Grains Research and Development

Date: 01.06.2002

Getting specific with lucerne

Purpose-bred lucerne to solve various problems, including salinity. Inset: SARDl lucerne breeder Geoff Auricht (left) inspecting one of 60 lucerne trial and evaluation sites.

LUCERNE DEVELOPMENT is getting more sophisticated with cultivars now being geared to solve specific problems for graingrowers.

Senior research scientist with the SA Research and Development Institute (SARDI), Geoff Auricht, and assisting scientist Alan Humphries have been tailoring lucerne cultivars into functional tools to address obstacles in southern farming systems.

Mr Auricht identified three priority roles for lucerne and three sets of distinct qualities needed to fill those roles.

Recharge management and intercropping

Growers can retire an area from grain cropping and run a 2-4 year lucerne pasture phase, allowing the deeper roots of lucerne to sop the excess water that has trickled beyond the shallow root zone of annual crops and flooded the watertable.

However, growers keen to avoid sacrificing the income of cereal crops from those paddocks can plant cereals and lucerne together (intercropping).

For best effect, these two approaches require different qualities from the lucerne in the system - winter-dormant cultivars that can co-exist with cereal crops in an intercropping system and highly winter-active cultivars for phase farming systems.

Through the GRDC, growers and the Federal Government have contributed over $325,000 towards assembling a log of genetic material to breed for these qualities.

Winter-dormant lucerne leaves important resources, such as soil nutrients, for use by cereal crops during their season, while winter-active lucerne in phase systems would absorb winter rainfall and prevent it draining into the watertable. Purpose-bred lucerne to solve various problems, including salinity. Inset: SARDl lucerne breeder Geoff Auricht (left) inspecting one of 60 lucerne trial and evaluation sites.

Grazing tolerance

During the domestication of lucerne, plants were selected for increased yield, resulting in plants tolerant of recurrent cutting, but with reduced ability to withstand continuous grazing and the stressful effects of daily defoliation. This project is also targeting the development of cultivars able to withstand constant grazing to help maintain stands and support livestock production. By early 2002 the project had tested 486 accessions in 23 field trials across SA and WA. The best of these lucernes will now be developed into new varieties for Australian farmers in a new five-year project. Germplasm from the USA's National Plant Genomic System, Ru ss ia's Vavilov In stitute and the Australian Medicago Genetic Resource Centre has been sorted into a shortli st of breeding material to deliver the required varieties.

Program 4 Contact: Mr Geoff Auricht 08 8303 9498 email auricht.geoff@saugov.sa.gov.au