Sequence comparison showed the high homology between rice repetitive DNAsequence pRRD9 and chloroplast gene psbA encoding QB protein. Southern hybridizationsof rice chloroplast and nuclear DNA with the two subcloned segments from pRRD9,pRRD9R and pRRD9L, revealed that psbA gene sequence was transferred from chloroplastto the nuclear genome in rice at a certain evolution stage. Significant differences occurredbetween the two segments in the evolution of rice variation. Southern analysis of wild and cultivated rices with the segments showed that the culfivated Asian rice had closer relatire of the wild rice with AA genome type．In addition， spedfic hybridization patterns were also detected in some wild rices．These findings suggest that pRRD9 may be a good molecular probe for the study of the evolution of rice ．
