The push is on, globally, to breed heat and drought tolerance into modern wheat cultivars.
PHOTO: Brad Collis
Delegates at a meeting of the Heat and Drought Wheat Improvement Consortium have agreed on a breeding strategy for protecting staple food crops from environmental shocks
Wheat pre-breeders globally are working to develop a collaborative international strategy to ensure wheat’s tolerance to environmental stresses can keep pace with extreme weather events that are becoming more frequent.
More than 100 plant scientists from 22 wheat-growing countries in both the global south and north, met in December 2014 in Frankfurt, Germany, to discuss research strategies. This followed the establishment of the Heat and Drought Wheat Improvement Consortium (HeDWIC).
HeDWIC is a 15-to-20-year partnership established by the Consultative Group on International Agriculture’s (CGIAR) Research Program on Wheat (CRP WHEAT), which is facilitated by the International Maize and Wheat Improvement Center (CIMMYT).
A group at the HeDWIC meeting discuss how changing wheat canopy characteristics could improve yields under hot and dry conditions. (From left) Dr Sigrid Heuer (Australia), Dr Michael Baum (International Center for Agricultural Research in the Dry Areas, Jordan), Dr Hafeez ur Rehman (Pakistan), Dr Hamlyn Jones (Scotland) and Dr Richard Richards (Australia).
The push coincides with modelling by the Intergovernmental Panel on Climate Change that is now showing global mean
temperatures rising by 2°C to 5°C by 2050. This is expected to be accompanied byincreasingly unpredictable rainfall (amount and distribution) and more extreme weather events.
Already, heat and drought are major causes of wheat yield losses around the world, even in once-reliable, temperate grain-growing countries such as France.
Discussion at the HeDWIC meeting focused on an international plan to incorporate the most advanced genetic technologies into traditional plant breeding to improve wheat’s heat and drought tolerance.
Dr Matthew Reynolds, the CIMMYT Distinguished Scientist who co-organised the three-day HeDWIC meeting, says that wheat’s wild ancestral relatives are set to play a key role in fortifying the world’s food supply as the planet warms.
“The wild ancestors look like wild grass,” he says. “Scientists are putting new effort into phenotyping [measuring physical plant traits] for abiotic stress, with plans to look at how quality proteins respond to heat stress so we can deliver end-use quality as well as stress-adapted material. The main challenge is to determine which traits to screen in a wild plant that will help improve a modern crop plant.”
He adds that the task will create an additional challenge for breeders because an ever-larger number of traits need to be accumulated into a single genetic background. “This is where molecular markers will help, especially when we have access to the wheat genome sequence – which is imminent,” Dr Reynolds says.
Australian HeDWIC participants
- Dr Bronwyn Barkla, Southern Cross Plant Science, Southern Cross University, NSW
- Dr Scott Chapman, CSIRO, Queensland
- Dr Karine Chenu, University of Queensland, Queensland
- Dr Nick Collins, Australian Centre for Plant Functional Genomics and the University of Adelaide, SA
- Dr Feike Dijkstra, University of Sydney, NSW
- Dr Fernanda Dreccer, CSIRO, Queensland
- Professor John Hamill, Deakin University, Victoria
- Dr Sigrid Heuer, Australian Centre for Plant Functional Genomics, SA
- Professor Peter Langridge, University of Adelaide, SA
- Dr Francis Ogbonnaya, GRDC, ACT
- Dr Jairo Palta, CSIRO Agriculture Flagship, WA
- Dr John Passioura, GRDC and CSIRO, ACT
- Dr Richard Richards, CSIRO Agriculture Flagship, ACT
- Professor Peter Sharp, University of Sydney, NSW
- Dr Nicolas Taylor, University of Western Australia, WA
- Dr Michelle Watt, CSIRO Agriculture Flagship, ACT
“A new generation of plant screening and molecular technologies can speed up our capacity to transfer stress-tolerance traits into new wheat varieties. Wild relatives of wheat that evolved in hot and dry places will provide the crucial genes we need for crop improvement.”
He expects the resulting wheat germplasm to look similar to modern high-yield varieties, except it will not collapse under heat and will find water deep in the ground during drought.
These characteristics are highly desirable in Australia, which sent 16 participants to the meeting – one of the most represented countries – says CIMMYT’s Dr Petr Kosina.
“Australia had representatives from the GRDC, CSIRO and several universities. All Australian participants were actively involved in discussions. CSIRO’s water use efficiency experts, Dr John Passioura, Dr Richard Richards and Dr Michelle Watt, passionately drove several discussions.”
