Seed Priming Does Not Improve Corn Yield in a Humid Temperate Environment

Early emergence and stand establishment of corn ( Zea mays L.) is considered to be one of the most important yield‐contributing factors in eastern Ontario. A pot experiment and two field experiments were conducted in Ottawa, Canada, to evaluate the effects of seed priming with water, osmotic solution (2.5% KCl), and plant growth regulators (indole acetic acid, cytokinin, ethephon and gibberellic acid) on emergence, seedling vigor, N response, and grain yield of corn. Time to seedling emergence, seedling vigor, and growth were measured in a pot experiment under a greenhouse condition while field performances, N response, and grain yield were determined in field experiments. In the greenhouse study, none of the treatments were better than the unsoaked control. Under field conditions, both hybrids and N application had significant effects on grain yield, but there was no yield advantage due to any of the seed treatments. Seed soaking with 20 ppm gibberallic acid (GA 3 ) solution for 30 min improved seedling vigor (i.e., seedling height and growth), but this was not translated into greater grain yield. Seed soaking with water for 16 h significantly reduced percentage emergence and final plant stand in 2002 while in 2003, seed soaking with 2.5% KCl and 20 ppm GA 3 solution for 16 h significantly reduced plant stand and grain yield under the 150 kg N ha −1 treatment. Despite some positive effects of seed priming on seedling vigor and stand establishment, none of the seed‐priming treatments tested showed beneficial effects on grain yield and N efficiency under the temperate‐humid conditions such as in eastern Ontario.