Apple Pollination & S-Allele Compatibility Matrix
Compare named apple cultivars genetically, then check overlap using your own observed flowering dates. Unreviewed genotypes are labelled.
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Optional: enter observed dates from the same site and season. Leaving them blank means flowering overlap is unknown.
How this tool works
Apples exhibit gametophytic self-incompatibility controlled by S-alleles. A pair with no shared S-alleles has full S-locus compatibility; one shared allele is a partial match. This genetic screen does not measure pollen quantity, bee activity, frost, rain, temperature, or actual local flowering dates. Triploids often have poor pollen viability and should not be relied upon as donors.
The tool distinguishes S-locus genetics from actual local bloom. Four older entries remain selectable but their genotypes are not re-certified here. The 12 reviewed genotype entries follow WSU Table 2. Dates are entered by you, not fetched from weather data, and must be from one season.
Frequently Asked Questions
Should Jonagold be used as the pollen donor for Honeycrisp?
No. Jonagold is triploid and is considered a poor or unreliable pollen donor. Plant compatible diploid cultivars with overlapping bloom instead.