Molecular characterization of olive cultivars grown in Iraq using amplified fragment length polymorphism and simple sequence repeat markers

Abstract

In this study, genetic relationships among olive cultivars grown in Iraq were investigated by means of two DNA molecular marker classes: amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR). Total genomic DNA was isolated from young leaves of the selected olive cultivars. Namely ‘Arbqween’, ‘Baashiqi’, ‘Dahkan’, ‘Labeeb’, ‘Khdhier’, ‘Manzenllo’, ‘Nepali’, ‘Qaysi’, ‘Shami’ and ‘Sorani’. AFLP-PCR technology was performed using nine selective primer combinations, yielding 250 bands, 145 (58%) of which were polymorphic while 10 SSR primer pairs generated 85 polymorphic bands on a total of 283 fragments (30%). According to AFLP markers, the unweighted pairgroup method with an arithmetic average (UPGMA) ordered olive cultivars into two main clusters irrespective of their origin at similarity level of 0.48. Similarly, UPGMA based on 85 polymorphic SSR loci ordered the olive cultivars into two main clusters at similarity level of 0.54. The combination of AFLP and SSR markers was then performed, thus generating two groups with 50% similarity. Genetic similarity index estimated by both DNA markers used in this study proved three cultivars to be very close to each other (‘Qaysi’, ‘Baashiqi’ and ‘Dahkan’) as they always clustered together in the resulting dendrograma. The scatter diagrams of the first two (PC1 and PC2) of the Principal Component Analysis (PCA) confirmed the results obtained by the two marker classes. The results of this research confirmed AFLP and SSR to be useful tools in genetic relationships among olive cultivars, in creating a molecular database for Iraqi olive cultivars, in breeding strategies and in correct cultivar identification.

Keywords: Olea europaea, genetic diversity, amplified fragment length polymorphism (AFLP), sequence repeat (SSR) markers.

African Journal of Biotechnology Vol. 12(25), pp. 3914-3921