century, has been placed on a firm scientific foundation and carried out systematically thanks to the rediscovery of Mendel’s laws, Johannsen’s pureline theory, and DeVries’ mutation researches uncovered or published concurrently at the turn of present century. Conventional as well as old-timed breeding has centered on the selection of useful variants from population of variations induced or spontaneously occurring. With the improvement of DNA manipulation techniques developed in the last decade or so, however, it has become possible to transform the genome of living organsim by inserting known DNA fragments or modified own genes to fit for our purposes. This sort of genomic changes have led to the birth of new breeding method which is based not on the selection of variants but on the construction or fabrication of desirable genome. Differentiation of varied tissues and organs from a fertilized egg has been a mystery since the era of Aristotles 2,000 odd years ago, and still remains one of the most insolvable questions in modern biology. Differentiation of organs is the end-product of seried of selective gene expression. Even though strenuous research efforts have been made on the regulation of gene expression, this problem along with the mechanism of differentiation is expected to be the major subject of biological researches in the coming century. Once the differentiation mechanism be clarified, it would be possible to regulate the pathway of differentiation, giving rise to the unexpected modified, sometimes monstrous, organisms. This kind of technological innovation would lead to the development of new breeding-the differentiation breeding, changing the concept of breeding and departing far from the conventional Mendelian breeding and DNA manipulation method. Present paper has dealt mainly with the description of present day breeding including the selection breeding vs construction breeding and field breeding vs in vitro breeding, briefly mentioning possible future breeding based on the regulation of differentiation pathway.