Effect of Selenium Priming duration on Germination and Early Seedling Development of Arachis hypogaea L. Across a Salinity Gradient

Soil salinity as a result of global warming and poor agro-cultural practices poses a significant challenge to food production. Selenium (Se) has emerged as a promising micronutrient capable of mitigating abiotic stress in plants by reducing reactive oxygen species and supporting cellular metabolism. This study investigated the effects of selenium seed priming on germination and early seedling development of an Arachis hypogaea L. landrace under a gradient of saline conditions. Seeds were primed with selenium at five concentrations (0, 1.5, 2.5, 5, and 10 mg L⁻¹) for three durations (3, 6, and 9 h) and sown in Petri dishes containing sodium chloride solutions ranging from 0 to 7 g L⁻¹. Germination indices—including germination percentage, mean germination time, germination rate index, and germination velocity—along with seedling growth parameters and biochemical contents were evaluated. A composite Z-score integrating all measured parameters was used to rank the most effective selenium treatment at each salinity level. Selenium treatments exhibited concentration-dependent responses, with lower to moderate concentrations showing optimal or suboptimal effects, while higher concentrations induced inhibitory effects, indicating a clear hormetic response. These findings demonstrate that selenium seed priming at appropriate concentrations and durations represents a simple and cost-effective strategy for enhancing peanut establishment under saline soil conditions.