Advances made through family breeding at the Aquaculture Genetics and Breeding Technology Center (ABC) at the Virginia Institute of Marine Science have yielded substantial gains in economically-important traits for the eastern oyster, Crassostrea virginica, including improvements in survival, growth rate and meat yield. Shape characteristics, such as fan shape and cup depth, are monitored and included in a multi-trait selection index. Genetic gains from family breeding are transferred to the commercial oyster industry through yearly production of two licensed family-based broodstock lines. The lines are derived from top families for improved performance in low salinity, low disease-pressure environments and moderate salinity, high disease pressure environments.
Through combined efforts of the East Coast Oyster Breeding Consortium members, a 66K SNP genotyping array has been developed specifically for east coast oyster populations. ABC has utilized this tool to genotype 10,570 individuals (2,277 parents, 8,293 progeny) from 10 years of family production and testing (2013-2023).
In spring 2023 and again in 2024, genomic selection was used to select broodstock candidates through the calculation of genomic estimated breeding values (GEBV). The spread of GEBV within families indicated a high degree of genetic gain was possible using genomic selection to select the best individuals with families over pedigree-based approaches in operation. In 2023, the first GEBV-based spawning designs were executed to create 57 high salinity, 57 low salinity and 5 low-ranked GEBV families. Families were replicated across 3 field locations in spring 2024 covering a range of environments with variable salinity (6-24ppt) and disease pressure. Local endemic pathogens include Perkinsus marinus and Haplosporidian nelsoni. Progeny tests for the 2023 families were completed in November 2024, at which time survival was assessed for each family replicate and randomly-selected samples of oysters from each replicate were analyzed to collect data on traits including total weight, length, height index, width index and meat yield. This data has been used to compare the improved accuracy for selection using genomic information and rate of genetic gains forecasted by GEBV as the first validation of genomic selection in this breeding program.