Scientists discovers which cereals our ancestors cultivated

After mapping the genome of wheat, scientists have reconstructed its breeding history. They examined the genetic diversity of wheat varieties and discovered which cereals our ancestors cultivated, where today's wheat comes from, and what the Cold War has to do with it all. The study 'WHEALBI' was published in the journal Nature Genetics.

As the population grows and climate change progresses, food resources could become scarce in future. In view of the impending scenarios, plant breeders are faced with the challenge of improving the yield of crop plants. Scientists analysed the genomes of 480 wheat varieties, including wild grasses, ancient grains and modern high-performance types. To learn about the evolution and cultivation of today's bread wheat, the geneticists also linked the development of wheat to geographic and geopolitical events in human history.

Modern bread wheat originated around 10,000 years ago in the region of modern-day Turkey from a cross between durum wheat and a wild grass (Aegilops tauschii), while the grain we call spelt stems from cultivated emmer and various types of bread wheat. "The occurrence of cultivated plants is closely linked to human migrations over the millennia," said bioinformatician Michael Seidel, along with Daniel Lang one of the lead authors of the study. Both researchers work in the Plant Genome and Systems Biology group (PGSB).

The PGSB team identified three gene pools in the bread-wheat varieties used today that are closely linked to historical events: one from high-yielding varieties domesticated in the near east that spread as part of the green revolution and two separate gene pools from Western and Central Europe. They diverged between 1966 and 1985 as a result of geopolitical and socio-economic separation during the Cold War. With the fall of the Iron Curtain in 1989, the wheat lines gradually admixed again, as their genomes reveal.

Even the emergence and expansion of the European Union can be seen in the genome of today's wheat. Wheat lines that used to be cultivated mainly in Central Europe are now used throughout Europe. "These examples demonstrate the influence of humans on the distribution and evolution of crop plants- beyond their actual development into cultivated plants," said Lang.

Knowledge of the genetic diversity of wheat is a prerequisite for optimising modern wheat varieties. Familiarity with the key characteristics for breeding is the essential precondition for rendering future varieties more productive and meeting the demands of a growing world population and imminent climate change. Together with corn and rice, wheat ranks as one of the world's three most important staple foods. Growing wheat in spite of dwindling soil and water resources in potentially challenging climatic conditions could become vital in the future.

Consequently, the researchers involved in the WHEALBI study identified previously unknown genes that influence the yield, flowering time, height and stability of wheat plants. For the corresponding author Georg Haberer of the PGSB, this is just the beginning: "We expect a large number of further studies that will make good use of these findings for breeding research."

(With inputs from agencies.)