Australia leads global effort to break wheat yield ceiling

Key points

  • Researchers from six Australian institutions are part of multinational projects selected in the first round of the International Wheat Yield Partnership (IWYP)
  • By pooling the world’s best science and research efforts, IWYP’s long-range, calculated gamble is to lift wheat yield potential by up to 50 per cent over 20 years
  • With 100 per cent direct backing through the GRDC, researchers are capitalising on Australia’s coordinated national R&D model to help secure the future of wheat production and boost world food supply 

A world response to slowing wheat yield improvement is now underway in earnest and Australian researchers are leading the multinational R&D projects being rolled out

Optimising canopy architecture and photosynthesis rates, such as the experiment pictured here at the Australian Plant Phenomics Facility, will be among the research proposals for breaking through the wheat yield ceiling.

PHOTO: Brad Collis

Eight multinational projects are gearing up around the globe in the first round of a ‘blue sky’ attempt by the International Wheat Yield Partnership (IWYP) to find a way to break through the wheat yield ceiling, which many regard as having reached a crisis point.

Wheat yield advances have effectively stopped, with critical implications for global food security given the twin pressures of wheat providing 20 per cent of all calories consumed by people worldwide and the inexorably increasing human population.

Five of the projects involve Australian researchers from the Australian National University, the University of Sydney, the University of Melbourne, the University of Adelaide, the University of Western Australia, and CSIRO (Table 1).

IWYP is the result of a commitment of G20 Agricultural Ministers in 2011 in response to the stark and growing disequilibrium between demand for wheat from a growing global population and stagnating rates of yield increases, including as a result of environmental and disease stresses.

The IWYP initiative explicitly seeks to lift wheat’s yield potential by up to 50 per cent over 20 years.

In October 2015, IWYP announced the eight projects selected in the first competitive call, which involved a rigorous international peer-review process.

GRDC chair Richard Clark says it is exciting that Australian researchers and the GRDC have a major role in the IWYP initiative.

“Given the calibre of grains R&D in Australia it is no surprise that three of the eight first-round projects selected are being led by Australian researchers, with an additional two projects drawing heavily on Australian input,” Mr Clark says.

“We congratulate the research teams involved from the Australian National University the universities of Sydney, Melbourne, Adelaide and Western Australia, and CSIRO.

“IWYP is recognition that we could only ever hope to achieve the impact we need for step-change in wheat yield by coordinating worldwide research.

“And while it’s a calculated, long-range gamble that even global R&D might not lead to the necessary step-change breakthroughs to lift yields, at least by working collaboratively at the international level we can offset the risks of such blue-sky R&D.”

Globally, wheat is the most important staple crop, and with population growth and changing diets, demand is expected to increase by 60 per cent by 2050. To meet this demand, annual wheat yield increases must grow from the current level of less than 1 per cent to at least 1.7 per cent.

The first round of research activity focuses on issues that are likely to be of strong interest to Australian grain growers. These include optimising plant architecture, modifying flowering time and optimising harvest index (the amount of grain as a percentage of the whole plant).

“The success of Australia’s research proposals demonstrates the strength of our national pre-breeding research base, its standing in the international science and, in particular, wheat-research community, and its relevance to the real-world issues facing grain growers,” Mr Clark says. 

The GRDC is contributing more than $10 million over three years to fund the Australian streams of the IWYP projects.

“The GRDC has an important role in representing Australia’s R&D community through this global-level engagement and advocating our immense R&D capacity to help tackle the key constraint facing the wheat industry.

“As one of IWYP’s investment partners, we look forward to deepening the relationship,” Mr Clark says.

 

Table 1 Australian leadership roles.

