- Author: Jeannette E. Warnert
As a Peace Corps volunteer in Niger in the early 1980s, Dahlberg was intrigued by sorghum, a staple food being cultivated by the country's vast population of subsistence farmers.
“I was impressed with the fact that sorghum was so drought tolerant,” Dahlberg said. “Nigerien farmers relied solely on rain for their sorghum and millet crops.”
Upon returning to the U.S., he earned a master's degree at the University of Arizona and a Ph.D. at Texas A&M, where his research focused on sorghum. He worked with the USDA Agricultural Research Service in Puerto Rico for 7 years and then spent the next 10 years as research director with the National Sorghum Producers in Lubbock, Texas.
When Dahlberg took the helm of the 330-acre UC agricultural research center in 2010, he and colleagues at the UC West Side Research and Extension Center and at UC Davis began conducting sorghum forage variety trials. Sorghum wasn't new to California. In the past, it had mainly been used for animal feed. But Dahlberg believed the crop's adaptability – excellent for forage, biofuels and gluten-free human food – offered the grain a rosy future in the Golden State.
"With our research, we have provided California farmers who are thinking about growing sorghum access to locally generated, research-based information to help them make the decision," Dahlberg said.
In 2015, Dahlberg and UC Berkeley specialist Peggy Lemaux launched a sweeping drought research project at KARE. The five-year study, funded with a $12.3 million grant from the Department of Energy, researched the genetics of drought tolerance in sorghum and how soil microbial communities interacted with sorghum roots to battle drought stress.
A journal article published in Proceedings of the National Academy of Sciences in 2018 presented the first detailed look at the role of drought in restructuring the root microbiome. The plant switches some genes on and some genes off when it detects water scarcity and access to water.
“That has implications for feeding the world, particularly considering the changing climate and weather patterns,” Dahlberg said.
In recent years, Dahlberg helped reestablish tea research at Kearney, initiated nearly 60 years ago in a study funded by Thomas J. Lipton, Inc. At the time, Lipton was seeking to grow tea for the instant tea market. When the Kearney tea research program was scrapped in 1981, a researcher had a handful of the best tea clones planted in the landscape around buildings at Kearney.
Those shrubs became the basis for a new tea research trial planted at Kearney in 2017 with UC Davis professor Jackie Gervay Hague to determine whether drought stress impacts the production of phenolics and tannins in the tea.
“We know we can grow good tea here and we can grow high tonnage,” Dahlberg said. “We want to determine if we can do that on a consistent basis and whether we can improve tea quality through irrigation management.”
In retirement, Dahlberg plans to relocate to Lake Ann, Mich., to be close to family. UC Cooperative Extension irrigation specialist Khaled Bali will serve as interim director of the UC Kearney Agricultural Research and Extension Center.
UC Agriculture and Natural Resources researchers are working in the San Joaquin Valley with UC Berkeley and Department of Energy (DOE) scientists to examine the role of epigenetics in plant survival under drought conditions, an increasing concern for agriculture as the effects of climate change are felt in California and globally.
The five-year study is funded with a $12.3 million grant from the DOE.
Epigenetics is the study of trait variations caused by environmental factors that switch genes on and off. At the UC Kearney Agricultural Research and Extension Center in Parlier and the UC West Side Research and Extension Center in Five Points, sorghum nurseries will be grown under drought and well-watered conditions to compare the environmental impacts on the plants' gene expression.
“We hope to tease out the genetics of drought tolerance in sorghum,” said Jeff Dahlberg, a sorghum expert who will manage the trials at Kearney. “Using sorghum as a model, we expect this research to help us understand drought tolerance in other crops as well.”
Dahlberg is the director of the UC Kearney Research and Extension Center. The director of the UC West Side Research and Extension, Bob Hutmacher, will manage the sorghum nursery at that facility. Funds from the DOE grant will allow Dahlberg and Hutmacher to hire two research associates and purchase new research equipment, including a new planter, a plot combine, a forage chopper and specialized tools for measuring data.
Peggy Lemaux, UC ANR Cooperative Extension plant biology specialist based at UC Berkeley, is the overall leader of the project, titled Epigenetic Control of Drought Response in Sorghum or EPICON. Other collaborators are Devin Coleman-Derr, Elizabeth Purdom and John Taylor from UC Berkeley; Chia-Lin Wei from the DOE Joint Genome Institute; and Christer Jansson from the DOE Pacific Northwest National Laboratory.
Over the next three years, a variety of observable plant traits will be followed, such as plant height and grain yield. In addition, leaf and root samples will be taken to investigate responses to drought at the molecular level, including how gene expression changes and which proteins and metabolites are altered.
Researchers will also be tracking changes in the sorghum-associated microbial communities in the soil to determine whether they correlate with changes that directly contribute to the crop's drought tolerance. It is now well known that associations of specific bacteria and fungi with plants and animals have positive effects on host fitness. For example, microbes in both plants and humans are known to help fight disease and, in the soil, can help deliver nutrients and other resources to plants.
EPICON efforts will generate a variety of large datasets, which will be shared via an open, online platform that will include methods and results.
"Availability of this data in an open forum will enable comparative genomic studies by other scientists," said Coleman-Derr, a UC Berkeley adjunct assistant professor in plant and microbial biology. "Being able to analyze the large datasets in an integrated fashion will enable a more thorough understanding of the complex and interconnected processes responsible for sorghum's ability to respond positively to drought."
The researchers expect that the project will allow better predictions of how sorghum and other cereal crops are affected by future climate scenarios, and will lead to approaches to improve growth and production of sorghum and other crops under water-limiting conditions in commercial fields and on marginal lands.
The Energy Department's Genomic Science Program is funding this project through its Office of Biological and Environmental Research.
Jeff Dahlberg, firstname.lastname@example.org, (559) 646-6060
Bob Hutmacher, email@example.com, (559) 884-2411, Ext. 206
Peggy Lemaux, firstname.lastname@example.org, (510) 642-1589