Some plants can't fruit from their own pollen
Some plants can't fruit from their own pollen, so they need a second plant of a different variety nearby.
As recorded: Self-incompatible species require 2+ genetically distinct plants.
Well established A person has checked it against its sources. If you skip this, you lose real yield. The planner warns you.
How it works
Many fruit trees carry self-incompatibility alleles at a single locus. When a pollen grain shares an allele with the pistil it lands on, the pistil rejects it and no seed sets. A plant's own pollen always shares its alleles, so it cannot fertilize itself. Neither can a second tree of the identical variety, which is genetically the same. Fertilization needs pollen from a genetically distinct plant.
What to do about it
Plant at least two, and where the species needs a second cultivar make them different varieties. Two of the same will not pollinate each other.
The evidence
Evidence: checked against 2 sources in the research-based literature.
The 2 sources
Chestnut, Chinese: All are self-sterile. Two or more varieties or seedling trees are necessary to ensure adequate cross-pollination.
Japanese plum exhibits gametophytic self-incompatibility (GSI), a prezygotic reproductive barrier where genetically related pollen is rejected by the pistil ... governed by a polymorphic locus (S) ... Self-incompatibility occurs when the same S-allele is expressed in the haploid pollen grain and the diploid pistil.
Plant teams that rest on it
- Blackberry hedge
- Blueberry ring
- Currant ring
- Fruit tree ring
- Fruit tree ring (dwarf)
- Grape arbor
- Salsa garden
- Tomatillo pair
- Tomatillo pair (small bed)
Read next
- Why is my squash not setting fruit? Pollination for the home gardenerLots of flowers and no fruit is usually a pollination problem. How squash, cucumbers, corn, and the crops that need a partner get pollinated, and the short list of what you can do about it.
- Saving seed that comes trueTomatoes, peppers, beans and peas come true from saved seed. Squash, corn and the cabbages will surprise you. Which is which, and how to clean, dry and store seed.
How this rule has changed
Every change is dated, newest first. The full record, with each reason, is in the data download.
- Sources updated
- Details updated
- Wording made clearer
- Wording made clearer
- How it works updated
- Advice on what to do added
- A person read the sources and confirmed it
- Added to the rules
Plan a bed with Blackberry hedge ›
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Cite this page
Milpa Gardens. “Some plants can't fruit from their own pollen, so they need a second plant of a different variety nearby.” Evidence grade: Well established. https://milpa.garden/rules/self-incompatible-species-require-2-genetically-distinct/
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How we grade evidence
- Well established
- The rule names its mechanism and is settled, by sources a person has read and checked or by plain arithmetic and geometry.
- Promising
- The mechanism is named and the literature backs it. A few questions are still open.
- A good hunch
- Plausible by its mechanism, but field studies are thin, so treat it as a lean.
- Contested
- The evidence points both ways, or no study has tested it, so the planner does not enforce it.
- Refuted
- The claim did not survive its sources. It is kept so the folklore can be answered.