Seed saved from an open-pollinated variety grows plants like its parents, while seed saved from an F1 hybrid splits into a mixed, unpredictable crop, so a seed bank should be built from open-pollinated varieties. An F1 hybrid is the first-generation cross of two inbred parent lines, and the cross has to be made again from those lines every year.
Part of Community Seed Bank Management
Open-pollinated varieties are populations whose seed reproduces the parent type; F1 hybrids are one-time crosses whose seed does not.
Open-Pollinated Seed Grows Like Its Parents
An open-pollinated (OP) variety is a population that has been kept to a recognisable type for generations. Seed from its plants grows into plants that look and perform very much like the parents, with some natural variation. That is the property a community seed bank depends on: you can plant, harvest, save and plant again without buying anything.
“Heirloom” is a claim about age (a variety handed down for a long time), not a separate kind of seed. Every heirloom is open-pollinated, but not every open-pollinated variety is old. A landrace is an open-pollinated population adapted to one place (Landrace Development).
F1 Hybrid Seed Splits Into Many Types
A breeder makes an F1 hybrid by crossing two inbred parent lines, each self-pollinated for many generations until it is uniform. The F1 plants are uniform and often vigorous. Their own seed is the F2 generation, and in the F2 the genes inherited from the two grandparents reassort.
The arithmetic is simple. One gene with two variants gives three possible combinations in the F2 (AA, Aa and aa, in the ratio 1 : 2 : 1). With 10 independent genes, each with three combinations, the number of different genotypes is 3 × 3 × … × 3 = 3^10 = 59,049. Real crops differ in many more than 10 genes, so no two F2 plants are expected to match. The practical result is a field of uneven size, maturity and quality, some plants poor or sterile.
For the full genetic argument see Hybrid vs Open-Pollinated.
How To Tell Which You Hold
| Clue | Means |
|---|---|
| ”F1” or “hybrid” on the packet or catalogue | Do not save seed for planting |
| ”Open-pollinated”, “OP”, “heirloom” | Can be saved, if kept from crossing |
| Seedless fruit (for example triploid watermelon) | Produces no usable seed |
| Unlabelled seed from a market or salvaged packet | Unknown; grow a small trial and watch for uniformity |
A uniform crop does not prove a variety is open-pollinated, because hybrids are uniform too. The test is the next generation: if saved seed gives a mixed result, it was a hybrid.
What To Do With Hybrids You Already Have
Eat the crop; the fruit is fine. Do not rely on its seed. If a hybrid is the only source of a useful crop, a breeder’s route exists: grow the F2, keep only plants close to the type you want, and repeat over several generations until the line settles. That takes years and works far better in self-pollinating crops than in cross-pollinating ones (Self-Pollinators).
Common Mistakes
- Saving seed from a hybrid “just in case”. The seed germinates, so it feels like a success, and the mixed crop is discovered only at harvest.
- Assuming open-pollinated means pure forever. Seed stays true only if the plants were not crossed with another variety of the same species (Isolation & Cross-Pollination).
- Treating “heirloom” as a quality guarantee. It says the variety is old, not that it suits your soil or climate.
What’s Next
- Learn next: Isolation & Cross-Pollination — keeping an open-pollinated variety true
- Combine with: Seed Maturity and Harvest Timing — when to take the seed