Heat stress caused by climate change is threatening to reduce peanut crop yields and burnout this source of income and food for millions of people worldwide.
But a group of researchers led by Clemson University Plant and Environmental Sciences assistant professor Sruthi Narayanan is working to develop heat-tolerant peanut varieties they hope will help maintain peanut production and profitability. Their latest venture focuses on how lipids (fats) in peanut plant anthers are altered by heat stress.
Clemson assistant professor Sruthi Narayanan and graduate student Zolian Zoong Lwe study how heat stress affects peanuts as they work to develop heat-tolerant peanut varieties.
“Understanding these changes will aid in understanding the mechanisms of heat tolerance and help us determine how to develop heat-tolerant peanut varieties,” Narayanan said.
Peanuts are grown on about 42 million acres worldwide. They require temperatures of at least 56 degrees, with 86 degrees the optimal growing temperature. Higher temperatures can hurt yields. The Earth’s average yearly temperature has increased 2 degrees since the pre-industrial era of 1880-1900. This extra heat is driving up regional and seasonal temperatures, reducing snow cover and sea ice, intensifying heavy rainfall and changing habitat ranges for plants and animals.
Lipids provide energy for plant growth and survival. Anthers are plant male reproductive organs that produce pollen, which is transported to the stigma of the female reproductive organ in the flower, pistil, for pollination to occur and plants to reproduce.
“Reduced pollen production and viability are the major reasons for loss of peanut yields when heat stress occurs during the flowering stage,” said Zolian Zoong Lwe, a former Clemson master’s student who conducted the study under Narayanan’s guidance and is now a doctoral student at Kansas State University. “Understanding the mechanisms underlying the decrease in peanut pollen performance during heat stress will help develop tolerant peanut varieties.”
This study, funded by the National Peanut Board and the South Carolina Peanut Board and supported by the United States Department of Agriculture National Institute of Food and Agriculture, began at Clemson in 2018. It involved six varieties – Bailey, Georgia 12Y, Phillips, Sugg, Tifguard and Wynne – and one breeding line, SPT06-07.
“These varieties were selected so that the study would have a range of sensitive and more heat and/or drought-tolerant cultivars,” said Dan Anco, one of the study’s researchers, as well as Clemson Extension peanut specialist and assistant professor housed at the Edisto Research and Education Center in Blackville.
Test varieties were grown in fields at the Simpson Research Farm, following field operation recommendations in the Clemson Peanut Money-Maker Production Guide. The plots received just rainwater, no irrigation. No pests nor pathogen problems were detected.
Heat tents were used to heat-stress the plants for 17 days in 2018 and 18 days in 2019. Lipids were extracted from anthers in flowers collected from the plots. Researchers found heat stress caused changes in lipids needed for the plants to reproduce. The study identified lipid metabolic traits associated with heat tolerance.
“This discovery is useful in determining lipid biomarkers (measurable/observable changes) that have important applications in breeding climate-resilient varieties,” said Sachin Rustgi, a plant breeder at the Clemson Pee Dee REC in Florence who also is part of the research team.
Other researchers involved in the study are Salman Naveed, a doctoral student at Clemson University, and Ruth Welti, a biology professor at Kansas State University.
A paper about their study appeared in the Scientific Reports journal’s Dec. 17, 2020, edition of Springer-Nature.
Clemson University contributed this article.