An assessment of tissue culture-induced genetic variability in olive (Olea europaea L.) using chloroplast rpl16 intron sequences and single primer amplification reaction (SPAR) markers

Abstract

SUMMARYOlive (Olea europaea L.) is an important tree crop grown throughout the Mediterranean Basin and Iran. Propagation of true-to-type olive plants is important for olive-growing companies and farmers. For this reason, we performed a genetic analysis of 49 randomly selected tissue culture-regenerated olive plants of the cultivar ‘Koroneiki’ and compared them with the mother plant. We used the sequence of the chloroplast rpl16 intron and ten single primer amplification reaction (SPAR) markers to test for genetic fidelity vs. somaclonal variation. A Neighbor-Joining dendrogram based on the RAPD data produced four major clusters. The mother plant, along with ten regenerated plants, were placed far from the others and formed Cluster I. Members of this Cluster had the highest genetic distance from members of Cluster III (0.266), followed by plants of Cluster IV (0.177). Analysis of molecular variance (AMOVA) produced significant differences (PhiPT value = 0.37; P≤ 0.01) among these clusters. The Neighbor-Joining tree, neighbor-Net method, and Tree analysis using New Technology (TNT) based on RAPD marker and rpl16 intron sequence analyses respectively, separated the mother plant and some of the regenerated plants in a separate cluster. Tajima's test produced a diversity (D) statistic value of = −2.17 (P ≤ 0.05) based on the intron sequence data. We also identified some regenerated plants that were true-to-type with the mother plant.