Keywords: Amomum; Karyotype; Simple Sequence Repeat (SSR); Genetic diversity; Unweighted Pair Group Method with Arithmetic Mean (UPGMA); Tripura
The genus Amomum of Zingiberaceae comprising a large number of aromatic plants, with its main centre of distribution in North Eastern India, is facing the threat of extinction due to anthropogenic disturbances. In this study, the somatic chromosome number of two wild populations with each of three species of Amomum viz. A. maximum, A. corynostachyum and A. aromaticum from the state of Tripura was determined by modifying aceto-orcein staining technique. Additionally, genetic diversity was assessed using Simple Sequence Repeat (SSR) molecular markers. The somatic chromosome count was 2n=48 with one pair of nearly metacentric chromosomes bearing secondary constriction noted in all the species even at the population level. A considerable homogeneity in their karyotype was observed both at interspecific and intraspecific level suggesting a karyotype stasis. In contrast, SSR analyses indicated a high degree of genetic polymorphism (75.00-100.00%). UPGMA dendrogram revealed two different clusters with inherent variability between the populations. Our findings suggest that the morphological distinction among the species, which could not be resolved at cytological level probably due to intrinsic characteristic of the karyotype itself, can be assessed through SSR fingerprinting.
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This work was supported by a BSR doctoral Fellowship from the U.G.C., New Delhi, India. KS is grateful to Dr. A. K. Banerjee, PMB Lab., IISER, Pune for providing laboratory facilities. The contribution of Dr. B. Dholakia, NCL, Pune in preparing the manuscript is thankfully acknowledged.