Molecular analysis of wild relatives of rice

Rice (Oryza sativa L.) has been cultivated as a major crop for more than 7000 years and it is the major source of human food. The wild relatives of cultivated rice are an important source of useful genes for genetic improvement of rice production and quality. Cultivated rice belongs to the genus Oryza in the tribe Oryzeae. There are 12 genera and about 70 species in this tribe. Most of these species have not been the subject of molecular genetic analysis. We have investigated species from 2 genera, Zizania from North America and Potamophila from Australia and related them to Oryza. Zizania palustris is now cultivated and has been considered as a source of cold tolerance for rice improvement. Potamophila parviflora is endemic to the northern rivers of New South Wales. We have traced wild population of this species and initiated a program of collection of germplasm and analysis of genetic diversity and relationships. The nucleotide sequences of the first internal transcribed spacer (ITS 1), between the 17S and 5.8S ribosomal DNA genes of these wild rice have been used to determine genetic relations. This information will be used in attempts to introduce genes from these wild relative into commercial rice.