Fusarium wilt Tropical Race 4 research program (BA14014)

What was it all about?

This investment, which ran from 2015 to 2020, built a strong foundation for the Australian banana industry to manage Fusarium wilt with minimal impact on production, by addressing three key areas: prevention, resilience and resistance.

For prevention: improving on-farm biosecurity using new tools

On-farm biosecurity is a crucial part of the strategy for managing Fusarium wilt in Australia, and this investment developed tools to help banana growers implement effective biosecurity practices. The Quality Banana Approved Nursery (QBAN) scheme for banana planting material has been updated under this work, allowing banana growers to have greater confidence in the planting material used to establish new fields. Also, the Best Management Practices for Biosecurity online tool has been rolled out via www.bmp.abgc.org.au, to allow growers to check their current practices and produce reports for their current situation.

Together, these outputs place Australian banana growers in a better situation to prevent the incursion of Fusarium wilt on their farms.

For resilience: establishing management practices to help supress Fusarium and increase plant tolerance

By understanding how the Fusarium wilt organism produces spores, how it survives in the soil and how it sues alternative hosts, better management advice can be developed to assist in avoiding the spread of the disease. The foundations for understanding the epidemiology of Fusarium wilt have been built in this project, resulting in a greater understanding of the infection process and how inoculum can build up in the soil, such as during the desiccation of the bananas or other plant material.

The research team established a benchmark for healthy plants where there is a relatively stable microbial community, which promotes healthy plant function. In systems where homeostasis can be maintained or enhanced there is slow progression of Fusarium wilt, and plants appear asymptomatic. There are strong indications this occurs in north Queensland banana soils which have a higher clay content, increased vegetative ground cover and where nitrogen fertilisers are not overused.

There may be other practices that promote homeostasis, which can further enhance the resilience of the banana production system. However, there are also ‘disruptors’ to microbial homeostasis that enhance the expression of Fusarium wilt in susceptible cultivars.

Disruptors to homeostasis can be environmental stresses imposed on the plant such as weather extremes, heat, cold, waterlogging and drought, and those imposed by management practices, such as nutritional deficiencies, excessive nitrogen, poor soil management, soil acidity, loss of microbial diversity and tillage.

The research found that all plants found within banana plantations have the potential to host Fusarium wilt if the level of inoculum is great enough. However, the progress of re-infection can be slowed either by reducing inoculum or enhancing microbial competition. Fusarium spp. have been found to be a dominant component of the banana microbiome and it is when the microbial competition is reduced that pathogens like Fusarium wilt can dominate the soil microbial community, rapidly reinfecting plants and causing disease.

For resistance: evaluating and using resistant cultivars

Banana cultivars with enhanced resistance are a key component in continuing banana production where TR4 has become widespread. This research has demonstrated that it is possible to have a relatively low budget banana breeding and selection program within Australia using currently available resources. This work is commencing with cultivars that have shown some resistance to TR4 and then selecting plants with improved agronomic characteristics. This approach has been successful in fast tracking banana lines with potential suitability for the Australian market that have productivity equivalent to Williams, but with enhanced TR4 resistance.

The cultivars that were successfully used to produce new lines, GCTCV119, CJ19 and GCTCV215, and tested against TR4, all retained their resistance to the disease. This demonstrated that the lack of Cavendish banana cultivars with resistance to TR4 is not the greatest constraint to the development of cultivars, but rather is their agronomic suitability for the Australian banana market. Subsequently, greater success in developing suitable banana cultivars could be achieved by screening of plants that have known resistance to TR4, based on improved agronomy in north Queensland and then confirmation of their resistance to TR4 in the Northern Territory.

ACT NOW

Access The Banana Best Management Practice (BMP) online system which supports environmental and on-farm biosecurity

You can also read more about the project in these articles in Australian Bananas magazine:

• See page 18 in the April 2019 edition to learn about the progress of Goldfinger mutagenesis – elite tasting selections to be propagated for detailed evaluations
• And on page 19 of the same edition, learn more about the importance of retaining organic ground cover to help develop disease suppressive, productive soils in Wanted, dead or alive - ground covers
• Read more about the research in the update provided from p15 of the April 2018 edition
• See an update on the project on p8 of the April 2017 issue.

And in these articles published on the Australian Bananas website:

• Progress on TR4 mutagenesis and varietal screening 
• The banana microbiome research and opportunities to suppress Panama disease.
• What happens to soil organisms and banana production when nitrogen applications are manipulated.
• Goldfinger evaluations and get further updates from the levy-funded Better Bananas
• How Fusarium moves through the plant
• Developing banana varieties resistant to Panama disease

You can also watch:

• This ABC Landline story featuring Dr Tony Pattison from the project talking about the benefits of vegetated interrows based on the team’s results – Banana Resilience: Banana industry stronger than ever
• This video looking at combatting the disease with soil management.
• This short video detailing a recent NextGen group visit to some of the field trials in the Northern Territory.