Evaluation of Genetic Diversity and Phylogenetic Relationship among the Major Banana Varieties of North-Eastern India Using ISSR, IRAP, and SCoT markers

Abstract

India is one of the secondary centers of origin for both wild and domesticated bananas, with the north-eastern region holding the greatest repository. Therefore, the present study used three different molecular marker systems viz., inter simple sequence repeats (ISSR), inter-retrotransposon amplified polymorphism (IRAP), and start codon targeted (SCoT) polymorphism to analyze the genetic diversity among 17 cultivated varieties of the north-eastern region belonging to different genomic groups. The percent polymorphism was found to be 91.79, 86.78, and 82.35 in ISSR, IRAP, and SCoT markers respectively. ISSR had the highest values for all the marker parameters. However, IRAP outperformed SCoT and ISSRs by recording the highest values for effective number of alleles (N_e), Shannon index (I), and Nei’s (1973) gene diversity (H). The dendrogram obtained using ISSR, SCoT, and combined data had two major clusters and the clustering pattern was almost similar, but it differed slightly in IRAP markers. To learn more about the population structure and allelic diversity, model-based structural analysis was carried out in addition to phylogenetic analysis and principal component analysis (PCA). The structure analysis identified three subpopulations in ISSR, four in IRAP, and five in SCoT and combined marker data. The Q-value indicates that almost all the subpopulations are composed of varieties with and without admixture, thereby suggesting that more alleles are being shared among the varieties used in this study.