RAPD markers for discriminating tea germplasms at the inter-specific level in China

For the discrimination of tea germplasms at the inter-specific level, four tea species and varieties (Camellia sinensis, C. sinensis var. assamica, C. sinensis var. pubilimba, C. sinensis var. kucha) and their 20 wild allied species (C. sp.) preserved in the China National Germplasm Tea Repositories (CNGTR) were investigated using randomly amplified polymorphic DNA (RAPD) markers. Fifteen primers were chosen from the 61 screened for RAPD amplification. The average DNA polymorphic frequency of RAPD primers at the inter-specific level was 0.30, varying from 0.16 to 0.60, lower than that at the intra-specific level. Using the presence, sometimes absence of unique RAPD markers, it was possible to discriminate 14 of the germplasms investigated. No single primer could discriminate all the 24 germplasms. However, OPO-13 provided rich band patterns and it could discriminate 10 genotypes. The combination of two and three primers made it possible to discriminate 15 and 21 germplasms, respectively. Furthermore, the combination of band patterns or the DNA fingerprinting based on specific RAPD markers generated by OPO-13, OPO-18, OPG-12 and OPA-13 allowed the discrimination of all 24 germplasms investigated. Therefore, RAPD markers also provide a powerful tool to differentiate tea germplasms at the inter-specific level.