Assessment of genetic variation in turmeric (Curcuma longa L.) varieties based on morphological and molecular characterization

Turmeric (Curcuma longa L.) is an economically valuable spice crop with a wide range of applications. Crop improvement efforts in this crop had led to identification, selection, and release of several varieties with desirable traits for yield, curcumin content etc. Understanding of genetic variation is a pre-requisite for any crop improvement programme. In this study, we examined the genetic variation present in prominent 18 improved varieties of turmeric in India using morphological and microsatellite markers. We studied 12 morphological characters including 11 quantitative traits, and curcuminoid content following the DUS guidelines of turmeric. For molecular characterization, we used 56 molecular markers including SSRs, and ISSRs to determine the genetic polymorphism among the genotypes. PIC value of these markers ranged from 0 to 0.5. Our study thus confirms the reliability of these molecular markers to study the genetic variation of turmeric varieties. The combination of methods i.e., cluster analysis based on morphological characterization and the UPGMA dendrogram based on molecular characterization revealed both the phenotypic and molecular variation among the improved turmeric varieties. This has helped us to understand pattern of variation, the level of genetic similarity and the genetic divergence among them. It was found that the varieties Varna, Megha Turmeric and Suvarna were the most divergent while Punjab Haldi 1 and Sudarsana were the least divergent among the improved varieties. The results from this study can be used in designing breeding programmes in turmeric.