To determine whether the recombinant RNA 3s derived from C1C2 W2B T3 or C1C2 W2B T3 Á163(G) , both of which contained a 19-nt repeat sequence, might represent an intermediate, buffered extracts from plants infected by viruses containing these recombinant RNA 3s were passaged onto five healthy plants for more than 20 passages done at 1-week intervals. RT-PCR and sequence analyses of the recombinant RNA 3s from the passage plants showed no sequence difference from the original recombinant RNA 3s described above, indicating that the 19-nt repeat was still present in the same position as before (data not shown). These results indicate that recombinant RNA 3 derived from C1C2 W2B T3 or C1C2 W2B T3 Á163(G) containing the 19-nt repeat was not an intermediate, but the stable recombination end-product.