Effect of Stimulating Maize Seeds with Potassium Nitrate and Licorice Extract on the Seed Viability and Vigor

Germination and field emergence are delayed and their duration is prolonged due to the declining soil temperature during the spring season, which is reflected in the subsequent stages of crop growth, therefore, this study aimed to improve germination. Under a wide range of environmental conditions, a laboratory factorial experiment was carried out to study the effect of seed stimulation with potassium nitrate (distilled water only (0), 2, 4, and 6 mg L^-1) and with an aqueous extract of licorice roots (distilled water only (0), 3, 6, and 9 g L^-1) on the seed viability and vigor. The laboratory experiment was carried out according to the Completely Randomized Design (CRD) with four repetitions. The results showed the superiority of the interaction treatment between the two concentrations 6 gm L^-1 and 6 mg L^-1 for each of licorice root extract and potassium nitrate by giving the highest average of the final germination 99%, the seedling vigor index reached 3846, the germination percentage at accelerating age test of 75%, and the germination percentage at the cold test of 76%. We can conclude that there was a response to soaking the seeds in licorice root extract at specific concentrations, with a clear response to potassium nitrate, and the response could be better when soaking in potassium nitrate at concentrations higher than 6 mg L^-1. We also recommend that the soaking duration in any of the two factors is 18 hours to improve germination under a wide range of environmental conditions.