Australian-led projects

Title Project lead
Principal partner
Improving wheat yield by optimising energy use efficiency Barry Pogson, Australian National University
  • University of Western Australia
  • University of Adelaide
  • CIMMYT
Increasing carbon capture by optimising canopy resource distribution Richard Trethowan, University of Sydney
  • University of California, Davis (US)
  • Agharker Research Institute (India)
Three high-value genes for higher wheat yield (AVP1, PST01, NAS) Stuart  Roy, University of Adelaide
  • University of Melbourne
  • Arizona State University (US)
  • CIMMYT
  • University of California, Riverside (US)

Significant Australian input

Title Project lead Principal partners
Using next-generation genetic approaches to exploit phenotypic variation in photosynthetic efficiency to increase wheat yield Anthony Hall, University of Liverpool (UK)

A CIMMYT diversity toolkit to maximise harvest index by controlling the duration of developmental phases Simon Griffiths, John Innes Center (UK)

Additional projects

 Title Project lead
 Principal partners
Realising increased photosynthetic efficiency to increase wheat yields Christina Raines, University of Essex (UK)
  • Lancaster University (UK)
  • University of Illinois (US)
  • Rothamsted Research (UK)
Molecular dissecition of spike yield components in wheat Cristobal Uauy, John Innes Centre (UK)
  • University of California, Davis (US)
  • CIMMYT
Wider and faster: high-throughput phenotypic exploration of novel genetic variation for breeding high biomass and yield in wheat Erik Murchie, University of Nottingham (UK)

Rigorous selection process

Dr Jeff Gwyn, IWYP program director, says its first competitive call for research proposals was announced in January 2015, with the successful project proposals selected by an international expert peer review for scientific excellence.

“It is important to note that the goals and criteria that the IWYP associates with this initiative are purposely very demanding,” says Dr Gwyn, who is coordinating and guiding the multinational research initiatives.

“The IWYP mission is that wherever these breakthroughs are found, we will seek to integrate and build them into elite, commercially relevant germplasm, in liaison with the International Maize and Wheat Improvement Center (CIMMYT) or other public and private-sector breeding programs, as rapidly as possible,” he says

The call invited international applications to specifically address how genetic yield potential in wheat can be enhanced. The successful proposals address several pivotal topics, including:

  • finding and employing traits and genes to increase photosynthesis;
  • genes to boost spike development;
  • reducing respiration and thereby enhancing photosynthetic efficiency;
  • optimising canopy architecture to increase carbon capture and conserve nitrogen;
  • using selected genes to increase biomass and yield; and
  • optimising phenology (the timing of plant development, such as flowering) leading to increased harvest index.

From IWYP’s inception in 2011 to the rollout of the first phase of research activities in 2015, Australian researchers – many well known to Ground Cover readers – have played important leadership roles. These continue with the first round of projects selected for funding. 

NORTH

Efficient nutrient distribution

Dr Richard Trethowan: photosynthesis could increase by up to 20 per cent

PHOTO: Dr Gio Braidotti

Lead: Professor Richard Trethowan

Organisation: Plant Breeding Institute, University of Sydney

Private industry partners: Australian Grain Technologies, Mahyco, Maharashtra Hybrid Seeds Company, Krishidhan Seeds Private Limited

The project: Photosynthesis does not occur uniformly across the canopy of wheat plants and regions of suboptimal photosynthesis rates in the canopy mean an uneven distribution of resources, such as nitrogen.

Professor Richard Trethowan says a vast body of literature – overlooked in crop pre-breeding – shows that whole-canopy photosynthesis is substantially reduced in the upper-canopy leaves, due to limited photosynthetic nitrogen, while lower-canopy leaves receive too much.

“Redistribution of this capacity could increase canopy carbon uptake and nitrogen use efficiency by nearly 20 per cent without affecting the total supply of nitrogen available for grain filling,” he says.

This project will apply a novel and rapid phenotypic screening method to identify variation in the efficiency at which canopy resources are distributed. The new methods will be applied to 310 genetically diverse wheat lines. Included are cultivars developed from wild wheat, and wheat relatives and ancestors, along with all parental materials and recently released cultivars.

The lines with the most contrasting resource-distribution behaviours will provide a window into the key traits that control canopy physiology and structure, as well as the genetic markers that are associated with those traits.

The goal is a better-balanced photosynthetic capacity (or the maximum rate at which leaves fix carbon during photosynthesis) in the upper and lower canopy. However, it is known that additional nitrogen investment in photosynthesis earns diminishing returns, resulting in a smaller increase in carbon gain than the previous addition.

