Analysis of genetic diversity of safflower (Carhamus tinctorius L.) genotypes using agro-morphological traits and molecular markers

In spite of being one of the major oilseed crops, little is known about genetic diversity and relationships between species of safflower. Genetic variation in twenty safflower (Carthamus tinctorius L.) accessions was characterized by means of agro-morphological traits, random amplified polymorphic DNA (RAPD) and inter-simple sequence repeats (ISSR) markers. A field trial was conducted to evaluate 17 agro-morphological traits. To study RAPD and ISSR, initially, 53 primers were screened, of which 22 produced reproducible amplification products. Using 13 selected RAPD primers 74 markers were generated of which 60 were polymorphic (81.08%). The number of amplified bands varied from three to nine, with size range from 250 to 2,500 bp. The nine selected ISSR primers produced 50 bands across 20 genotypes, of which 48 were polymorphic (96.00%). The number of amplified fragments with ISSR primers ranged from three to eight and varied in size from 250 to 1,450 bp. By all primers (RAPD + ISSR), a total of 124 bands were detected, of which 108 bands (87%) observed with combined markers data revealed high level of genetic variation existing among the accessions. Genetic relationship estimated using similarity coefficients (Jaccard's) values between different pair of accessions varied from 0.26-0.84 in RAPD, 0.28-0.86 in ISSR and 0.29 to 0.78 with combined markers suggested a variation (dissimilarity) ranging from 16 to 74%, 14-72% and 22-71%respectively. ISSR markers were relatively more efficient than the RAPD assay. The Mantel matrix correspondence test between two Jaccard's similarity matrices, showing statistical significant correlation between ISSR- and RAPD-based similarities. Cluster analysis based on combined data of both molecular markers (ISSR+RAPD) separated the accessions into 5 groups and based on morphological traits, RAPD and ISSR data accessions formed into four distinct groups. Classification schemes generated by morphologic and molecular markers data did not coincide. The grouping of accessions was supported by principal coordinate analyses (PCoA). It is suggested that ISSR and RAPD are effective markers system for detecting variation among safflower genotypes.