A Chronicle of Cassava in Australia
This commentary provides a viewpoint of the activities, knowledge and experience of cassava (Manihot esculenta Crantz) in Australia. It was first compiled in 2021 from historical records originating from the reports of Dr Brian Keating and added to from the literature and from personal contributions. Brian’s PhD on environmental effects on growth and yield of cassava was awarded by the University of Queensland in 1981. This chronicle remains a work-in-progress and while we have spent much time and effort to decipher the cassava story, we welcome the indulgence and offerings of those who can help to tell it fully.
The historical records of cassava in Australia suggest that cultivars were introduced (probably not via formal channels) from various South Sea Islands, Indonesia and PNG over extended periods, perhaps going back to the early days of the sugar industry in the late 19th century associated with the movements of Pacific Islander workers to and from Australia.
Towards the end of 1925, about 56,600 metres of cassava planting material was introduced from Indonesia for the establishment of a cassava industry in Queensland. In the following year more than 40 ha of cassava were planted in the Mackay District and subsequent plantings were made in Bundaberg and Rockhampton. At one stage, there were 84 cultivars reported to be under investigation in Queensland.
Following the opening of the Sarina power alcohol factory in 1926, it became apparent that its power/alcohol needs could be met from sugarcane by-products and interest in cassava declined. Residents in the Mackay/Sarina area attribute the disappearance of the crop in the area to a systematic eradication campaign by farmers fearing that cassava might become a weed of sugarcane farms.
Cassava Cultivar Introductions and Nomenclature
In the early 1970s, interest was revived in cassava as a source of starch, stock feed and ethanol. The University of Queensland began the Australian Cassava Collection in 1972 following a collection trip to north Queensland where cultivars had survived in private gardens, along roadsides and on the few farms where it was grown as pig food. Varieties in the collection were originally given UQ numbers but those were later changed to CUQ numbers. A set of cultivars were introduced from Puerto Rico (via Hawaii) in 1972 and those cultivars retained their original names in the collection. A second lot of introductions came in 1974 from Thailand containing CIAT cultivars and one local Thai cultivar.
Fielders Ltd began a cassava collection of their own at Yandaran in the Bundaberg region in 1975. Their agronomist Noel Harris had spent some time with James Cock and the cassava program in CIAT, Cali Colombia, and started to build this collection with some local Bundaberg collections, additions from the UQ collection and some introductions from CIAT. A second much larger set of introductions came from CIAT to Fielders Ltd in 1975 and, after quarantine, were added to the Fielder’s collection around 1977.
Fielder’s and later Australian Cassava Products (ACP), a co-owned entity of CSR Ltd and Fielders also introduced seeds of various crosses and grew out and selected from subsequent F1 seedlings over the 1978-84 period. Some references to those ACP cultivars, and in one case to superior yield of ACP444 remain, but there is no public information as to its current status.
Around 1977, Fielders started to use the MAus naming convention for everything in their collection, irrespective of origin. UQ moved to this convention at that time as well with one important distinction from what Fielders had done. The UQ convention was to use MAus names ONLY for varieties collected in Australia of unknown international origin. Known varieties introduced into Australia since 1972 retained their international names. This convention has been adopted and maintained throughout this chronicle.
The University of Queensland’s program (in part) sought to collect and describe the range of cassava varieties that were then growing in Australia and, where possible, associate the collected varieties with earlier cassava introduction and evaluation activities.
It seems that the University of Queensland’s cassava collection provides the earliest plant descriptions of cassava varieties in Australia. The collection commenced in about August 1972 and was maintained at the Universities Research Station in Redland Bay, Brisbane until about the late 1990s. Despite varieties from the collection having been previously dispersed throughout Australia, it is not evident whether the collection was abandoned in its entirety or, at least in part, transferred to another location.
It is fortunate that a record of known cultivars in the UQ collection during the 1972 to 1984 period was complied, and that information and various photographs of cultivar traits were retained.
Cassava Research and Industry Development
Cassava work In Australia has been motivated by various plant attributes that may have had commercial relevance. Those past interests can be roughly gleaned from the record.
Late 19th century – as a food for Pacific Islanders working in the sugar industry and as a source of starch and ethanol.
Late 1920s – as a feedstock for power alcohol at least supposedly for a Sarina factory.
Early 1970s – saw the first University of Queensland cassava variety field collection trips in North Queensland.
Mid 1970s to 1990 – various groups considered cassava’s use for alcohol production, starch production and animal feed.
In the mid-1970s – agronomic research on cassava was initiated by the Queensland Department of Primary Industries, the University of Queensland, Fielder Gillespie and CSR. Research funding was provided by the Commonwealth Government’s National Energy Research Development and Demonstration Committee (NERDDC).
The cassava research program at the University of Queensland was developed in response to the oil shocks of the early 1970s and the use of cassava as a feedstock for ethanol. The work initially focussed on plant mineral nutrition in the labs and glasshouses of Colin Asher and David Edwards and was followed by agronomic and crop physiological studies by John Evenson, Graeme Wilson and Shu Fukai. A non-citable collection of abstracts from the University’s Cassava Research Program (up until about 1984) was published.
