Effect of elevated temperature on the morphology and phytochemical profile of Withania somnifera’s varieties

Four different varieties of Ashwagandha (Withania somnifera Dunal) viz.  Vallabh 01 (V01), Vallabh 02 (V02), Pratap (P), and Chetak (C) were investigated to determine the impact of elevated temperature (ET) levels on the morphology, biomass, and concentration of phytochemicals. The plants were exposed to ET (AT ± 3˚C) from November to March 2022. Results showed an increase in the shoot length (53.1% in V01 and 22.4% in V02, P, and C), and a 70% decrease in the root length of all the varieties under ET. Enhancement in the shoot biomass production (14.05, 11.3, 1.15, and 10.29% in V01, V02, P, and C) while the decline in the root biomass production (17.07, 34.6, 1.54, and 2.33% in V01, V02, P and C) were found under ET. Under ET, V01 showed a 3.6 % decrease in the phytochemical content while the other three varieties (V02, P, C) had an increase in the phytochemical content (45.2%, 10.02%, and 32.14% respectively). The ET significantly enhanced terpenoids, steroids, and alkaloids in all varieties of W. somnifera. These findings showed that V01 is most tolerant while P is sensitive to temperature stress (V01> V02> C> P). The study revealed the tolerance ability of Withania somnifera to temperature stress in the context of climate change.