A comparative assessment of DNA fingerprinting assays of ISSR and RAPD markers for molecular diversity of Saffron and other Crocus spp. in Iran

Abstract

Genetic diversity among 25 accessions of Crocus L. (Iridaceae) representing 5 accession of cultivated C. sativus, and 20 accessions belonging to wild species namely, C. speciosus, C. cancellatus, C. haussknechtii, C. michelsonii, and two unknown accessions, obtained from different geographical locations of Iran were studied using 7 ISSR and 10 RAPD primers. Out of 78 bands generated from 7 ISSR primers, 71 were polymorphic (90.2%), whereas out of 94 bands generated from 10 RAPD primers 83 were polymorphic (88.3%). The average PIC value obtained with ISSR and RAPD markers was 0.366 and 0.324, respectively. Marker index (ISSR = 3.71; RAPD = 2.68) and resolving power (ISSR = 5.31; RAPD = 4.12) indicated that the ISSR markers were relatively more efficient than RAPD assay in respect of revealing the genetic diversity of Crocus species. Based on percentage of polymorphic bands; resolving power; polymorphic information content; and Marker Index, the A1 (ISSR) and OPB-12 (RAPD) primers were the most informative ones. Clusters obtained from ISSR, RAPD and a combination of both data sets did match the actual taxonomic classification. The mantel test between two Jaccard’s similarity matrices gave r = 0.862, showing very good fit correlation in between ISSR and RAPD based similarities. The analysis of molecular variance showed that the total polymorphism was largely because of within-group variance (ISSRs 57%; RAPDs 64%; Combined RAPDs + ISSRs 60%). Principal coordinates analysis of the pooled data of both the markers, also supports their UPGMA dendrogram. The results will help in future genetic improvement programme of Crocus species.