Genetic variations and evolutionary relationships among radishes (Raphanus sativus L.) with different flesh colors based on red pigment content, karyotype and simple sequence repeat analysis

To determine the genetic diversity and evolutionary relationships among red radishes, 37 accessions with different flesh colors were analyzed in terms of the red pigment content, karyotypes, and simple sequence repeat markers. Red pigment content of red radish was 3.4 to 28.8% with an average of 15.62%. The karyotype formulas were 14 m (median) + 4 sm (submedian), 16 m + 2 sm, and 18 m for radishes with the same number of chromosomes. The number of alleles detected among the 86 simple sequence repeat primers was 2 to 15 in red-flesh radishes and 2 to 11 in white-flesh radishes. Clustering analysis separated the accessions into three clusters, with most accessions from the same region clustering together. The results indicated that (1) red radish is abundant in red radish, which is a valuable material in red pigment industry; (2) the white-flesh radish is an ancestor of the red-flesh radish, which should be considered a variety in Raphanussativus, and (3) a low level of genetic diversity exists among the 37 accessions. The available radish germplasms should be expanded by creating new hybrid or introducing genes from other crops.   Key words: Genetic diversity, karyotypes, Raphanus sativus, red pigment content, radish, simple sequence repeat.