(Laboratory of Plant Gene Expression, RISH, Kyoto University)

A natural forest, which is a population made up of individuals, carries genetic diversity even if they consist of the same species. Such diverse population provides the traits resistant against environmental stress. On the contrary, plantation prefers generally to being consisted of a dominant tree or a selected clone because diverse quality is undesirable character. Even in a natural forest stand, the population may suffer from a selective pressure by pathogen, causing biased traits in the population. The latter example is a breeding by selection of survived trees in the natural forest stands suffered from pine wilt diseases. Japanese pine forest has been severely suffered from pine wilt diseases and the dead trees are the biggest loss in biomass of Japan. Furthermore, the diseases have ignited in East Asia and Europe, causing political affairs. Pesticide spray for controlling pine wilt diseases has gradually been diminished because of environmental concerns. New strategies are now required for controlling pine wilt disease. In administration related works, survived pine trees have been selected from the natural pine forest stands, being suffered from the pine wilt disease. There have been many debates on the diversity of a population from viewpoints of wood utilization and ecology. Newly selected traits such as the resistant pine trees will be examined in various aspects. We found that a gene in a secondary metabolism shows such diversity in a pine population