This sort of work is deemed necessary because the soaring demand for water by both fruit and vegetable growers in competition with other large users will make effective water use vital.

“We need to optimise strawberry plants’ water use by being able to breed varieties with high water-use efficiency,” said EMR environmental physiologist Dr Olga Grant. She was addressing growers at the annual viewing of the EMR strawberry breeding programme’s latest selections.

“Very little was known about the strawberry’s water-use efficiency when we began the project (in 2007),” added Grant. “It’s quite a complicated trait to breed for although it has been done quite successfully with cereals.”

In the first year she compared the water-use efficiency of a number of June-bearing varieties and how they reacted when subjected to water stress. There was a lot of variation between varieties, she noted. Then this trait was measured against that of a North American wild species (Fragaria chiloensis) that is well adapted to growing under drought conditions and has very good water-use efficiency.

The next step was to cross this species with the commercial variety Elvira, which has poor water-use efficiency. The progeny’s drought tolerance is set to be assessed both this year and in 2010. It has already proved to vary widely.

“We’re measuring the amount of water we give the (progeny) plants and the soil moisture level and looking at how quickly their stomata close,” explained Grant. “At the same time we’re looking for differences in their DNA to see if these are linked to their water-use efficiency. We hope to pick out DNA (genetic) markers that are linked to good water use.”

David Simpson, who runs the EMR breeding programme, said once the markers are identified it will be possible to use them for selecting breeding lines with efficient water use and then for other desirable traits, such as yield.