The conservation of Chinese rice biodiversity: genetic erosion, ethnobotany and prospects

As one of important original centers of Asian cultivated rice Oryza sativa L., China is abundant in genetic resources of rice and its wild relatives. They are not only useful for mountainous farmers to cope with heterogeneous microclimates, but also of extremely significance for rice genetic improvement programs in the future. Unfortunately, the combination of new conditions, including rapid population growth, new agricultural technology and swift economic & cultural changes produces a new environment. As a result, most of wild populations have disappeared, and others are at the edge of the extinction. Moreover, widespread adoption of high-yielding rice varieties (HYVs) have led to biological impoverty of rice germplasms, as local rice varieties are abandoned for modern varieties. These processes, known as "genetic erosion'', are generally summarized as two types in Chinese rice genetic resources. Based on our recent studies on the conservation of Chinese rice biodiversity, this paper reviews the biodiversity, ethnobotany and genetic erosion of rice and its wild relatives in China. Finally, some suggestions for the ways to enhance efforts to conserve rice genetic resources, including investigation of genetic erosion, studies on population genetics and conservation genetics using molecular approaches, settings of in situ & ex situ conservation priorities, significance of ethnobotanical knowledge for taking in situ conservation, and necessities of extensive participation in the conservation activities, are given.