Heatwave Threatens Barley Yield, but Solutions Exist

The global rise in temperatures significantly reduces the production and quality of crops, and barley is no exception. This cereal, essential for animal feed and beer production, sees its development disrupted by excessive heat. Heatwaves cause damage to cell membranes, alter proteins, and increase the production of reactive oxygen species, which are harmful to cells. These disruptions hinder photosynthesis and plant reproduction, leading to significant yield losses.

To address this, physiological and molecular mechanisms are being studied. On the physiological side, optimizing the sowing date allows barley to avoid periods of intense heat during critical phases such as flowering and grain filling. Adapted irrigation and rigorous fertilizer management also help plants resist better by maintaining good hydration and nutrient levels. Inoculation with beneficial fungi and bacteria further strengthens barley’s tolerance by stimulating its growth and improving its defense system against stress.

Microorganisms, such as certain strains of Bacillus, produce plant hormones and fix nitrogen, which promotes better nutrient absorption. They also help neutralize reactive oxygen species, responsible for ionic imbalances in plants under thermal stress.

On the molecular level, significant progress has been made. Heat resistance genes, identified in model plants like Arabidopsis, have been introduced into barley. For example, the HvGST4 gene, derived from wild barley, has been overexpressed in Arabidopsis, improving its tolerance not only to heat but also to drought, salt, and cold. This gene stimulates the production of glutathione, a natural antioxidant that protects cells. Another gene, TaHsfA6b, from wheat, has been integrated into barley through genetic editing, enhancing its ability to withstand high temperatures without altering its normal characteristics.

Researchers have also identified genetic regions, called QTLs, linked to heat tolerance. Three of these regions have been associated with thermal stress resistance in 120 barley varieties, while ten others influence both resistance and grain quality. These discoveries enable the selection of more robust varieties through genomic selection techniques, which analyze DNA to predict plant performance.

Genetic editing using CRISPR, a precise DNA modification method, also offers promising prospects. It allows targeting specific genes to improve barley’s resistance without introducing undesirable mutations. The modified varieties produce more heat shock proteins, which protect cells under stress.

Finally, agricultural practices such as thermal priming, which involves briefly exposing young seedlings to moderate heat, prepare barley to better withstand higher temperatures later on. This technique activates defense mechanisms, such as the production of antioxidant enzymes and protective proteins, which limit cellular damage.

These advancements, combined with optimal crop management, could help maintain or even improve barley production despite climate warming. Current losses, which can reach up to 50% in some regions during heatwaves, could thus be reduced, ensuring a stable supply for the industries that depend on it.

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Cited Publication

DOI: https://doi.org/10.1007/s44372-026-00718-6

Title: Evaluation of molecular and physiological mechanisms underpinning heat stress tolerance in barley (Hordeum vulgare L.): an approach towards heat resilient barley production

Journal: Discover Plants

Publisher: Springer Science and Business Media LLC

Authors: Ali Hasnain; Muhammad Naveed Anjum; Zahid Mehmood; Adeel Mustafa; Muhammad Umer Farooq Awan