Construction of Molecular identification key of Iranian olive cultivars using SSRs

For true identification and investigation of inter and intra cultivar variation of six olive collections of Iran (Roodbar, Zanjan, Ahvaz, Dezfoul, Kazeroon and Shiraz), 18 local cultivars were compared with 30 imported cultivars using 16 SSR primers. All microsatellite loci were polymorphic, except GAPU14 and GAPU113, which were monomorphic. In 87 selected olive accessions, 312 different banding patterns were obtained by 126 polymorphic alleles at 14 polymorphic loci. The average number of alleles per locus was 9, ranging from 3 to 14. Power of discrimination (PD) was 0.85. The genetic similarity based on Jaccard coefficient ranged from 0.15 to 1. All cultivars which were known by same names were different from each other, except Shenge (D) and Shenge (A) which were similar to each other. A close relationship was observed among accessions within same cultivar. To partitioning genetic diversity within and among cultivars (including 3 or more accessions), analysis of molecular variance (AMOVA) revealed higher genetic variation within cultivars (62.76%) than among (37.24%) them. The inter-intra cultivar variation was significant statistically. The considerable diversity observed within cultivars is probably due to mislabeling and presence of homonyms in cultivars produced by vegetative propagation from original plants. Two-dimensional scatter plot of principal component analysis revealed a clear separation of Iranian olives from Syrian and other introduced cultivars. The cultivar Molasani (A) with unique morphological characters, clustered far from other accessions. This dissimilarity suggests that Iranian cultivars have different origin related to West-Mediterranean basin cultivars. Also, existence of O.ferrugina and O.ocherri olives in Zagros mountains and south of Iran amplifies this assumption that Iran might be another origin for olive.

Keywords:

olive (Olea europaea L.) , Microsatellite markers , identification , inter-intra cultivar genetic diversity , analysis of molecular variance