Sweetpotato industry tackles viruses through science

As far back as the 1980s, Queensland scientists realised that Sweetpotato Feathery Mottle Virus (SPFMV) infected almost all sweetpotato crops in commercial production.

Over the next 20 years, it became apparent that yields and quality were being severely compromised by these infections.

Researchers and the sweetpotato industry decided to do something about it, and the result has been a very positive story of collaborative industry development.

Starting around 2001, Queensland scientists successfully adapted and commercialised a scheme to remove known viruses from sweetpotato cultivars, and then quickly multiply those pathogen-tested mother sweetpotatoes to generate planting material for 95 per cent of the Australian industry.

It’s no coincidence that during the ensuing 15 years, the industry value has increased at around 17pc per annum to be currently worth about $90 million per year at the farm gate.

The Australian sweetpotato industry is not resting on those past successes.

Through the support of the Australian Sweetpotato Grower organisation (ASPG), Queensland Department of Agriculture and Fisheries (DAF) and Horticulture Innovation Australia (HIA), scientists and industry continue to ramp up the battle against sweetpotato viruses.

Queensland DAF horticulturist Sandra Dennien said researchers have great resources, great scientists and access to great growers

"Using our new qPCR machine, we’ve been able to establish which viruses the industry currently has, and develop better ways of managing them in commercial production," Ms Dennien said.  

"As far as we can detect, the sweetpotato seed roots currently being supplied to growers are free of important sweetpotato viruses, and the systems growers are using to then generate cuttings on their farms are still pretty effective."

As a result, Australian sweetpotato yields are the highest achieved commercially anywhere in the world.

Ms Dennien double checks the lab results by observing symptoms on indicator plants in glasshouses at the DAF Gatton Research Facility.

She is recognised as a world authority on the indexing method and is in regular communications with experts at international universities and research centres.

"Indexing is very time consuming, but we need to be absolutely sure that our lab procedures are as reliable as they can be because viruses in sweetpotato plants are very hard to detect so using indicator plants is still our most certain technique for virus diagnostics," she said.

"Developing lab diagnostics that can be equally reliable is a real priority for our current research."

Working at the DAF Gatton Research Facility has been a boon to the sweetpotato virus research.

Apart from the glasshouses and laboratories, it also helps that there aren’t many commercial sweetpotato crops nearby.

"Sweetpotato viruses are really well established in the main sweetpotato production areas around Bundaberg and Cudgen," Ms Dennien said.

"Viruses can host on weeds and volunteer plants, and there’s heaps of aphids and whiteflies to spread the viruses.

"Being that bit more isolated means it’s easier for us to prevent contamination, and be more confident of our results."

The Australian sweetpotato industry is also looking over the horizon at the rest of the world.

There are some concerning viruses and virus complexes that cripple production in other parts of the world, such as West Africa.

"We know that Sweetpotato Chlorotic Stunt Virus (SPCSV) is in Papua New Guinea and the Solomon Islands, however all our surveys indicate we currently don’t have it in Australia," Ms Dennien said.

"We’d like to keep it that way, as it can complex with one of the main viruses we do have (SPFMV) to devastate sweetpotato plantings.

"We’re keeping a close eye out for SPCSV, and consistently reminding industry what to look for, so if it does arrive we can get on top of it early."

Ms Dennien and her fellow project team of growers and other scientists recognise effective industry development is about collaboration and information sharing.

"An important part of our work is sharing our ideas and results with industry as the project is going, rather than just waiting to produce a final report after four years," Ms Dennien said.

"As we discover things, we update our virus fact sheets and management guides on the industry websites.

"It really helps that we get great feedback from growers on what they are seeing, and what is or isn’t working for them.

"I find researching in an industry that collaborates and is hungry for innovation creates a terrific culture and helps drive everyone involved."

The current sweetpotato research is supported by HIA, through the vegetable levy and support from the Australian Government, along with the Queensland DAF and Australian Sweetpotato Growers Inc.