Genetic and postharvest factors affecting macadamia kernel quality

Abstract

Macadamia (Macadamia integrifolia, Macadamia tetraphylla and hybrids) is cultivated in regions of Eastern Australia. Genotype and geographical location, a factor seldom studied, may influence kernel quality. Macadamias from three cultivars were harvested from three commercial plantations, each in a different region of Eastern Australia over three consecutive seasons. Kernel quality was assessed by whole kernel, shoulder damage, weight of pieces, oily kernels and dusty kernels. Whole kernel was strongly influenced by genotype. Shoulder damage and weight of pieces were variable and not related to genotype. Shoulder damage rates were low and numbers of oily and dusty kernels were negligible. The influence of genotype on whole kernel highlights the importance of cultivar selection from macadamia quality management. High kernel quality of kernels from nuts harvested and handled with care in this study emphasizes that the best practice postharvest management of macadamia nut-in-shell is the most important means of maintaining kernel quality. Key words: Macadamia, kernel quality, genotype, whole kernel, shoulder damage, geographical location, post-harvest handling.