They already taste pretty good, but the next generation of avocados could be even better, right down to their DNA.
In a world-first, Onkar Nath completed his PhD candidacy at The University of Queensland by creating a near-complete genome sequence of Hass avocados, the most detailed map of the genetics of the popular fruit ever made.
It puts researchers across the globe a 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 per cent complete — the first in the world of such complexity," Dr Nath said.
"Avocado already tastes very good, but there is still scope 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 characteristic.
"We can now, through new research, identify opportunities for Australian growers to improve on-farm productivity and sustainability including driving efficiencies across time, labour and land."
Avocado 2.0
The work, published in Horticulture Research, follows years of research at the Queensland Alliance for Agriculture and Food Innovation's (QAAFI) Centre for Horticultural Science.
Its director, Neena Mitter, said the difficult task of unravelling such a complex genome was a team effort.
"It is not an easy task, and that's why for so long ... avocado was even beaten by brussels sprouts in not having that information available," Professor Mitter said.
"It does involve a lot of analysis, a lot of sequencing tools, which have advanced as we are progressing, and that's what has made it possible for us to map this genome to the chromosome level.
"So not only [do we have] 98 per cent of the DNA sequence, we know now that avocado has 12 chromosomes on which these genes are located."
Professor Mitter said it would allow global research to unlock the genetic potential of the "super fruit" through modern breeding programs.
"That's where the power of the genome will lie — how we can have Hass version 2.0, which is even better in some of those traits," she said.
While the work started with the Hass variety, which made up 80 per cent of global consumption, Professor Mitter said the lab had now sequenced 55 other cultivars and rootstocks.
"If we have a high-quality genome that serves as the basis not only to understand how avocado has evolved over the years, but it is an excellent tool in the development of varieties," she said.
"[Varieties] that may have increased fruit quality, resistance to pests and diseases, or [improve] the issue of shelf life of avocado."
Better fruit in the DNA
Grower Tom Duncan has grown Hass avocados with his wife Donna in a small orchard at Childers, south of Bundaberg, since the 1970s.
He said there were key characteristics that had made it the dominant variety.
"Economics has a lot to do with it … because you don't have to snip them, you can actually pick them," he said.
"They don't get as many bugs on them … and also the Hass is a more open tree so you don't get as much disease in that.
He said the main challenge with all avocados was ensuring they reached the consumer free of damage, even the hard-skinned Hass variety.
"They're just as delicate as everything else," he said.
"Some other fruit have got a good flavour, but if you get a good Hass it's as good as any of them."
While the breed improvements would take some time to reach orchards such as the Duncans', Professor Mitter said it would lead to trees that produced better-quality fruit.
"Avocados have very unique sugars, a very unique fruit ripening system, a very high potassium content," she said.
"These are the kinds of tools we will now have to understand what makes this fruit really healthy and how we can make it better."
For consumers, an avocado that lasted longer, tasted better, and had even more health benefits could become the new reality.
"I'm sure we will all love that," Professor Mitter said.
"It is a step in the right direction, but the first step in that direction."
