Jerusalem, 26 October, 2026 (TPS-IL) — Plants don’t always have to choose between fertilizing themselves and relying on pollen from other plants. A new study by Israeli researchers has found that populations can sustain both reproductive strategies for generations, even as the balance between them swings dramatically, challenging the idea that one strategy must eventually win out.
Using evolutionary computer simulations, Dr. Tamar Friedlander, Dr. Amit Jangid and Prof. Ohad Noy Feldheim of the Hebrew University of Jerusalem identified what they call a “volatile mixed mode,” in which plants capable of fertilizing themselves coexist with plants that require pollen from other individuals. Although the proportions of each type continually change, neither necessarily disappears.
“What surprised us was that instability does not necessarily mean that a population is on its way to one final state,” the researchers said. “In our model, self-compatible and self-incompatible plants can coexist for a very long time while their proportions continually change, even in the absence of fluctuations in external conditions.”
The findings were published in the peer-reviewed journal PRX Life.
Self-fertilization allows a plant to reproduce without relying on another individual’s pollen, which is an advantage when mates or pollinators are scarce. But repeated self-fertilization can increase the risk that harmful genetic mutations will affect offspring, a problem known as inbreeding depression.
Other plants use a genetic mechanism called self-incompatibility to recognize and reject their own pollen. This encourages cross-fertilization and helps preserve genetic diversity. The mechanism occurs in around 40% of plant families, including groups containing crops such as apples, pears, citrus fruits, potatoes and coffee.
Genetic changes can disrupt this mechanism, so populations can contain both self-compatible and self-incompatible plants.
A Third Possibility
Scientists have debated whether such mixed populations are temporary, with one strategy eventually prevailing, or whether they can maintain a stable balance. The simulations suggest a third possibility: populations can remain mixed for long periods without settling into fixed proportions.
The researchers varied two factors: the genetic costs of self-fertilization and the tolerance of the molecular system plants use to recognize acceptable pollen. This let them map when populations were likely to become entirely self-compatible, entirely self-incompatible or remain mixed.
The simulations also produced a counterintuitive finding. When pollinators are scarce, plants receive less pollen from others, which seemingly gives self-fertilization an advantage. Yet the model showed that pollen limitation could expand the conditions under which self-incompatibility persists. The researchers attributed this to different evolutionary pressures on the male and female components of the self-incompatibility system.
The findings could help scientists predict how wild plants and agricultural crops respond to declining pollinator populations and changing environmental conditions. They could also help farmers and plant breeders manage pollination in crops such as apples, pears and citrus fruits while preserving genetic diversity.
The study also suggests that evolutionary shifts between reproductive strategies are not necessarily irreversible. Populations that shifted toward self-fertilization might later return to favoring cross-fertilization.
The researchers stressed that their findings are theoretical. Although mixed populations have been observed in nature, long-term field studies are needed to establish whether the volatile mixed mode occurs in wild populations.
