Andrew W. Harmon, Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL and Frederick E. Below, University of Illinois-Urbana-Champaign, Urbana, IL
Due to the projected global population increase, food production will need to utilize new technology to reach its fullest potential. Field experiments were conducted during 2015 at Urbana, Illinois to assess the ability of strigolactone plant growth regulator (PGR) to relieve high population stress and increase grain yield of corn (Zea mays L.). A versatile high-yielding commercially available hybrid was grown at 79,000 or 109,000 plants ha-1 with 0.76 m row spacing. Strigolactone was tested as a seed treatment at planting and as foliar application at the VT/R1 growth stage, and compared to a foliar fungicide application of Headline AMP at the VT/R1 growth stage. For untreated or Headline AMP treated plants, increasing the planting population to 109,000 plants ha-1 increased yield by 0.59 to 0.78 Mg ha-1 while the strigolactone treated plants had no yield change. At the standard planting population of 79,000 plants ha-1, the strigolactone treated plants tended to have increased grain yield, with the seed treatment producing the greatest yield increase of 0.93 Mg ha-1. These results indicate that strigolactone PGR's could be used in-season to alleviate stress and increase overall productivity under standard planting populations.