Just like results of a DNA test could disrupt a person’s understanding of their family tree, an apple can also be subject to surprising revelations about its ancestry. This was the case for one of the most commercially successful apples on the market today, the Honeycrisp. In 2005, it was discovered that Honeycrisp’s parents were not who we thought they were.
To make sense of how this happened it is important to understand how new apple cultivars are created in the first place. Apple trees cannot fertilize their own flowers, instead pollen must be exchanged between the flowers of different trees for an apple to develop. Apple breeders do the job of what in nature is usually left to the bees, they intentionally place pollen from one tree onto another through what is called a controlled cross. In doing so apple breeders aim to combine the genetics, and thus the properties, of two parental cultivars into one. Controlled crosses are usually done in the hopes of creating an apple that has better flavour, texture, or growing habits. Apple breeders keep careful records of what cultivars they cross with one another so that the pedigrees of apples can be tracked. It was likely a mix up in the handling of seeds that led to Honeycrisp being incorrectly recorded as the offspring of the cultivars ‘Macoun’ and ‘Honeygold’.
Fortunately, genomics is able to provide clarity to situations muddled by human error. In 2005, a genetic study revealed that ‘Macoun’ and ‘Honeygold’ were not responsible for the creation of Honeycrisp. It took 12 more years before another genetic study uncovered that Honeycrisp’s true parents were ‘Keepsake’ and an unnamed apple tree referred to as ‘MN1627’. What is interesting about this discovery is that the true parents of Honeycrisp are relatively unassuming since they never became successful commercial cultivars. In fact, ‘MN1627’ no longer exists because it was deemed unpromising and therefore removed from the orchard in Minnesota where it was being grown. When making new crosses, apple breeders tend to reuse a small number of cultivars in hopes of replicating what has already been successful. Dalhousie researcher Dr. Zoë Migicovsky shows in her recently published paper that all but one of the top eight apple cultivars produced in the United States are closely related to one another. Therefore, not only are a small number of cultivars being used over and over again in breeding, but the cultivars tend to be closely related. The exception is Honeycrisp and although it is not directly related to any of the other top eight cultivars it has managed to carve out a substantial place for itself on the grocery store shelf.
Just like Honeycrisp’s pedigree sets it apart from the other top eight cultivars, you can tell from the first bite that Honeycrisp tastes different. Honeycrisp is exceptionally crisp and stays that way for extended periods in storage. Consumers are therefore willing to pay three times the regular price of an apple for a Honeycrisp. Honeycrisp’s success has been nothing short of a game changer for the Nova Scotia apple industry, allowing farmers to once again profit from apple farming. Honeycrisp’s unassuming parentage makes a case for harnessing diverse apple cultivars to breed new apples with novel and exceptional characteristics. As we think about what the next industry-changing cultivar will be, Honeycrisp is an important reminder that a lot can be gained by trying something new.