Abstract:

To study the genetic variation of 53 olive (Olea europaea) cultivars in China, 107 accessions of 13 domesticated cultivars and 40 imported cultivars were collected from 5 sites of olive culture regions in three provinces of China (Gansu, Sichuan and Yunnan) and analyzed using 20 fluorescent polymorphic simple sequence repeats (SSRs). Twenty SSR primers amplified 294 polymorphic alleles in the 107 selected olive accessions. The average number of alleles per locus was 14.7, ranging from 9 to 26. Polymorphic information content (PIC) was 0.73 on average. The genetic relationships among accessions were investigated using cluster analysis based on NJ with Jaccard coefficient. The 107 accessions from different regions were separated into two groups. Although there was no clear separation between domesticated and imported cultivars, most of the accessions with the same cultivar name were grouped together. As expected, close relationship was observed among accessions within the same cultivar. The analysis revealed the high level genetic diversity within these cultivars, regardless of selected domestic cultivars and introduced cultivars from foreign country. Between and within cultivars (cultivars including three or more accessions) originated from 5 different countries genetic diversity was analyzed using analysis of molecular variance (AMOVA). AMOVA revealed that genetic variation within cultivar was higher (86.61%) than that between populations and between cultivars among populations (13.39%). The high level of genetic variance within cultivar could be due to 1) inaccurate information related to origin and source of cultivars during long-term and large-scale introduction and 2) mislabeling and presence of homonyms in cultivars produced by vegetative propagation from original plants.

Key words: Olea europaea, fluorescent SSR markers, genetic diversity, analysis of molecular variance (AMOVA)