Drought resistant crops for the future

Dr Cate Williams: IBERS, Aberystwyth University.

- Dr Cate Williams

Climate change is a defining issue that has far-reaching consequences for all life on planet earth. One result of climate change is the occurrence of extreme weather (heatwaves, drought and flooding) and changes in temperature and precipitation patterns. As a result, the frequency and severity of drought, heatwaves, and flooding are predicted to increase and pose a direct threat to food security across the globe. There are two approaches to addressing climate change: adaptation (coping with the effects of climate change) and mitigation (reducing the factors contributing to climate change).

Within the agricultural industry, a variety of interventions are being explored to cope with the effects of climate change and to also mitigate future contributions. Selective breeding of crops, and indeed animals, is an essential part of the adaptive response. Resistance to drought (and associated conditions such as heatwaves) and flooding are the most common climate-related traits for which crop varieties are bred, with the view to coping in extreme weather and improving global food security.

Mechanisms of drought resistance In general, plants have a wide range of adaptive mechanisms to cope with drought conditions, with different species and cultivars displaying different responses. Many different drought tolerance and avoidance strategies come together to give a drought-resistant plant.

Drought avoidance strategies aim to minimise the effects of drought mostly through reducing water loss, for example, changing the number of stomata and/or the size of these openings. Stomata are microscopic pores mainly found on leaves that allow for gas exchange, reducing the number or closing them can also reduce the chance of water loss. Other traits include increasing levels of cuticle wax, rolling of leaves to reduce the overall surface area or changing leaf orientation, all of which work to prevent water loss.