Scientists have unlocked key components of the genetic code of a type of wheat plant, which they claim represents a major breakthrough in breeding wheat varieties that are more productive and better able to cope with disease, drought and other stresses that cause crop losses.

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Wheat is the world's most widely grown grain. The first analysis of the "complex and exceptionally large" bread wheat genome, was published on Thursday (29th November) in Nature. The scientists behind the research, an international coalition including teams from the Universities of Liverpool and Bristol as well as Norwich’s John Innes Centre, said the identification of around 96,000 wheat genes, and insights into the links between them, will enable them to improve wheat varieties, "accelerating wheat improvement through advanced molecular breeding and genetic engineering."

The breakthrough was made after two years of study. Researchers in the UK first generated the wheat gene sequence in 2010. Teams from the UK, Germany and the United States sifted through vast amounts of DNA sequence data, translating it into something that scientists and plant breeders can use effectively.

Although the researchers have promoted their breakthrough as a leap forward in efforts to achieve global food security, they freely acknowledge the genome mapping will be useful in creating controversial genetically modified crops. However, they said "All of their data and analyses were freely available to users world-wide."

Professor Neil Hall of the University of Liverpool said on Thursday (29th November), "The raw data of the wheat genome is like having tens of billions of scrabble letters; you know which letters are present, and their quantities, but they need to be assembled on the board in the right sequence before you can spell out their order into genes."

Klaus Mayer, also from Liverpool, added, "Bread wheat is a complex hybrid, composed of the complete genomes of three closely related grasses. This makes it very complex and large; in total it is almost five times bigger than the human genome."

"Because of this, we took a novel approach to analysing the data, and we have been successful in turning it into accessible and useful resources that will accelerate breeding and the discovery of varieties with improved performance - for example better disease resistance and stress tolerance."

Wheat yield genome and climate change

Since 1980, the rate of increase of wheat yields has declined. Yields are expected to stagnate or even decline as climate change continues to take effect. Although government and industry maintain production must increase through 'sustainable intensification;' increasing yields while reducing inputs, policy makers including the UN Food and Agriculture Organisation have said greater environmental and social justice is needed in order to create sustainable food systems able to resist the ravages of climate change.

This includes preserving local varieties of crops which are well adapted to their region and provide a wide range of genetic variation. Furthermore, EU environment watchdog the European Environment Agency has advocated greening food production as a priority, arguing that, of the four categories of natural resources humans rely on to survive, current methods of food production are fragile and "may well be the most vulnerable [to the effects of climate change]." The 'social vs technological' debate continues.  

Nevertheless, the scientists behind the wheat genome sequencing project said that, thanks to their efforts, breeders and researchers are now able to select plants with desirable combinations of genes using the genetic landmarks in the wheat genome, making breeding programmes more reliable and allowing for deliberate choices of wheat varieties that exhibit specific traits.

The researchers said, "Bread wheat provides over a fifth of the calories that we eat. As the global population and the demand for wheat rises, major efforts are underway to improve productivity by producing varieties that can withstand adverse weather and disease, and that provide greater yields. However, until now the very large size and complexity of the genome have been significant barriers to crop improvement."

The research was part-funded by the BBSRC, whose chief executive Professor Douglas Kell commented, "In the face of this year's wheat crop losses, and worries over the impact on prices for consumers, this breakthrough in our understanding of the bread wheat genome could not have come at a better time. This modern strategy is a key component to supporting food security and gives breeders the tools to produce more robust varieties with higher yields."

"The complexity of the wheat genome means that there is still more to learn and international efforts to complete a full sequence are vital to further maximise the potential of new wheat varieties."

Professor Hall of the University of Liverpool, explained that a complete, "polished" version of the genome may still be several years from completion, as more decoding work is needed.

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