The work at the Queensland Department of Primary Industries focussed on the effects of climatic variables on the growth and yield of cassava. Experiments were conducted initially at eight locations in Queensland: Walkamin, Kairi, Southedge, South Johnstone, Millaroo, Gatton and Coolum; cultivar evaluations and (at some locations) sequential growth and yield harvests over two years were reported for north Queensland by Richard Hobman and for South Queensland by Graeme Hammer.
Between about 1976 and 1984 there was active dialogue, collaboration and extensive sharing of germplasm between UQ, QDPI and industry, and culminating in the development of a crop simulation model to estimate cassava productivity published by Shu Fukai and Graeme Hammer in 1984.
In 1974 – Techno-Proteins Pty Ltd reportedly funded the University of Queensland to conduct a small cassava variety trial in Cains, North Queensland.
Cassava agronomy research was also done on the Daly River in the Northern Territory by the Northern Territory Department of Primary Industries and Fisheries.
Between 1979 and 1986 – Australian Cassava Products (ACP) operated as a company part-owned by Fielder Gillespie, CSR and Bundaberg Sugar.
In 1988, Dr Howard Bradbury of the Australian National University in Canberra began work on cassava and its cyanogenic glycosides, it seems primarily because cyanogenic compounds were linked to several serious diseases including Konzo. In 1995, he and his colleagues invented a series of simple kits for analysing the cyanogenic potential of cassava products in the field. The kits enable health workers to quickly and easily measure the potential for cyanide ingestion in villages. But perhaps of more value was an additional kit to test how much cyanide has been ingested by individuals. Cyanide ingested in food is detoxified in the body to thiocyanate and excreted in the urine, thus a simple test of thiocyanate in the urine was used to quantify people’s exposure to cyanide in their food. The group at ANU subsequently studied ways to reduce the amount of cyanide ingested by people. In 2005 they developed the “wetting method” which is a simple one-step addition to traditional food preparation that can remove nearly all the cyanide from cassava. The wetting method has since been taught to women in parts of the DRC and in Mozambique; and studies with colleagues in the DRC in 2010 showed that it was a robust way of reducing the exposure of people to cyanide in their food and thus eliminating the incidence of Konzo. Protocols and tests for total cyanide in leaves or tubers continue to be available from the Konzo Prevention Group at ANU. The ‘wetting method’ remains the basis for the recommendation for cassava food preparation in the Australian Food Standards Code in 2021.
Also, in about 1988 –Stephen Ockerby began privately collecting cassava varieties from around Queensland. The varieties form the basis of the current AgSight collection, and serendipitously created a link between some work he did modelling the cassava crop undertaken during his undergraduate study in 1983 and the current ‘Remastering Cassava in Australia’ project.
In 2005 – there was a cassava study for Meat and Livestock Australia Ltd. into the feasibility of an integrated cassava based stockfeed industry in south-east Queensland around Maryborough and in the Northern Territory. The study involved two companies: Integrated Animal Production Pty Ltd and Macadamia Farm Management Pty Ltd.
In 2007, cassava work began at Plant Sciences at Monash University where Ros Gleadow had established the cyanogenesis group to study toxic plants especially those that naturally make and release hydrogen cyanide. Her lab group worked on the effects of rising CO2, drought, salinity and temperature on the growth of cassava and the concentration of linamarin (the toxic cyanogen in cassava), and successfully demonstrated why drought-stressed cassava plants are particularly toxic. The work featured in various reports including the United Nations Standing Committee on Nutrition in 2010 and has given impetus to efforts by public health officials in Mozambique and the Democratic Republic of Congo to improve methods of cassava food processing. Ros Gleadow led the Oceania part of the international team on the Cassava Genome Project and, at a farming level, has studied cassava in Mozambique, Fiji and Australia – the latter via collaboration with the company CassTech. The Monash group’s work on cassava toxicity is well-known via international workshops and the popular press in Australia (e.g., The Science Show and the ABC’s Catalyst).
In 2008 – there was a major cassava production project by CassTech, a company reportedly with links back to ACP. The company imported several new cultivars to Australia from a research facility in South America and these are thought to be still maintained on a farming property in the Burdekin Irrigation Area of Queensland. The company grew several 100 hectares of commercial cassava crops in the early 1990s but failed to establish a commercial enterprise and, consequently, moved its operations away from Australia. Part of the reason that the cassava enterprise did not proceed, it seems, was that there was a disparity between the potential benefits of cassava to sugarcane farming systems and a concern that the harvesting of root crops may affect soil stability and subsequently the marine health of the off-shore Great Barrier Reef. That perceived conflict between industry and Government authority appears not to be publicly documented.
For about the last decade – a small online cassava company called Three Spades also believed to have links with CassTech has operated from the Burdekin area growing and producing organic cassava flour.
Cassava in the Home and Market Gardens
One aspect of the Australian cassava story that is difficult to tell is the roll of backyard and market gardeners, and the sale of cassava storage roots in local markets. We would love to mention those people in an historical list and have some knowledge of the varieties they have collected and grown.
2021: Brian Keating, Stephen Ockerby, William Foley, Ros Gleadow.