Evaluation of genetic relationships among promising and commercial olive varieties using gene-targeted CAAT box-derived polymorphism (CBDP) markers

The olive is considered as one of the most important horticultural crops, with more abundant number of cultivars. Thus, the aim of this research was to study the genetic diversity in a set of olive cultivars in Taroum station of Tran. In this research, 25 CBDP markers were used to study the genetic diversity and relationships of 20 promising and commercial Iranian and foreign varieties of olive. The 25 used primers amplified a total of 755 polymorph alleles, and the mean of PIC and MI indices were 0.941 and 5.64, respectively, indicating the high efficiency and differentiation power of CBDP markers. The genetic parameters of Nei and Shannon indices were higher in foreign cultivars than those of Iranian cultivars. The high gene flow (4.46) was observed among olive cultivars, which confirmed the low values of the inter-population differentiation (Gst) and FsT indices. Analysis of molecular variance (AMOVA) differentiated the total genetic variation into inter-group (Iranian and foreign cultivars) (17%) and within-group (83%) diversity. The cluster analysis using Dice coefficient and UPGMA method divided the Iranian and foreign cultivars into five groups, which the promising cultivar T24 and Koroneiki with the maximum difference with others were placed in separate groups. The Principal Coordinate Analysis (PCoA) was able to distinguish promising Iranian cultivars from the other commercial cultivars. The population structure analysis confirmed the results of the cluster and PCoA analysis and clearly separated the two groups of Iranian and foreign cultivars. In conclusion, it was observed that the promising cultivar T24 with having a genetic similarity to both groups of Iranian and foreign cultivars can be a suitable candidate for commercialization with complementary characteristics of both groups. Also, it is recommended to use this marker to study the genetic diversity of other olive varieties.