Avocado 2.0 made possible by Australian scientist’s first genome map in the world

They already taste good, but the next generation of avocados could be even better, right down to their DNA.

In a world first, Onkar Nath has completed his doctoral application at the University of Queensland by creating a nearly complete genomic sequence of Hass avocados, the most detailed map of the genetics of the popular fruit ever.

It puts researchers around the world one step closer to developing a next generation fruit that grows better, lasts longer and is even healthier than current varieties.

‘Our Hass genome is 98 percent complete, the first in the world of this complexity,’ said Dr. Nath.

“Avocados already taste very good, but there is still room for improvement for many useful characteristics such as tree height, architecture, and resistance to pests and diseases.

“We now know which genes are responsible for which trait.

“We can now, through new research, identify opportunities for Australian growers to improve on-farm productivity and sustainability, including driving efficiency over time, labor and land.”

Onkar Nath studied avocado chromosomes for his PhD.(Provided: UQ)

Avocados 2.0

The work, published in Horticulture Research, follows years of research at the Queensland Alliance for Agriculture and Food Innovation (QAAFI) Center for Horticultural Science.

Its director, Neena Mitter, said the difficult task of unraveling such a complex genome was a team effort.

‘It’s not an easy task, which is why for so long… avocado was even beaten by brussels sprouts for not having this information available,’ said Professor Mitter.

“It involves a lot of analysis, a lot of sequencing tools, that have advanced as we’ve gone along, and that’s what has allowed us to map this genome at the chromosomal level.

“So not alone [do we have] In 98% of the DNA sequence, we now know avocado has 12 chromosomes on which these genes are located.”

Intermediate shot of a woman in a white jacket standing with her arms crossed against a blurred background
Professor Neena Mitter says the research positions Australia as a global leader in avocado science.(Provided: Lyndon Mechielsen/QAAFI)

Professor Mitter said it would allow global research to unlock the genetic potential of the ‘superfruit’ through modern breeding programmes.

“That’s where the power of the genome is going to be: how can we have Hass version 2.0, which is even better at some of those traits,” he said.

While the work started with the Hass variety, which accounted for 80% of global consumption, Professor Mitter said the lab has now sequenced a further 55 cultivars and rootstocks.

“If we have a high-quality genome that serves as a foundation for not only understanding how the avocado has evolved over the years, but it’s an excellent tool for variety development,” he said.

“[Varieties] which may have higher fruit quality, resistance to pests and diseases, or [improve] the issue of avocado shelf life”.

Better fruits in the DNA

Grower Tom Duncan has been growing Hass avocados with his wife Donna in a small orchard in Childers, south of Bundaberg, since the 1970s.

He said there were key characteristics that made it the dominant strain.

“Economics has a lot to do with that…because you don’t have to cut them, you can actually pick them,” he said.

“They don’t have as many bugs on them…and the Hass is also a more open tree, so you don’t get as many diseases.

He said the main challenge with all avocados has been ensuring they get to the consumer without damage, even the hard-skinned Hass variety.

“They’re as delicate as everything else,” she said.

“Some other fruits taste good, but if you get good Hass it’s as good as any.”

Mid shot of hass avocados hanging from a tree
Hopefully, the research will lead to improved varieties.(Provided: QAAFI/via Pexels)

While breed improvements would take some time to reach orchards like the Duncans’, Professor Mitter said it would lead to trees that will produce better quality fruit.

“Avocados have very unique sugars, a very unique fruit ripening system, very high potassium content,” she said.

“These are the kinds of tools that we’re now going to have to figure out what makes this fruit really healthy and how we can make it better.”

For consumers, an avocado that lasts longer, tastes better and has even more health benefits could become the new reality.

‘I’m sure we’ll all love it,’ said Professor Mitter.

“It’s a step in the right direction, but the first step in that direction.”


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