Influence of stress signals on phenotypic characters, rhizome yield and secondary metabolite production of turmeric (Curcuma longa) cv. ‘Pragathi’

Abstract

Turmeric plants are exposed to a variety of stress signals which influence not only the vegetative growth and yield but also the secondary metabolite production. An exposure study on the stress-induced changes in turmeric morphological characters, biomass production, and phytochemical changes will help to identify useful stress signals under field conditions. This study identifies the influence of stress signals such as salicylic acid, ZnSO4, and cow urine on phenotypic characters, rhizome yield, and secondary metabolite production in ’Pragathi’ variety of turmeric. The present investigation was conducted during June (2019) to January (2020) at Kakkur Panchayath, Kozhikode district, Kerala. One way ANOVA results showed that except for the number of tillers and number of mother rhizomes, all other features showed significant difference in means(P<0.05). Among the various stress signals used, 10% cow urine solution was found to be most effective in promoting the height of the plants and leaf length and 5% cow urine solution was found to be effective in leaf induction. Use of 0.2% Salicylic acid solution was found to be most effective in increasing the production of secondary metabolites like Curcuminoids and Oleoresins. About a 35% increase in the production of Curcuminoids and a 23% increase in the production of Oleoresins were observed in plants treated with 0.2% Salicylic acid solution. The results obtained in the present studies could be used for increasing vegetative growth and secondary metabolite production in turmeric cv. ‘Pragathi’.