A COMPARISON OF THE PERSISTENCE OF MEDICAGO-TRUNCATULA CV PARAGGIO WITH OTHER ANNUAL MEDICS IN THE VICTORIAN MALLEE

The annual medic Medicago truncatula cv. Paraggio has been widely sown in pastures throughout the Victorian Mallee region; however, its abil ity to persist in cereal pasture rotations is not known. Seed permeabi lity and production, and plant regeneration of Paraggio, were studied in the field over 4 years, and the changes in its seed reserve were ex amined under 3 different cereal-pasture rotations. When compared with medic cvv. Parabinga, Harbinger, and Jemalong, Paraggio had up to twic e the level of permeable seed over the summer-autumn period in 2 years (7-36% v. 2.5-19%). Paraggio produced 336-928 kg/ha of seed over 3 ye ars, and after seed production was halted, it regenerated at densities of 150-1438 plants/m2 over the next 4 years. These results were gener ally the same as, or better than, the other cultivars. When seed set o ccurred in 1 and 2 years in the pasture phase of a 2- and 3-year rotat ion, respectively, Paraggio seed reserves were maintained at >4000 see ds/m2. This study demonstrated that Paraggio resulted in superior plan t densities when grown in a number of typical rotations. It persisted satisfactorily and is expected to improve agricultural productivity in short-term cereal-pasture rotations.