CSIRO honorary research fellow Dr John Passioura says it's a case of getting "more crop per drop, crops that will use more of the available water supply and commit more biomass into grain".

His CSIRO Plant Industry colleague, Dr Richard Richards, says Australia is leading the world in successfully increasing crop yields in water-scarce environments. Given the Australian climate, and the quality of our scientists, that's no surprise.

Australian scientists are taking a number of approaches to achieving "more crop per drop", and one of them is improving transpiration efficiency (TE), dry matter production per unit of water transpired.

Dr Richards' CSIRO wheat breeding team used carbon isotope discrimination (the delta process) to develop varieties whose high transpiration efficiency has given them up to 30 per cent yield advantage in dry seasons while retaining grain quality and disease resistance.

In a few years time we can expect to see the results of similar transpiration efficiency research - also using carbon isotope discrimination - in sunflowers, carried out by University of Queensland molecular plant breeding research fellow, Chris Lambrides.

Like the CSIRO's work with wheat, Dr Lambrides' sunflower research at the University of Queensland was supported by the Grains Research and Development Corporation (GRDC).

Experimental sunflower hybrids developed in the research increased yield in dry conditions by up to 35 per cent, but Dr Lambrides says a more realistic expectation will be more like 10 to 15 per cent better yield when the high transpiration efficiency characteristic moves into growers' paddocks.

The university's technology commercialisation company UniQuest has licensed drought tolerant sunflower germplasm to companies like Pacific Seeds, Lefroy Valley Seeds and Hylan Seed Company, which will use it in their development of commercial hybrids for sale to farmers.

Dr Lambrides says his germplasm has an additional advantage - in that it has also been selected for rust resistance - and comes with molecular markers that will allow seed company breeders to select for the transpiration efficiency genes.

Currently Dr Lambrides is researching transpiration efficiency in canola, in collaboration with Professor Graham Farquhar and Dr Josette Masle, and in mungbeans with Dr Merrill Fordyce.

Queensland Department of Primary Industries and Fisheries scientists are using the process to develop drought tolerant peanuts.

The Crop Doctor, Peter Reading, is managing director of the Grains Research and Development Corporation (GRDC), Canberra.