Abstract:Some repetitive sequences have been cloned from rice genome by DNA renaturation kinetics. Using them as probes, Southern blotting analyses in 30 species of Oryza and Poaceae were carried out. The authors‘ results indicated that hybridization band patterns correlated with relationship of plants. The use of these repetitive sequences as probes in phytogenetic classification is considered. The fragment of pRRD9 also showed polymorphisms among some ecological types of wild rice ( O. rufipogon), suggesting that it could be used as a probe in the study of rice evolution.