Getting the balance right will depend on a measurable criterion called the PC/DI ratio in which the photosynthetic capacity (PC) is proportional to leaf-level daily irradiance (DI).

“Modelling has demonstrated that if photosynthetic capacity was distributed optimally across the canopy, photosynthesis could increase by up to 20 per cent,” Professor Trethowan says.

“The resulting knowledge, germplasm and tools will be delivered to project partners in the breeding industry in Australia and India, the International Maize and Wheat Improvement Center and to the International Wheat Yield Partnership.”

Principal investigators

  • Dr Thomas N Buckley - IA Watson Grains Research Centre,
    University of Sydney
  • Dr Helen Bramley - IA Watson Grains Research Centre,
    University of Sydney
  • Assistant Professor Matthew Gilbert - University of California – Davis (US)
  • Dr Andrew Merchant - Centre for Carbon, Water and Food, University of Sydney
  • Dr David Fuentes - Centre for Carbon, Water and Food, University of Sydney
  • Professor Peter Sharp - Plant Breeding Institute, University of Sydney
  • Dr Satish Misra - Agharkar Research Institute (India)
  • Dr B K Honrao - Agharkar Research Institute (India)
  • A M Chavan - Agharkar Research Institute (India)

More information:
Professor Richard Trethowan,
richard.trethowan@sydney.edu.au

SOUTH

High-value genes

Dr Stuart Roy

PHOTO: GRDC

Lead: Dr Stuart Roy

Organisation: Australian Centre for Plant Functional Genomics, University of Adelaide

The project: Using information already obtained from transgenic experiments, this project seeks to generate non-GM wheat that exploits three genes (Table 2) implicated in physiological processes that can improve wheat yields. The genes, originally characterised in Arabidopsis and rice, have been expressed in wheat lines. They have distinct effects but studies indicate that synergistic effects between them could help raise wheat yields. When over-expressed individually, the genes were found to increase nutrient uptake by enhancing root growth (PSTOL1), increase plant biomass production (AVP1) and increase grain yield (NAS2) in transgenic plants grown under optimal conditions.

Analysis of the wheat genome has identified wheat counterparts of these genes (called wheat orthologs) that form the basis of this project.

“Research will analyse naturally occurring variation of these three genes within wheat populations,” says project leader Dr Stuart Roy. “The aim is to identify the best gene variants to cross into elite wheat cultivars in order to push up yields.”

Concurrently, the existing transgenic wheat lines will be used in experiments to determine the optimal combination of the three genes. That information will then guide development of conventional, non-GM wheat lines that exploit yield-lifting gene combinations.

“The combination of improved sugar metabolism and remobilisation mediated by AVP1 with enhanced root growth conferred by PSTOL1 and enhanced tillering due to NAS2 expression has the potential to result in a highly productive wheat plant with significant increases in grain yield under optimal growing conditions,” Dr Roy says.

The transgenic work could guide the development of markers to produce non-GM wheat lines with enhanced yield.

“Individually, the over-expression of either AVP1, NAS2 or PSTOL1 has shown the potential to improve the yield of wheat,” Dr

Roy says. “The pyramiding of these genes together provides a unique opportunity to explore their synergistic positive effects for a significant step-change in wheat yield.”


Principal investigators

  • Associate Professor Sigrid Heuer - Australian Centre for Plant Functional Genomics, School of Agriculture, Food and Wine, University of Adelaide
  • Dr Alex Johnson - School of BioSciences, University of Melbourne
  • Associate Professor Roberto Gaxiola - School of Life Sciences, Arizona State University (US)
  • Dr Ravi Valluru - CIMMYT (Mexico)
  • Professor Julia Bailey-Serres - Center for Plant Cell Biology, Botany and Plant Sciences, University of California, Riverside (US)
Gene/function  Original source
Table 2 Genes being exploited for yield.
AVP1: Vacuolar pryophospatase 1
 Arabidopsis
Function  Over-expression increases shoot and biomass, photosynthetic capacity, yield and nutrient use efficiency under normal and stressed conditions.
PSTOL1: Phosphorus starvation tolerance 1  Rice
Function  This gene is found primarily in rainfed and drought-tolerant rice. Multiple copies of a similar gene are present in sorghum. When over-expressed in rice it confers enhanced root growth.
NAS2: Nicotianamine synthas
Rice
Function  Required to absorb iron-containing materials from the rhizosphere and in transporting and remobilising metal cations such as zinc, nickel, manganese and copper within plant tissues. Over-expression in rice and wheat lead to grain with increased concentrations of iron and zinc. Increased tiller number and yield (20-30 per cent) were also observed.