Also present was the GRDC’s Dr Francis Ogbonnaya, senior manager for crop genetics and coordinator of the ‘Improving crop yield’ theme.
“The timing of the HeDWIC meeting coincides with the GRDC’s development of its own R&D strategy to tackle the impact of heat on Australian growers,” Dr Ogbonnaya says.
He is one of two Australian members of HeDWIC’s provisional Technical Advisory Committee, along with Professor Peter Langridge from the University of Adelaide.
The sense of urgency behind the creation of HeDWIC is not only due to concern for growers, but also the fact that wheat provides about 20 per cent of calories consumed worldwide and is an important source of protein, especially in poor countries.
“People living in some of the world’s most vulnerable areas could see entire seasonal food supplies wiped out with increasing frequency if we don’t quickly boost wheat’s resilience to heatwaves and more extreme periods of drought,” Dr Reynolds says.
Dr Hans Braun, director of CIMMYT’s Global Wheat Program, says the meeting was a good example of the private and public sectors coming together to solve a global problem: “We’ve laid the foundations for research that will help farmers and many of the world’s most marginalised people living in some of the most difficult environmental conditions,” he says. “From here, we’ll produce a comprehensive road map.”
Partnerships forged by heat and drought
Present at the meeting of the international Heat and Drought Wheat Improvement Consortium (HeDWIC) were Australia’s water use efficiency researchers from the CSIRO Agriculture Flagship – Dr Richard Richards, Dr Michelle Watt and Dr John Passioura.
Here, in their own words, they describe the road ahead for HeDWIC
Protecting crop yields from drought and high temperature is not new to Australian growers. For grain growers there is an incessant effort to reduce the impact on yield and quality of both dry and hot periods or seasons. Changes are made to agronomy, such as sowing date or tactical nitrogen application, or to the choice of variety to better suit regions and systems.
PHOTO: Brad Collis
The purpose of the Heat and Drought Wheat Improvement Consortium (HeDWIC) is to mount a coordinated global effort to increase wheat yields in climates prone to dry and/or hot conditions. The principal focus of HeDWIC is to improve the livelihoods of resource-poor growers using state-of-the-art pre-breeding and the development of elite germplasm.
Australian researchers have an opportunity to be involved with the international scientific community in drought and heat-tolerance research. This should benefit Australian growers by introducing new ideas, novel germplasm and techniques previously untested in Australia.
Australia could play a significant role in HeDWIC. Australian researchers have been world leaders in identifying opportunities to improve crop yields in our hot, dry climate.
A recent example is the team led by Dr John Kirkegaard and Dr James Hunt from CSIRO and Stuart Kearns from the GRDC, which showed that a 10 to 20 per cent average improvement in water use efficiency is achievable with different agronomy and appropriate varieties.
Australia can also draw on proven leadership in developing national research priorities in pre-breeding and it has a record of coordination across research agencies. This has resulted in significant advances in pre-breeding. Advanced genomic and phenotyping methods used by breeders in Australia have improved yield performance of varieties in dry and hot environments.
Improving the grain yield of our major crops under the ever-present spectre of limited and unpredictable rainfall and unpredictable hot spells is like finding a cure for cancer. There is no single universal solution.
In addition, success also requires coordinated activities. Management practices are required to store as much pre-season rainfall in the soil as possible and ensure that sowing times are as early as possible to avoid frost damage and subsequent dry weather and high temperatures.
Improved varieties are next. Favourable plant traits that protect from heat and drought are hard to breed. There are no miracles and few simple traits. Even so, some traits appear to be advantageous, such as waxiness and some canopy traits. The most important traits are complex and hard to improve through breeding. A good example is a deeper root system to extract more water and to keep the crop growing for longer. This also keeps the crop cooler.
There is reliable data from Australian farms showing that root systems that are an extra 10 centimetres in length could achieve a much higher yield. CSIRO has been developing faster and more effective methods to measure root systems in the field. In the past, it was only possible to examine a few varieties in a day; now we can measure roots in up to 250 different soil cores per day down to two metres.
HeDWIC will complement these Australian efforts as it addresses delivery of the best products to growers, particularly in the form of new varieties. This is also a critical issue in Australia, where public research agencies and growers, through the GRDC, invest significant funds in drought and heat-related research. Growers often do not see the benefits of this research for several decades or even longer.
Finding better ways to build effective bridges between researchers, breeders and agronomists for faster delivery to growers will be a major objective of HeDWIC.
Dr Francis Ogbonnaya, GRDC senior manager for crop genetics
Julie Mollins is a communications officer with the CIMMYT in Mexico.
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