Like humans, plants experience stress. One of those stresses is temperature changes. And, to continue having food security in a changing climate, scientists are working to make more heat resilient crops.
Wheat is a staple crop to 35% of the world population. It’s a temperate crop, meaning it is sensitive to increasing temperatures. Wheat is particularly sensitive during the growth stages when it produces flowers and seeds (which are also grains). This is usually a fairly short period of time, but every 1°C rise in temperature above optimum can cause up to a 4-6% decrease in the yield! An even larger decrease in yield happens when the crop experience heat and drought at the same time – up to 9-10%. Thus, developing climate resilient wheat is critical for food security.
Another aspect of developing climate resilient wheat is that more than 80% of our food is grown by “smallholder farmers.” These are farmers, usually in developing countries, who farm five acres or less. They are particularly vulnerable to yield losses. This makes the search even more important.
Here are a few areas of research in wheat resilience:
Identifying germplasm that is most resilient to climate – Scientists around the world are screening hundreds of wheat lines to identify lines better suited to climate change. They are looking at both the phenotype and the genotypes. DNA markers can help researchers identify genes potentially involved in climate tolerance. Scientists study wheat genetics, but they also look to other crops. Corn, rice and sorghum tend to have more heat resilience. Breeders can then apply some of this knowledge to wheat. Some labs are using high-throughput phenotyping and genotyping tools to identify better prediction models used in breeding for developing climate resilient varieties.
Breeding more photosynthetically efficient wheat – Plants vary in their photosynthesis efficiency. That means that some crops are able to use the sun to process carbon dioxide from the air to create necessary sugars at higher rates than other crops! Wheat is a photosynthetically less efficient crop (1%) compared to maize (4%) and sugarcane (8%). Thus, even a slight increase in the efficiency (0.5%) would substantially increase the wheat yield around the globe. Some scientists are looking at the genes that regulate how well wheat pulls in the carbon dioxide from the atmosphere. Others are looking at the enzymes in the plants that help with converting carbon dioxide to sugars. These enzymes are sensitive to temperature changes. Some are also looking for ways to increase biomass, spike photosynthesis and grain size.
Looking to the roots – Roots not only hold plants in place, they are the major way plants get water and nutrients. Developing wheat breeds with longer root systems may help the crop be more drought (and heat) tolerant.
Using gene editing tools – New technologies like CRISPR/Cas9 genome editing techniques can edit genes affecting yield like grain weight or grain size to increase wheat yield. The new gene editing technology creates mutants* that can be used in breeding programs to develop high-yielding wheat varieties.
Employing new technologies to collect information – Scanning large fields of wheat to identify areas that are undergoing stress – or thriving – can be difficult on foot. Tools like drones and satellite images can help researchers collect information faster. Drones are able to determine plant height, moisture content, and temperature. They can even collect other data important to the scientific process. By using them, researchers can generate precise information by screening large populations. This same data collection would take a human workforce longer. In some cases, human data collection might be impossible due to terrain and other factors.
Just like the human genome sequence project, the wheat genome sequence was recently released by International Wheat Genome Sequence Consortium. This will help researchers to look for genes and their regulatory pathways. Now, researchers have roadmap of wheat genes. This information is critical for rapidly developing varieties with better tolerance, yield, diseases and more!
Scientists around the world are well aware of the effect of climate change on wheat yield. They are incorporating ground breaking tools and techniques to develop climate resilient wheat. They are collaborating either by global public-private partnership or at a national level. A few international initiatives/consortiums working globally with a goal to increase wheat yield by developing geographically adapted new wheat varieties includes:
- International Wheat Yield Partnership (IWYP)
- Feed the Future, US Agency for International Development (USAID)
- Delivering Genetic Gain in Wheat
- International Maize and Wheat Improvement Center (CIMMYT)
Research is an ongoing process. The varieties breeders develop in the lab and greenhouse must then be tested in the field. Then, field trials need to go further, to make sure that the wheat grain is acceptable in attributes like flavor, cooking and baking ability, and its ability to be stored. Creating new varieties is a long-term process – one that began many decades ago, and will continue into the future. This will help us to continue to have a nutritious, safe food supply for the world’s growing population.
Answered by Amita Mohan, Washington State University
*Gene editing and genetic modification are techniques to change the genetic make-up of an organism. Gene editing products are not necessarily designated as GMO.
About us: This blog is sponsored and written by members of the American Society of Agronomy and Crop Science Society of America. Our members are researchers and trained, certified, professionals in the areas of growing our world’s food supply while protecting our environment. We work at universities, government research facilities, and private businesses across the United States and the world.