Host and donor influence on pearls produced by the silver-lip pearl oyster, Pinctada maxima

The value of a pearl depends upon five major traits - pearl size, colour, lustre, shape, and surface. To determine host and donor oyster contributions to these traits, a large-scale mantle seeding experiment was conducted in which grafts from 56 donors were used to induce pearl production in 1099 hosts of the silver-lip pearl oyster, Pinctada maxima. Pearls were harvested two years after seeding and individually graded. The amount of nacre deposition, lustre, and two types of defects were associated with host traits, whereas all traits were significantly associated with the donor oyster. A number of correlations between pearl quality traits were also found. These results suggest that potential exists to increase pearl quality via the selective breeding of host and donor oysters, but reveals that careful attention must be paid to potential trade-offs in the design of such breeding programmes.