Abstract

Rhodiola imbricata Edgew. (Crassulaceae), well acknowledged medicinal plant is widely distributed in trans-Himalayan region of India. It has multiple uses in cuisine, forage, health care and ornamental worth. In the present investigation, 70 wildly grown Rhodiola genotypes, collected from three different sampling sites in trans-Himalayan region of Ladakh were analyzed using 40 DNA-based markers (20 random amplified polymorphic DNAs (RAPDs) and 20 inter simple sequence repeats (ISSRs). RAPD analysis yielded 134 fragments, of which 130 were polymorphic, with an average of 6.5 polymorphic fragments per primer. Of the 20 ISSR primer screened, only 8 were amplified in the present investigation. These amplified primers produced 59 bands, of which 57 were polymorphic with an average of 7.12 polymorphic fragments per primer. RAPD markers were found more efficient with regards to polymorphism detection, as they detected 98.28% as compared to 97.55% for ISSR markers. Clustering of genotypes within groups was remained more or less same when RAPD, ISSR and RAPD + ISSR derived dendrograms were compared. The results of principal coordinates analysis (PCA) analysis were corresponding to the dendrogram analysis. These analyses allowed us to identify the groups corresponding to the three Rhodiola collection sites. Analysis of molecular variance (AMOVA) showed that genetic variation within the populations was found maximum than among populations in all the three cases. It may because of high level of differentiation within populations due to geographical and genetic isolation of populations in a harsh mountainous environment. With reference to the management of Rhodiola, the high genetic separation of population indicates the requisite of conserving the extreme possible number of populations from diverse parts of trans-Himalayas.

Key words: Rhodiola imbricata, genetic diversity, random amplified polymorphic DNA (RAPD), intergenic simple sequence repeat polymorphism (ISSR), analysis of molecular variance (AMOVA).