Development of Novel Microsatellite Markers and Construction of a Microsatellite Database Containing 288 Radish (Raphanus sativus L.) Commercial Cultivars in Korea

Radish (Raphanus sativus L.) belongs to Brassicaceae family and is a close relative of Brassica. This species shows a wide morphological diversity and is an important vegetable in Korea. Microsatellite is one of the most suitable markers for cultivar identification as it has great discrimination power for cultivars with narrow genetic variation. Unfortunately, there are no reports on the use of microsatellite markers to characterize commercial radish cultivars in Korea. The microsatellite markers were developed using the biotin-streptavidin enrichment procedures. Seven-hundred-eight clones containing microsatellite sequences from GA/CT microsatellite enriched library were identified and 237 primer pairs designed and synthesized. The polymorphism level between these microsatellite primer pairs and 11 commercial radish cultivars was investigated. A set of 30 primer pairs showed high polymorphism on the basis of allele numbers. These markers were applied for constructing DNA profile data base of 288 commercial radish cultivars through automatic detection system. A total of 233 polymorphic amplified fragments were obtained by using 30 microsatellite markers. The number of alleles per locus ranged from 2 to 18 with an average of 7.77 alleles. The average polymorphism information content was 0.738 ranging from 0.491 to 0.906. The unweighted pair group method with arithmetic mean cluster analysis based on the Jaccard's similarity coefficient values was utilized to construct a dendrogram. Two-hundred-eighty-eight cultivars could be divided into 8 major groups corresponding to varietal types. Almost all of the cultivars were discriminated by markers genotypes. This information may be useful to compare through genetic relationship analysis between existing cultivars and candidate cultivars in distinctness tests and protection of plant breeders’ intellectual properties rights through cultivar identification.