Corn Drought Stress Tolerance

Corn response to drought stress is a complex process involving many environmental factors and hybrid characteristics.

Long-Term Average Yield Loss to Drought

Map: Long-term average yield loss to drought (U.S.)

How Pioneer Rates Drought Tolerance

Pioneer Rates Drought Tolerance From 1-9

  • Current commercial hybrids have ratings of 4-8
  • Hybrids below 4 are discarded during testing
  • Future drought products will be rated 9

Chart: Hybrids from eight decades (1920s to 1990s) grown under drought demonstrate significant improvement for drought tolerance.

Hybrids from eight decades (1920s to 1990s) grown under drought
demonstrate significant improvement for drought tolerance,
especially in the last 20 to 30 years.

Agronomic Factors That Affect Drought Tolerance

  • Root system structure
  • Insects
  • Diseases

Root System Structure

  • A drought tolerant hybrid must have a root system that efficiently accesses all available moisture.
  • A root system that penetrates deeply into the soil is more capable of reaching soil moisture as drought develops.


  • Planting into wet or compacted soil can restrict root growth and increase susceptibility to drought stress later in the season



  • Corn roots can be attacked by soil insects from germination through grain development
  • The insect most damaging to corn roots by far is corn rootworm. Pioneer® brand hybrids with the Herculex® RW (HXRW) or Herculex XTRA (HXX) traits offer the best rootworm protection



  • Seedling diseases can reduce root systems and drought tolerance of hybrids
  • Pioneer hybrids rated highly for stress emergence are less affected by common seedling diseases.


Yields Under Stress

Hybrid Characteristics That Contribute to Increased Yield Under Drought Stress


Strong root system


Prolific silking under drought


Reduced tip kernel abortion

Pioneer Drought Tolerance Research


Conventional Breeding

  • Germplasm improvement through traditional breeding techniques

Drought I

  • Advantage: 5-10% yield increase in dryland and limited irrigation areas of the western Corn Belt
  • Development: Native drought tolerance genes identified through marker-assisted selection and advanced into elite genetics using Accelerated Yield Technology (AYTTM System) tools
  • Hybrids are currently available.

Drought II

  • Advantage: Improved yield and drought tolerance across all growing environments
  • Development: A combination of native drought tolerance genes and transgenes
  • Future product currently under development.

HX1 – Contains the Herculex® I Insect Protection gene which provides protection against European corn borer, southwestern corn borer, black cutworm, fall armyworm, lesser corn stalk borer, southern corn stalk borer, and sugarcane borer; and suppresses corn earworm.
HXRW – The Herculex® RW Insect Protection trait contains proteins that provide enhanced resistance against western corn rootworm, northern corn rootworm, and Mexican corn rootworm.
HXX – Herculex® XTRA contains both the Herculex I and Herculex RW genes.
Herculex® Insect Protection technology by Dow AgroSciences and Pioneer Hi-Bred. Herculex® and the HX logo are registered trademarks of Dow AgroSciences LLC.