Abstract:Copy number of cloned repetitive DNA sequence pRRD9 has been determined within the genus Oryza, including 15 cultivated rice (7 belonging to Oryza sativa L. Japonica, 8 belonging to Oryza sativa L. Indica) and 16 wild rice entries (belonging to AA, A~I A~I, A~cu A~cu, BBCC, CC, CCDD, EE and FF genome types respectively). This was done by using quantitative filter hybridization technique named'SLOT-BLOTTING'. The result shows that pRRD9 copy number is markedly variable between cultivated and wild rice entr...