2010/724 Development of tools for the sustainable management of genetics in polyploid Pacific Oysters

By Penny Miller

The commercial production of triploid Pacific Oysters (Crassostrea gigas) has grown rapidly in recent years. There is now a push to move away from commonly used mass spawning techniques towards single pair cross selective breeding programs in an effort to improve growth and disease resistance within the triploid product. Before this can be achieved, there is a need to understand some of the fundamental genetics behind polyploid production and to develop molecular tools and techniques that can be used in establishing breeding programs.

This thesis developed and utilised suites of microsatellite markers to determine the baseline diversity of native, naturalised and cultured diploid oysters. It was found that the high diversity within naturalised oysters may provide a genetic reservoir for future breeding programs. The same microsatellite markers were used to determine diversity and pedigree assignment within a mass spawned tetraploid population across two successive generations. The first generation showed a high diversity, which significantly decreased in the second generation produced via mass spawning.

Family selection breeding programs for the production of commercial triploids is the way of the future for the Pacific oyster aquaculture industry. This research provided some of the fundamental information required for the establishment of such a program and developed some of the genetic tools and techniques that will aid in its implementation.