Genetic relationships among common bean (Phaseolus vulgaris L) genotypes using ISSR markers

Common bean (Phaseolus vulgaris L.) is an important nutritional leguminous, which is rich in protein, fiber, carbohydrates, minerals (iron and zinc), and essential vitamins. Among different methods which are used to study the genetic diversity of plants, molecular markers (such as ISSR) have been used as a powerful tool. In this study, 20 ISSR markers were used to investigate the genetic diversity of 41 genotypes of common bean (including 36 new lines and five cultivars). Sterilized seeds of genotypes were sown and their fresh leaves were harvested for DNA extraction using the CTAB method. DNA amplification was done using 20 ISSR markers, the obtained bands were scored as 0 (band absence) and 1 (band presence). Finally, statistical analyses were performed. Based on genetic diversity indices UBC835, UBC842, UBC853, UBC857, and UBC859 loci had the highest (0.5) and UBC830 locus had the lowest (0.26) values of polymorphism information content. The highest Shannon index was for UBC856 (10.6) and the lowest for UBC853 (1.23). The highest (8.3) and the lowest (0.7) marker index were related to UBC856 and UBC830 primers, respectively. Cluster analysis classified the 41 common bean genotypes into four main groups. The clusters formed by molecular data indicated some crosses between the genotype KS21633 (the fourth group) and the second group genotypes with a greater probability of obtaining superior lines. Also, KS920056 and KS920049 genotypes showed the lowest Jaccard similarity coefficient (0.099) which indicates a large genetic distance between these two genotypes. Genotype grouping by the first two principal components partially confirmed the classification of cluster analysis. The results of this study showed the high efficiency of ISSR molecular markers in the differentiating of common bean genotypes. The wide variation observed among the studied genotypes can be used in breeding programs of common bean.