Macadamia researchers are breeding thinner shells for bigger kernels and tougher husks for resisting pests. The University of Queensland’s Professor Bruce Topp said these combined attributes would boost Australia’s $270 million industry, which earns $190 million in export income annually. “Two thirds of every harvested kilogram is in the weight of the macadamias’ extremely tough shells. That’s a lot of wasted productivity,” Professor Topp said. “The goal for many growers is to produce less shell and more kernel from each nut but with the shell still tough enough to resist pests.” Macadamias are native to south-east Queensland and northern New South Wales but are grown commercially in places including Hawaii, South Africa and Brazil.