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Planet Wheat

Planet Wheat

1 July 2014

Every year farmers grow around $150 billion worth of wheat, providing 23% of the calories we live on. But some years it all goes wrong.

2010 was a bad year for wheat: a heat wave in Russia, cold weather in Canada, drought in China and heavy rain in Australia all brought down harvests in major production regions. As a result, 2011 was a bad year for wheat importing countries. Over $50 billion of wheat was imported that year at great cost. Out of the top nine wheat importers per capita, seven experienced volatile political protests resulting in civilian deaths.

The history-making revolutions of the Arab Spring weren’t caused by the price of bread alone. But recurrent food crisis does inevitably fuel political turmoil – not to mention very personal turmoil for millions of the poor.

Projections show that demand for wheat in the developing world will increase as much as 60% by 2050. There’s no guarantee that farmers will keep up; on the contrary, climate change will continue to hit harvests hard. Temperature increases could reduce production in the same developing countries, in the same years leading to 2050, by 20-30%.

With wheat already in climate crisis, a disease from the past has returned in a devastating new form code-named Ug99, spurring a global effort to protect harvests.

Stem rust is an ancient disease in wheat farming, but after the 1970s it was thought to be one problem that modern plant breeding had solved. Then in 1999 a new strain appeared in Uganda and began attacking formerly resistant varieties, wiping out entire fields. The so-called Ug99 was kept contained to the region for years, but eventually found its way through the Arabian Peninsula and as far as Iran, drifting on the wind towards the major wheat growing regions of South Asia and China.

As soon as Ug99 was discovered, the race began to find new sources of resistance and breed these into suitable varieties for the regions under attack. With international cooperation, the long process of developing new varieties has been accelerated to stay ahead of the threat. Breeders in Kenya, the first country to be badly hit by the disease, developed six Ug99-tolerant varieties in less than nine years. By 2013, Pakistani and American scientists were releasing locally adapted resistant varieties in Pakistan – even before the disease had crossed the border from Iran.

A study that year showed the importance of ongoing stem rust research, before and after Ug99’s arrival. Without investment in these efforts between 1961 and 2006, 1.3% of the world’s wheat harvest would have been sacrificed. The wheat saved every year is worth more than a billion dollars at current prices; in other terms, it’s enough food to satisfy almost the entire annual calorie deficit of sub-Saharan Africa’s undernourished poor.

Popular wheat varieties are planted uniformly over millions of hectares, courting genetic disaster. However, the genus of grasses we call wheat actually contains more than twenty species, hundreds of subspecies, and a bottomless toolbox of adaptations.

Species of the genus Triticum were domesticated at the dawn of agriculture in the Fertile Crescent. Today some species are still growing wild, while others are only found in farmers’ fields. The diversity of types – winter and spring wheat; hard, high-gluten wheat and soft, starchy wheat; wheat for noodles, bread or pastry – follows the diversity of human cultures and environments, from the north of Norway to the south of Argentina. This means that different farmers need different types of wheat, but there’s strength in that diversity.

In the case of stem rust, advances in genetic knowledge have revealed that our temporary victory in the 1970s was based on a single gene shared by almost all of the resistant varieties. It was only a matter of time before the fungus evolved a way around it. When Ug99 eventually did, 80% of the world’s wheat was at its mercy.

Kenya has led the way towards a more diverse defense. The early incursion of Ug99 into the country was used as an opportunity to set up a massive search for different sources of resistance to the strain. Each year, the researchers of the Kenya Agricultural Research Institute field test as many as 50,000 lines of wheat under high disease pressure. The candidates are sent by other research organizations and genebanks in more than 25 countries.

The threats to wheat from climate change and disease reveal just how interdependent all nations are when it comes to crop diversity. Genebanks conserve material from many countries, and make it available to breeders in many more. A strong variety is a citizen of the world with a rich family tree.

For instance, a typical modern wheat line called Veery remains popular for its tolerance to cold, heat and drought. Veery was born from a cross between a Russian winter wheat and a Mexican spring wheat in 1973, the progeny of which were further crossed with a variety from India. Each of these was also of mixed heritage. In fact, Veery was the final result of 3,170 crosses between 51 parents from 26 different countries. The International Maize and Wheat Improvement Centre (CIMMYT), which developed Veery, has since released the line in 35 countries.

CIMMYT stewards more than 110,000 accessions of wheat in its genebank in Mexico, representing about 14% of all collected diversity. The Crop Trust has pledged to support the collection in perpetuity so that CIMMYT can conserve this genetic wealth forever and make it available to all. The Crop Trust has also supported smaller collections in 15 countries, from Angola to Mongolia, helping national institutions to rescue material at risk and evaluate the wheat they hold. After all, any of these collections may hold the makings of the harvest of 2050.

Categories: Climate Change, Food Security

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