Climate change continues to impact crop yields worldwide, ramping up scientific efforts at making them heat resilient. While methods like altering gene expressions are promising, they are not easy to implement at the scale needed “to keep the world fed,” according to a review by US-based researchers.

Long timelines, extensive field trials, cost, and regulatory complexity are some of the substantial barriers to scaling innovations across global agriculture addressed in the study.

“The threat of an increasingly hotter world, driven by greenhouse gas emissions, presents significant challenges to society,” Carl Bernacchi, author and professor at the University of Illinois Urbana-Champaign, US, tells Food Ingredients First.

“Safeguarding agriculture, including food, feed, biofuels, and a wide range of other bioproducts, requires coordinated effort across the plant sciences.”

He explains that gaining insight into how crops interact with rising temperatures is a crucial step toward ensuring agricultural productivity now and into the future.

The review, published in Science, explores the current scientific understanding and innovations centered around enhancing crop resilience to rising global temperatures by modifying photosynthesis and plant traits.

Photosynthesis, the process by which plants make food, is impacted by temperature. All crops suffer declines in photosynthetic rate when temperatures cross critical thresholds, with “irreversible losses typically occurring above 40° to 45°C.”

Overcoming “blanket resistance” to crop innovation

Experiments and field trials have shown that altering crop canopy leaf orientation through plant breeding or bioengineering can “optimize light distribution” over the entire plant and minimize the scorching of leaves in high temperatures.

Increasing the reflectivity of plant leaves or regulating water loss through pores in plant leaves without reducing productivity can also help increase crop resilience to heat stress.

However, engineered crops like GMOs struggle to find social acceptance, Bernacchi notes.

“Many people are rightly concerned about how their food is produced. However, a blanket resistance to safe biotechnologies may slow progress in crop improvement and hinder efforts to safely meet growing global demands.”

“It’s also important to note that non-genetically modified options remain viable and should continue to be pursued. A major hurdle, however, lies in the ability to scale data collection to match the vast natural genetic variation present in many crops.”

He adds that the team is working to address this by developing high-throughput techniques to bridge the data gap.

Time and cost constraints

Timing is critical to overcoming the heat-related challenges of climate change. Projected temperature increases between 2010 and 2050 are expected “to depress yields of the major grains by 6%-16%, against a backdro of a potential >50% increase in demand over this period,” the authors report.

“The timeline from identifying a beneficial trait to getting it in a farmer’s field is long,” says co-author Donald Ort. The breeding cycle for a conventional trait can be ten to 12 years.

Additionally, lengthy regulatory frameworks and the high cost of taking a bioengineered trait to market also present challenges, says Stephen Long, who co-authored the review with Ort and Bernacchi.

“There are various estimates out there, but the one you hear most often is that for a single transgenic trait, it costs about US$115 million to get it deregulated and takes more than 16 years to go from invention to seed systems,” he adds.

Bernacchi says enhancing photosynthesis can help tackle this challenge by boosting productivity, but it is “only one of several tools available to help secure our food supply.”

“I also believe improved alignment of agricultural practices is a valuable strategy for enhancing food security. By this, I mean promoting greater diversity in wher we grow food and what kinds of crops we cultivate.”

Advancing farmer-industry collaboration

Bernacchi observes an increasing collaboration between academia and the food production industry, which can advance crop resilience. This includes joint funding programs, proposal co-development, and direct research partnerships. 

“On a practical level, more farmers are opening their fields to researchers, enabling studies that assess how real-world agricultural systems respond to environmental stress, with an emphasis on physiology, growth, and yields.”

When asked about the potential of resilient crop traits to stabilize prices and supply chain continuity, he points to supply variability as a key factor driving price instability. “Since grain crops are globally traded commodities, both spatial and temporal fluctuations can disrupt markets.”

“Enhancing crop resilience could play a critical role in reducing such variability, thereby contributing to greater price stability and supply chain continuity,” he concludes.