Broodstock Offerings

Selection Salinity

ABC lines are deployed to multiple sites where they experience different environmental pressures. 

One of these is salinity. 

Some of our lines are specifically bred to be able to withstand lower salinities, such as those found in the upper Chesapeake Bay and its tributaries, i.e. LOLA or LILY

Salinity also plays an important part in disease pressure, with higher salinities are more likely to experience exposure to Dermo (Perkinsus marinus) or MSX (Haplosporidium nelsoni), thus oysters tested in moderate salinity can develop resistance or tolerance to Dermo and MSX and be bred to pass that on to future generations.

Breeding Technique

We utilize two main methods of breeding: Mass Selection and Family Breeding.  These techniques describe how our lines are created and maintained over time

• Mass selection is a term used to define a breeding technique that is based on growing a lot of oysters out in intentionally stressful locations, then picking the "best" ones based on the survivors. Over many generations, mass selection gradually leads to improvements in heritable traits such as survival and growth. ABC has used this technique to develop lines and continues to do so, emphasizing the use of a large number of parents in our annual spawns in order to maintain a high level of genetic diversity. This genetic diversity is especially helpful in dynamic environments as it preserves the variation needed to handle stressors.  Lines that are spawned using mass selection typically contain 100-150 parents each year.  Lines produced in this manner are genetically stable, and tend to perform consistently from year to year
• Family based breeding is much more sophisticated.  Family breeding uses a smaller number of individuals to make a line, but the “best of the best”. Families are made in our hatchery using 1 male and 1 female, then the seed from each family are tested across ABC's selection sites.  When the field data is collected and analyzed, we are able to accurately see what traits are heritable and what families have the best breeding potential across the range of our selection traits.  Our current selection traits are:  survival, total weight, length, meat yield, shell roundness and cup depth.  We then select 4-5 of the top performing families based on this complete suite of traits to cross together for the new, family-selected line.  We spawn and test new families every year, so these lines are being constantly, deliberately improved.

Annual Breeding Strategy

While breeding techniques describe how ABC develops its lines, the annual breeding strategy explains what ABC focuses on each year to maintain and improve them.

• Line Maintenance and Genetic Diversity – For mass-selected lines like LOLA and DEBY, the goal each year is to preserve genetic diversity while making steady gains in growth,survival, and overall performance. Because these lines are bred from many parents, they remain genetically stable and consistent, allowing farmers to depend on similar performance year after year. 

• New Line Development – For family-selected lines like HNRY, LILY or FYR, a new version is created each year by selecting and crossing the top-performing families from all families maintained in ABC’s genetic archives. This approach allows ABC to capture the best genetics from a large pool of families after new data is collected, producing lines that are derived from parents with the highest performance potential across a suite of traits. Due to the nature of utilizing different family crosses every year, these lines may vary slightly from one year to the next, keeping in mind that variation is meant to coincide with improvements across multiple traits.

Breeding Focus and Line Attributes

The breeding focus for each line come from a combination of the annual breeding strategy as well as the breeding technique, which ultimately gives specific characteristics such as high survival or disease resistance that is passed on to the offspring.  While many of our lines have overlapping breeding focus, some of the key differences lie in the selection environment and historic line attributes, which include the origin source for the founding populations such as Delaware Bay (DEBY) and Louisiana (LOLA)

Terminal Line

A line produced from the best-performing families each year from the breeding program. Rather than being maintained as a continuous breeding line from one generation to the next, each generation is created using parents selected from the top-performing families based on traits such as survival, growth, meat yield.  This approach incorporates the latest genetic improvements each year.

Disease resistance/tolerance

Disease resistance is the ability of an oyster to reduce infection by a pathogen. Disease tolerance is the ability of an oyster to remain healthy and survive despite becoming infected. In practice, oysters selected for disease resistance often exhibit a combination of both traits, making them more likely to survive in areas where diseases such as Dermo or MSX are common.

It's important to remember that no oyster line is completely immune to disease. When we describe a line as "disease resistant," we mean that the line has demonstrated better survival under disease pressure than unselected populations. Individual oysters within the line can still become infected or succumb to disease, and performance will vary depending on environmental conditions, disease intensity, and the specific genetics of each individual oyster.

Historically Resistant

Some of our lines are considered “historically resistant” to Dermo or MSX because they were developed from oyster stocks imported from locations where those diseases were already common and so natural disease resistance or tolerance had already started to develop in that imported material. Disease prevalence, especially for MSX, can fluctuate over time, meaning recent generations may not have experienced the same level of disease pressure. While these lines retain the some of the early genetic improvements gained through past selection, the term “historically resistant” reflects the environment from which the line was developed and the focus of some of these lines has shifted to targeting other commercially relevant traits rather than disease.

Maximize Triploid Performance

 When producing triploid oysters, it's easy to focus on the diploid parent because it is the named commercial line. However, the tetraploid parent is just as critical to determining the performance of the resulting triploids. A triploid inherits one set of chromosomes from the diploid parent and two sets from the tetraploid parent, meaning the tetraploid contributes two-thirds of the offspring's chromosomes. This is why ABC invests heavily in developing and selecting improved tetraploid lines—to maximize the performance of the triploid oysters they produce.

Because of this, selecting high-quality tetraploid broodstock is just as important as selecting the right diploid line. Traits such as growth, shell shape, meat yield, and disease resistance are influenced by both parents. For example, while a diploid line may not have been selected for disease resistance, crossing it with a tetraploid line that does experience that disease pressure can contribute to improved disease performance in the resulting triploids. Likewise, the best triploid performance is achieved when both the diploid and tetraploid parents have been carefully selected for the traits most important to the production environment.