Focused man in a beige shirt tending potted plants in a sunlit greenhouse
Jeffrey Groh, a former Ph.D. student at UC Davis, examines an avocado plant at a greenhouse at UC Berkeley, where he is now a postdoctoral fellow. His new study provides a genetic explanation for one of avocado pollination's oldest mysteries. (Brandon Mejia)

Study Reveals How Avocados Reverse Sexes Throughout the Day

Avocados Have Followed the Same Flowering Rhythm for Over 40 Million Years

To avoid self-pollination, avocado trees alternate between opening male and female flowers at different times of day. Some avocados are female in the morning and male in the afternoon, while others are on the opposite schedule. How avocados do this has been unclear — until now.

In a new study, a team led by researchers from the University of California, Davis, revealed that this rhythm is dictated by variation in a single gene that evolved about 42 million years ago. Published in Proceedings of the National Academy of Sciences, this finding could help avocado breeders and researchers quickly sort seedlings to maximize yield and develop new varieties.

“Our study provides a genetic explanation for a century-old mystery of avocado pollination,” said first author Jeffrey Groh, who led the project as a Ph.D. student at UC Davis and is now a postdoctoral fellow at UC Berkeley. “Flowers are not just static decorations; they are highly evolved and dynamic structures. We can see this in the pulsating rhythm of avocado flowers opening and closing throughout the day. Through the power of genetics, we can detect traces of this rhythm far into the ancient past.”

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