Varietal performance of turmeric (Curcuma longa L.) with special reference to curcumin and essential oil content under climatic conditions of Indogangetic plains

The field experiments were conducted in the years 2011–14 in the climatic conditions of Indogangetic plains at Botanical garden, Department of Botany BHU, Varanasi, using 35 varieties of turmeric. Variety Rajendra Sonia recorded highest fresh rhizome mass (3550 g/plant) followed by Rajapuri and GL PurmI, while in oil content Suvarna (1.40%), Sugandhum (1.20%) and Ranga (1.09%) were found to be superior followed by Suroma, Roma and Kasur. The yield related trait rhizome number was more in Suroma (129) followed by Rajendra Sonia (117) and RCT1 (101); while Rajendra Sonia, Rajapuri and GL PurmI were recorded as higher rhizome mass producing varieties. As curcumin is the most potent medicinal compound, Rajendra Sonia recorded significantly highest curcumin content (2.18%) followed by RH -5 (1.55%). Rhizomes harvested from each variety were also hydrodistilled for their essential oil. The oil content of rhizomes varied between 1.4% and 0.05% on a fresh weight basis. The essential oil of each variety was evaluated for its major terpenes: â-pinene, n-cymene, a-curcumene, âcurcumene, ar-turmerone, a-turmerone and â-turmerone. Cluster analysis revealed that high yielding varieties in terms of rhizome number and curcumin content can be clustered together viz, Vontimitra, GL Purm1, Rajapuri, Rajendra Sonia and Dindigram in cluster IIA. Interestingly the correlation between rhizome mass and curcumine showed positive and highly significant correlation. Curcumin also showed positive correlation with a-Turmerone. The rhizome of Rajendra Sonia variety was found rich in total Turmerone. The total oil content was also positively correlated with Arcurcumene, linalool and zingiberene. Results suggest that Rajendra Sonia have greater medicinal potential than other tested varieties.