Nitrogen is so vital because it is a major component of chlorophyll, the compound by which plants use sunlight energy to produce sugars from water and carbon dioxide (i.e. photosynthesis). It is also a major component of amino acids, the building blocks of proteins and potassium is associated with the movement of water, nutrients and carbohydrates in plant tissue. It's involved with enzyme activation within the plant, which affects protein, starch and adenosine triphosphate (ATP) production. The production of ATP can regulate the rate of photosynthesis. The research was conducted to know the effect of nitrogen and potassium levels on the vigor and viability of maize seeds at Agronomy Research Laboratory, The University of Agriculture Peshawar during 2021-2022. The experiment was laid out in randomized complete block design (RCBD) having three replications. The experiment is consisted of two-factors in which one factor was nitrogen levels (0, 60, 120 and 180 kg ha^-1) and the other was potassium levels (0, 30, 60 and 90 kg ha^-1). Based on experimental results nitrogen applied at the rate of 180 kg ha^-1  increased germination (90.0 %), germination rate (9.0), plumule length (10.2 cm), root length (12.4 cm), seedling fresh weight (0.32 g), seedling dry weight (0.01 g), electrical conductivity(179.5 µS/cm) and vigor (1568.7). The application of potassium at the rate of 90 kg ha^-1 showed positive response in all the parameters and increased  germination (90.0 %), germination rate (9.0), plumule length (8.7 cm), root length (10.6 cm), seedling fresh weight (0.33 g), seedling dry weight (0.01 g), electrical conductivity(182.0 µS/cm) and vigor (1499.2). Interaction between nitrogen and potassium levels was found significant for seedling fresh weight and electrical conductivity. From the results it was concluded that nitrogen application at rate of 180 kg ha^-1 and potassium at rate of 90 kg ha^-1 is recommended for increasing vigor and viability of harvested maize seeds.

Keywords: Vigor, Viability, Maize, Nitrogen, Potassium