Cultivated apple trees (Malus domestica) employ both sexual and asexual methods of reproduction, leading to two distinct answers regarding which part can grow into a new tree. The choice depends on the goal: seeking the genetic unpredictability of natural growth or the commercial consistency of a cloned variety. For the average person seeking to grow the same type of apple they just ate, the answer lies in a specific part of the stem, not the seeds.
Seeds and the Path of Genetic Variation
The seeds, or pips, result from the apple tree’s sexual reproduction cycle, beginning with pollination and fertilization. Apple flowers contain both male and female reproductive organs, but most varieties require cross-pollination from a different variety to set fruit. This process involves the transfer of pollen, typically by insects like bees.
Once fertilized, the ovules develop into seeds, each containing a unique combination of genetic material from two parent trees. This genetic mixing, known as heterozygosity, means a seed from a named variety (such as Fuji or Honeycrisp) will not grow into a tree that produces identical fruit. Instead, the resulting seedling will be a new, genetically distinct variety, often yielding apples that are small, sour, or undesirable for eating.
This “genetic lottery” is why apples grown from seeds are rarely used in commercial orchards, though it is how new varieties are discovered naturally. The taste and quality of the fruit from a seed-grown apple tree are unpredictable, promoting genetic diversity rather than consistency. The resulting tree may bear little resemblance to its parent, which is a complication for fruit production.
The Scion and Cloning Through Grafting
To reliably grow an apple tree that produces a specific, named variety of fruit, growers use grafting, which relies on a part called the scion. The scion is a small cutting—a shoot or piece of budwood—taken from the desired parent tree. This stem piece must contain dormant buds and is typically collected during the winter when the tree is inactive.
Grafting is a form of asexual propagation that clones the parent tree. The process involves physically joining the scion onto a separate, existing root system called the rootstock. Success depends on aligning the cambium layers—the thin, actively growing tissue just beneath the bark—of both the scion and the rootstock, allowing them to fuse and grow as one plant.
This method ensures the upper portion of the new tree (which grows the branches and fruit) is genetically identical to the original tree. For example, a single bud taken from a Gala apple tree can be used in a specific grafting method called budding to clone the exact Gala variety. The scion is the part responsible for determining the type of apple the new tree will produce.
The rootstock, the base of the grafted tree, is chosen for traits like controlling the tree’s eventual size (e.g., dwarfing characteristics) or providing disease resistance. The scion and the rootstock are compatible but retain distinct genetic identities. The scion provides all above-ground growth and fruit characteristics, allowing growers to combine desirable fruiting traits with advantageous rootstock habits.
Root Systems and Sprouting Suckers
Another part of the apple tree that can grow into a new tree is the sucker, a shoot that arises from the root system or the base of the trunk below the graft union. The graft union is the visible point, often a slight bulge, where the scion and the rootstock were joined together. Since the rootstock is a different genetic variety from the scion, any growth below this union belongs to the rootstock.
If these suckers are allowed to grow, they will develop into a new tree, but the fruit they produce will match the genetics of the rootstock, not the desired apple variety of the scion. Rootstocks are often selected for their hardiness or size-controlling properties, not for the quality of their fruit, which can be small, bitter, or inedible. Consequently, suckers are usually removed by growers because they compete with the main tree for water and nutrients.
Suckers clarify the distinction between the two parts of the commercially grown apple tree: the rootstock provides the foundation, and the scion provides the fruit. Suckers are a physical manifestation of the rootstock’s desire to grow, proving the root system itself is a viable, tree-producing part, even if the resulting fruit is not the intended variety.