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June 10, 2004
Source: CSIRO Newsletter Issue 6 Winter 2004
Outsmarting wheat disease
In an
effort to combat the devastating fusarium fungus, wheats with
improved resistance have been identified using a new rapid
screening technique.
Fusarium
fungus causes both Crown Rot, which costs the Australian wheat
industry $50 million in lost yields every year, and Head Blight,
which seriously affects grain quality in northern Australia.
CSIRO's new rapid screening
method has been used to test over 150 wheat lines and varieties
and is progressively testing new lines from Australia, Mexico,
Japan, Korea, India, Pakistan and China.
To test the wheat, seedlings are grown in tiny pots for ten days
then administered a dose of fusarium.
Over the following month measurements are taken to record the
amount of damage caused by the fusarium and the rate of
infection.
This is much quicker than conventional field-based screening
methods which require the wheat to be grown over a full season
of up to eight months.
One of the most promising candidates so far is a wheat line from
Japan which demonstrated excellent fusarium resistance.
This and other lines will be tested in the field to confirm
their resistance.
'Enemy intelligence' is also being gathered about the different
fusarium strains. When coupled with the identification of
resistant wheats, this will help breed the most effective
fusarium resistant wheat varieties in the future.
INFORMATION
SHEET
Tailoring wheat to northern Australia
Wheat is one
of the most important plant commodities produced in northern
Australia. CSIRO Plant Industry
is working in this region to understand the factors that affect
wheat production in this region and develop better wheat
varieties.
Around 20 per cent of the nation's
wheat is grown in the northern region from central Ner South
Wales north into Queensland. Wheat production differs in this
region from the wheat belts in southern and western Australia
because, moving northward, rain falls increasingly in summer,
rather than winter.
Growers in the northern region aim to
produce prime hard wheat, the highest quality wheat that
attracts a premium price, but they also produce other grades.
Drought and diseases are the two most important constraints of
wheat in northern Australia.
Improving wheat yields
under drought
Wheat grown in northern Australia,
and particularly in Queensland, is often dependent on water
stored in the soil from summer rains. To varying degrees every
year this results in the wheat suffering from stress due to lack
of available water, reducing yield and profit for the farmer.
 Two
CSIRO bred wheat varieties, 'Drysdale' and 'Rees', are
particularly suited to these warmer dryland conditions. They use
water more efficiently than other varieties because of how they
exchange water for carbon dioxide to photosynthesise and grow.
CSIRO Plant Industry is identifying the genes in wheat
responsible for this specific ability to use water more
efficiently.
Using a broad range of wheat
varieties sourced from all over the world CSIRO Plant Industry
is identifying other plant features useful for improving wheat
yield under drought conditions in northern Australia. Plant
attributes for both conventional and newer farming systems, like
wider rows, are being examined.
From here CSIRO Plant Industry will
identify the genes responsible for these features and 'molecular
markers' that flag their location. This means that the desirable
features can be selected far more easily, making classical
breeding quicker and more effective.
Overcoming fusarium
diseases of wheat
'Crown Rot' and 'Head Blight' caused
by the fungus fusarium are among the most important diseases
that plague Australian wheat farmers. Crown Rot is a chronic
problem across Australia costing $50 million in lost yield each
year. Head Blight is a particular problem in the north that can
seriously affect grain quality for animal and human consumption.
 At
least 17 different species of fusarium cause Head Blight
worldwide and several of these can cause Crown Rot, but only two
are prominent in Australia. By studying the characteristics of
these two species and the most virulent individuals within the
species, CSIRO Plant Industry will be able to gather 'enemy
intelligence' to develop a better picture of the nature of
fusarium in Australia. This will assist in developing control
strategies.
The other important step in tackling
fusarium is to search for resistant wheats and their resistance
genes that prevent a fusarium infection or reduce its negative
effect on yield and quality. CSIRO Plant Industry has developed
a high throughput system that can readily screen hundreds of
wheat plants for their ability to resist fusarium. Once
resistant wheats have been found the search will begin for their
resistance genes. Promising genes can then be used to help breed
new fusarium resistant wheat varieties.
Wheat research
highlights
A new wheat for dry times
Source:
Innovate Australia
newsletter
Dr Richard
Richards from CSIRO Plant Industry says Rees was developed using
an innovative technique called carbon isotope discrimination,
otherwise known as the DELTA technique.
The technique was developed by scientists from CSIRO and the
Australian National University, with the support of growers and
the Australian Government through the Grain Research and
Development Corporation (GRDC).
The DELTA technique involves crushing up the leaves of plants
and using a ratio mass spectrometer to measure how much of
various carbon isotopes they contain.
Having acquired this measurement through DELTA, the wheat
researchers were able to select the high water-efficiency
characteristics found in Rees.
Says Dr Richards: “The DELTA technique flows out of the
observation that some plants are hungry for any form of carbon
dioxide they can get. Most plants prefer the common form of
carbon dioxide (12CO2), which is found in the air and used by
plants as food for photosynthesis.
“Many plants don’t like the rarer form of carbon dioxide (13CO2)
as much and will discriminate against it. However we have found
that some plants are hungry for any form of carbon dioxide (12C
or 13C) as a food source and these are the ones we selected in
the development of Rees.”
Dr Richards says plants that are hungry for carbon 13C also
produce more grain per millimetre of rainfall.
Rees is the second wheat variety released under the Graingene 1
joint venture – a partnership between AWB Limited, CSIRO Plant
Industry, GRDC and Syngenta. The first variety released as part
of this joint venture was Drysdale.
“These sorts of partnerships are the way of the future and the
way to better crop varieties because they bring together
complementary skills and resources,” says Dr Richards. “It is
very rare for one particular organisation to be able to put
together all of the complex traits we look for in new
varieties.”
The breeding team and AWB Seeds, which is responsible for
commercialising Rees and distributing seed, is excited about its
potential in the Asian noodle markets.
“Rees is showing excellent potential for yellow alkaline noodle
quality in Asia – a premium market for Australian wheat,” says
Roger Tripathi, AWB Seeds acting general manager.
“Because of its outstanding milling qualities, we may end up
with a separate segmentation for Rees. Before this is possible
we need to quantify some of the results and get further feedback
from South Korea and Japan.”
Queensland growers and collaborating growers in southern NSW,
central NSW, WA and some parts of Victoria have been trialling
Rees and growing it for bulk seed.
They started with 10 tonnes at the beginning of 2003 and 1000
tonnes is expected to be available for Queensland and northern
NSW for planting this year, according to Mr Tripathi.
Some seed will also be available in Western Australia.
Additional
release:
http://www.seedquest.com/News/releases/2003/september/6631.htm
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