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An Apple Is An Ovary: The Science of Apple Breeding

November 18, 2025

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  • All commercially available apples of the same variety (like Rosalie or Honeycrisp) are genetic clones propagated from a single original plant. 
  • Creating a new apple variety is an extremely labor-intensive process involving hand-pollination, seed extraction, seedling growth, and years of taste-testing, often taking around 20 years from cross to market. 
  • Apple breeders like Susan Brown are researching DNA testing to speed up the selection process, but with 54,000 genes in apples, the traditional taste-testing method remains necessary for now. 

Segments

Cloning Apple Varieties
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(00:00:22)
  • Key Takeaway: Apples of the same variety, like Rosalie, are genetically identical clones propagated from the original plant.
  • Summary: All Rosalie apples purchased in different locations are genetically the same because they originate from the same source plant. Propagation involves grafting a bud from the desired tree onto a rootstock to create a new, genetically identical tree. This cloning process is similar to how people propagate houseplants from cuttings.
Creating New Apple Crosses
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(00:02:21)
  • Key Takeaway: New apple varieties are created by manually crossing two parent trees, requiring the removal of petals and anthers to control pollination.
  • Summary: To create a cross, like the Rosalie (a Honeycrisp/Fuji cross), breeders must prevent natural pollination by emasculating the seed parent tree by removing its petals and anthers. Pollen is then collected from the pollen parent and manually applied to the stigma of the seed parent’s flowers. This process is extremely labor-intensive, requiring hand-pollination of every individual flower.
Developing and Testing Apples
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(00:09:04)
  • Key Takeaway: Developing a new apple takes about 20 years due to the extensive process of growing seedlings, grafting them, and rigorous taste-testing.
  • Summary: After pollination, seeds are extracted by hand from the resulting fruit and planted as seedlings, which are then grafted onto rootstocks to accelerate fruiting. Breeders must taste-test thousands of resulting apples, often spitting out undesirable ones referred to as “spitters.” This multi-stage selection process contributes to the average 20-year timeline for developing a new variety.
Future of Apple Breeding Research
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(00:11:20)
  • Key Takeaway: DNA testing research aims to predict apple traits like color before fruiting, but mapping the 54,000 apple genes remains a significant hurdle.
  • Summary: Researchers are exploring genetic markers to predict traits like color early in the seedling stage, which could drastically improve efficiency. However, apples possess 54,000 genes, far more than humans, making comprehensive genetic mapping a long-term goal. Until then, breeders must rely on the traditional, time-consuming taste-testing method.
Preserving Apple Genetic Diversity
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(00:13:14)
  • Key Takeaway: Wild apple diversity is preserved as living trees in orchards, unlike seeds stored in vaults, because the next generation of apples is always genetically unique.
  • Summary: Plant geneticists preserve genetic diversity by maintaining thousands of unique apple trees, often including wild varieties from regions like Kazakhstan and Turkey. Unlike other crops, apples must be preserved as living trees because the seeds produced by any apple are a new, unique genetic cross. This living archive holds traits, such as disease resistance, that could be crucial for future apple development.