NaCl priming enhances germination, physiological vigor, and rhizome quality in turmeric (Curcuma longa L.)

Pre-sowing halopriming with sodium chloride (NaCl) was evaluated as a strategy to improve germination, growth, physiological performance, and rhizome yield in turmeric (Curcuma longa L. cv. IISR Pragati) through a multi-year assessment. A preliminary optimization experiment evaluating NaCl concentrations from 0 to 500 mM in a randomized design with three replicates identified 250 mM as the optimal priming concentration, resulting in the highest germination (92.66%) and improved physiological and biochemical responses, whereas higher concentrations were inhibitory. The optimized treatment was subsequently evaluated over three consecutive years (2022-2025) under open growbag conditions. NaCl priming exerted significant treatment effects (P < 0.05) across all parameters, enhancing germination (92.77-94.44%) and vegetative growth, while year and interaction effects were largely non-significant for most traits, indicating consistent performance. Primed plants exhibited higher relative water content (92.58%) and increased chlorophyll and carotenoid contents, indicating improved physiological status. Biochemical analysis showed increased carbohydrate and protein accumulation, elevated proline levels, and reduced malondialdehyde (MDA), reflecting improved osmotic adjustment and membrane stability. SDS-PAGE analysis revealed changes in protein banding patterns and band intensity, suggesting modulation of the overall leaf protein profile following NaCl priming. These physiological and biochemical responses were accompanied by enhanced rhizome development, with fresh rhizome yield increasing from 95.0 to 147.83 g plant^- 1 in the control to 287.45-339.56 g plant^- 1 in primed plants across years. Curcumin and essential oil contents were also improved. Overall, NaCl halopriming at 250 mM provides a practical pre-planting treatment for enhancing turmeric growth, yield, and quality under the tested conditions. Further field validation across diverse agro-climatic regions is required to confirm its broader applicability.

The online version contains supplementary material available at https://doi.org/10.1007/s12298-026-01810-7.