AbstractThe widespread adoption of improved high-yield rice varieties , which in a large scale replaced traditional and local rice varieties , has resulted in a great genetic erosion of the cultivated rice genepool. This process has narrowed genetic background of the cultivated rice. As a result , modern rice varieties become vulnerable and can not stand the attack of new disease and insect pests , and the unfavorable changes of environments. Meanwhile , the long2term use of chemical pesticides and herbicides significantly deteriorated agricultural ecosystem. In order to change this vicious cycle of the rice ecosystem , it is very important and necessary to explore and utilize the genetic biodiversity in the rice genepool to broaden the genetic background of the cultivated rice. The rice genepool encompasses varieties of Asia rice and African rice , weedy rice , wild species of rice in the genus Oryz a , and species in the related genera of the tribe Oryzeae. These are the essential germplasm resources for the further improvement of cultivated rices. However , due to the change of agricultural patterns , rapid development of social economy , industrialization and urbanization , biodiversity of the rice genepool , including wild species of rice , is under threat . Many populations of wild Oryz a species have been extinct from their original sites or are diminishing. Therefore , it is absolutely necessary and essential to strategically safeguard and conserve biodiversity of the rice genepool and to effectively utilize the elite rice germplasm resources in rice breeding programs. This is the only way to guarantee the long2term and sustainable production of rice varieties.