EST-SSR marker-based genetic diversity and population structure analysis of Indian Curcuma species: significance for conservation

Protection and utilization of plant genomic resources are greatly perceived these days. The possibility of their dwindling genetic diversity along with the augmented demands for the resources has necessitated immediate concern for their conservation and sustainable plant utilization. The genus Curcuma (family Zingiberaceae) is well known for its valuable multipurpose products for medicine, spices, food, fragrance, flavoring agents, condiments as well as ornamentals. Because of the resurgence of curiosity in the commercial development and conservation of Curcuma, it has become essential to precisely characterize the existing genetic diversity at the species level. In the present study, 109 EST-SSR markers showed cross-transferability among 9 Curcuma species, among which 33 showed polymorphism. These 33 polymorphic EST-SSRs were utilized to assess genetic resemblance and distance among Curcuma species. The results of cluster analysis and principal coordinate analysis highly correspond to each other. AMOVA showed higher genetic variation among Curcuma species. The population genetic study revealed the genetic differentiation of species. The mean values of Nei's gene diversity (H), Shannon's information index (I), polymorphic information content (PIC), percentage of polymorphic bands (PPB), and resolving Power (RP) were found to be 0.3314, 0.49, 0.66, 88.57% and 7.24, respectively. Values of Nei's gene diversity in C. longa indicated the need for its large-scale cultivation and conservation prioritization of wild taxa of C. caesia, C. aromatica and C. amada. These SSR markers could also be utilized to identify morphologically similar Curcuma species.