A comparative genetic diversity analysis in mungbean (Vigna radiata L.) using inter-simple sequence repeat (ISSR) and amplified fragment length polymorphism (AFLP)
Amplified fragment length polymorphism (AFLP) and inter-simple sequence repeat (ISSR) markers were used to study the DNA polymorphism in elite mungbean genotypes. A total of nine AFLP primer combination and 22 ISSR primers were used. Amplification of genomic DNA of the 30 genotypes, using AFLP analysis, yielded 300 fragments that could be scored, of which 192 were polymorphic, with an average of 21.3 polymorphic fragments per primer. Number of amplified fragments with AFLP primers ranged from 29 (E-AAC: M-CAG) to 10 (E-ACG: M-CAT). Percentage polymorphism ranged from 46.3% (E-AAC: M-CCA) to a maximum of 100% (E-AAC: M-CAC), with an average of 64%. The 22 ISSR primers used in the study produced 108 bands across 30 genotypes, of which 68 were polymorphic. The number of amplified bands varied from two UBC820) to ten URP 6F). The average numbers of bands per primer and polymorphic bands per primer were 4.9 and 3.1, respectively. Percentage polymorphism ranged from 25% (UBC844) to 85% (UBC846, UBC864, UBC895), with an average percentage polymorphism of 58.3% across all the genotypes. AFLP markers were more efficient than the ISSR assay, as they detected 64% polymorphic DNA markers in Vigna radiata as compared to 58.3% for ISSR markers. The Mantel test between the two Jaccard's similarity matrices gave r = 0.19, showing low correlation between AFLP- and ISSR-based similarities. Clustering of genotypes within groups was not similar when AFLP and ISSR derived dendrograms were compared.
Key words: AFLP, ISSR, Vigna radiata (mung bean), marker index, unweighted pair-group method with arithmetic averages (UPGMA).