Grains Research and Development

Date: 01.07.2005

New lines of defence

Prevention is better than cure when it comes to fighting grain disease, as west Asian-based Australian plant pathologist Dr Julie Nicol explains to Rebecca Thyer

Adopting a preventative strategy that makes the most of the growing knowledge on resistance could help the Australian grains industry win the battle against existing and emerging grains diseases.

Australian soil pathologist Dr Julie Nicol says it is important to develop crop varieties that are resistant to diseases not yet affecting Australian graingrowers, and have a preventative plan in place for when they hit Australian shores.

Dr Nicol works with the Turkish Ministry of Agriculture under the International Wheat and Maize Improvement Center"s (CIMMYT) Rainfed Wheat Systems Program and has been based in Ankara, Turkey"s capital, for the past four years.

Her work focuses on resistance to soilborne pathogens, including microscopic cereal nematodes and root-rotting fungi. Along with her Turkish and CIMMYT colleagues, she is trying to find resistant germplasm from a wide genetic base to combat soilborne problems.

Working in western Asia, Dr Nicol is well placed to understand soilborne pathogens and their effects on crops. This region is where cereals originated and where pathogen variation is extensive, enabling her to work on a number of problems that Australia has yet to encounter.

For example, CIMMYT has worked with Australia on diseases such as Russian wheat aphid and Karnal Bunt, and because conditions in Turkey are comparable to Australia, any discoveries are valuable for both countries.

"Turkey"s environmental extremes are similar to Australia"s," she says. "Micronutrient deficiencies, drought and salt conditions are alike, as is disease and yield.

"Stripe rust is one disease we can help Australian growers with. It"s a major disease in western Asia with a lot of pathogen diversity, and CIMMYT, Turkey and the International Center for Agricultural Research in the Dry Area (ICARDA) have done a lot of work establishing the pathogen diversity and breeding wheat-resistant lines."

Some of the team"s other work concentrates on demonstrating the yield losses soilborne diseases can cause. Losses of 38 per cent have been found for cereal root rots and 50 per cent with cereal nematodes.

Her studies are also looking into different management systems and rotation and the role they can play in an integrated management system.

Dr Nicol, who spent three years with CIMMYT in Mexico after completing her agricultural science degree and PhD at the University of Adelaide, says that her career has diversified through her latest work.

"I"m a nematologist," she says, "but I"ve become broader now and look into plant pathology issues under rainfed systems with a strong focus on plant breeding to incorporate the resistances into wheat."

Dr Nicol is working closely with her Australian pathology and breeding colleagues through two GRDC-funded projects.

One project follows from her work in Mexico on soilborne pathogens - including cereal cyst nematodes, root lesion nematodes and crown rot - that uncovered sources of genetic resistance.

To understand the genetics and molecular basis of new sources of resistance, a joint project between CIMMYT, Turkey and CSIRO, Brisbane is underway and has shown that resistance to the nematode P. thornei can be improved.

The other project is part of a CIMMYT/ GRDC alliance and involves delivering high-yield lines back to Australia.

About 18 months ago, Dr Nicol"s team sent back more than 180 new lines to Australia. "They"ve now gone through quarantine. We"ve had more than 17 requests from Australian breeding companies and pathologists to assess them and determine their value as sources of disease resistance under Australian growing conditions."

A CIMMYT spring wheat breeder, Mexico-based Dr Richard Trethowan, has demonstrated that under Australian-type field conditions several of these lines can yield 20 per cent more than the Australian parent.

"This indicates the progress we have made on incorporating resistance and yield," Dr Nicol says. "It is an extremely exciting stage of the research and I believe that several of the lines sent to Australia have potential for breeders to use."

She believes Australia is a world leader in grain marketing, research and production, but the environment is challenging.

"We are defeated by our climate. We need to continue to meet yield and production rates with lower input costs so farmers can still make a profit. "We will only achieve this through making gains in more difficult areas of research, such as drought potential and finding effective control of soilborne constraints.

"The management practices that growers are using are also a key to long-term sustainability and profitability, to ensure we have healthy, well-balanced soils through appropriate rotations and management will also keep the soilborne constraints at bay. "Healthy soil is needed for a healthy plant."

GRDC Research Code CIM12, CIM00011
For more information: Dr Julie Nicol, CIMMYT, Turkey, j.nicol@cgiar.org