More information:
Dr Stuart Roy,
stuart.roy@acpfg.com.au

WEST

Energy use efficiency

Lead:

Professor Barry Pogson: a small gain in energy redistribution can impact positively on biomass accumulation and yield.

PHOTO: Plant Energy Biology

Professor Barry Pogson

Organisation: Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, Australian National University

Private industry partners: Photon Systems Instruments (Czech Republic), Astec Global Consultancy (the Netherlands)

The project: More than 85 to 90 per cent of energy captured by plants is used in what Professor Barry Pogson labels ‘futile cycles’ and high-cost cellular processes, such as transport of nutrients and respiration.

“Only 10 to 15 per cent is allocated to yield,” he says. “That means any small gain in energy redistribution can impact positively on biomass accumulation and yield. So our International Wheat Yield Partnership (IWYP) project proposal relates to a trait we call energy use efficiency (EUE).”

When 138 Australian commercial cultivars were previously screened, untapped genetic variation in EUE was discovered that Professor Pogson believes is amenable to fine-tuning, with concomitant positive knock-on effects on yield.

Improvements in EUE can be achieved at the cell, tissue and whole-plant levels. However, the leeway to improve yields in this project arises from naturally occurring variation in the efficiency of energy production and energy use, and also from differences in the efficiency with which respiratory products are used to synthesise new biomass or maintain existing tissues. These translate into measurable traits such as:

  • rates of leaf respiratory carbon dioxide release per unit growth
  • optimised levels of sugars, organic and amino acids for growth
  • increased biomass at flowering

“We have found a two-fold variation in leaf respiration, an associated threefold variation in EUE, and a significant heritability (about 35 per cent) in our recent preliminary survey of a subset of the International Maize and Wheat Improvement Center (CIMMYT) wheat panel and other Australian cultivars,” Professor Pogson says.

This project will screen and identify lines and markers that facilitate breeding high-yielding germplasm based on EUE outliers.

“With just 10 to 15 per cent of carbon captured by photosynthesis being partitioned into yield, even under ideal conditions, it is imperative to look beyond improvements in photosynthesis and also increase the efficiency with which photo-assimilates are incorporated into biomass and yield,” Professor Pogson says.

Investment in this new and emerging area of research is substantial, with the $2 million IWYP grant being leveraged to draw in an additional $3.3 million co-investment from the associated research institutes and their industry partners, as well as $910,200 from the GRDC.

Principal investigators

  • Professor Owen Atkin - ARC Centre of Excellence in Plant Energy Biology, Australian National University
  • Professor Justin Borevitz - ARC Centre of Excellence in Plant Energy Biology, Australian National University
  • Professor Robert Furbank - ARC Centre of Excellence for Translational Photosynthesis, Australian National University
  • Professor Harvey Millar - ARC Centre of Excellence for Translational Photosynthesis, University of Western Australia
  • Dr Matthew Reynolds - CIMMYT (Mexico)
  • Associate Professor Matthew Gilliham - ARC Centre of Excellence in Plant Energy Biology, University of Adelaide
  • Associate Professor Nicolas Taylor - ARC Centre of Excellence in Plant Energy Biology, University of Western Australia

More information:
Professor Barry Pogson,
barry.pogson@anu.edu.au 

More information

Ground Cover TV – International Wheat Yield Partner

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GRDC Project Code IWYP25FP, IWPY39FP, IWYP60FP, IWYP64FP, IWYP89FP

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