Century-Old Experiment Ensures Future of Beer and Whiskey

Researchers have identified the genes responsible for barley's adaptability, a key ingredient in beer and whiskey. This discovery stems from an experiment initiated before the Great Depression, offering hope for barley's survival amid climate change challenges.

Barley flourishes globally, from Asia and Egypt to Norway and the Andes. It is a vital cereal crop with a history spanning at least 12,000 years. As it spread, random DNA changes enabled barley to survive diverse environments.

To ensure that barley varieties thrive in regions facing rising temperatures and extreme weather, identifying these genetic changes is essential.

Dan Koenig, a geneticist at UC Riverside, explained the significance of breeding locally adapted crops. "A century ago, breeders launched an experiment in Davis, California, collecting barley varieties worldwide to identify those suited to local conditions," he stated.

Early scientists lacked the technology to pinpoint barley’s successful genes, but contemporary methods allow researchers to analyze millions of genetic changes.

A recent study in Science highlights numerous genes affecting barley's adaptability. Koenig emphasized that some genes regulate barley's reproductive timing for optimal breeding.

"Flowering too early or late affects seed production," Koenig remarked. "To maximize seed yield, flowering must occur during a narrow timeframe."

In California’s climate, barley must finish flowering before the dry season to secure enough water for seed production. If flowering occurs too early, plants may face frost exposure. The researchers discovered how genetics ensure flowering occurs within this ideal timeframe, with certain genes promoting early flowering and others curtailing late flowering.

The gene identification process proved challenging. Koenig noted, "Understanding genetic adaptations can take decades since only one generation of barley is grown per year."

Access to the Barley Composite Cross II experiment — a research initiative started in 1929 — has been beneficial. This ongoing experiment aims to discover new barley varieties for the California region.

Breeders tested thousands of genetically distinct barley types over decades in Davis. Over time, the barley best adapted to California's hot, dry climate dominated the fields.

Koenig’s team utilized seeds from this experiment as a "time machine" to directly observe adaptation processes and identify the essential survival genes.

During 58 growing seasons, the number of genetically distinct plants reduced from 15,000 to a single lineage making up 60% of the population, evolving without human selection.

"The extent of change within such a brief evolutionary timeline shocked us," Koenig recalled. "Natural selection profoundly reshaped genetic diversity across the genome in one human lifespan."

The research team aims to conduct further studies using long-term environmental data to investigate how flowering timing might differ based on climatic variations.

Additionally, they are intrigued by the marked yield increases observed during the Davis experiment. As plants adapted to Northern California, their yields nearly doubled, though remaining below the potential heights achieved through manual selection by breeders.

Koenig explained, "Yield may conflict with traits like rapid growth or height." Growers seek plants that are environmentally cooperative, yet beneficial traits may hinder environmental adaptation.

Insight into barley's genetic resilience can inform strategies for other cereals such as wheat, rice, and corn, which share genetic similarities.

With advancements in genome engineering and CRISPR technology, researchers could engineer crops to flower at optimal times.

"Barley’s adaptation has significantly contributed to civilization development. Understanding barley is crucial, not only for alcohol production but for advancing crop adaptability in a changing world," Koenig concluded.

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