How barley evolved to become Soctland's main crop

19th Nov 2012

How was barley, a plant native to the Middle East and South-Western Asia, able to grow all over the UK and become Scotland’s main arable crop? The answer lies in the combined forces of evolution and selection, according to an article published by a scientific team from the James Hutton Institute in the journal Nature Genetics.

In research that could have significant implications for the ability of breeders and farmers to respond to our changing climate and ensure food security, the Scottish researchers – along with colleagues in Germany and Italy – highlight the potential benefits of understanding the huge natural diversity that is found in collections of crop plants and their close relatives.

Wild barley comes originally from the region called the Near East Fertile Crescent (present-day Egypt, Israel, Syria, Jordan, Iraq and Iran). There, after a hot dry summer, barley seeds germinate with the first autumn rains, using the residual heat of summer and the newly available moisture to establish vegetative growth before winter sets in. The cold of winter then provides a signal within the plant that programmes it to grow, flower and set seed in early spring before the crippling heat of summer once again begins.

However, as barley was carried by ancient farmers and traders as they migrated west and then north into temperate climates, this ‘lifestyle’ became less ideal. Over time barley evolved into a crop that could be planted in the spring, allowing it to avoid the ravages of harsh northern European winters and benefit from the long cool days of summer, finally maturing in early autumn.

Using the latest genetic approaches, the international team identified highly characteristic ‘signatures’ on the barley genome that differentiate the ancestral ‘winter’ from the derived ‘spring’ lifestyle. Focussing specifically on one of these signatures they identified a highly specific genetic change that alters the function of a single gene in spring planted varieties. The change makes spring crops flower and set seed much later than their ancestors, allowing them to grow longer and convert more sunlight into harvestable yield.

Professor Robbie Waugh, leader of the research effort, commented: "Understanding the natural adaptations that have occurred in the genes and genomes of crop plants as they encountered new environments – and eventually flourished in them – is especially important as we face the uncertainty of climate change and the need to maintain crop yields.

"Knowing each of the genes responsible will help breeders tailor new varieties of barley, and possibly its close relative wheat, to emerging climate scenarios in the UK, but also to more marginal environments as cropping areas are forced to expand to tackle the challenge of food security."

Professor Waugh and the James Hutton Institute also led the UK effort in the international consortium of scientists responsible for a high resolution draft of the barley genome, which will help to produce new and better barley varieties that are vital for the food, beer and whisky industries.

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