In this section:
Response of lucerne to drought
Drought response of Lucerne in South East & Mallee environments in SA
Marshall, E.M., Humphries, A.W., Kobelt, E.T., Rowe, T.D. & Auricht, G.C.
Email: erica.marshall@sa.gov.au
The response of lucerne to drought conditions in 2006-2007 was monitored using nine established trials in the South East and Mallee regions of South Australia sown between 1999 and 2007. All lucerne populations at all sites experienced a decline in plant frequency over time, and this was particularly pronounced over the drought period. However, all trial sites were able to maintain 15-25% groundcover, which is still acceptable in terms of stand production and reducing recharge (Latta et. al, 2002). Winter active lucernes SARDI Seven (parent line) and Hunterfield were the most persistent cultivars across each site, except for Marcollat where winter activity class five cultivar “SARDI Five” was the only cultivar with improved persistence.
Establishment and root morphology of eight diverse Lucerne populations in a low rainfall, South Australian, environment
Erica Marshall, Alan Humphries, Eric Kobelt, Trevor Rowe and Geoff Auricht
contact: erica.marshall@sa.gov.au
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.
Image of a root system undergoing analysis in Multispec W32 showing how the different colour clusters separate the main roots from the finer roots.
