Heat and drought caused by recent climate change threaten the world’s production of wheat, but scientists are looking back 300 years for a solution.
Geneticists at the Natural History Museum in London are poring over 12,000 samples of ancient wheat brought back by explorers centuries ago and preserved in cardboard files stacked in the museum vaults. Like botanical art, the plant samples are pressed onto paper in delicate patterns of leaves, stems and heads of grain. Each is labeled with the date and place of collection. At least one example carries a famous name. It’s a wild wheat plant collected by Captain James Cook on his first exploration of Australia.
Place is important. Scientists are looking for wheat that grew naturally in hot, dry climates. They hope to isolate those genes that make for hardy plants and splice them into other wheat to develop heat-and drought-resistant varieties that will thrive in a changing climate. Average temperatures are expected to rise by 2.7 degrees Fahrenheit by the year 2050. It’s estimated that a two-degree increase in temperature means a 6.4 percent reduction in wheat production.
Wheat crops are already being impacted. Close to 15 percent of wheat-producing areas experience drought attributed to global warming that has already occurred.
Scientists are also looking at the old seeds in order to learn how ancient wheat thrived before the introduction of modern agriculture methods such as fertilization. Most modern fertilizers are derivatives of fossil fuels. Finding a strain of wheat that grows well with less fertilizer would make it easier and cheaper to produce, cut the use of fossil fuels, and help reduce heat-trapping carbon dioxide pollution.
More than three billion people around the world depend on wheat as a primary food. It’s familiar as an ingredient in bread, pasta, and cereal. It’s also cooked by itself, in whole or cracked form, as an important part of the diet in most countries. Reduction of this vital crop could result in widespread food shortages and even famine. What’s more, dependence on wheat is expected to grow as the world population increases in the coming decades.
Climate change is a major threat to wheat supply, but it’s not the only one. War in Ukraine, an important producer of wheat, has cut off exports to nations that depend on it. Disease also wreaks havoc. A fungus called yellow rust is affecting wheat everywhere it is grown. It appears as yellow stripes on young plants, and it can cut yields from 5 percent up to 30 percent. Wind spreads the fungus, so once an infection takes hold, it quickly becomes a problem throughout an entire agricultural region.
Scientists at the John Innes Centre in Norwich, UK, are searching their archives of ancient seeds in order to develop disease-resistant wheat. Their collection dates back 100 years, and its seeds are maintained at a cool temperature of about 40 degrees Fahrenheit. That means the seeds are viable. They can be put into soil and grown, not only studied for their genetic makeup. Because of the scientists’ research, breeders have successfully cross-bred these ancient grains with modern varieties to make wheat that can stand up to yellow rust.
Growing more wheat is one answer to crop depletion, but it’s not the only one. Growing highly nutritious wheat can also be part of the solution. To that end, scientists are looking to develop strains that are more nutrient-dense than current varieties. That would give consumers more food value per grain of wheat.
Most crop improvement plans dating back to the 1950’s and 1960’s focused on growing bigger harvests. Wheat with large heads of grain that grew prolifically was considered most desirable. In the process, some of the hardier and more nutrient-dense types were abandoned. Diversity was reduced. Enormous tracts of land planted with a single variety are more vulnerable to mass kill-offs by pests, disease and extreme weather. With greater diversity, there’s a better chance that a percentage of the crop will survive a natural disaster.
Scientists hope that by exploring ancient seeds they will help breeders discover wheat that can grow in harsh climates, fend off disease, and continue to feed the world.