Kansas State University scientists, in collaboration with the International Wheat Genome Sequencing Consortium, have finally nailed down a detailed description of the complete genome of bread wheat, the world’s most widely-cultivated crop.
This work will pave the way for the production of varieties better adapted to climate challenges, with higher yields, enhanced nutritional quality, and improved sustainability. The article is titled “Shifting the limits in wheat research and breeding using a fully annotated reference genome.”
The research article — authored by more than 200 scientists from 73 research institutions in 20 countries — presents the reference genome of the bread wheat variety Chinese Spring. The DNA sequence ordered along the 21 chromosomes is the highest-quality genome sequence produced to date for wheat. It is the result of 13 years of collaborative international research and the support of the National Science Foundation, Kansas farmers, and many others.
“It is a dream come true for Kansas wheat farmers, who were the first to invest in the wheat genome sequencing project and were pivotal in rallying U.S. wheat farmers in support of the wheat genome sequencing project,” said Bikram Gill, distinguished professor emeritus of plant pathology at Kansas State University who organized the first National Science Foundation and U.S. Department of Agriculture-sponsored workshop planning meeting on wheat genome sequencing in Washington, D.C., in 2003.
A key crop for food security, wheat is the staple food of more than a third of the global human population and accounts for almost 20 percent of the total calories and protein consumed by humans worldwide, more than any other single food source. It also serves as an important source of vitamins and minerals.
Kansas farmers grow an average of 340 million bushels of wheat each year, but acres planted to wheat have dropped dramatically over the past decade, from 10 million acres to fewer than 8 million. To meet future demands of a projected world population of 9.6 billion by 2050, wheat productivity needs to increase by 1.6 percent each year. To preserve biodiversity, water and nutrient resources, the majority of this increase has to be achieved via crop and trait improvement on land currently cultivated, rather than committing new land to cultivation. In order for farmers to dedicate these precious resources to wheat production rather than production of other crops, wheat farming must become profitable.
With the reference genome sequence now completed, breeders have at their fingertips new tools to address global challenges. They will be able to more rapidly identify genes and regulatory elements underlying complex agronomic traits such as yield, grain quality, resistance to fungal diseases and tolerance to physical stress — and produce hardier varieties.
“Completion of the sequence is a landmark event that will serve as a critical foundation for future wheat improvement,” said Allan Fritz, Kansas State University professor of agronomy and wheat breeder. “It is the key to allowing efficient, real-time integration of relevant genetics, making the selection process more efficient — it’s a turbocharger for wheat breeding.”
It is expected that the availability of a high-quality reference genome sequence will boost wheat improvement over the next decades, with benefits similar to those observed with maize and rice after their reference sequences were produced.
“Kansas wheat farmers have been supporting the wheat genome sequencing efforts through the Kansas Wheat Commission’s wheat assessment since the establishment of the International Wheat Genome Sequencing Consortium in 2005, with a cumulative amount of nearly a quarter of a million dollars,” said Justin Gilpin, chief executive officer for Kansas Wheat. “The sequence of the bread wheat genome has already had a positive effect on wheat improvement, which not only affects the science behind wheat breeding, but has a long-lasting positive outcome in regard to wheat producer productivity, profitability and, ultimately, livelihoods.”
Sequencing the bread wheat genome was long considered an impossible task because of its enormous size — five times larger than the human genome — and complexity — bread wheat has three sub-genomes and more than 85 percent of the genome is composed of repeated elements.
“It is exciting to be a part of this landmark achievement,” said Jesse Poland, associate professor at Kansas State University and director of the Wheat Genetics Resource Center and the U.S. Agency for International Development Innovation Lab for Applied Wheat Genomics. “This international effort, toward something that was once deemed impossible, will have tremendous impact on wheat in Kansas, and the world.”