Breeding lucerne for Australia's southern dryland cropping environments

Lucerne is a deep-rooted perennial forage legume with an important role in preventing dryland salinity in southern Australian cropping regions. Annual cereal production has created a water-use imbalance, which is placing the industry under threat through rising saline watertables and resultant dryland salinity. Lucerne is being incorporated into cropping systems to reduce groundwater recharge and improve the sustainability of grain production. Existing lucerne varieties have been developed for the animal industries, primarily for the areas with high rainfall or irrigation. The new challenge is to develop lucernes specifically for southern Australian cropping systems. This paper provides a background literature review of the breeding challenges that are anticipated in the development of these new types of lucerne. Lucerne is intolerant of acidic soils, waterlogging, saline soils, and intensive grazing. Other important attributes covered include the ability of the plant to fix nitrogen with existing rhizobia and be resistant to diseases that affect lucerne and other crops in the rotation. Finally, this paper addresses some of the breeding strategies that will be used to screen lucerne germplasm for tolerances to these soil conditions and diseases.