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Cultivation and Harvest Quality of Native Food Crops
by Maarten Ryder, Yvonne Latham and Bruce Hawke
February 2008
RIRDC Publication No 08/019 RIRDC Project No CSL-24A
Who is the report targeted
at
The information should be
of interest to existing and potential growers of native food crops and
to buyers and sellers of native food produce. The produce quality information
sheets may also be a useful guide for consumers.
Aims of the research
Methods
The research reported here
followed previous reports on the establishment of native food crops in
south-eastern Australia, and on problems with establishment and maintenance
of quandong orchards (RIRDC reports 04/178 and 03/138). The native food
field trials which were established in 2001 were monitored for plant survival,
growth and yield of produce up to 5 years after planting. Information on
pests and diseases and on flowering and fruiting times was collected. Quandong
disease was investigated in a set of glasshouse experiments where different
levels of watering and plant pathogens were applied, with and without a
host plant. Produce quality information sheets were developed in partnership
with industry participants, following the recommendations of a workshop
and using information collected from a number of growers and processors
of native foods.
Results
A range of native food crops
originating from the arid zone through to higher rainfall areas were planted
in a range of field site locations, from inland to coastal, in south-eastern
Australia.
Information on survival, growth, plant vigour and yield of produce was collected. Pest and disease problems were recorded. Yield of produce was documented up to 5 years after planting. Where plants performed well, figures indicated what can be expected in good situations with respect to plant material and location. Many trees in the trials had not yet come into full bearing. Recovery of native food plants after fire was also recorded. Working with industry participants, a set of produce quality information sheets were developed for the species in the field trials. These sheets will improve levels of product knowledge and communication within the industry.
The crops trialled were quandong, Acacia victoriae, three Citrus, mountain pepper, lemon myrtle, white aspen, riberry, muntries and bush tomato (desert raisin). Every native food crop performed well in at least one location, and many species performed well at several trial sites. At every field trial site, several species performed well. Tables summarizing survival and plant performance across the field trial sites are included as Tables 6 and 7.
Yield information from several seasons and locations is presented for muntries and wattle seed.
Evidence from the Junee field trial site in 2007 shows that good wattle seed yields can be produced with very little water input (no irrigation and drought conditions). Good bush tomato yields 5 years after planting were seen at one field trial site. Other crops (white aspen – Acronychia oblongifolia, Citrus, quandong) are still in early stages of coming into production. Some native food plants, particularly those from the arid zone (Acacia victoriae, quandong, bush tomato) are fire-tolerant.
Evidence for this comes from monitoring recovery after fire at two of the trial sites (Stawell and Junee) which suffered bushfire damage at the end of 2005.
Pests and diseases noticed during the trial included Citrus black scale and sooty mould on Citrus and white aspen and a stem canker of mountain pepper, possibly caused by Macrophomina phaseolina.
Pathogenicity of Phytophthora and Pythium fungi towards quandong was tested and only a moderate effect on plant growth was found. In quandongs, a large effect of watering level on the formation of haustoria (specialized structures by which the plant attaches to its host plant) was found. When less water was supplied, many more haustoria were formed, indicating a strong reliance of quandong on its host for water in drier conditions.
The produce quality information sheets developed as part of this project include the names of produce, their uses, produce quality requirements and suggested conditions and methods for post-harvest handling to keep produce in good condition.
Implications
Growers can benefit from
trialling different selections of native food plant species wherever possible,
and choosing selections that are best adapted to their situation. Some
species can produce good crops with minimal water inputs after initial
establishment (eg seed from Acacia victoriae).
For some species in the field trials, yield figures have been collected from plants which are growing in good conditions and these data can be used as a guide to expected production levels and timing. The yield figures presented in this report could be improved by various means, such as selection of better plant material, and improved water and fertilizer management. For crops which are currently grown from genetically variable seed (e.g. Acacia and bush tomato), selection and breeding are required, to improve the consistency of yield between plants.
Information has been collated on produce quality requirements and post-harvest storage conditions which will help to keep produce in good condition. The industry, and therefore consumers, may benefit from more widespread knowledge about produce quality and attention to methods of postharvest treatment and storage. Further research is needed on these aspects. The work on produce quality has highlighted some important knowledge gaps in post harvest handling of produce.
Recommendations
In establishing native food
production in a new area, it will be beneficial to trial a number of different
selections of the chosen plant species, if available. This will enable
growers to choose selections that are best adapted for their location.
Information sheets on native food produce quality have been developed. These information sheets are appended to the report and will be published on line. They are intended for use by the native foods industry as a guide, to improve knowledge about produce quality and about post-harvest treatment and storage.
Future research is required particularly on improving the uniformity of yield, quantity and quality of produce, and on a number of produce quality characteristics.
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