Assessment of Genetic Relationships among Cultivated and Wild Pistachios (Pistacia vera L.) using Molecular Markers

Iran is one of the main diversity centers and origins of pistachios in the world. Pistachio cultivation spread first within the ancient Persian Empire and then moved gradually westward. Knowledge of the genetic relationships among wild and cultivated varieties of pistachio is important for the efficient utilization of the available germplasm resources. Three molecular marker strategies, namely, inter-simple sequence repeat (ISSR), inter-retrotransposon amplified polymorphism (IRAP), and retrotransposon microsatellite amplified polymorphism (REMAP), were used to study the genetic relationships among 35 pistachio accessions including 15 wild-type genotypes of Pistacia vera and 20 important cultivars from Iran. According to the results, high levels of polymorphism were observed for all three marker systems. REMAP and IRAP techniques had the higher mean values of genetic relationships parameters than ISSR technique. The results from this study showed that the 5′LTR2, Sukkula, Sukkula + UBC855, and 5′LTR2 + UBC811 primers were the most informative and could be used to evaluate the genetic relationships of pistachios accessions. Cluster analysis using the unweighted pair group method with arithmetic mean (UPGMA) properly separated the accessions and divided them into four main groups. The presence of most cultivated genotypes in a group indicates genetic erosion of cultivated pistachio in Iran. Wild-type genotypes of P. vera are located in different clusters indicating the high diversity of the genotypes. The results provide useful genetic information about wild pistachios in northeastern of Iran and indicate that the use of wild pistachios in breeding programs could be useful for generating new genotypes with interesting characters.