The Next Generation of Apple Breeding

摘要

The breeding of new apple varieties is unlike other crops. While a consumer could easily tell you their favourite apple, most would struggle to name their favourite strawberry variety. This consumer awareness gives apple breeders the unique opportunity to release new varieties that can achieve considerable market demand. Honeycrisp is one such success story in Atlantic Canada, where its price per pound is well above other varieties. In addition to the consumer, there is another pressing reason for continued innovation and variety releases; apple trees do not breed true. For example, if you were to plant seeds from a Royal Gala fruit, you would end up with trees that looked nothing like a Royal Gala. This is because apples are outcrossers: for the most part, the pollen from a tree cannot fertilize its own flowers. This means that pollen needs to come from another source to generate fruit, and the offspring contain a genetic component from a maternal source (i.e., Royal Gala) and a combination of paternal sources. This observation led to the development of grafting to ensure consistent orchards. For a farmer, having an orchard of identical trees simplifies management, but there are inherent risks with growing monocultures. While the pests and diseases that plague a variety continue to evolve and change over time, a vegetatively propagated variety stays the same, frozen in genetic time. While current sprays may be sufficient, resistance does occur, and prolonging the lifespan of chemical combatantsis a challenge for growers. Developing new varieties with several genetic sources of pest and disease resistancecould help farmers face this battle and safeguard their orchard investments.