Summary

Quandong’s potential as a fully realised industry is yet to be explored and while advances have occurred in propagation and cultivation, much is still unknown. The removal of the hard-shell from seeds has been shown to improve germination but this may not be a practicable method on a large scale as it is difficult to obtain undamaged kernels. Chemical seed treatments can produce successful germination consistently and many studies have highlighted plant hormones; gibberellic acid in particular plays an important role in the release from seed dormancy (Lang 1965; Khan 1981). The application of plant growth regulators and different other tactics on quandong seed to release it from dormancy is a potential research area to evaluate for commercial purposes.

The project will commence with a detailed literature review, compiling the known literature on quandong and survey of natural and cultivated quandong populations in southern Australia followed by several targeted laboratory, controlled environment, and field studies. The outcomes of this project will deliver advanced eco-physiological knowledge that will be used to develop novel agronomic practices for profitable quandong production. It is expected that the new agronomic approaches may reduce production costs by 20% and increase orchard production by 20%.

Program

New and Emerging Industries

Research Organisation

Charles Sturt University

Objective Summary

One of the most pressing issues of quandong establishment and growth is that of host selection (PIRSA, 2006). Although this parasitism mechanism is non-specific, and the range of possible hosts is apparently quite wide, there is evidence that some hosts are better than others (Loveys and Tyerman, 2002; Lethbridge, 2003). Host species that have been commonly used in planting include myoporum, kikuyu, clovers, prostrate lucerne and acacias. The exact nature of what determines a good host at different locations and climate is poorly understood. It is also likely that as plantings age there may be a need to provide a range of hosts that more closely match the size of the quandong plants, from small herbaceous in early years to shrubs and trees in later years also need to be considered as part of the whole host-parasite management equation.

Climate change is a looming crisis for Australia and concern exists over the potential impacts of drought on Australian native commercial plants including quandong. Planting densities and patterns need to be evaluated for their role in resilience and productivity under the challenging environmental conditions. Currently there are no specific recommended ratios and sowing patterns for quandong-hosts and quandong-pollinator plants respectively.

Quandong is highly sensitive in early growth for water and resources competition by neighbouring weed plants. Translocated herbicides, such as glyphosate, could be passed from target weeds to quandongs causing damage. Even mechanical cultivation or the use of knock-down herbicides may be detrimental to quandong. Weeds potentially could be removed by soil residual herbicides, which destroy germinating weeds before they can be parasitised although their use in quandong production has not been studied.

There are five project objectives:
1. Conduct a benchmarking survey to document quandong distribution and production.
2. Conduct a wild population survey to examine wild populations in situ to observe host-parasite relationships, variability in fruit production, and provide leads for better management of quandong.