Elicitors induced changes in essential oil constituents of turmeric (Curcuma longa L.) rhizome

An experiment was conducted at IISR, Kozhikode to study the effect of foliar application of chemical elicitors, namely, chitosan (100, 200 and 500 ppm), phenylalanine (0.1, 1 and 10 mM) and salicylic acid (0.01, 0.1 and 1 mM) on volatile constituents of turmeric rhizome essential oil (EO). Three genotypes (Pragati, Rajapuri and Acc.849) which vary in growth duration and volatile profile were taken for the study in randomized block design with three replications. The highest EO content in Pragati (6%) and Acc. 849 (5.3%) was found in Phenylalanine (1 mM) treatment. No significant changes in EO content were observed in the genotype Rajapuri. Phenylalanine and salicylic acid were found to have positive influence on ar-turmerone, the major sesquiterpenoid in Pragati. Acc.849 and Rajapuri did not produce any significant changes to ar-turmerone content in elicitor treated samples. Moreover, the treatment related variation in the total monoterpenes and total sesquiterpene content was found significant among the genotypes. Multivariate analysis using partial least square discriminant analysis supported the variation observed among the treatments and variable importance in projection scoreidentified the metabolites responsible for variation among treatments.