Genetic diversity and population structure studies of the wild apple genotypes using RAPD markers

Abstract

The wild apples (Malus sp.) are important genetic resources for apple improvement programmes. In the present investigation, 32 Malus genotypes including indigenous Himalayan crab apples and exotic wild apples collected and maintained in the field gene banks at different ICAR institutes, were selected for genetic diversity and population structure analysis using the RAPD markers. The mean diversity indices, viz., Rp, PIC, EMR and MI of 18 RAPD markers were 5.829, 0.326, 8.432 and 2.851, respectively among the wild Malus genotypes. The cluster analysis segregated the wild Malus genotypes into two major clusters and the Jaccard's similarity coefficient ranged from 0.66 to 0.90. The first three axes of PCoA explained 40.26% variation and AMOVA explained 2% between the indigenous and exotic wild apple genotypes. The model based population structure studies revealed three major populations in the present set of genotypes. It could be concluded that there was substantial level of genetic diversity and population differentiation among the wild apple genotypes maintained at different research stations. Thus, the available diversity among the present set of wild apples could be explored for the scion as well as for rootstock breeding.