New Scientific Discovery Could Help Accelerate Avocado Breeding

Scientists have found a genetic switch that could shave years off avocado breeding by allowing researchers to identify one of a young tree’s most important traits long before it flowers. Researchers at UC Riverside (UCR) helped identify the gene that controls whether an avocado tree has an A- or B-type flowering pattern. These flowering patterns determine how neighboring trees exchange pollen, making them an important factor in avocado production.

Published in the Proceedings of the National Academy of Sciences, the study was led by researchers at UC Davis in collaboration with UCR scientists, whose avocado breeding collections, field observations, and genetic analyses were essential to the discovery.

“This gives us a shortcut we’ve never had before,” says Eric Focht, Staff Research Associate in UCR’s Department of Botany and Plant Sciences and a co-author of the study. “Instead of waiting years for a tree to flower, we can identify its flower type almost immediately using its DNA. That allows us to make much smarter breeding decisions.”

Understanding these flowering patterns has long been important to growers, but until now, scientists did not know what controlled them.

Avocado growers typically plant a mix of A- and B-type trees because the two flowering patterns complement one another. When one type is releasing pollen during its male phase, the other is more likely to be receiving pollen during its female phase, increasing the chances of successful pollination and fruit production.

All avocado flowers first open as female before reopening later as male. What differs between varieties is the timing of those two phases. Trees are classified as A or B flower types based on that timing, allowing neighboring trees to exchange pollen instead of fertilizing themselves.

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“Our study provides a genetic explanation for a century-old mystery of avocado pollination,” says first author Jeffrey Groh, who led the project as a doctoral 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.”

For avocado breeders, however, the biggest impact is immediate.

For more, continue reading at news.ucr.edu.