Yields grow as science refines strains of wheat

While research into these and similar crop research programs are essentially medium to long term in outcome, often involving considerable expenditure, they offer great long-term grower returns as well as assist in maintaining our competitiveness.

Perhaps no better example of the value of long term so-called pre-breeding research is the rust resistance provided by the Australian Cereal Rust Control Program (led by Sydney University, but involving other researchers across the nation) for inclusion into most of today’s widely grown wheat varieties.

Rust resistance research against stem leaf and stripe rust, all potentially devastating Australian diseases, has involved finding resistant genes for each disease.

These genes come from various world sources, often in totally unsuited wheat types.

And commonly from this research it has been possible to include several resistance genes against each disease in the one variety therefore adding to greater protection. 

Dr Phil Davies, Sydney University (IA Watson Grains Research Centre at Narrabri) leads the national crown rot resistance program, largely funded by GRDC.

Excellent progress is occurring in improving resistance for future varieties. 

Unlike rusts no single gene provides crown rot resistance.

Dr Davies and team’s approach is to search the world for improved resistance and combine any found resistance into a breeding line.

Commonly resistance is from wheats totally unsuited to Australian growing conditions, with no other disease resistance like rusts and poor quality.

It is a challenge to incorporate their genes into good breeding material. 

Phil Davies’s aim is to combine as many sources of crown rot resistance as possible into the one variety and backcross the combined resistance into suitable agronomic, quality and yielding breeding lines.

More than 1500 selections from around the world have been assessed with 200 selected as having useful resistance. Promising selections are culled heavily for other diseases like rust, yield, agronomic type and quality.

Breeding lines from the research program with good agronomic type and performance combined with better crown rot tolerance than any current commercial variety are now almost ready for uptake by Australian wheat breeding programs.

It’s likely Australian farmers will begin to see the benefits of this program within the next few years with progressive further improvement to crown rot resistance to come through. 

Richard Trethowan Professor of Plant Breeding and Dr Rebecca Thistlethwaite, Sydney University, have identified several lines that are more heat tolerant than current leading varieties.

Their research shows several modern varieties have been selected with improved heat tolerance compared with previous generations, so progress in this attribute, like crown rot resistance has been occurring. 

But their studies indicate that heat stress improvement can be accelerated.

This speed-up is achieved by selecting more tolerant lines from world germplasm collections, including deliberate searches in environments such as Mexico, the Middle East and North Africa.

Professor Trethowan and Dr Thistlethwaite have identified at least a further 10 per cent yield gain when greater heat tolerance so far identified is incorporated into current breeding germplasm.

Next week. Benefits from fertiliser application can last for decades.