Heat stress reduces yields of all grain crops and is one of the major abiotic stresses that limit grain yields worldwide. As such, meeting increased global demand for grain is tightly linked to making breakthrough gains in crop resilience to this stress.
Heat stress causes an average of 13 to 15 per cent yield reduction in wheat and barley in Australia. With average temperatures expected to rise between 0.99°C and 2.2°C by 2050, greater reductions in yield – of between six to seven per cent – are predicted for every 1°C increase in average temperature. In wheat alone, yield losses due to heat stress are estimated to cause an average economic loss of $655 million.
Extended periods of high temperature stress and short periods of heat shock (greater than 30°C) during flowering and seed filling are also a significant constraint for canola, with an estimated annual economic loss of more than $400 million.
GRDC has long maintained an extensive investment portfolio looking to improve the heat tolerance of grain crops. Inbuilt into these investments is a three-pronged strategy.
First, GRDC works with researchers, breeders, agronomists and growers to better understand how heat affects crop yields and how this stress interacts with other critical processes, such as water and nitrogen availability.
Second, the knowledge gained is translated into paddock-relevant innovations. These have primarily taken two forms:
- agronomic innovation, including heat-avoiding practices (such as early sowing); and
- genetic-based improvements in phenology, canopy and root architecture, and in heat tolerance traits that aim to complement the new agronomy.
Third, GRDC has fostered improvements in the foundational technologies needed to make previously unachievable gains possible into the future. This includes investments in field trial capabilities, phenomics, genomics, data analytics and modelling (including AI and machine-learning techniques).
Previous investment in building capabilities in each of these three areas – knowledge acquisition, translation and foundational technologies – has led to entirely new opportunities to improve the heat tolerance of grain crops. The 2024 September–October issue of GroundCover™ Supplement ‘High yields in a hot climate’ is dedicated to providing a snapshot of the current phase of innovation.
In the September-October GroundCover™ Supplement article AI fast-tracking wheat heat tolerance gains, Richard Trethowan reports on gains made in stabilising wheat yields under heat stress during grain filling by drawing on genomic prediction technology. This requires the consolidation of several foundational technologies and many decades’ worth of data and insights into heat tolerance mechanisms.
The September-October GroundCover™ Supplement also highlights how insights in one crop help to drive gains across all crops, including barley (Gains in barley heat tolerance prove possible), canola (Canola heat tolerance genetics discovered) and chickpeas (Yield advantages with new chickpea heat tolerance traits and A new framework for chickpea heat tolerance).
The September-October GroundCover™ Supplement also explores the work of researchers who are discovering novel wheat heat tolerance traits and selection tools for use by breeders. Australian wheat breeding companies are actively engaged in these projects to ensure outputs can be rapidly adopted.
Finally, Modelling to help manage temperature stress highlights developments made in analytics and modelling, including predictive models that would support growers to make better-informed crop choices and time-of-sowing decisions.
Overall, the September-October GroundCover™ Supplement highlights that innovative heat-tolerant germplasm, DNA markers, high-throughput screening tools and prediction methods are under development for deployment by breeders. The goal? To rapidly develop novel varieties with significantly greater heat tolerance and a reduction in losses due to reduced yield and quality premiums.
Written by Prameela Vanambathinan in her role as GRDC genetic technologies officer.
More information: Allison Pearson, allison.pearson@grdc.com.au