ISSR analysis of chosen Gleditsia accessions obtained from Polish collections

Species of Gleditsia show considerable morphological variability that makes them difficult to distinguish using either vegetative or floral characters. Honeylocusts, especially the thornless cultivars, are popular ornamental, shade, street, attractive landscape trees. In this study the ISSR technique was used to evaluate the range of genetic variability between seven genotypes of Gleditsia cultivated in Polish dendrological collections [Gleditsia caspica Desf., Gleditsia japonica Miq., Gleditsia japonica Miq. var. korainensis (= G. korainensis Nakai), Gleditsia triacanthos L., Gleditsia triacanthos L. (bulk), Gleditsia triacanthos f. inermis (L.) Zabel (bulk). Forty ISSR primers were tested and 18 were selected for their ability to produce clear and reproducible patterns of multiple bands.A total of 177 loci of 260-2600 bp were amplified, of which 89 (50%) were polymorphic, 14 (8%) monomorphic and 74 (42%) were accession-specific. Accession-specific ISSR loci were obtained for all of the seven accessions tested. A dendrogram generated using the UPGMA, based on a similarity measure of total character difference, showed that the Gleditsia accessions were clustered into two main groups (‘a’ and ‘b’). The first grup –‘a’– included: Gleditsia triacanthos L., Gleditsia triacanthos L. (bulk) and Gleditsia triacanthos f. inermis (L.) Zabel (similarity 0.61–0.75), the second –‘b’– included 2 species: Gleditsia japonica and Gleditsia japonica var. korainensis (similarity 0.43). Analysis of the phylogenetic similarity dendrogram has shown wide range of diversity between studied accessions. The clustering pattern obtained in our experiment was in agreement with the data based on morphological, allozyme and ITS analysis.