Early Heat and Drought Stress Can Have Lasting Effects on Corn

Research reveals why developing resilient crops requires testing heat, drought, and their combination—and tracking plants over time. 

 

ST. LOUIS, MO (October 14, 2026) — A brief period of heat and drought early in a corn plant’s life can affect its growth and flowering months after the stress ends, according to new research from the Donald Danforth Plant Science Center and the University of Minnesota. The findings could help guide efforts to develop crops better equipped to withstand hot, dry growing conditions.

 

Published in The Plant Journal, the study tracked 47 genetically diverse corn varieties under normal conditions, drought, heat, and combined heat and drought. Researchers found that responses to drought alone did not predict responses to the combined stresses in the traits measured, underscoring the importance of evaluating both stresses together when identifying promising plants for breeding. 

 

“A corn plant that performs well under drought may respond very differently when heat is added,” said Malia Gehan, PhD, Danforth Center principal investigator and director of research for innovation. “By measuring plants day after day through images, we can see differences that a single measurement would miss. This gives us a more complete picture of how plants cope with stress.” 

 

The conditions tested were representative of those corn can encounter during early summer in the Midwest. Although researchers often focus on heat and drought around flowering, when crops are particularly vulnerable, these findings show why early-season stress and its effects later in the plant’s life also deserve attention. 

 

The team used the Danforth Center’s Bellwether Phenotyping Facility to capture daily images during 13 days of treatment beginning shortly after seedlings emerged. PlantCV, an open-source image analysis platform developed at the Danforth Center, helped researchers measure changes in plant size, height, water use, and color. 

 

Heat and drought impacted plants differently. Both reduced plant size, but drought also slowed development and reduced leaf number and greenness. For most of the varieties tested, the combination of heat and drought amplified reductions in plant size beyond the effects expected from the individual stresses. 

 

Tracking those changes over time also revealed that an early visible response did not consistently signal a more severe outcome. Plants that showed signs of drought stress sooner were not necessarily the most affected by the end of treatment—a distinction that could help researchers avoid overlooking useful genetic variation. 

 

To explore whether early stress had lasting consequences, the researchers conducted additional experiments with two of the most interesting corn varieties, returning plants to normal growing conditions after approximately two weeks of stress. The early drought exposure delayed flowering, while heat exposure advanced it. The effects of combined stress on flowering differed between the two lines. Plants exposed to combined heat and drought also remained significantly smaller than unstressed plants at 61 days after planting, weeks after the stress had ended. 

 

“Farmers need crops that can withstand difficult conditions from the start of the growing season,” said Giles Oldroyd, PhD, president of the Danforth Center. “The remarkable variation in how these plants respond gives us opportunities to understand what makes some more resilient than others. Our goal is to turn that understanding into impact: better crops that help farmers protect their livelihoods and feed their communities.” 

 

The team is now conducting a small follow-up study with selected corn varieties at the Danforth Center’s Field Research Site. The publicly available varieties evaluated in the study could provide useful genetic variation for future efforts to develop more resilient crops. 

 

The research was led by Malia Gehan, PhD, at the Danforth Center and Cory Hirsch, PhD, at the University of Minnesota. Anna Casto, PhD, Katie Murphy, PhD, and Alejandra Quinones contributed equally as co-lead authors. Support included funding from the US Department of Agriculture’s National Institute of Food and Agriculture, National Science Foundation, Wells Fargo IN2 Program, Taylor Geospatial Institute, and University of Minnesota Experimental Station.