Drought tolerance traits could soon be picked off the shelf by plant breeders now that researchers have identified characteristics which coincide with dry weather survival.

Neil Turner of CSIRO has targeted drought tolerance in two of Western Australia’s most popular legume crops, lupin and chickpea, which annually fetch about 100 million export dollars for Western Australia.

They also provide legume options for the deep acid sands and heavier neutral-to-alkaline clay loam WA soils, where they deposit up to 40 kg per hectare of nitrogen to drive cereal production.

“Lupins and chickpeas struggled during recent droughts and so we need robust varieties that yield and fertilise soils during dry years,” Dr Turner explained.

His project, supported by the Grains Research and Development Corporation (GRDC) and the Federal Government, searched for characteristics which helped these crops survive in the dry.

Dr Turner’s colleagues, Dr Jairo Palta of CSIRO, and Drs Bob French and Bevan Buirchell of the Department of Agriculture, found that for lupins the magic formula was quick seed growth to help the plants mature before drought set in, while for chickpea it was superior osmotic adjustment. 

“Osmotic adjustment distinguishes a plant’s ability to accumulate sugars which attract and bind available water to better maintain internal moisture levels, prevent wilting and aid ongoing plant processes,” Dr Turner explained.

“During simulated drought trials at Merredin Research Station, chickpeas yielded between 0.6 and 2.6 t/ha, with higher yields at higher levels of osmotic adjustment.”

Importantly, trials also showed that osmotic adjustment is heritable, meaning breeders can target the trait by selecting suitable parents. DNA tests to help quickly identify those parents are being developed under the supervision of Dr Susan Barker at the Centre for Legumes in Mediterranean Agriculture.

Besides developing a surrogate marker for drought tolerant chickpea, the GRDC project has also determined characteristics indicating drought tolerance in lupins.

According to Dr Turner, the quick seed filling corresponding with drought tolerance in lupins affects the pod length at the end of the linear seed filling phase of plant growth.

“That phase concludes within 17 days of the pods changing colour from dark to light green and so at that stage we can determine if a line is a quick filler and therefore drought tolerant,” he noted 

As with chickpeas, this sign-post to drought tolerance will help breeders choose hardy parents, with Dr Buirchell already crossing fast and slow seed-filling genotypes to see how regularly the quick seed filling trait passes to the next generation.