Fingerprinting 128 Chinese clonal tea cultivars using SSR markers provides new insights into their pedigree relationships

The improved clonal tea cultivars play a crucial role in the modern tea industry. In present study, we analyzed 128 elite clonal tea cultivars in China with 30 well-chosen simple sequence repeat (SSR) markers, aiming at (1) characterizing a set of DNA markers for unambiguously fingerprinting clonal tea cultivars and (2) confirming or identifying the parent-offspring (PO) relationships among them. The results showed that the markers are highly polymorphic among the tested cultivars with an average allele number of 10.4 per locus and an average polymorphic information content of 0.704. Robust fingerprinting power was demonstrated: It was possible to fully discriminate all 128 cultivars by a combination of four markers, and the overall possibility of finding two random individuals having the same genotypes across the 30 loci was estimated to be 4.8 x 10(-33). Eight SSR loci were further recommended as a core marker set for fingerprinting the tea plant. Meanwhile, parentage analysis based on the fingerprint data revealed 47 pairs of putative PO relationships, among which 33 were in agreement with the known pedigree information, whereas the other 14 were newly identified in this study. The SSR markers and pedigree relationships reported here are valuable for tea cultivar identification and new breeding programs.