We need to nearly double the amount of food we grow by mid-century if 9 billion people are going to have enough to eat. Yet most of the world’s prime farmland is already planted. The rest of the available land tends to lie under forests, or suffer from problems that keep it fallow. But feeding the world will mean redefining what is “arable” land.
Earlier this year, researchers in Australia successfully pushed out that definition a bit further. By crossing an ancestor of ancient wheat with today’s commercial wheat, they have bred a strain that thrives in saline soils, expanding where the grain can be grown. Wheat is already the world’s most widely planted cereal grain, covering about 17% of all cultivated land, and supplying more calories and protein in the world’s diet than any other.
Yet wheat struggles in soils with high concentration of salts. And too-salty soil now covers an area roughly equivalent to that of the U.S., about 3.8 million square miles, mostly in the arid–semiarid regions of Asia, Australia, and South America, but they are spreading. As we pump billions of tons of irrigated water onto the land, and deplete groundwater reserves that pull seawater into underground aquifers, the situation is worsening in many of the same areas where we need to grow more food in the future: arid regions with low rainfall.
Researchers from CSIRO Plant Industry (part of Australia’s national science agency) and other institutions set out to create a variety of durham wheat, the kind used in pasta and couscous, that could thrive in these soils. The scientists pulled off the trick by introducing a gene from one of wheat’s wild cousins to draw out sodium molecules from water moving up the plant’s water system, known as xylem, before reaching the leaves. The new crossbreed yields 25% more grain from saline soils than conventional varieties, according to a study published in Nature Biotechnology. These new miracle wheat plants can carry on photosynthesizing in salty soils despite sodium molecules that would otherwise interfere. In non-saline soils, no drop in yields was observed, so they can be planted everywhere.
Next up will be breeding the gene into other varieties of wheat. One day, amber waves of grain may grow where few other plants dare to put down roots.