Researchers identify a barley gene variant that delays flowering in long-day regions
An international team led by the Leibniz Institute of Plant Genetics and Crop Plant Research has identified a small but consequential mutation in the PPD‑H1 gene of barley (Hordeum vulgare) that delays flowering under long-day conditions. The discovery—centered on a single-nucleotide polymorphism called SNP22—could help plant breeders adapt barley to northern growing regions and improve yields as climates change.
Large-scale genomic survey and experimental confirmation
The researchers analyzed more than 2,000 samples of wild and domesticated barley, focusing on the genomic region around PPD‑H1. They searched for single-nucleotide polymorphisms (SNPs) that alter flowering time and tested candidate variants across multiple field sites and in controlled long- and short-day growth chambers to confirm effects on flowering behavior.
“Our data clearly show that this small but crucial genetic change in the PPD‑H1 gene triggers delayed flowering under long-day conditions. Earlier studies led to different assumptions, but we have now been able to correct them,” said Dr. Rajiv Sharma, the study’s first author.
Origin and historical context
The team traced the late-flowering trait to a single ancestral haplotype, H10, which they found in 16 wild-barley types, primarily from Israel. The researchers also examined a roughly 6,000-year-old barley specimen from the region and identified the earliest form of the PPD‑H1 variation as SNP22. Natural selection appears to have favored this variant as cultivated barley spread north into Europe, where longer summer days make delayed flowering advantageous.
Why this matters
Barley is one of the world’s major cereal crops—domesticated more than 10,000 years ago—and is used for animal feed, brewing (beer and whiskey), and food products, with global production exceeding 170 million tonnes annually. About 70% of produced barley goes to animal feed. Identifying genetic variation such as SNP22 gives breeders a precise target to fine-tune flowering time, helping crops complete their life cycle under different day-length regimes and potentially improving yield and climate resilience.
Broader food-security context
In 2024, an estimated 8.2% of the global population—roughly 673 million people—faced hunger. While conflicts contribute to shortages, more frequent extreme weather, higher temperatures, drought and unpredictable seasons driven by climate change are major drivers of food insecurity. Genetic discoveries like the PPD‑H1 SNP22 variant, together with other strategies (e.g., breeding for improved nutrient uptake and agrivoltaics that combine solar energy with farmland), can help strengthen food and energy security.
Looking ahead
Because the effect of SNP22 is specific to long-day conditions, breeders can use this knowledge to develop regionally adapted barley varieties—delaying or advancing flowering as appropriate to local day length and climate—rather than relying on broad, less predictable interventions. The study illustrates how combining ancient DNA, large genomic datasets and controlled experiments can reveal small genetic changes with outsized agricultural impact.
