Every year, billions of dollars’ worth of crops worldwide perish due to pre-harvest sprouting (PHS), a phenomenon in which grain or seeds germinate on the plant before harvest. The process is triggered by a variety of factors, such as warm, moist weather, which can spoil the crop and threaten the global food supply. But this could be a thing of the past, as a team of researchers, primarily from the Carlsberg Research Laboratory in Denmark, has uncovered the genetic mechanism that controls when barley should sprout.
Self-inflicted problem
PHS is entirely a problem of our own making. When early farmers domesticated barley, they wanted a crop that would sprout soon after planting. So, they selected strains with less natural seed dormancy, a pause that stops seeds from sprouting until conditions are just right. While this allows farmers to plant quickly after harvest, sometimes yielding two crops, it comes with a considerable downside.
If perfect weather conditions hit before harvest, the entire crop starts to sprout early on the stalk. This is a problem because even if you could pick it early, the grain is often too wet for storage or has already started the biochemical changes that ruin its quality for food or brewing.
To better understand the causes of PHS, scientists focused on MKK3, a gene known to play a role in controlling dormancy in barley and other cereals. They analyzed the DNA of more than 1,000 barley types from farms and seed banks worldwide.
They also cultivated barley varieties in fields over several seasons, subjecting half to conditions that would cause PHS. This allowed them to compare affected grain against normal grain. Back in the lab, researchers studied gene expression and measured protein activity to see how MKK3 genes directly influenced dormancy.
Genetic insights
The key findings, according to their study published in the journal Science, are that dormancy is controlled by multiple versions of MKK3, not one. Wild barley has one copy, while domesticated varieties have several. What this means is that the more MKK3 genes a barley plant has, the stronger the signal to sprout and shorter seed dormancy.
The study also examined how MKK3 variants spread in response to the climate and the needs of ancient farmers. Some were hyperactive and were chosen by farmers in Northern Europe for their superior malting quality. Others were less active (high dormancy) and favored by farmers in wet climates, such as East Asia. This meant that crops could survive monsoons without sprouting early.
With these deep genetic insights, the study authors hope that today’s farmers can cultivate the perfect barley variety for any region. “Our work shows that understanding the genetic complexity of dormancy can help breeders develop barley that is both productive and resilient to climate change.”
Written for you by our author Paul Arnold, edited by Gaby Clark, —this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive.
If this reporting matters to you,
please consider a donation (especially monthly).
You’ll get an ad-free account as a thank-you.
More information:
Morten E. Jørgensen et al, Postdomestication selection of MKK3 shaped seed dormancy and end-use traits in barley, Science (2025). DOI: 10.1126/science.adx2022
© 2025 Science X Network
The content is provided for information purposes only.