Comparative analysis of the efficiency of SAMPL and AFLP in assessing genetic relationships among Withania somnifera genotypes

Abstract

Withania somnifera is a subtropical shrub with important medicinal properties. In the present study, the efficiency of Selectively Amplified Microsatellite Polymorphic Loci (SAMPL) assay in assessing the levels of genetic diversity among W. somnifera genotypes was analysed. Some genotypes of W. coagulans were used as outlier. A comparison of the SAMPL assay was made with the standard Amplified Fragment Length Polymorphism (AFLP) technique. The SAMPL assay revealed higher levels of polymorphism among the tested W. somnifera genotypes compared to the use of AFLP. Significantly higher level of polymorphism was detected with SAMPL within both Kashmiri and Nagori genotypes. Cluster analysis showed clear groupings within the W. somnifera Kashmiri, W. somnifera Nagori and W. coagulans genotypes. The Nagori genotypes are separated from the Kashmiri genotypes at low similarity value, indicating that Nagori and Kashmiri types are highly divergent. One of the W. somnifera-specific bands generated with SAMPL was used to develop a simple PCR-based assay. The diagnostic markers thus generated can be used at the seedling stage to distinguish W. somnifera Kashmiri, W. somnifera Nagori and W. coagulans genotypes.