Novel Propagation Technologies for Australian Macadamia

Australia’s macadamia industry is worth around A$855M in 2021, with both global demand and production set to increase in the future. However, the expansion of the industry faces several hurdles, such as slow tree growth, resources and environmental costs of increasing tree supply, and the preservation of cultivar and germplasm resources in the face of climate change. While current industry-wide initiatives have enabled productivity improvements to meet increasing global demand, novel technologies that could help push production barriers would still be required to meet future demand and address climate uncertainties. This project is developing a novel high-throughput tissue culture-based propagation system for macadamia, and is critical for addressing limitations in macadamia tree production, aiming to minimize resources and the carbon footprint for propagation. This system requires innovative plant tissue culture techniques, optimized culture conditions, and novel media composition to enable high shoot multiplication capacity and large-scale propagation of multiple healthy plants from minimal plant material. It will address existing issues such as loss of shoot vigor, poor survivability, and rooting difficulty reported in previous attempts of macadamia tissue culture, while facilitating the study of underlying molecular mechanisms regulating root induction in woody plant species. This system is also being leveraged for cryopreservation of macadamia germplasm, for long-term preservation. At present two cultivars; Beaumont and MCT1, have been initiated into tissue culture, with shoot production and multiplication optimisation ongoing. Successful development and employment of this system in the industry will enhance the productivity and sustainability of the macadamia industry in Australia.