A progeny test evaluates a parent by measuring its offspring. In cannabis breeding, the method can reveal whether a promising parent transmits useful performance consistently, but the result is only as reliable as the mates, family sizes, environments, measurements, and comparisons used.
Why the Parent’s Own Appearance Is Not Enough
A plant’s phenotype reflects its genotype, environment, and development. A visually impressive parent may carry alleles it doesn’t visibly express, and some of its performance may come from conditions that offspring won’t share. The distinction between genotype and phenotype is therefore central to progeny testing.
Offspring provide repeated samples of what the parent can transmit. That doesn’t make them identical samples: each seed receives a different allele combination, and the other parent contributes half of its inherited DNA.
Define the Question Before Making Crosses
A useful progeny test begins with one measurable question. “Is this a good parent?” is too broad. “Do families from this parent show earlier flowering than connected comparison families under the same protocol?” is testable.
Define the trait, observation stage, comparison group, target environment, and minimum useful difference before seeing the result. This reduces the temptation to choose whichever outcome looks favorable afterward.
Common Progeny-Test Designs
- Common tester: candidate parents are crossed with the same tester so their families share a comparison point.
- Multiple mates: each candidate is evaluated across more than one mate to reduce dependence on one pairing.
- Selfed family: offspring from self-pollination can reveal segregation, although inbreeding changes interpretation.
- Connected families: checks or shared parents connect separate groups and environments.
No design is universally best. The choice depends on the breeding question, reproductive biology, available space, and whether the goal concerns general or specific combining behavior.
A Practical Evidence Ledger
- Assign stable parent, cross, and seed-lot identifiers.
- Record the mating design and any failed or uncertain crosses.
- Grow enough offspring to observe segregation rather than relying on one standout.
- Use consistent measurements and blinded labels where practical.
- Keep family mean, within-family variation, and missing data separate.
- Repeat important results in another cycle or environment.
The site’s article on genotype-by-environment interaction explains why a family ranking from one setting may not transfer unchanged.
Progeny Test Versus Test Cross
A test cross is a specific mating used to infer a genotype under a defined inheritance model. A progeny test is the broader practice of judging a parent’s transmitted performance from offspring. A test cross can be part of a progeny test, but the terms aren’t interchangeable.
Make the Decision Reproducible
Before retaining or rejecting a parent, write the criterion, comparison, family evidence, uncertainty, and environment in one paragraph. A progeny test supports a bounded breeding judgment; it doesn’t prove universal superiority or guarantee every future seed. Formal programs should involve an experienced plant breeder or quantitative geneticist when designs, sample sizes, or statistical models affect costly decisions.
