New Zealand farmers are not alone in facing the challenge of striving for value while mitigating their environmental footprint. Senior reporter Richard Rennie is in Australia to find out how our neighbours are approaching the issues of gene technology, carbon farming and sustainability.
Smaller, more efficient, higher yielding avocado and citrus trees could be the reality for orchardists in coming years thanks to a collaborative effort between Plant & Food Research and Australian genetic researchers.
Earlier work by Plant & Food Research has identified the gene marker in apple root stock that causes dwarfism, a desired trait that enables growers to plant trees in higher densities and increase fruit yield in an orchard’s early years of establishment.
It has been the single most significant factor contributing to remarkable gains in apple orchard productivity that amounts to a 10-fold increase in fruit yield in the past 40 years.
Now Australian genetic researchers at the Queensland University of Technology (QUT) in Brisbane are working with Plant & Food Research to deliver the same benefits in avocado and citrus root stock, using gene editing technology.
The university’s work recently gained global profile when the first gene-edited banana variety got the green light for commercial release in Australia, providing a lifeline for growers around the world hit by a debilitating tropical fungal disease.
Professor Peter Prentis heads up QUT’s centre for agriculture and the bioeconomy.
He said his team have cleared some important milestones in their work, gene editing citrus and avocado root stock plants in tissue culture.
Today an array of tiny root stock specimens is emerging in the research lab, and the next challenge will be to regenerate them.
“With woody plants, unlike something like grasses or clovers, breeding is quite a slow process.
“However, gene editing will still look to reduce the time it takes to breed in the dwarfism trait. For avos it could take as long as 25-40 years conventionally. Potentially with GE we can get that down to less than 10.”
In contrast, for apples the dwarfism trait has taken 40 years to get to today’s sized tree, using conventional breeding methods.
Gavin Ross, Plant & Food Research group general manager, said working with the Australian team has given the effort greater impetus.
“The Australian science environment is big on leveraging funding. We bring dollars, they put dollars in. That has probably been a greater factor than the differences in each country’s GE regulations.
“The problems we are trying to solve are quite big, and there is a high calibre of scientists, and we have the potential to grow the size of the pie.”
Prentis is optimistic about how the trials are progressing and sees potential for the technology’s application across a wide range of crops.
“We have the likes of the mango here in Australia which could benefit from having a smaller stature tree size and have a more regular fruiting pattern.
“In NZ there is the kiwifruit, where you could look to edit for a shorter juvenile period, and against disease.”
A key benefit of the GE tech is its ability to allow breeders to target the feature they want.
“The problem with conventional breeding methods is that you can also end up bringing other traits across. GE enables you to be specific.”
The benefits of smaller rootstock are not only the ability to plant more densely, but to also set orchards up for greater automation, in both management and harvesting.
Avocado trees, for example, can grow multiple metres high, requiring risky and time-consuming harvesting methods.
Thanks to dwarfism, and Plant & Foods’ work developing the “two dimensional” tree shape, modern apple orchards frequently feature in-orchard automation at various stages of management.
Acknowledging his native bias, Prentis said that NZ’s GE regulations are significantly more restrictive than Australia’s.
As Australia’s research advances in the agricultural-horticultural field, he believes commercial GE varieties are likely to start proliferating within the next five to seven years.
“But it will not replace conventional breeding entirely. At the end of the day, it is important to have multiple approaches to help us deal with food security and disease response.”
Ross said despite NZ’s cumbersome GE regulations, the country’s researchers have not been sitting on their hands. He is confident a change in rules would see NZ quickly catch up to Australia.
