MEFs pave way for drought rankings

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The MEF program has been established to enable wheat breeders to assess the economic value of selecting for specific water productivity traits across a range of environments.

Photo of irrigation system

Central to the benchmarking and other Managed Environment Facilities (MEF) research is the irrigation system StressMaster (details below), which has been established at the MEF sites to control soil water relations and create the different environments under which the cereal lines are being assessed.

PHOTO: CSIRO

A sophisticated benchmarking program now in place across the three Managed Environment Facility (MEF) sites will soon be delivering regular drought-tolerance ratings for a wide range of cereal germplasm, commercial varieties and advanced breeding lines.

The benchmarking system is the result of several years of preliminary research to develop consistent protocols to identify and assess water productivity traits in cereals and to establish the managed environments in which they can be evaluated.

The ultimate aim of the benchmarking program is to have all National Variety Trials (NVT) material assessed through the MEF sites for its capacity to yield under a range of environments.

The program is assessing about 140 wheat varieties, including widely grown commercial varieties and pre-release breeding lines of main season wheats from the NVT.

In addition to the MEF sites, 20 NVT sites are also sampled for benchmarking data to better evaluate the potential value of water productivity traits in different target environments.

Without accurate benchmarking it is not possible to determine the yield value of a specific water productivity trait or to accurately compare cereal varieties and breeding lines for their drought tolerance.

Consolidating drought research

Photo of Celia Du Plessis (DAFWA) demonstrating the rapid assessment of early vigour at Merredin MEF trialsPhoto of Celia Du Plessis (DAFWA) demonstrating the rapid assessment of early vigour at Merredin MEF trials

Department of Agriculture and Food, WA, research officer Celia Du Plessis demonstrates the capacity of the ‘Mike-mobile’ to carry out rapid assessment of early vigour on the hundreds of plots in the Merredin MEF benchmarking trials.

PHOTOS: Grant Stainer, DAFWA, Merredin

Past drought research in Australia has traditionally been very fragmented, with many research groups working in isolation on a range of traits and crops and under different drought conditions.

A major benefit of the MEFs is the bringing together of different pre-breeding organisations to collaborate with breeding companies in consistent environments and using the same protocols and check lines.

In this way, the benchmarking system should result in more rapid uptake by plant breeders of the very best pre-breeding research and, ultimately, speed up the delivery of new drought-tolerant varieties to growers because the commercial value of specific traits for different production regions will be better understood and quantified.

Simulating drought

Using irrigation, a range of production environments has been generated across the three MEF sites. The environments are typical of those experienced across western and southern Australia and represent a wide range of yield potential from less than 0.5 tonnes per hectare to about 8t/ha (Figure 1).

FIGURE 1 MEF predicted yields by environment, 2010-13.

Graphic showing MEF predicted yields by environment 2010–2013

As would be expected, the impact of variety on grain yield is less in low-yielding environments than in higher-yielding environments. However, there is still significant variation in water productivity traits among the germplasm within any one season, as indicated by the spread in yield at each of the three sites listed in Figure 1.

Within-season variety performance at the Yanco and Merredin MEF sites has been more similar than at Narrabri.

Phenotyping tools

In 2013, significant progress was made in the assessment of water-soluble carbohydrates under drought conditions as MEF researchers could screen large numbers of breeding lines for this trait. In addition, a low-cost system has been developed for the rapid and cost-effective estimation of early vigour via an automated GreenSeeker® and digital photo system attached to an electric tricycle (see photos above).

Nicknamed the ‘Mike-mobile’ (after technical officer Mike Baker from the Department of Agriculture and Food, Western Australia), the electric tricycle has front and rear powered electric hubs to ensure a consistent ground speed of about five kilometres per hour. A Trimble FmX® display enables RTK-corrected mapping of the GreenSeeker® (normalised difference vegetation index) values and triggering and geo-referencing of the digital SLR for ground cover photos.

Automation of data capture enables the operator to concentrate on driving (autosteer options are being investigated) while checking data quality on the display. The system has enabled early vigour data to be collected much more rapidly: what used to take one person four days now takes, with the right weather conditions, just one day.

Preliminary analysis of the Merredin 2011–13 data indicates varieties with high early vigour yielded 10 to 14 per cent more than varieties with low vigour.

Further analysis across the full set of sites and seasons is being carried out (2014) for a range of water productivity traits including water-soluble carbohydrates, transpiration efficiency and water use efficiency.

StressMaster

Central to the benchmarking and other Managed Environment Facility (MEF) research is the irrigation system StressMaster (developed under GRDC-supported project UQ00064), which has been established at the MEF sites to control soil water relations and create different environments under which the cereal lines are assessed.

StressMaster is a decision-support tool that ensures irrigation schedules match the desired drought type based on the current modelled soil water and anticipated probability of further rainfall. Previous research characterised the major drought patterns across each of the GRDC growing regions. Four drought patterns or environment types were identified ranging from almost no stress to severe and lasting stress between flowering and maturity. It is these typical drought patterns that the MEF researchers are targeting at each site.

More information:

Dr Karine Chenu
karine.chenu@uq.edu.au

GRDC Research Code UQ00064

More information:

Dr Ben Biddulph, DAFWA
08 9368 3333
ben.biddulph@agric.wa.gov.au

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Early vigour avoids drought stress

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GRDC Project Code DAW00215, UQ00064

Region West