Tracking water-use efficiency

Researchers at CSIRO Plant Industry in Canberra are developing water-use efficient and salt-tolerant durum wheats, to try to increase durum yields in current production areas as well as new environments.

Dr Tony Condon and his team are improving water-use efficiency by trying to combine several traits: high transpiration efficiency, long coleoptiles and early vigour.

"We have found, using 50 years of climate data and computer simulation, that combining high transpiration efficiency and early vigour is likely to make durum wheat much more suitable for growing in both southern and northern cropping areas," says Dr Condon.

Elite durum varieties have low transpiration efficiency, but Dr Condon"s team has found a highly transpiration-efficient durum to cross with them. This will give the plants a water-use efficiency trait similar to that of the new bread wheats "Drysdale"Variety protected under the Plant Breeders Rights Act 1994 and "Rees"Variety protected under the Plant Breeders Rights Act 1994.

The team is also introducing alternative dwarfing genes from European durum wheats into commercial varieties. These genes restrict plant height, but allow the expression of long coleoptiles (about 15 centimetres compared with 9cm for "Tamaroi"Variety protected under the Plant Breeders Rights Act 1994).

Dr Condon says longer coleoptiles provide insurance that the shoot will reach the soil surface, even when deep sowing is required because of receding topsoil moisture, or when there is uneven sowing depth due to stubble or direct drilling.

He says durum lines combining the high transpiration efficiency and long coleoptiles may be available within four to five years.

Dr Rana Munns is developing salt-tolerant durum wheats, to allow durum to be grown in areas affected by subsoil salinity.

She searched through the Australian Winter Cereal Collection in Tamworth and found ancient Persian durum wheats with the ability to exclude salt from their roots. Elite lines derived from crosses between "Tamaroi"Variety protected under the Plant Breeders Rights Act 1994 and the sodium-excluding ancestors were grown in saline and non-saline soils for the first time in the 2004 season and appear promising.

Dr Munns says her team has so far identified two major genes that confer the salt tolerance and a molecular marker has been found for one. There is ongoing research to find a marker for the other.

The research is being conducted through the AUSGRAINZ joint venture between CSIRO and NZ Crop and Food Research.

GRDC Research Codes: CSP344, CSP298, CSP00058.

For more information:
Dr Tony Condon, 02 6246 5034;
Dr Rana Munns, 02 6246 5280

PBR Varieties displaying this symbol beside them are protected under the Plant Breeders Rights Act 1994.