The Japanese Rice Genome Research Program.

Through his experiments using garden peas, Mendel's recognition of the significance of the number 2 in inheritance, heralded the dawn of theoretical genetics. However, in agriculture, for centuries farmers had improved crops and vegetables by selection based on desired traits such as adaptability to the environment or quantity of product. They planted seeds from individuals of preferred traits and continued further selection to fix those characteristics. A number of plant varieties have been established in this way, and the method used by farmers was based on Mendelian principles. Even since the discovery of the mechanism of inheritance by Watson and Crick, breeding has been largely based on the crossing of favorable traits and selection after observation of phenotypes among the progeny. The main reason genetics has not always been used to improve agricultural products is that there has been a lack of information linking phenotype and genotype, particularly given the complicated nature of the inheritance of important agronomical traits. Analysis of the human genome promises to help elucidate the characteristics of inherited diseases and to provide the possibility of overcoming them. It is equally rational that staple foods necessary to sustain human life should be chosen as targets of genome analysis, with the goal of accelerated production and improvement. Rice is one of the most important crops for people living in the Asian monsoon area. It has been estimated that -50% of the human population depends on rice as their daily food (White 1994). Rice is cultivated under a wide range of environments, from arid highlands to flooded lowlands. The mechanisms by which a single species, Oryza sativa, can adapt to such wide conditions must be programmed into its genome, and an under-