Analysis of genetic diversity and population structure of the indigenous and exotic wild Malus species using ISSR markers.
The genetic diversity and population structure studies on 32 wild Malus species were conducted using the nine inter simple sequence repeat (ISSR) markers. The average value of diversity indices, viz. resolving power (Rp), polymorphic information content (PIC), effective multiplex ratio (EMR) and marker index (MI) of ISSR markers were 2.389, 0.388, 16.429 and 6.228, respectively, while the Jaccard's similarity coefficient ranged from 0.46 to 0.97. The cluster analysis divided the selected Malus species into two major clusters and principal coordinate analysis (PCoA) further reconfirmed the result of the cluster analysis. The first three axes of PCoA explained 43.49% variation and analysis of molecular variance (AMOVA) explained 16% variation between the indigenous and exotic Malus populations. The studied Malus species were genetically differentiated into four distinct populations which were revealed through the model based population structure analysis. Thus, the present investigation revealed substantial genetic diversity among the studied wild Malus species and existing genetic diversity could be valuable genetic resources for future apple improvement programme.