Spring radiation frost causes significant economic losses for farmers throughout the southern and western wheat belts, as most growers will attest in recent seasons.

Frost events that occur close to flowering cause sterility, significantly reducing yield. Subsequent frost events during grain filling can increase the percentage of screenings, and result in a downgrade of grain quality.

It has been estimated that in Victoria and South Australia, the annual cost of frost damage to the barley industry alone is $9.2m from direct yield losses, $22.5m from indirect yield losses and $1.9m from quality downgrading.

In a significant step forward in cereals research, scientists from the University of Adelaide have identified the genes responsible for frost tolerance in barley.

The scientists, conducting a project supported by grain growers and the Australian Government through the Grains Research and Development Corporation, have subjected barley varieties from around to world to frost conditions in a screening nursery based at Loxton, South Australia. The scientists found marked differences in frost-induced grain sterility between varieties. Several Japanese varieties recorded particularly low rates of frost-induced sterility compared with commercial Australian varieties.

For example, two Japanese varieties, Haruna Nijo and Amagi Nijo, had frost-induced sterility at rates of 4.5 percent and 5.4 percent, compared with Schooner at 79.1 percent, Arapiles 27.2 per cent, and Galleon 40.3 per cent.

Unfortunately the Japanese varieties are poorly adapted to growing conditions in frost-prone grain production areas of Australia. However, the identification of genetic variation for reproductive frost tolerance and the genetic location of the major genes involved, means there is potential to incorporate frost tolerance into locally adapted varieties.

The new information about the genetics of frost tolerance means that plant breeders can use fast breeding strategies such as Marker Assisted Selection. Crosses can be made between the Japanese frost tolerant varieties and locally-adapted varieties.

The lines resulting from the crosses can be assessed using the marker technology and undesirable progeny quickly discarded from the breeding program. Plant breeders are able to screen large populations for the trait, previously an impossible task with field-based screening methods. Marker Assisted Selection also reduces the error associated with field methods as selection is based on the genes controlling the trait, without potential confusion caused by environmental effects.

The marker technology, combined with the new information on the genetics of frost tolerance could reduce the development time of a plant variety by several years. The release of frost-tolerant Australian barley varieties - malting and feed - is looking promising. This research should significantly reduce the risk and cost of frost damage for barley growers.

Based on the exciting results of this project, GRDC has commissioned further research with the University of Adelaide to apply the successful strategies to improving frost tolerance in wheat and triticale.

For more information please contact Jason Eglinton, University of Adelaide, on (08) 8303 6553.