2012/760 Genetic selection for resistance to Pacific Oyster Mortality Syndrome

By Peter Kube

Pacific oyster mortality syndrome (POMS) is a newly identified disease of Pacific oysters in Australia. The likely causative agent is the virus OsHV-1, which is the same virus that has devastated Pacific oyster production in Europe and New Zealand. The oyster industry has a strategic plan to address this threat. It has three components which are: (1) The maintenance of quarantine barriers and stock movement controls; (2) identification of husbandry aspects that can mitigate disease effects, and (3) genetic selection for disease resistance. This project addresses genetic selection.

Initial research both in Australia and overseas has found genetic variation in POMS resistance. A project done in Australia, as a variation of Project CRC 2009-743, measured genetic variation in survival in the Georges River, NSW. This trial used spat of pedigreed families from the ASI breeding population, aged 5 months. Genetic differences were measured and these differences appear of sufficient magnitude to warrant continuing work in this area. Observations from this trial are also supported by information from France and New Zealand, which is mostly anecdotal. However, there is insufficient knowledge from any source to enable breeding for resistance to this disease to move to a fully operational phase. The objectives of this project were designed to reach that goal.

Project Objectives

1. Improve knowledge of the patterns of genetic inheritance of POMS resistance, including the potential rate of genetic gain through selective breeding, genetic relationships with other commercial traits, and relationships between resistance at different ages.
2. Develop protocols for screening large numbers of pedigreed families in an artificial challenge at EMAI and validate these by comparing the genetic rankings for field challenges and laboratory challenges.
3. Continue to screen and select within the Australian selective breeding population (the ASI population) under natural infections in the Georges River, and ensure these selections are available for commercial use.
4. Recommend a selective breeding strategy that includes resistance to POMS as part of the breeding goal for ASI.