A progeny test evaluates a parent by its offspring rather than its own appearance. The candidate is crossed (to one standard tester or to several partners), the seed is grown in uniform conditions, and the offspring are scored. The parent's breeding value is the average performance of its offspring.
In practice
Progeny testing is how breeders choose males with confidence. Three candidate males are crossed to the same female; the offspring of each are grown side by side. Male B's seedlings are the most vigorous and uniform with the best aroma: male B is kept, the others dropped.
It also checks females. A gorgeous clone may pass on her traits poorly if they come from a heterozygous combination; her offspring will show it.
For low-heritability traits such as yield, progeny testing is far more reliable than looking at the parent itself, because averaging many offspring cancels out environmental noise.
Don't confuse with
- Test cross: a specific cross to a homozygous recessive to diagnose one locus.
- Test grow (tester grow): grow-outs of released or candidate seed to evaluate a line, often by several growers.
- Pheno hunt: selecting individuals, not testing parents by offspring.
A seedling is a young cannabis plant from emergence of the cotyledons until it has several sets of true leaves, typically the first 2-3 weeks.A plant is heterozygous at a locus when it carries two different alleles there (Aa), so its offspring can inherit either one and segregate.A test cross mates a plant of unknown genotype with one that is homozygous recessive for a trait, so the offspring ratios reveal what the first plant carries.A plant is homozygous at a locus when it carries two identical alleles there (AA or aa), so it passes the same allele to every offspring.A recessive allele only shows its effect when a plant carries two copies of it; in a single copy it is masked by a dominant allele and carried silently.A locus is the fixed position on a chromosome where a particular gene or DNA marker sits; the plural is loci.In grower slang, a pheno is one individual plant from a seed lot, usually numbered during a hunt, as in "the #4 pheno".Male selection is the choice of which male plants become parents, judged by their vigour, structure, early aroma and above all by the quality of their offspring.A test grow (tester grow) is growing out a sample of a new seed line, often by several independent growers, to measure uniformity, vigour, chemistry and herm rate before release.Heritability is the share of a trait's variation within a population that is due to genetic differences rather than environment, on a scale from 0 to 1.Selection in breeding is choosing which plants become parents, so that alleles behind the chosen traits become more common in the next generation.
