Cultivar identification and genetic diversity in onion (Allium cepa L.) as evaluated by random amplified polymorphic DNA (RAPD) analysis

Twenty-two onion (Allium cepa L.) cultivars were examined by using randomly amplified polymorphic DNA (RAPD) markers. Seventeen of the 100 primers screened produced clear, reproducible, polymorphic banding profiles. A total of 88 fragments were produced by 17 primers, of which 35 were polymorphic among the cultivars. All 22 cultivars could be distinguished by the combinations of polymorphic bands generated by various primers. The similarity values which range from 0.836 to 0.979 indicate that genetic diversity is low among onion cultivars. The dendrogram generated by the unweighted paired group method with an arithmetic average (UPGMA) cluster analysis reveals six clusters, only 'Super Hi Gold' in cluster F is comparatively separated from the other cultivars. Comparison between clusters and various characteristics, did not demonstrate any relationship. The RAPD marker OPD-03-850 tends to be absent in cultivars which have a high regeneration capacity.