Propagation Protocol of Withania somnifera (L.) Dunal and Phenotypic Adaptability of Transplanted Seedlings Raised at Various Altitudes

Abstract

Plants in the temperate zone face extreme climate and resource constraints. The purpose of this study was to develop a propagation protocol for a medicinally important plant, Withania somnifera in a temperate climate. Climate change has an impact on plant morphology and reproduction. The phenotypic plasticity of developed seedlings transplanted at various altitudes was investigated. Three replicates of 25 seeds were sterilized with 1-ml L-1 tween 20, 1 g L-1 bavistin, and then treated with organic fertilizer (manure, organic compost, vermicompost, organic compost + vermicompost); inorganic fertilizer (urea, NPK, DAP, NPK+urea, DAP+urea), gibberellic acid (GA, plant growth regulator), and polyethylene glycol (PEG). Phenotypic plasticity was examined in three replicates of seven seedlings from each treatment at altitudes of 400, 900, and 1900 m. Germination parameters such as germination (100%), germination energy (86.67%), and vigour index (543.33) were maximum in seeds treated with gibberellic acid, whereas mean germination time (5.45 days) was minimum. Shoot length (58.77 cm), number of nodes per plant (77.67), and number of leaves per node (4.00) were also exhibited maximum during GA 500 mg L-1 treatment. Transplanted seedlings at high altitude showed a decrease in morphological traits such as shoot length, root length, and leaf area. Reproductive traits such as berries per plant and seeds per berry also decrease in seedlings. This study recommends 500 mg L-1 GA for seed propagation of W. somnifera for temperate regions. The study also concluded that when raising this species at different altitudes, it exhibits variation in morphological and reproductive traits. This ensures that Withania somnifera can grow in different altitudes, undergoing different morphological adaptations.