SPAR profiles and genetic diversity amongst pomegranate (Punica granatum L.) genotypes

Abstract

We are interested in studying the distribution and range of diversity amongst the pomegranates in India. Single Primer Amplification Reaction (SPAR) profiling using Random Amplified Polymorphic DNA (RAPD) and Directed Amplification of Minisatellite DNA (DAMD) methods enabled the determination of the genetic diversity amongst a total of 64 Indian pomegranate genotypes including 15 wild, 34 semi-wild and 14 cultivated types. SPAR profile data were scored for the computation of pairwise distances as well as a Neighbour Joining (NJ) tree of all the genotypes. Eight RAPD and four DAMD primers showed discrete polymorphic patterns amongst these genotypes. From the profiles obtained with all the 12 primers considered together, 259 bands were scored. The NJ tree generated after a 1000 bootstrap test using Jaccard coefficient showed separation of Lagerstroemia speciosa used as the out-group taxon, while the pomegranate genotypes were resolved into distinct genetic lineages such that all the cultivated (except CBd70), and wild genotypes (except W101) clearly separated from other genotypes in distinct sub clusters while the semi-wild genotypes were resolved into three sub-clusters. The greatest and least distances detected between genotypes were 0.94 and 0.12, 0.97 and 0.24 and 0.95 and 0.38, amongst the cultivated, semi-wild and the wild genotypes respectively. The results indicate the high levels of genetic diversity present amongst the genotypes. Significantly, the wild genotypes also have a reasonably good range of diversity. A good germplasm collection, especially including the wild genotypes will enable a better pomegranate improvement program. Both SPAR methods, RAPD and DAMD, are found to be useful for studying the genetic diversity of pomegranate.