Chromosomal and PCR-based molecular characterization of Hedychium spp. of Tripura, North-East India

Abstract

Hedychium is an important genus of Zingiberaceae because of its medicinal and horticultural importance. Investigations on chromosomal and polymerase chain reaction (PCR) based molecular characterization of the genus Hedychium at inter-specific and intra-specific levels have been undertaken for the detailed study of the karyotypes as well as for assessing the genetic diversity. We have analysed chromosomal and molecular marker based characters of three Hedychium spp., viz., H. coccineum, H. coronarium and H. thyrsiforme from the state of Tripura but because of their restricted distributions in this biodiversity hotspot we included only two populations of each species in intra-species analysis. Numerical data of karyotypes reveal that Pop-I and Pop-II of all the three species have the same chromosome count 2n = 34 with a basic number X = 17. In-spite of the close resemblances of their karyotypes, chromosomal data based clustering pattern and their sub-grouping at intra-species level validates the taxonomic status of the species. The inter simple sequence repeat (ISSR) and simple sequence repeat (SSR) dendrogram obtained by unweighted pair group method with arithmetic mean (UPGMA) analysis depicts a local position effect based clustering pattern with intra-specific diversity. Our results also indicate that SSR marker is more reliable in assessing the genetic relationship between and within the species of Hedychium. As Gower’s similarity coefficient is an indicator of cryptic changes in chromosome structure, we propose that dissimilarity in mean centromeric asymmetry (MCA) value at inter-specific level can be related with molecular markers based genetic diversity having high degree of polymorphism.