Researchers smash avocado production bottleneck

UQ scientists are revolutionising the way avocados are grown in Australia by successfully propagating trees using plant stem cell technology.

Growers currently get one avocado tree from a single cutting and it then takes up to five years before a grafted tree begins bearing commercial quantities of fruit.

With this world-first breakthrough, one piece of tissue culture can produce 500 avocado plants in less than 12 months. 

Project leader and director of UQ’s Centre for Horticultural Science Professor Neena Mitter said this process could completely change the industry.

"Every cell in that cutting has the potential to grow into a plant just by giving them proper nutrition, proper light and darkness conditions, and proper temperature," Professor Mitter said.

“The plant stem cell technology allows for up to 500 more plants to be grown from a single cutting in just 10-12 months – significantly reducing the resources required and the time it takes to produce a plant for sale in an orchard.”

This is not just about producing more fruit, but about giving a choice to the growers for planting rootstocks with desired traits.

“Trials show that the clonal tissue culture rootstocks are yielding high-quality fruits in the field,” she said.

Queensland produces most of Australia’s avocados, accounting for 55 per cent of the national crop.

The $493 million industry is feeding a voracious market, with Australians consuming 3.8 kilograms of avocados per person every year according to Avocados Australia.

The new propagation method is being trialled on five farms across the country, including near Bundaberg in southern Queensland and Tully and Lakeland in the state’s far north.

A survey of avocado growers undertaken by CQUniversity found 72 per cent cannot access enough plants and nearly half indicated they already have the skills and knowledge to work with tissue culture trees.

Childers grower Lachlan Donovan has been growing laboratory-propagated Hass avocado trees for three years and is hungry for more. 

“In the past, the delay between ordering new trees and planting has been two to three years,” Mr Donovan said.

“The biggest advantage of this new technology for us is to be able to get desired rootstocks and varieties into production quickly.”

Economic modelling conducted by the University of Southern Queensland and the Queensland Department of Agriculture and Fisheries suggests that the new tissue culture technology offers good returns for growers, with the potential for a 21 per cent return on investment.

Queensland Minister for Agricultural Industry Development and Fisheries and Minister for Rural Communities Mark Furner said this was a Queensland-owned and invented technology platform validated from lab to orchard, and was now progressing to commercial roll out.

“Queensland produces the majority of Australia’s avocados and this innovation offers opportunities for growers across the state,” he said.

Five different rootstock varieties have been trialled and one is ready for commercial application.

"We have just commercially licensed one of our earlier rootstocks that we were successful with,” Professor Mitter said.  

"We are now in discussions for the other rootstocks as well, about how to take them forward."

Tissue culture propagation is not a new concept and has been used for different fruits including bananas for many years.

However, woody species like avocado trees are trickier to work with and commercial tissue culture propagation has not been possible until now.

Professor Mitter said there was also environmental advantages for this growing method.

“This is a sustainable technology that reduces the need for water, fertilisers, pest management processes and farming land used to produce rootstocks,” she said.

“Another advantage with tissue culture propagation, particularly in this day and age, is that the movement of soil and the biosecurity risks this entails can be eliminated.”

Fresh produce industry leaders sampled the first Hass avocados grown from the tissue culture propagation at the annual Hort Connections Conference in Brisbane in early June, the industry’s largest event.

Despite avocados being a huge focus of her research work, Professor Mitter recently told ABC Radio that it took some time to acquire a personal taste for the fruit.

“I had never tasted an avocado until I landed in Australia from India in 2000,” she said.

“It was a love-hate relationship, it took me a while, but we now love avocados in our team.

“We love challenges and the avocado does throw a lot of challenges to us.”

Image above left: Professor Neena Mitter. 

Media: Professor Neena Mitter, Director, Centre for Horticultural Science, n.mitter@uq.edu.au, +61 434 628 094; Margaret Puls, QAAFI Communications Mob +61 0 419 578 356, qaaficomms@uq.edu.au