When a plant is described as “growing true to seed,” it means the offspring grown from its seeds will be genetically identical to the parent plant, reliably producing the same type of fruit or flower. Apples, however, do not grow true to seed; the seed from a McIntosh apple will not produce a McIntosh apple tree. This lack of genetic consistency is central to understanding how apple varieties are created and maintained for commercial markets. This biological reality explains why nearly all commercially grown apples are propagated through methods other than planting a seed.
The Genetic Reason Apples Don’t Grow True
The primary biological factor preventing apples from growing true to seed is a condition known as extreme heterozygosity. This means that a single apple tree carries two different versions of many genes, a genetic makeup that is far more complex than in many other plants. The apple genome has such a high degree of internal variation that the genetic combinations in the seed are highly unpredictable.
The apple’s genetic complexity is further compounded by its need for cross-pollination to produce fruit. An apple flower requires pollen from a different, genetically distinct apple tree to successfully fertilize the ovule and create a viable seed. This process ensures the seed receives DNA from two separate parents, effectively shuffling the genetic deck with every generation.
The necessity of this genetic shuffling is an evolutionary advantage for wild apples, allowing them to adapt to changing environments by increasing the diversity of their offspring. From a human perspective, however, this genetic complexity makes the outcome of planting a seed a near-random event. Even if a farmer were to plant seeds from a single, desirable apple, each resulting tree would be genetically unique, with only a small chance of producing high-quality fruit.
What Happens When You Plant an Apple Seed
A gardener who plants an apple seed will successfully grow a tree, but the resulting fruit is a gamble. The new tree will develop into a standard-sized apple tree, potentially growing 30 to 40 feet tall if left unpruned. Unlike grafted trees, which can bear fruit in as little as two to four years, a tree grown from seed typically enters the fruit-bearing phase much later, usually requiring seven to ten years to produce its first harvest.
The fruit produced by the seedling tree is almost never identical to the parent apple and is often of significantly lower quality. The apples from a seedling frequently revert to the characteristics of their wild ancestors, tending to be small, sour, or bitter. Many of these apples are only suitable for cider production or are simply inedible, rarely possessing the sweetness, texture, or size desired for commercial eating.
The genetic uniqueness of each seed means that every tree planted represents a new, unnamed apple variety. Though the chance is remote, this is exactly how all new apple varieties, like ‘Granny Smith’ or ‘Fuji,’ were originally discovered: as a random, fortunate seedling. The vast majority of seedlings, however, produce unpalatable fruit, demonstrating the high degree of genetic randomness inherent in sexual reproduction for apples.
How Commercial Apple Varieties Are Maintained
The only way to guarantee an apple variety—such as a ‘Gala’ or ‘Fuji’—grows true is by bypassing sexual reproduction entirely and using a technique called grafting. Grafting is a form of asexual reproduction that creates an exact genetic copy, or clone, of the parent tree. This process involves taking a small cutting, called a scion, from the desired variety and physically joining it to the root system of another tree, known as the rootstock.
The scion dictates the type of fruit that will be produced, ensuring every apple is genetically identical to the original variety. The rootstock, while not affecting the fruit type, is selected for characteristics like size control, disease resistance, and adaptability to specific soil conditions. This combination allows growers to produce the exact fruit variety they want on a tree that is perfectly suited to their orchard.
This cloning method is why all ‘Honeycrisp’ apples, for example, taste the same, regardless of the orchard they come from—they all share the exact same genetic code as the original tree discovered decades ago. Without grafting, popular apple varieties would be impossible to maintain, as planting their seeds would simply result in a new, unpredictable, and usually inferior apple. Commercial growers rely on this horticultural cloning to ensure the consistency and quality demanded by the modern market.