Avocado trees have puzzled botanists for over a century due to their unique reproductive cycle. Each tree possesses both male and female organs, yet they must avoid self-pollination to remain genetically healthy. They manage this through a process called temporal dichogamy, where trees effectively switch sexes on a daily basis to ensure cross-pollination occurs.
Researchers from UC Davis, UC Riverside, and UC Berkeley have now identified the specific genetic mechanism controlling this behavior. By mapping the genomes of hundreds of trees, the team isolated a gene variant known as SDMYB. This gene acts like an internal clock, determining whether a tree functions as an A-type, opening female flowers in the morning, or a B-type, which operates on the opposite schedule.
Previously, avocado breeders faced a significant time barrier. It often takes a decade or more for a tree to reach maturity and reveal its flowering type. Growers had to plant large numbers of seedlings and wait years to determine their utility for cross-pollination. This delay made orchard planning and variety development inefficient for commercial agriculture.
With these new genetic markers, breeders can identify the flowering type of a plant at the seedling stage. This shift allows for precise orchard design, ensuring that pollinizer trees are placed strategically among commercial varieties without the guesswork. While this discovery does not lead to immediate fruit engineering like flavor modification, it provides a clear path for faster, more accurate crop development for future harvests.