Efficiency of random amplified polymorphic DNA (RAPD) and inter-simple sequence repeats (ISSR) markers for genotype fingerprinting and genetic diversity studies in canola (<i.Brassica napus</i>)

Abstract

Genetic diversity evaluations among 10 canola (Brassica napus) genotypes were determined using RAPD and ISSR markers. The RAPD and ISSR primers with the highest degree of polymorphism were selected. A total of 67 bands of polymorphic RAPD bands were detected out of 77 bands, with an average of 13.4 polymorphic fragments per primer. The number of amplified fragments with RAPD primers ranged from 8 to 21, with the size of amplicons ranging from 162 to 3154 bp. The polymorphism ranged from 68.4 to 100.0, with an average of 87%. The five ISSR primers produced 94 bands across 10 genotypes, of which 76 were polymorphic, with an average of 15.2 polymorphic fragments per primer. The number of amplified bands varied from 4 to 32, with size of amplicons ranging from 127 to 3011 bp. The percentage of polymorphism using ISSR primers ranged from 25 to 100.0 with an average of 78.8%. Dice similarity coefficient was calculated for all pairwise comparisons and was used to construct a UPGMA dendrogram. Clustering of genotypes within the groups was not similar when RAPD and ISSR derived dendrograms were compared, whereas, the pattern of clustering of the genotypes remained akin in ISSR and the combined data of RAPD and ISSR. The similarity coefficient ranged from 0.44 to 0.78, 0.41 to 0.72 and 0.47 to 0.73 with RAPD, ISSR and combined dendrogram, respectively. These results provided valuable information for fingerprinting that can be used to create wider genetic base for future canola breeding program.

Key words: Brassica napus, inter-simple sequence repeats (ISSR), random amplified polymorphic DNA (RAPD), genetic diversity.