New genetic discovery could help peanuts beat the heat

This study gives us the tools to future-proof peanut crops.

Sachin Rustgi, molecular breeder

FLORENCE, S.C. — As global temperatures rise, peanut farmers face a growing challenge: Heat stress threatens crop yields by reducing plants’ ability to reproduce.

But a new study by Clemson University scientists offers hope. The scientists recently discovered a key section of DNA that helps peanuts stay productive in hot weather. They also found a genetic marker and a few plant types that produce healthy pollen even under heat stress.

These findings could help breeders develop peanut varieties that not only survive the heat, but also produce high-quality, nutritious seeds.

Peanuts, a vital source of nutrition and income for millions worldwide, are especially vulnerable to heat during flowering.

According to the United States Department of Agriculture (USDA), peanuts are primarily grown in the southern U.S. — Alabama, Florida, Georgia, North Carolina, South Carolina and Texas — where the climate is warmer and growing seasons are longer than in northern zones.

When temperatures climb above 86 degrees, peanut pollen often fails to properly develop and germinate, leading to fewer pods and lower yields.

To tackle this problem, scientists led by Sachin Rustgi, a molecular breeder at the Pee Dee Research and Education Center near Florence, South Carolina, studied 72 peanut genotypes from across the globe, including a popular U.S. runner type, Georgia Green.

The scientists placed the plants in a greenhouse, exposing them to high temperatures and evaluating them to determine the impact of heat stress on pollen viability and germination.

The results were striking. Some peanut varieties, like PI 200441 from Japan, maintained high pollen viability, while others, like PI 504614 from Colombia, struggled. Using advanced genetic tools, the team pinpointed a small region on chromosome 20—dubbed “qPPVA20″—that appears to play a significant role in helping pollen survive heat stress, or remain viable during hot weather.

“This is the first time we’ve identified a specific genetic marker linked to pollen viability under heat stress in peanuts,” Rustgi said. “It’s a big step toward breeding heat-tolerant peanut varieties.”

The scientists also found that this genetic region contains key genes, including one that helps transport copper. Another key gene helps build ribosomes—tiny cellular machines that make proteins. Both genes are highly active in peanut flowers, suggesting they may help protect reproductive tissues from heat damage.

In addition to pollen viability, the team also looked at peanut seed quality, focusing on healthy fats like oleic acid. They identified several genetic markers linked to these traits, laying the groundwork for future studies on how heat affects peanut nutrition.

Peanuts are essential for the South Carolina economy. The USDA reports that in 2024, South Carolina farmers harvested 79,000 acres of peanuts for a production value of more than $75 million.

But warming temperatures are threatening this economic stronghold.

Information from the South Carolina State Climatology Office shows that since the mid-1970s, the state’s average temperatures have become warmer.

The warmest year on record for the state is 2017, with an average temperature of 65.1 degrees. Seven of the top 10 warmest years have occurred since 2010.

“This study gives us the tools to future-proof peanut crops,” Rustgi said. “By selecting for these genetic markers, we can help farmers grow resilient, high-yielding peanuts.”

In addition to Rustgi, other scientists involved in the study are Hrishikesh P. Ingole, Gautam Saripalli, Zachary T. Jones, Manikannan Parthiban, Johnson Toyinbo, Sruthi Narayanan and Reyazul Rouf Mir.

For information, read Genome-wide association analysis for pollen viability under heat stress in peanuts in the Plant Stress journal from ScienceDirect online.

Peanut planting in South Carolina begins in the spring, ideally in May, and extends through the summer. Harvest occurs in the fall.

Information from Eldred E. Prince, Jr. in the South Carolina Encyclopedia shows peanuts have been cultivated and consumed in South Carolina since colonial times. Today, the peanut industry contributes significantly to the state’s economy, generating substantial revenue.

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This research supported by grants from the USDA-NIFA Hatch/Multi-state Grants, National Peanut Board, S.C. Peanut Board – South Carolina Department of Agriculture, and the Clemson University Support for Early Exploration and Development.