Breeding lucerne for persistence

Cultivated lucerne is the most widely grown forage legume in pastoral agriculture. Persistence is critical for most pastoral production systems and its definition includes concepts of productivity, but maintenance of adequate plant numbers is essential. There were three important eras in lucerne persistence breeding: species introduction leading to local varieties and land races (adaptation), development of multiple pest-resistant, autumn dormancy-specific cultivars, and introducing complex traits and the use of biotechnologies. Today’s persistent cultivar needs, at a minimum, adaptation, proper autumn dormancy, and targeted pest resistances. Adding complex, ‘persistence-limiting’ traits to these minimum base traits, such as tolerance to grazing, acid, aluminum-toxic soils, and drought, is successfully being achieved via traditional selection, but biotechnologies and inter-specific hybridisations are also being employed in some cases. The main issues around biotechnologies are public perception and regulatory issues which continue to hamper transgene deployment while genetic marker programs need to lower costs and concentrate on successful application. There is not one persistent ‘ideotype’ that will fill all situations, but specific ones need to be developed and targeted for geographies such as the subtropics. Finally, breeders need to understand what persistence traits lucerne producers are willing to pay a premium to obtain.