Establishment and root morphology of eight diverse Lucerne populations in a low rainfall, South Australian, environment

A field trial was established in 2007 at Coomandook, SA, to look at the impact of drought conditions on the establishment and survival of 8 diverse lucerne ( Medicago sativa spp.) populations. Winter active and semi- dormant populations L775 and SARDI Five established with a greater density than the highly winter active cultivar Siriver. The root morphology of each population was assessed by carefully excavating surviving plants to determine if root morphological traits can be attributed to survival over the first summer. SARDI Five and varia populations displayed an increased taproot diameter, taproot area, fine root area, number of laterals, and number of new crown buds, leading to larger plants. Conversely, the falcata and caerulea populations previously thought to be drought tolerant had poor establishment, a very low root dry weight, taproot diameter, and number of new crown buds in this study.