GENETIC-RELATIONSHIPS AMONG JAPANESE WILD RADISHES (RAPHANUS-SATIVUS F RAPHANISTROIDES MAKINO), CULTIVATED RADISHES AND R-RAPHANISTRUM REVEALED BY RAPD ANALYSIS

The phylogenetic relationships among Japanese wild radishes, cultivate d radishes, and wild R. raphanistrum species were examined using rando m amplified polymorphic DNA (RAPD) analy sis. We compared the PCR prod ucts of 61 plants belonging to fourteen strains or varieties within th e three categories, by using seven 10 mer random primers. Similarity r atios were calculated for all of the combinations of the individual pl ants based on 73 polymorphic DNA bands and cluster analysis was perfor med on these ratios using the average linkage method. Within the strai ns, the Japanese wild radishes and R. raphanistrum had lower similarit y ratios of 51-73%, those of the cultivated radishes were over 80%. Ho wever, these similarity ratios were distinctly higher than those betwe en different strains belonging to the same category. As a consequence, almost all strains and varieties formed unique clusters within themse lves. The three strains of the Japanese wild radishes formed a cohesiv e cluster, showing a genetic resemblance among them, and they clustere d with most of the cultivated radishes except for 'Tokinashi' and 'Min owase'. R. raphanistrum stood apart from the large cluster that includ ed the cultivated radishes and Japanese wild radishes. These results i ndicate that the Japanese wild radishes are a part of a large group of cultivated radishes (R. sativus) which does not include R. raphanistr um.