If you’ve ever risked your fingers while hitting a macadamia with a hammer, you’ll know that the nuts can be tough to crack, yielding a small but tasty kernel inside.
- Just one third of a macadamia nut is edible
- Macadamias have three layers: the outer husk, the shell and the inner kernel
- Scientists aim to breed nuts that have tougher husks, thinner shells and larger kernels
Some of Australia’s brightest horticultural minds are trying to change that by selectively breeding for macadamias with thinner shells, larger kernels and tougher exterior husks to protect the nuts from birds and insects.
In the Queensland Alliance for Food and Agriculture’s nut lab on the Sunshine Coast, Professor Bruce Topp and his team have set a cracking pace, studying nuts from a selection of 5,000 trees.
Professor Topp, the leader of Australia’s macadamia breeding program, explained that just 33 per cent of the average nut is edible.
“We’re looking at selecting for increased kernel recovery.”
Borers have been released into bags to test the performance of the green husks that protect the nut and kernel on macadamia trees.
“Some varieties have a thicker husk and some have have a harder husk and so one of the things that we’re looking at is, can we increase the kernel recovery, but get protection for the kernel by having thicker or harder husks?” the University of Queensland scientist explained.
Demand outstripping supply
Australian Macadamia Society CEO Jolyon Burnett said despite the impact of COVID-19 on service industries and duty-free sales at airports, demand for macadamias remained as strong as ever.
“People still cannot get enough macadamia nuts, whether that’s here in Australia or one of the 44 countries around the world that we export to,” Mr Burnett said.
“Every year there are new product developments that include macadamias, they are one of the few products available in over seven aisles of the supermarkets.
In 2019, growers were paid an average price of $5.81 per kilogram of nut in shell and those returns are expected to increase to $6.00 or higher when figures are tallied for last year.
Professor Topp collaborates with the Queensland Department of Agriculture and Fisheries, the New South Wales Department of Primary Industries and the University of the Sunshine Coast on projects which are funded by Horticulture Innovation Australia.
Its research and development manager, Vino Rajadran, said the $2.2 million breeding program used the best genetics available to generate the best returns for growers.
“What we’re working with is a crop that hasn’t really been bred for agriculture, so we’re at the start of the journey.
“I’m very excited to see where we end up with the future of this breeding program.”