This study was carried out to determine the genetic structure of the 7 black pine (Pinus nigra subsp. pallasiana (Lamb.) Holmboe) populations (Eybekli, Asar, Katrandağ, Kalkım, Gürgendağ, Kapıdağ, Mıhlıdere) sampled from Kazdağları. Kazdağları is one of the pilot sites selected for the “In situ Conservation of Plant Genetic Diversity in Turkey Project” which is financed by the World Bank. 

      29 loci were resolved for the 17 enzyme systems assayed. Data provided by the isozyme analysis showed that heterozygosity ranged from 0.122 in Gürgendağ to 0.186 in Asar. Percentage of polymorphic loci was the highest in Asar and Mıhlıdere populations (58.6). The 94 percent of total genetic variation was observed within populations. Nei’s genetic distances also showed that differentiation among populations is relatively low. 

      Finally, based on the genetic diversity measures and genetic distance between populations; Asar, Mıhlıdere and Gürgendağ seem to be genetically differentiated from others. Thus, these populations were recommended as Gene Management Zones - GMZ.

      Key Words: Pinus nigra, isoenzymes, genetic diversity, GMZ.