Seed World

Maize Heat Tolerance has Increased to Moderate Stress

With temperatures on the rise due to climate change a new study looked at how maize crops are responding. The study by Aaron Kusmec at Iowa State University and colleagues was published in PLOS Genetics, according to a release. It suggested that through trait selection in maize, the plant has an increased tolerance to moderate levels heat stress but a decreased tolerance to severe heat stress.

High temperatures can stress the maize plant and reduce crop yields. The genetic adaptation to heat isn’t thoroughly understood in maize. According to the release, “researchers collected 81 years of public yield trial records, including 4,730 maize hybrids.” Researchers compared the maize yield data to historical weather records during the same time frame. The team was then able to model genetic variation for temperature responses in maize hybrids.

The researchers model found that maize has become more tolerant to moderate heat stress and less tolerant to severe heat stress. According to the release, “the study was limited by potential confounding factors such as environmental conditions other than temperature and precipitation.” In the future, more studies will be needed to further understand temperature adaptation.

“Because climate change is expected to increase the incidence of severe heat stress in particular, these findings indicate the need for more detailed genetic and physiological studies of heat tolerance and their incorporation into plant breeding efforts,” said the study authors. “They also highlight the past successes of plant breeders at adapting maize to moderate heat stress.”

“Using 80 (plus) years of corn yield data stored by research libraries in hard-copy format, we discovered that plant breeders have increased the tolerance of hybrid corn to moderate heat stress, while inadvertently decreasing its tolerance to severe heat stress. Unfortunately, the frequency of severe heat stress is expected to increase due to climate change,” continued the authors of the study.