Trying to settle sports
At the most recent Great Lakes Expo, a team comprised of Hannah Cushman, Alex Engelsma, Alaina Cavin, Rebecca Grumet, Randolph Beaudry, Ning Jiang and Courtney A. Hollender from the Department of Horticulture at Michigan State University shared the presentation “Mutations Matter: Apple Sport Research May Lead to Greater Harvest Time Control & Reversion Prediction.” They’re exploring how tiny genetic changes could have a tremendous impact on commercial apple production.
A brighter blush. An earlier harvest. A better apple. Sometimes all it takes is a tiny genetic twist to create the next standout fruit. Yet in commercial orchards those welcome changes can come with an unwelcome surprise. Sometimes, they vanish.
The MSU researchers are digging into the genetics behind these natural “sport” mutations in apples, hoping to solve two stubborn problems for growers. They want to predict when prized varieties will revert to their original form and gain greater control over harvest timing.
A sport is a naturally occurring mutation that appears on a single branch or bud producing fruit with a desirable characteristic, like improved color or earlier ripening. Many of today’s commercial apple cultivars began as these chance discoveries before being propagated into entire orchards. Those lucky limbs have shaped modern apple production but their success isn’t always secure.
Nature has a habit of changing her mind.
Over time, some sport cultivars revert, losing the very traits that made them valuable. A tree expected to produce brilliantly colored fruit may suddenly bear apples resembling its less desirable parent variety. The result is inconsistent crops, complicated orchard management, reduced profits and frustrated growers who never know when a prized performer might disappear.
The problem is more common than many people realize. In October 2025, researchers documented widespread reversion in a commercial block of Gale® Gala apples near Grand Rapids, MI. Fruit on affected trees showed noticeably less red color than true Gale Gala apples and could not be harvested at the same time.
Similar reversions also appeared in the early-maturing Maslin® Pink Lady. Entire limbs and even whole trees produced yellow fruit that later proved to be less mature during testing.
While preventing reversions is one challenge, controlling harvest timing is another. Modern orchards often contain several cultivars that ripen within a narrow window. When too many apples mature together, growers face labor shortages, crowded packing facilities, storage bottlenecks, reduced profits and unnecessary food waste. Plant growth regulators and carefully selected cultivars can spread harvest dates but both approaches have limits. Scientists believe genetics may provide a smarter solution.
Their previous research revealed an intriguing pattern. Fruit maturity appears to be linked not to bloom time or carbon availability but to how quickly young fruit grows shortly after flowering. Studies comparing the early-maturing Maslin Pink Lady with its later-maturing parent Cripps Pink showed that only 26 days after full bloom, the Maslin fruit was already growing significantly faster. That speedy start suggests the mutations responsible for earlier harvest may influence genes involved in cell division during the earliest stages of fruit development.
If that connection proves true, manipulating cell division could become a practical tool for adjusting harvest windows. Researchers even suggest that increasing or decreasing cell division during early fruit development, perhaps with treatments such as the plant hormone cytokinin, could eventually help growers fine-tune when fruit reaches maturity.
Finding those genes requires careful detective work. The research team is sequencing DNA from several early-maturing sport cultivars including Premier™ Honeycrisp, Maslin Pink Lady, Barnsby® Pink Lady and September Wonder® Fuji. Using both long read sequencing alongside existing short read DNA data and gene expression analyses, they are building detailed cultivar-specific genomes capable of revealing the precise mutations behind these valuable traits.
Not all mutations behave the same way. Single polymorphisms and small insertions or deletions generally remain stable, making reversions unlikely. Mutations involving transposable elements – often called jumping genes – may be far more likely to reverse, depending on how they move within the genome.
That discovery could power a practical prediction pipeline. By combining DNA sequencing and gene expression data, researchers hope to identify unstable mutations before nurseries begin propagating new sport cultivars. Growers could avoid risky varieties while breeders focus on dependable performers.
More reliable cultivars, more predictable harvests and fewer costly surprises would strengthen orchards from blossom to bin, proving that even the smallest mutations can make a mighty difference.
by Enrico Villamaino
