William Bellotti¹, Geoff C. Auricht², Rex Williams³ and Michael J. Hill⁴
1. The University of Adelaide, Roseworthy, South Australia, 5371
2. South Australian Research & Development Institute, Adelaide, SA, 5001
3. New South Wales Agriculture, Tamworth, New South Wales, 2340
4. CSIRO Animal Production, Perth, Western Australia, 6014

The area of lucerne (irrigated and dryland) in Australia is expanding rapidly. In the past decade, the official (Bureau of Statistics) estimates of lucerne area have more than doubled, from 351,000 ha (1982/83) to 772,000 ha (1993/94). These figures underestimate the total area of lucerne containing pastures as they include only ‘pure’ lucerne stands. Other area estimates, based on surveys of agronomists (Pearson et al., 1997) and bioclimatic modelling (Hill, 1996) indicate further large increases are entirely feasible.

Two driving forces behind the current expansion include:

1. Use of lucerne for grazing, forage conservation, seed production, and for rotational benefits (soil nitrogen, soil structure) in cropping systems is highly profitable.

2. Lucerne has several advantages for addressing a growing number of land degradation issues such as; dryland salinity (lucerne has high water use compared to annual plants), soil acidification (lucerne can reduce the rate of soil acidification through recovery of leached soil nitrate), and herbicide resistant weed populations (lucerne provides the basis for integrated weed management).

To better fulfil these new roles in developing more sustainable farming systems, there needs to be a shift in emphasis in Australian lucerne improvement programs. Traditional lucerne breeding objectives have included; disease resistance (Phytophthora root rot, Colletotrichum crown rot, stem nematode); pest resistance (spotted alfalfa aphid, blue green aphid); high herbage production, long-term persistence (> 7 years); across a range of dormancy types (winter dormant to highly winter active). More recently, ease of establishment and removal have been included as desirable traits for inclusion of lucerne leys in cropping systems.

New breeding objectives, in addition to the traditional objectives listed above, would be related to enhancing the ability of lucerne to perform its sustainability function and to expand lucerne adaptation onto less favourable soil types. Possible objectives are suggested in the table.

Hill, M.J. 1996. Aust. J. Agric. Res., 47, 1095-1117.

Lamb, J.F.S., et al. 1995. Crop Sci., 35, 153-157.

Meyers, L.J., et al. 1996. Agron. J., 88, 67-72.

Pearson, C.J., et al. 1997. Aust. J. Agric. Res., 48, 453-465.

Smith, S.E., et al. 1994. Crop Sci., 34, 690-694.