How a world’s first genome map paves the way for “Avocado 2.0”

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

In a world first, Onkar Nath has completed his PhD candidacy at the University of Queensland by creating a nearly complete genome sequence of Hass avocados, the most detailed genetic map of the popular fruit ever made.

This brings researchers around the world closer to developing a next-generation fruit that grows better, lasts longer, and is even healthier than current varieties.

“Our Hass genome is 98% complete – the first in the world of such complexity,” said Dr. Nath.

“Avocado already tastes very good, but there is still a long way to go for many useful characteristics such as tree height, architecture and resistance to pests and diseases.

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

Lawyer 2.0

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

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

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

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

Professor Mitter said this would enable global research to unlock the genetic potential of the ‘super fruit’ through modern breeding programmes.

“That’s where the power of the genome will be – how we can have the 2.0 version of Hass, which is even better in some of these traits,” she said.

While work began with the Hass variety, which accounted for 80% of global consumption, Professor Mitter said the lab had now sequenced 55 other cultivars and rootstocks.

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

“[Varieties] which may have improved fruit quality, pest and disease resistance, or [improve] the question of the lawyer’s shelf life.”

Better fruit 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.

“The economy has a lot to do with it…because you don’t have to cut them, you can actually choose them,” he said.

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

He said the main challenge with all the avocados was to make sure they reached the consumer without harm, even the hard-skinned Hass variety.

“Some other fruits have good flavor, but if you get a good Hass, it’s as good as any of them.”

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

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

“These are the kinds of tools we will need now to understand what makes this fruit really healthy and how we can improve it.”

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 like it,” Prof Mitter said.

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