Improving the Germination Performance of Kalmegh (Andrographis paniculata Wall. ex Nees) through Hydropriming, Halo-Priming and Osmopriming Under Salinity Condition

Salinity is a significant global issue that adversely affects seed germination and seedling vigour across a wide range of crops. Priming, however, is considered a basic method to enhance seed performance (germination and vigour) under saline conditions. The aim of this study is to evaluate the effects of different priming treatments on seedlings under varying salinity levels (0, 4, 6, 8, and 10 dS m⁻¹) in Kalmegh, a traditionally valuable medicinal plant. Seeds were primed through four methods viz., T0- Non-primed (control), T1- Hydro primed (distilled water), T2- halo priming with NaCl (0.8%), T3- halo priming with CaCl2 (0.8%) and T4- osmo priming with KNO3 (1%) for 6 hours at 25ºC in the dark. This experiment was arranged in a factorial design based on a CRD (Completely Randomized Design) with three replications. The results demonstrated that priming treatments significantly improved germination percentage, seedling length (cm), seedling fresh weight (mg), seedling dry weight (mg), and vigour indices. Notably, seeds primed with KNO3 showed the highest germination performance at all salinity levels. Even at the highest salinity level, they achieved a germination percentage of 94% and a Seedling Vigour Index I of 506, compared to the control group, which exhibited a germination percentage of 88% and a Seedling Vigour Index I of 298. KNO3 priming at 0 dS/m produced the highest seedling length (8.5 cm), root length (2.7 cm), shoot length (6.4 cm), fresh weight (26.32 mg), and dry weight (10.3 mg).