Efficiency of using RAPD and ISSR markers in evaluation of genetic diversity in sugar beet

Random amplified polymorphic DNA (RAPD) and intersimple sequence repeat (ISSR) markers were used for comparative analysis of genetic variation in 42 sugar beet accessions. A total of 24 polymorphic primers (12 RAPD and 12 ISSR) were used. The RAPD primers generated 204 amplification products and the ISSR primers produced 178 fragments, 190 and 173 of which were polymorphic, respectively. The average polymorphism level with the ISSR markers (97.2%) was higher than that with the RAPD primers (93%). High genetic diversity indices for both marker types (0.86 for RAPD and 0.91 for ISSR) suggested that these methods were equally effective in determining genetic variation in sugar beet accessions. Cluster analysis of the RAPD, ISSR, and combined datasets revealed similar grouping patterns. However, the dendrogram created from analysis of the combined RAPD+ISSR data was more similar to the RAPD-only dendrogram than the ISSR-only analysis, indicating that RAPD could determine genetic diversity with higher resolution than ISSR in the cultivars tested. High correlation between the RAPD and ISSR marker systems was shown using a Mantel test (r = 0.92). Screening a higher number of anonymous loci in sugar beet using these molecular markers will enable the selection of the best parent cultivars for the development of novel varieties.