Genetic Diversity and Relationship of Mulberry Genotypes Revealed by RAPD and ISSR Markers

Abstract

ABSTRACTTo improve mulberry (Morus spp.) foliage productivity, assessment of relatively underexploited genetic resources is essential. A core panel of 14 mulberry genotypes, shortlisted from 45 lines based on molecular profiling, was screened using random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) markers, to assess genetic diversity among them. Out of 25 primers each of RAPD and ISSR screened, 20 polymorphic primers (8 RAPDs and 12 ISSRs) were used in this study. Amplification of genomic DNA of the 14 genotypes, using RAPD analysis, yielded 67 fragments, of which 87.5% were polymorphic. The number of amplified fragments ranged from 6 to 11, with the size of amplicons ranging from 300 to 1,300 bp. The 12 ISSR primers produced 106 bands across 14 genotypes, of which 93% were polymorphic. The number of amplified fragments ranged from 5 to 12, with the size of amplicons ranging from 200 to 1,100 bp. Similarity coefficient ranged from 0.29 to 0.90 for RAPD and 0.36 to 0.81 for ISSR. For RAPDs the polymorphic information content (PIC) values ranged from 0.280 to 0.496, with an average of 0.351. For ISSRs, the PIC values ranged from 0.325 to 0.428, with an average of 0.375. There was a slight difference between RAPDs and ISSRs in their average resolving power (Rp). Using unweighted pair group method with arithmetic mean (UPGMA), a process of hierarchical clustering by Numerical Taxonomy and Multivariate Analysis System (NTSYS-pc), RAPD-, and ISSR-derived results were grouped the 14 genotypes into 2 and 5 clusters, respectively. Principal coordinate analysis also showed gross similarities with UPGMA-based dendrograms, with minor deviations. Morus indica L. (C-2016) exhibited highest divergence in cluster and lowest similarity coefficient value. This identified elite line may be utilized in mulberry improvement programs. The RAPD and ISSR markers were successfully used in assessing the genetic diversity among the tested mulberry genotypes.